Changes In Surface Area Research Articles

Metal and Oxide Sublimation from Lunar Regolith: A Kinetics Study

When considering the extraction of metals from lunar regolith for use in space, one reductive method of interest is vacuum thermal dissociation. Given the high vacuum environment on the Moon, the sub-liquidus operation of such a process, i.e., sublimation, warrants investigation. In the current work, the kinetics of the vacuum sublimation of the more volatile major oxides found in the lunar regolith, Na2O, K2O, and FeO, are evaluated. Two distinct factors are accounted for in the current work: the change in the evaporation flux due to temperature; and the reduction in available surface area for evaporation due to sintering of the feedstock. Surface area change due to the sintering of compressed LMS-1 regolith simulant pellets was quantified via a Brunauer–Emmett–Teller analysis. The surface area of the samples was measured to vary from 3.29 m2/g in the unsintered sample, to 1.04 m2/g in the samples sintered at 800 °C, and down to 0.09 m2/g in the sample sintered at 1150 °C. Evaporation flux was calculated using the Hertz–Knudsen–Langmuir equation using saturated vapor pressures predicted from the FactSage thermochemical package and verified against Knudsen Effusion Mass Spectroscopy data from tests conducted on lunar regolith sample #12022. The combination of these studies resulted in the conclusion that no local maxima in evaporation rate below the melting point was found for the current system, as such the highest rate of sublimation was determined to be 1200 °C for all species, at temperatures of 1200 °C and above, partial melting of the material occurs. The predicted maximum rate of sublimation for the species Fe, Na, and K at 1200 °C was 0.08, 1.38, and 1.02 g/h/g of regolith, respectively. It is noted that significant variation was seen between FactSage predictions of saturated vapor pressures and the measured values. Future work generating detailed thermochemical databases to predict the behavior of complex systems similar in composition to lunar regolith would benefit the accuracy of similar kinetic studies in the future.

Detection of Changes in Water Surface Area in Limboto Lake Using Landsat Data From 1990 to 2020

Lake Limboto is included in the fifteen priority lakes due to its increasingly critical condition. Long-term observations of changes in the lake water surface area are carried out to understand the impact of changes better and protect the ecosystem of water resources. The use of remote sensing technology products in Landsat 4 TM, Landsat 5 TM, Landsat 7 ETM +, and Landsat 8 OLI satellite images and Google Earth Engine is a suitable combination to study the dynamics of Lake Limboto. The water index used are NDWI (Normalized Difference Water Index), MNDWI (Modified Normalized Difference Water Index), and AWEI (Automated Water Extraction Index). The water surface area of Lake Limboto changes every year, starting in 1990 with an area of 1,976 Ha, increasing in 2000 to 2,039 Ha, and the widest inundation of water surface in 2002 was 2,889 Ha, a decrease occurred in 2009 to 2,498 Ha, to become 1,843 Ha in 2020. The objects above the water surface also change yearly, from 6% in 1990-2000, increasing to 10% in 2009, reaching a 16% increase in 2014, and decreasing to 9% in 2020. This changing trend can be used as the basis for government policies in the management of Limboto Lake.

EFFECT OF PARTICLE SIZE ON SIMULTANEOUS CALCINATION AND SULFATION OF LIMESTONE

The simultaneous calcination and sulfation characteristics of limestone in simulative CFB flue gas atmosphere is examined using a slidable tube furnace system combined with X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM) with a focus on the effect of particle size. The effect mechanism of particle size on simultaneous calcination and sulfation of limestone is further analyzed based on the effect of temperature and CO<sub>2</sub> concentration. The qualitative and quantitative results show that calcination reaction dominates in the early simultaneous calcination and sulfation reaction of limestone and the predominant effect transforms from calcination to sulfation reaction in the late simultaneous reaction of limestone. Compared with small particle size limestone, the big particle size limestone slows the weight loss rate and weight gain rate and needs more time to achieve the lowest weight point. This is related to lower mole fraction loss rate of CaCO<sub>3</sub> and mole fraction gain rate of CaSO<sub>4</sub> during simultaneous calcination and sulfation of limestone with big particle size. The effect mechanism of particle size on simultaneous calcination and sulfation of limestone is mainly due to the change of reaction specific surface area, heat transfer, and mass transfer from the surface to the inside of limestone with different particle sizes.

Применение спектральных водных индексов на хвостовом хозяйстве Дарасунского рудника по данным дистанционного зондирования Земли программы Landsat

At present, the problem of ensuring the environmental safety of tailings dumps and dams holding them is acute in the mining cluster not only in Russia, but also in the world. Stale tailings located in a hydraulic structure are man-made deposits and are considered as an object of development in the future. Therefore, the formation of a database of the areas of the water mirror of the basins of the cascade of tailings for a long period of operation is an urgent scientific problem. It is important to analyze and predict potential threats to the city-forming mining enterprise and nearby territories. This problem can be solved by using geoinformation systems and multispectral data. The object of the research is a complex of tailings dumps’ cascades of the Darasunsky mine. The goal is to provide spatio-temporal assessment of the areas of the water mirror of the basins of the tailings dumps’ cascade of the Darasunsky mine for the period from 1997 to 2022 in order to predict environmental safety. The research objectives are the following: assessment of the environmental situation at the Darasunsky mine; selection of the optimal method for decoding the water surface; collection and formation of an archive of remote sensing data; calculation of spectral indices and retrospective analysis of changes in the water surface area of the tailings of the Darasunsky mine; forecast of emergency situations of lithospheric, hydrospheric, airborne, biological pollution. A spatio-temporal assessment of the areas of the water mirror of the basins of the tailing dumps’ cascade has been made to assess the use intensity of these structures with the construction of graphs of changes in the areas of the water surface over a 25-year period. Thanks to the division of the tailings storage into cascades, it has become possible to locally determine the filling of 4 tailings sections with tailings pulp. The data obtained allow monitoring for the rational use, conservation, stopping the operation of hydraulic structures (in particular tailings dumps), their impact on the environment. The use of spectral water indices according to the remote sensing data of the Landsat program will allow predicting and preventing emergency situations at the tailings dump, which has been in operation for many decades, to prevent the overflow of water over the crest and body of the enclosing dams.

폐 패각을 이용한 다공성 여과재의 수질정화 성능평가

In this study, in order to evaluate the water purification performance of media filter using shell recycling, specific surface area and water purification experiments were performed after fabricating a filter medium mixed with fine oyster shell powder, zeolite, cement, water, and effective microorganims (EM). A comparative experiment was performed on the amount of change in specific surface area and BOD, SS, and T-P according to the blending amount of the media filter material. When zeolite was added to the media filter using shell recycling, the specific surface area increased, which was twice that of the meida filter using shell recycling without the addition of zeolite. In terms of water purification performance, the removal efficiency of SS and T-P was very high regardless of the type of media filter, but the BOD removal efficiency was different depending on the blending amount of the media filter. The BOD removal efficiency of MF-3 (120 g of fine oyster shell powder, 40 g of zeolite, 40 g of cement, 140 g of water and 10 g of EM based on 350 g) was 86.8 % after 3 and 4 weeks. So it is suitable for use. If the media filter using shell recycling is developed using the optimal blending amount of the media filter obtained in this experiment, it is expected that it can replace the existing media filter and become a new utilization method of the neglected shells.

Temporal and Spatial Evolution of Eichmann Lake Wetland in Aksu River Basin and Its Response to Ecological Water Supply.

Timely understanding and quantitative analysis of the changing trend in natural ecosystems in arid and semi-arid areas and their response to the ecological water supply process are of great significance for maintaining the health of oasis ecosystems. Taking the Eichmann Lake wetland of the Aksu River Basin in Xinjiang as the research area, the temporal-spatial distribution characteristics of the lake and the response of ecological water in recent years were studied based on remote sensing images and monitoring data. The results show that: (1) The water surface area of Eichmann Lake is shrinking, from 61.57 km2 in 1996 to 27.76 km2 in 2020. The changes in water surface area have experienced three stages: rapid decline, slow decline, and slow recovery. After the ecological water supply, the water surface area has obvious seasonal changes with hysteresis; (2) In areas with a low average water level, the ecological water supply has a significant impact on the groundwater level. The higher the water supply is, the higher the groundwater level will be. There is a significant lag effect between the change in the groundwater level and the response of the ecological water supply, which is 1-2 months; (3) The response characteristics of different natural vegetation to the ecological water supply were different in interannual, seasonal, and spatial contexts. The response of Populus euphratica to the ecological water supply is obvious, and its growth is the best within the range of 100-500 m from the water supply outlet. This research can provide the basis for the rational allocation of the Aksu River Basin's water resources, and also act as a valuable reference for the restoration and reconstruction of surrounding vegetation in the Aksu River irrigation area.

Experimental investigation on adsorbent composites for CO2 capture application: An attempt to improve the dynamic performance of the parent adsorbent

The present investigation aims at developing consolidated adsorbent composites with enhanced thermophysical and transport properties at the cost of a minimum sacrifice in equilibrium CO2 uptake. Twelve samples are synthesized using a coconut shell-derived activated carbon (CSAC) as the parent material, graphite, graphene nanoplatelets, and CuO as the additives and PVA as the binder. All the synthesized had undergone a proper characterization using N2 adsorption/ desorption and FE-SEM to highlight the changes in the BET surface area, pore volume, pore size distribution, and pore networking compared to the parent activated carbon and surface morphology. The thermophysical (specific heat capacity) and transport properties (thermal conductivity and thermal diffusivity) of all the composites of various mass fractions of the additives (10–40%) are measured using a TPS-2500 S transient hot disk method. The experimental results show that maximum thermal conductivity of 1.72 W/m K is achieved with graphite as the additive with a ratio of CSAC: graphite: PVA (Composite 4) of 50:40:10 wt%, corresponding to an increment of 606% compared to parent CSAC. The increment is comparable and better than the other consolidated adsorbent composites reported in the literature. All the constants of various isotherm models are obtained based on the experimentally obtained pressure-temperature and concentration data using the non-linear regression analysis. Based on the R2 values, the Toth model is identified as the best model for all the composites. A detailed thermodynamic analysis is further carried out, and important thermodynamic parameters, i.e., Enthalpy, Entropy, Gibbs free energy change associated with the adsorption process and the Isosteric heat of adsorption are obtained. The estimated thermodynamic parameters, isotherm and thermophysical data are crucial for the actual design and development of compact systems suitable for adsorption-based CO2 capture applications.

A combined experimental and modelling study of granite hydrothermal alteration

Geochemical reactions can induce significant changes of rock reservoir porosity and permeability via mineral dissolution and precipitation processes, affecting the long-term fluid behaviour within various geological systems. The understanding and quantification of these reactions rely on field and experimental studies and on the predictions of reactive transport models.The present study was aimed at assessing the extent to which current geochemical models integrating available mineral dissolution/precipitation rate equations can reproduce the experimental data obtained from 4 to 17-day long hydrothermal alteration experiments of a muscovite-biotite granite and, thus, help provide an accurate description of the evolution of geothermal systems within granitic reservoirs. The experiments were conducted at a constant temperature of 180 °C and over an aqueous fluid pH range of 2 to 8.5, using both mixed-flow and static batch reactors. Modelled major element (K, Al, Si, Ca, and Mg) concentrations were generally in satisfactory agreement with the corresponding measured elemental fluxes – the differences between modelled and experimental values were generally within a factor of 5 – and the predicted identity and mass of formed secondary phases were consistent with the microscopic observations of the reacted solids. However, larger differences between measured and modelled element concentrations were observed when significant amounts of secondary phases formed, notably at pH 2 to 3, and for longer-term batch experiments. Much of this concentration difference stems from the underestimation of the amounts of Al-phases formed at acid to near-neutral pH. Although an idealized rock composition was considered, the observed mismatch between model calculations and experimental data can be attributed to inadequate mineral precipitation reaction rates and a poor description of reactive surface areas in existing geochemical modelling codes. More accurate quantification of precipitation kinetics, including nucleation and growth, and improved descriptions of the temporal change of mineral surface area would enhance the predictive capabilities of reactive transport models and benefit, particularly, the efforts aimed at increasing the sustainability of EGS reservoirs.

Adsorption and Desorption Metal Cu (II) using Zeolite Synthetic by Bottom Ash Coal Modified Dithizone

Zeolite synthetic and zeolite modified dithizone has been succesfully created by hydrotermal method. The aim of this research is to know the characteristics of zeolite synthetic and zeolite modified dithizone and to know capacity of adsorption and desorption. The effect of various variables, such as pH, concentration of Cu (II), contact time and temperature was investigated using batch process, characterization zeolite modified dithizone and zeolite synthetic using XRD, XRF, FTIR and GSA. The result of characterization bottom ash coal by hydrotermal reaction using XRF, be discovered composition Si as many 82,01% and Al 8,54%. product of melting hydrothermally indicate a specific zeolite IR absorption at a wavelength of 300-1250 cm-1. The result XRD showed that be found zeolite-X, zeolite-A, zeolite sodalite and difatogram of dithizone. Zeolite modified dithizone has been succesfully synthesized with a marked presence group of –NH and –SH by using FTIR. Zeolite modified dithizone surface area change from 160,262 m2/g to 69,609 m2/g. The best adsorption metal Cu(II) by zeolite synthetic is pH 7. Kinetics adsorption zeolite synthetic and zeolite modified dithizone follow kinetics of pseudo second orde, with R2 respectively 0,7378 and 0,8689, rate constant of pseudo second orde adsorption at zeolite synthetic is -0,017 g/mg.min-1 and zeolite modified dithizone -0,013 g/mg.min-1. Isotherm type for both of adsorbent follow Langmuir isotherm. Desorption of metal Cu(II) on zeolite modified dithizone and zeolite synthetic a lot off obtained using HCl at level 47,08% and 41,49% respectively.

Copper–Cerium–Tin Oxide Catalysts for Preferential Oxidation of CO in Hydrogen: Effects of Synthesis Method and Copper Content

Copper was incorporated into the Ce-Sn and comparative Ce-Zr oxide supports by one-pot precipitation in the presence of CTAB template and by the impregnation of templated Ce-Sn and Ce-Zr oxides. The synthesized Cu-Ce-Sn and Cu-Ce-Zr catalysts were tested in the continuous-flow preferential oxidation of CO in hydrogen excess. The one-pot synthesized tin- and zirconium-doped catalysts demonstrated better CO conversion and CO2 selectivity than their impregnated counterparts. For the tin-modified ternary system that showed the best catalytic performance, the copper content was further optimized. The structure, reducibility, surface chemical state and textural properties of the catalysts were analyzed by SEM-EDX, XRD, H2-TPR, Raman spectroscopy, XPS and TEM. The nonmonotonic changes in the specific surface area, Cu+/Cu2+ ratio and ratio of lattice and non-lattice oxygen with increasing the Cu content are discussed in terms of copper distribution in the catalysts. The influence of the interaction between copper oxide species and the cerium–tin/cerium–zirconium oxide support on the performance of the ternary catalysts was thoroughly analyzed and discussed.

Does cognitive reserve or brain maintenance explain heterogeneity in episodic memory trajectories in late middle age?

AbstractBackgroundAging‐related episodic memory (EM) decline and Alzheimer’s disease (AD)‐related brain changes begin in late middle age around age 60. However, rate and severity of cognitive decline do not consistently correspond to the extent of neuropathological changes, suggesting a high degree of heterogeneity in EM trajectories. We tested if brain maintenance (BM; relative absence of changes in neural resources as a determinant of preserved cognition) and/or cognitive reserve (CR; a property of the brain that allows for sustained cognitive performance in the face of age‐related changes and brain insult or disease) explain individual differences and heterogeneity in EM in late middle age.MethodParticipants were 1604 men from the Vietnam Era Twin Study of Aging. A practice effect‐adjusted composite EM score based on six measures was calculated at three time points with mean ages of 56, 62, and 68. Young adult general cognitive ability (GCA) and lifetime years of education were used as proxy measures of CR. BM was assessed as relative change (from age 56 to 68) in cortical thickness and surface area in a bilateral cortical signature of AD regions‐of‐interest (N = 321). We used linear mixed effect modeling.ResultOn average, there was a significant decline in EM from age 56 to 68 (p<0.001). Education (p = 0.042) and young adult GCA (p<0.001) were positively related to EM, but there were no significant effects of education or GCA on the rate of EM change (all p’s≥0.316). Relative brain changes were not related to EM (all p’s≥0.067) and there were no significant interactions of CR proxies and brain changes on EM (all p’s≥0.379).ConclusionHigher education and higher young adult GCA were related to better EM performance across late middle age – with a stronger contribution of GCA compared to education – but EM change did not differ as a function of these proxy CR measures. Our results did not support effects of BM or CR on EM change in late middle age but rather reflected baseline differences in memory in those with low versus high education/cognitive ability. Whether differential change occurs at later ages or with increased AD pathology remains to be determined.

Heat–induced changes in soil properties: fires as cause for remobilization of chemical elements

Abstract Exposure of soil constituents to elevated temperatures during wildfire can significantly affect their properties and consequently, increase the mobility of the bound contaminants. To estimate the potential of wildfires to influence metal remobilization from the burned soil due to the changes in cation exchange capacity (CEC) after organic matter combustion and mineral alteration and degradation, changes in soil properties after exposure to different temperatures was investigated. This was accomplished through analysis of geochemical, mineralogical and surface physicochemical properties of a soil sample exposed to different temperatures in a laboratory. Heating the soil sample at 200 °C, 500 °C and 850 °C resulted in an increase in pH (from 5.9 to 12.3), decrease in cation exchange capacity (from 47.2 to 7.3 cmol+kg−1) and changes in the specific surface area (observed only at 500 °C), that are associated with structural modifications of clay minerals and ferromagnetic minerals. Extraction analysis showed the increase in the concentration of almost all analysed elements (Al, Cd, Co, Cr, Fe, Mn and Zn) in soil eluates. The observed increase, following high– temperature heating (500 °C and 850 °C), was as much as 15 times higher (e.g., Al), compared to the native soil sample (25 °C). This strongly indicates that wildfire can act as a trigger for remobilization of heavy metals.

Safe and Effective Lip Enhancement with VYC-15L in Chinese Adults.

Hyaluronic acid (HA) soft tissue fillers are used to restore volume loss to the lips and perioral area. Evaluate the safety and effectiveness of the HA filler Juvéderm® Volbella® (VYC-15L) for lip enhancement in Chinese adults. In this multicenter, evaluator-blind study, subjects seeking lip enhancement were randomized 3:1 to VYC-15L or no-treatment control group (with optional treatment delayed by 3 months). Effectiveness endpoints included 1-point improvement on the 5-point Lip Fullness Scale (LFS) assessed by evaluating investigators (EIs) and subjects, and overall volume of lips and change in lip surface area measured from 3-dimensional images. Safety assessments included procedural pain, injection site reactions (ISRs), and adverse events (AEs). The modified intention-to-treat population included 163 subjects (median age, 34 years; 96.9% female). More VYC-15L-treated subjects had a 1-pointreduction in EI-reported LFS score at month 3 versus untreated controls (84.7% vs 0%; p < 0.0001), and 65% of the treated subjects self-reported a 1-point LFS improvement at month 3. Procedural pain during injection was mild. The most common ISRs were swelling, tenderness to touch, and firmness. One treatment-related serious AE (injection site compression arterial ischemia) resolved in 16 days. VYC-15L treatment was superior to no treatment at 3 months and was well tolerated by subjects. NCT03519204.

Habitat Suitability of Fig (Ficus carica L.) in Mexico under Current and Future Climates

Emerging or alternative crops are those that have been recently introduced in response to new demands and commercial opportunities. The fig has been introduced as an alternative fruit crop in Mexico due to its high nutritional, nutraceutical, and antioxidant capacity. A total of 644 points of presence were downloaded and filtered according to climatic ranges and agricultural areas, leaving 68 records. The MaxEnt algorithm was used to develop the habitat suitability models for current and future climate. The bioclimatic variables of the global circulation models, Hadley Centre Global Environment Model version 2-EarthSystem (HADGEM2-ES) and Max Planck Institute for Meteorology-Earth System Model Low Resolution (MPI-ESM-LR), were used under scenarios 2.6 and 8.5. The changes in the fig area for Mexico were analyzed based on the generated models. Under the current climate, 359,575.76 km2 were estimated for 2050, and a loss of area for the excellent category was estimated for both models and scenarios; however, for the MPI-ESM-LR model projected to 2070, an increase of 5.51% and 0.39% was estimated for scenarios 2.6 and 8.5, respectively. The effect of climate change on agronomic species such as figs will be expressed in variations in climatic ranges and areas suitable for their development. The results of this study reveal the negative and positive effects of climate change on fig habitat suitability in Mexico. The dynamics of changes in surface area will be reflected mainly in northern and central Mexico.

Effects of cryogenic temperature on premixed hydrogen/air flame propagation in a closed channel

As a carbon-free fuel, hydrogen has received significant attention recently since it can help enable low-carbon-economy. Hydrogen has very broad flammability range and very low minimum ignition energy, and thereby there are severe safety concerns for hydrogen transportation and utilization. Cryo-compressed hydrogen is popularly used in practice. Therefore, it is necessary to investigate the combustion properties of hydrogen at extremely low or cryogenic temperatures. This study aims to assess and interpret the effects of cryogenic temperature on premixed hydrogen/air flame propagation and acceleration in a thin closed channel. Different initial temperatures ranging from normal temperature (T0 = 300 K) to cryogenic temperature (T0 = 100 K) are considered. Both one- and two-dimensional hydrogen/air flames are investigated through transient simulations considering detailed chemistry and transport. It is found that when the initial temperature decreases from T0 = 300 K to T0 = 100 K, the expansion ratio and equilibrium pressure both increase substantially while the laminar flame speeds relative to unburned and burned gasses decrease moderately. The one-dimensional flame propagation is determined by laminar flame speed and thereby the combustion duration increases as the initial temperature decreases. However, the opposite trend is found to happen to two-dimensional flame propagation, which is mainly controlled by the flame surface area increase due to the no-slip side wall constraint and flame instability. Based on the change in flame surface area, three stages including the initial acceleration, steady burning and rapid acceleration are identified and investigated. It is demonstrated that the large expansion ratio and high pressure rise at cryogenic temperatures can significantly increase the flame surface area in early stage and promote both Darrieus-Landau instability (hydrodynamic instability) and Rayleigh-Taylor instability in later stage. These two instabilities can substantially increase the flame surface area and thereby accelerate flame propagation in hydrogen/air mixtures at cryogenic temperatures. The present study provides useful insights into the fundamental physics of hydrogen flames at extremely low temperatures, and is closely related to hydrogen safety.

A look at the face of the molten globule: Structural model of the Helicobacter pylori apoflavodoxin ensemble at acidic pH.

Molten globule (MG) is the name given to a compact, non‐native conformation of proteins that has stimulated the imagination and work in the protein folding field for more than 40 years. The MG has been proposed to play a central role in the folding reaction and in important cell functions, and to be related to the onset of misfolding diseases. Due to its inherent intractability to high‐resolution studies, atomistic structural models have not yet been obtained. We present here an integrative atomistic model of the MG formed at acidic pH by the apoflavodoxin from the human pathogen Helicobacter pylori. This MG has been previously shown to exhibit the archetypical expansion, spectroscopic and thermodynamic features of a molten conformation. To obtain the model, we have analyzed the stability of wild‐type and 55 apoflavodoxin mutants to derive experimental equilibrium Φ values that have been used in biased molecular dynamics simulations to convert the native conformation into an MG ensemble. The ensemble has been refined to reproduce the experimental hydrodynamic radius and circular dichroism (CD) spectrum. The refined ensemble, deposited in PDB‐Dev, successfully explains the characteristic 1H‐nuclear magnetic resonance (NMR) and near‐UV CD spectral features of the MG as well as its solvent‐accessible surface area (SASA) change upon unfolding. This integrative model of an MG will help to understand the energetics and roles of these elusive conformations in protein folding and misfolding. Interestingly, the apoflavodoxin MG is structurally unrelated to previously described partly unfolded conformations of this protein, exemplifying that equilibrium MGs need not to reflect the properties of kinetic intermediates.

Spatiotemporal Dynamics of Landscape Transformation in Western Balkans’ Metropolitan Areas

Human-caused landscape transformation represents a danger to conserving the Earth’s natural habitats. Landscape fragmentation (LF) caused by transportation infrastructure and urban development poses a threat to human and environmental health by increasing traffic noise and pollution, reducing the size and viability of wildlife populations, facilitating the spread of invasive species, and reducing the recreational qualities of the landscape. It is especially noticeable in the metropolitan areas of developing countries due to rapid and unsupervised urban sprawl. In this context, this study aims to protect natural landscapes and biodiversity, promoting forms of sustainable development. To exemplify our aim, we bring a spatio-temporal analysis of landscape change comparing three metropolitan areas in the Western Balkans (WB). First, we compare the land use land cover (LULC) changes in Tirana (Albania), Skopje (North Macedonia), and Sarajevo (Bosnia and Herzegovina). The comparison was based on the Urban Atlas (UA) data of 2012 and 2018. The analysis was performed on two levels, at the metropolitan and urban spatial scales. Apart from descriptive statistics about the changes in surface area and patch counts, we used effective mesh size (meff) as a landscape metric to quantify the LF level. Our results show that each city has faced significant LULC change between 2012 and 2018, with a dominant increase in artificial surfaces. Furthermore, the cumulative natural surface area reduction is followed by increased landscape patch counts, indicating an increased LF at both levels. This study enhances public awareness about the landscape transformation trends in the developing metropolitan regions of WB. The respective administrative bodies at both local and central levels are invited to consider our results and adopt proper measurements to reduce the adverse consequences of subsequent spatial development decisions.

Can calcite play a role in the adsorption of glyphosate? A comparative study with a new challenge

Calcite as a sorbent can interact with both inorganic and organic substances through their functional groups. To measure its adsorption ability, another sorbent, saponite was selected because it can sorb glyphosate, an organic compound with a polar molecule and widely used as a herbicide. In this study, the two sorbents calcite and saponite were saturated by calcium chloride, and characterized by SEM-EDX, X-ray diffraction, and Zeta Potential Analyzer to investigate their capacity to sorb glyphosate. After saturation, the saponite became homoionic Ca-saponite with minor changes in morphology and specific surface area. But, the morphology of calcite transformed from rhombohedron to scalenohedron, with an increase of 75-folds in its specific surface, and the zeta potential became positive in alkaline pH, which contradicts the results of all previous research. The modified sorbents (Ca-calcite and Ca-saponite) were added to two soil samples to investigate each sorbent's effect on glyphosate sorption. Adsorption isotherm and percentage of glyphosate desorbed revealed the difference in binding and adsorption sites. The Langmuir and Temkin models fitted isotherm data in low concentrations better and suggested chemosorption for the uptake of glyphosate. FTIR analyses of samples with and without glyphosate were compared and results suggested that the bulk of adsorption happened in siloxane groups and on calcium carbonates surfaces.

(Digital Presentation) Nitrogen-Doped Highly Porous Carbon from Polyaniline Nanotubes for Supercapacitors

The rapid development of clean energy generation devices has invaded every nook and corner of cutting-edge technology. With time, supercapacitors play a foremost role as a promising candidate in energy storage systems. However, electrode material becomes a decisive factor in the electrochemical performance of the supercapacitor and its capacitance can be controlled by using activated agents. Herein, the electrochemical window of the highly porous nitrogen-doped activated carbon was enhanced through the process of carbonization and activation of polyaniline nanotubes with KOH. Polyaniline nanotubes were synthesized using a facile oxidative polymerization process. Moreover, the changes in surface area and porosity were examined via BET analysis for the samples having polyaniline to KOH ratio 1:0.5, 1:1, and 1:2. It was observed that the surface area and pore volume from as-synthesized polyaniline to chemically treated samples was significantly improved from 18 to 3525 m2/g. The highest specific capacitance of 317 F/g was observed at the current density of 1A/g for polyaniline activated using 1:1 ratio of an activating agent. The sample achieved a maximum energy density of 36 Wh/kg with a power density of 455 W/kg. Further, these supercapacitors provided a good coulombic efficiency of about 100% with capacitance retention of 92% after 5000 charge-discharge cycles. The research suggests our facile approach to synthesizing nitrogen-doped carbon for supercapacitors could be adopted for commercial applications.

Time-Dependent Development of Mesoporosity in Ionic Liquid Treated Cellulosic Materials

Natural Fiber Welding (NFW) is process that leverages the unique solvating power of ionic liquids (IL) to mobilize a natural fiber’s outermost polymer strands and enable these mobile polymers to reconfigure and interact with mobilized polymers of adjacent fibers. Upon removal of the ionic liquid via a solvent exchange and drying process, the biopolymer material is welded into a new matrix while still maintaining the vast majority of its native structural hierarchy. Recent work in our laboratory has shown relatively simple modifications to the NFW process can drastically impact the modified matrix morphology, particularly regarding surface structure. Changes in polarity during the solvent exchange process, for instance, can be used to very the surface area over a 1000-fold and produce high surface are materials with tunable mesoporosity. In the present work we investigate the impact of variable ionic liquid treatment time on the development of mesoporosity in fiber welded cotton substrates. Nitrogen gas adsorption/desorption measurements were employed to evaluate changes in surface area and pore size with ionic liquid treatment time. Raman spectroscopy was carried out on epoxy potted material cross sections to assess the impact of treatment time on cellulose decrystallization, and epoxy penetration measured by Raman spectroscopy was used to evaluate the continuity of the mesoporous regions and further asses material porosity.