2,215 research outputs found
Low pressure adsorption on kaolinite clay minerlas modified by cation exchange at the solid/liquid interface
No full textKaolinite is one of the most abundant aluminosilicate minerals, occurring primarily as clay-sized particles with high surface area-to-volume ratios. The surface of kaolinite particles can be considered as heterogeneous as crystallites present at least two different types of faces, basal and edge faces, with different surface chemistry and exchange proprieties. It is commonly believed that exchangeable cations of kaolinites are mainly located on the edge faces. However, the basal surfaces can also carry a constant charge due to isomorphous substitution of Si4+ by Al3+ in tetrahedra and Al3+ by Mg2+ in octahedra. This aim of this work is to study the influence of the nature of surface cations on the surface properties of kaolinite at the solid/gas interface. Argon low pressure gas adsorption coupled to the Derivative Isotherms Summation method [1-3], used for long time to derive geometrical properties of kaolinites powder was applied on monovalent kaolinite samples (Li+, Na+, K+, Cs+) [4-6]. By comparing the adsorption isotherms it appears that the nature of surface cation influences the adsorption phenomena on edge and basal faces. On edge faces, the exchanged cations generate nanorugosity and take part to the first argon monolayer. On basal faces, two families of cations are presents in small quantity: for the first family, argon adsorption energy is slightly sensitive to the nature of the cation; for the second one, argon adsorption energy depends on the nature of surface cation [4]. The influence of outgassing temperature (110°C-350°C) on surface properties of kaolinite shows that, for the first family, surface cations are strongly linked to surface and probably correspond to the compensation of local charge defects generated by tetrahedral or octahedral substitutions. For the second one, surface cations were physisorbed on the surface and correspond to neutral compounds [5]. On the quantitative point of view, it was shown that the estimation of the aspect ratio of kaolinite should be carried out with monovalent cations of small size (Li+, Na+) with surface outgassing at 200°C [4-6]. [1] F. Villiéras et al., Langmuir, 8 (1992) 1789. [3] J.M. Cases et al., C.R. Acad. Sci., Paris, 331 (2000) 763. [2] F. Villiéras et al., C.R. Géoscience, 334 (2002) 597. [4] M. Sayed Hassan et al., Langmuir, 21 (2005) 12283. [5] M. Sayed Hassan et al., J. Colloid Interface Science, 296 (2006) 614. [6] M. Sayed Hassan et al., Langmuir, Submitte
Low pressure adsorption on kaolinite clay minerlas modified by cation exchange at the solid/liquid interface
No full textKaolinite is one of the most abundant aluminosilicate minerals, occurring primarily as clay-sized particles with high surface area-to-volume ratios. The surface of kaolinite particles can be considered as heterogeneous as crystallites present at least two different types of faces, basal and edge faces, with different surface chemistry and exchange proprieties. It is commonly believed that exchangeable cations of kaolinites are mainly located on the edge faces. However, the basal surfaces can also carry a constant charge due to isomorphous substitution of Si4+ by Al3+ in tetrahedra and Al3+ by Mg2+ in octahedra. This aim of this work is to study the influence of the nature of surface cations on the surface properties of kaolinite at the solid/gas interface. Argon low pressure gas adsorption coupled to the Derivative Isotherms Summation method [1-3], used for long time to derive geometrical properties of kaolinites powder was applied on monovalent kaolinite samples (Li+, Na+, K+, Cs+) [4-6]. By comparing the adsorption isotherms it appears that the nature of surface cation influences the adsorption phenomena on edge and basal faces. On edge faces, the exchanged cations generate nanorugosity and take part to the first argon monolayer. On basal faces, two families of cations are presents in small quantity: for the first family, argon adsorption energy is slightly sensitive to the nature of the cation; for the second one, argon adsorption energy depends on the nature of surface cation [4]. The influence of outgassing temperature (110°C-350°C) on surface properties of kaolinite shows that, for the first family, surface cations are strongly linked to surface and probably correspond to the compensation of local charge defects generated by tetrahedral or octahedral substitutions. For the second one, surface cations were physisorbed on the surface and correspond to neutral compounds [5]. On the quantitative point of view, it was shown that the estimation of the aspect ratio of kaolinite should be carried out with monovalent cations of small size (Li+, Na+) with surface outgassing at 200°C [4-6]. [1] F. Villiéras et al., Langmuir, 8 (1992) 1789. [3] J.M. Cases et al., C.R. Acad. Sci., Paris, 331 (2000) 763. [2] F. Villiéras et al., C.R. Géoscience, 334 (2002) 597. [4] M. Sayed Hassan et al., Langmuir, 21 (2005) 12283. [5] M. Sayed Hassan et al., J. Colloid Interface Science, 296 (2006) 614. [6] M. Sayed Hassan et al., Langmuir, Submitte
Low pressure adsorption on kaolinite clay minerlas modified by cation exchange at the solid/liquid interface
No full textKaolinite is one of the most abundant aluminosilicate minerals, occurring primarily as clay-sized particles with high surface area-to-volume ratios. The surface of kaolinite particles can be considered as heterogeneous as crystallites present at least two different types of faces, basal and edge faces, with different surface chemistry and exchange proprieties. It is commonly believed that exchangeable cations of kaolinites are mainly located on the edge faces. However, the basal surfaces can also carry a constant charge due to isomorphous substitution of Si4+ by Al3+ in tetrahedra and Al3+ by Mg2+ in octahedra. This aim of this work is to study the influence of the nature of surface cations on the surface properties of kaolinite at the solid/gas interface. Argon low pressure gas adsorption coupled to the Derivative Isotherms Summation method [1-3], used for long time to derive geometrical properties of kaolinites powder was applied on monovalent kaolinite samples (Li+, Na+, K+, Cs+) [4-6]. By comparing the adsorption isotherms it appears that the nature of surface cation influences the adsorption phenomena on edge and basal faces. On edge faces, the exchanged cations generate nanorugosity and take part to the first argon monolayer. On basal faces, two families of cations are presents in small quantity: for the first family, argon adsorption energy is slightly sensitive to the nature of the cation; for the second one, argon adsorption energy depends on the nature of surface cation [4]. The influence of outgassing temperature (110°C-350°C) on surface properties of kaolinite shows that, for the first family, surface cations are strongly linked to surface and probably correspond to the compensation of local charge defects generated by tetrahedral or octahedral substitutions. For the second one, surface cations were physisorbed on the surface and correspond to neutral compounds [5]. On the quantitative point of view, it was shown that the estimation of the aspect ratio of kaolinite should be carried out with monovalent cations of small size (Li+, Na+) with surface outgassing at 200°C [4-6]. [1] F. Villiéras et al., Langmuir, 8 (1992) 1789. [3] J.M. Cases et al., C.R. Acad. Sci., Paris, 331 (2000) 763. [2] F. Villiéras et al., C.R. Géoscience, 334 (2002) 597. [4] M. Sayed Hassan et al., Langmuir, 21 (2005) 12283. [5] M. Sayed Hassan et al., J. Colloid Interface Science, 296 (2006) 614. [6] M. Sayed Hassan et al., Langmuir, Submitte
sj-pdf-1-vet-10.1177_03009858221082300 – Supplemental material for Neuropathology of feral conures with bromethalin toxicosis
No full textSupplemental material, sj-pdf-1-vet-10.1177_03009858221082300 for Neuropathology of feral conures with bromethalin toxicosis by Mauricio Seguel, Rita McManamon, Drury Reavill, Fern Van Sant, Sayed M. Hassan, Branson W. Ritchie and Elizabeth W. Howerth in Veterinary Pathology</p
‘Tenderstem’ Broccoli for Export Markets: an Analysis Study on the AgroFood Company
No full textDecision case, horticulture, agriculture economics, broccoli production, protected vegetable production, Agricultural Finance, Crop Production/Industries, Production Economics,
Revenue-productive income tax structures and tax reforms in emerging market economies - evidence from Bulgaria
No full textUsing a household budget survey for 1992, The author shows the poor revenue performance and distributional impact of Bulgaria's personal income tax system. He explores the implications for revenue and income distribution of two alternative tax systems - a flat tax and a progressive but simpler three-brackets tax system. He demonstrates that simpler tax structures with lower tax rates could achieve at least equal revenue and distributional objectives and are superior in terms of efficiency and equity. (The findings are robust when Bulgaria's significant tax evasion is included). But tax changes since 1992 have, if anything, moved Bulgaria even further from a simple income tax system: the number of rates and brackets increased from 7 to 10, and the levels of exemption remain unchanged. (Complex, higher rates complicate administration and enforcement and provide incentives for tax evasions. And in the alternative systems the author explores, the poor are protected with higher exemptions.) Fortunately, the country's personal income tax structure began to move toward less nominal progressivity after Bulgaria's 1997 tax reform program. The tax rate in thetop income bracket was reduced from 52 percent to 40 percent, the number of tax brackets was halved, and the exemption level was increased 20 percent (reducing tax burdens on the poor).Environmental Economics&Policies,Public Sector Economics&Finance,Regional Governance,Tax Policy and Administration,Economic Theory&Research,Governance Indicators,Economic Theory&Research,Public Sector Economics&Finance,Environmental Economics&Policies,Tax Policy and Administration
Impact of Poultry Manure-Derived Biochar and Bio-Fertilizer Application to Boost Production of Black Cumin Plants (Nigella sativa L.) Grown on Sandy Loam Soil
No full textBiochar derived from poultry manure increases nutrient availability and promotes plant growth. This study investigated the effect of biochar with mycorrhizal and/or plant growthpromoting rhizobacteria on soil fertility, chemical properties, oil, and seed yield of Black Cumin (Nigella sativa L.) plants. A split-plot design with three replicates was employed, with biochar derived from poultry litter (BC) applied at rates of 0, 5, and 10 t ha−1, with beneficial microbes such as arbuscular mycorrhizal fungi (AMF) and plant growth-promoting rhizobacteria (PGPR) affecting the growth of Black Cumin plants, and some soil properties, such as pH, electrical conductivity (EC), soil organic matter (SOM) and fertility index (FI), showing significant differences (p ≤ 0.05) among biochar and/or bio-fertilizer treatments. All biochar treatments with or without bio-fertilizers significantly increased pH, EC, OM and FI in comparison to the control treatment. The results demonstrated that applying biochar at the highest rate (10 t ha−1) increased fresh and dry capsule weights by 94.51% and 63.34%, respectively, compared to the control treatment (C). These values were significantly increased by 53.05 and 18.37%, compared to untreated plants when combined with AMF and PGPR. Furthermore, when biochar was applied in conjunction with both AMF and PGPR, fresh and dry capsule weights saw significant increases of 208.84% and 91.18%, respectively, compared to the untreated control treatment. The interaction between biochar, AMF, and PGPR
significantly improved plant growth, yield, soil properties, and the fixed and volatile oil content of Black Cumin. These findings suggest that the combined application of biochar, AMF, and PGPR enhances nutrient availability and uptake, leading to improved growth and higher yields in Black Cumin plants, resulting in increased yield productio
Conservation in an Islamic context a case study of Makkah
No full textThe Holy Qu’ rān contains many injunctions for Muslims to respect and conserve the natural environment but few address the built environment. Habitat at the time of the Prophet (PBOH) was in the vernacular and relatively impermanent. The first habitat was the cave, the second the tent and then simple flat roofed buildings of post and lintel construction made of mud and rubble. Later buildings were not indigenous but reflected the architectural styles and techniques of Muslim pilgrims from beyond the Arabian Peninsula. Permanent exotic buildings were later erected as reminders of holy places and events. This work advances a case to restore and preserve historic and religious sites in Makkah, Saudi Arabia. Makkah is the destination for millions of Muslim pilgrims who annually pay homage to Allah during the occasions of Hajj, Ramadan and Umra. The tranquillity and peaceful ambience that one associates with the holiest of Islamic experiences have, over the years, given way to jostling crowds of people who must be expediently housed, fed, transported, and protected. Due to the lack of planning and the insensitive but profitable development of the city, Makkah is in grave danger of becoming a bustling metropolis instead of a sanctuary where pilgrims gather to perform their religious rites and reaffirm their dedication to Allah. The author calls for professional planning and international cooperation to guide future development for this expanding and sensitive area. The author's ideas are grounded in practical and aesthetic study, therefore, the political, environmental and economic issues are examined in relationship to religious, historic and artistic values. The author makes proposals for a future Makkah that would provide pilgrims with the physical comforts, security, and serene environment they deserve—without destroying the city they came to visit. The author discusses preservation and conservation in the western world and the need for their acceptance in Muslim countries, the former being an aesthetic and intellectual concept sustained by law and the latter being the prescribed free expression of the individual unhindered by material considerations. Both worlds are rapidly being overwhelmed by materialism, but body, mind and spirit combine in making us aware of our surroundings and the way in what we see around us has come into being
Multi-Criteria Decision Making: Sustainable Water Desalination
No full textWith an increasingly more urbanised global population, surface water and groundwater resources are being/have become outpaced by growing demand. The oceans could address this pertinent scarcity issue, once their high-salinity content is removed. Water desalination could thus be a crucial pathway towards addressing global water scarcity. However, conventional desalination is known to be highly energy-intensive, with limited scalability and potentially significant negative environmental impacts. Multi-criteria Decision Making (MCDM) presents a novel approach towards sustainable water desalination based on sustainability-related criteria. The Fuzzy Analytical Hierarchy Process (FAHP) was implemented to determine the most optimal small-scale, modularised, and remote reverse osmosis (RO) desalination plant configurations. Twelve configurations were assessed, based on four plant capacities (50, 100, 150, and 200 m3/day) and three diesel-to-solar photovoltaic energy configurations (100–0%, 75–25%, and 60–40%). The hybridised diesel-to-solar configurations were generally ranked higher, particularly when less reliant on diesel, and at small(er) capacities, in terms of the criteria: sustainability, overall efficiency, and standalone potential while maintaining competitive costs. This can likely be attributed to their relatively lower fuel and energy consumption and associated costs. Further research should aim to consider additional criteria, such as battery cost, as well as life cycle assessments that include transportation-related costs/emissions
Holistically green and sustainable pathway prioritisation for chemical process plant systems via a FAHP-TOPSIS framework
No full textMulti-criteria Decision Making (MCDM) presents a novel approach towards truly holistic green sustainability, particularly within the context of chemical process plants (CPPs). ASPEN Plus v12.0 was utilised for two representative CPP cases: isopropanol (IPA) production via isopropyl acetate, and green ammonia (NH3) production. An integrated Fuzzy Analytic Hierarchy Process (FAHP) and Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) was modelled in MATLAB v24.1 to prioritise the holistically green and sustainable pathways. Life cycle assessments (LCAs) were employed to select the pathways, and the most suitable sub-criteria per the four criteria are as follows: social, economic, environmental, and technical. In descending order of optimality, the pathways were ranked as follows for green NH3 and IPA, respectively: Hydropower (HPEA) > Wind Turbine (WGEA) > Biomass Gasification (BGEA)/Solar Photovoltaic (PVEA) > Nuclear High Temperature (NTEA), and Propylene Indirect Hydration (IAH) > Direct Propylene Hydration (PH) > Acetone Hydrogenation (AH). Sensitivity analysis evaluated the FAHP–TOPSIS framework to be overall robust. However, there are potential uncertainties within and/or among sub-criteria, particularly in the social dimension, due to software and data limitations. Future research would seek to integrate FAHP with VIKOR and the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE-II)
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