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    Marine Invertebrates as Bioindicators of Heavy Metal Pollution
    (Scientific Research, 2014-12) Chiarelli, Roberto; Roccheri, Maria Carmela
    Atmosphere, earth and water compose the environment. The presence of heavy metals in the environment has grown because of their large employment in some industrial and agricultural activities. Although these metals are terrestrial products, they flow into the sea through effluents and sewage or are directly discharged from industries placed on the seawater front. It should be considered that metals concentrations vary widely according to different seawater latitudes and depths and can be strongly influenced by fresh water discharges from heavily polluted rivers. In this review recent studies on heavy metal pollution in marine ecosystems and their organisms will be presented. Metal speciation, bioaccumulation in biota, as well as abiotic and biotic factors affecting their bioavailability will be reviewed. Moreover, the use of bioindicator organisms for the biomonitoring of heavy metal toxicity and their ecological effects will be defined. Many marine invertebrate species fulfill the following criteria: Sensitivity to a wide range of chemicals (especially to heavy metals), cost-effectiveness for repeatable tests, readily interpretable biological consequences of pollution. Among the most important marine invertebrates used as bioindicators, the sea urchin embryo is one of the most suitable, especially to assess metal/heavy metal pollution.
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    Protection Systems for Reinforced Concrete with Corrosion Inhibitors
    (Scientific Research, 2014-12) Zacharopoulou, Angeliki; Zacharopoulou, Eugenia; Batis, George
    This paper examines the use of corrosion inhibitors in order to protect the reinforcement of concrete. For this purpose mortar specimens were constructed with or without corrosion inhibitors and were partially immersed in sodium chloride. Corrosion inhibitors were used as admixture into concrete and were sprayed on the external surface of mortar specimens. In all mortar specimens, electric junction between reinforcements was achieved. The methods that were used for the evaluation of the reinforcement corrosion in concrete, included half-cell potential measurements, polarization curves of reinforced rebars and mass loss of the reinforcement. Finally, the durability of concrete after the use of corrosion inhibitors was also examined.
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    Effect of Deformation during Stamping on Structure and Property Evolution in 3rd Generation AHSS
    (Scientific Research, 2018-06) Branagan, Daniel; Parsons, Craig; Machrowicz, Tad; Cischke, Jonathon; Frerichs, Andrew; Meacham, Brian; Cheng, Sheng; Justice, Grant; Sergueeva, Alla
    Over the past decade extensive development of advanced high strength steel (AHSS) was driven by the demand from the automotive industry for stronger materials that can enable lightweighting to meet increasing fuel efficiency requirements. However, achievement of higher strength in many AHSS grades comes with reductions in ductility, leading to geometric constraints on formability and limiting their application. In this paper, a 3rd Generation AHSS with a compelling property combination of high tensile strength of ~1200 MPa and total elongation > 40% was used for laboratory and stamping studies. Various auto related laboratory tests were done including tensile testing, 180 degree bending, bulge testing, and cup drawing to estimate the steel’s formability under different applied conditions. Additionally, since laboratory testing provides only an estimation of the potential stamping response, the 3rd Generation AHSS sheet was stamped into B-pillars under industrial stamping conditions. Non-destructive and destructive analysis of the resulting stampings were done to evaluate the microstructural and property changes occurring during stamping. Significant strengthening of material in the stamped part is attributed to the structural changes through the complex Nanophase Refinement and Strengthening mechanism.
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    Analysis of the Behavior of Local Cooking Utensils in Tap Water, Salt Tap Water and Vegetable Oil According to the Temperature
    (Scientific Research, 2013-12) Ndiaye, Mamadou Babacar; Bec, Sandrine; Coquillet, Bernard; Cissé, Ibrahima Khalil
    In Senegal the aluminum scrap are mainly recycled kitchen utensils [1]. The craftsmanship poses the problem of the quality of finished products [1] especially when we know they are used for everyday cooking. Given that none of these alloys should not be used to make cooking utensils if we refer to the EN 601 standard in July 2004, which refers to this regard [1], this study aims at analyzing behavior of these alloys reconstructed in three settings (tap water, vegetable oil and salt water more than 3 grams per liter), chosen for their importance in Senegalese cuisine. Significant loss of material was observed mainly by intergranular corrosion. It would be interesting that additional studies be conducted to examine the impact of the daily use of these alloys on the health of Senegalese.
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    Quantum Chemical Studies on the Corrosion Inhibition of Mild Steel by Piperidin-4-One Derivatives in 1 M H3PO4
    (Scientific Research, 2014-12) Kathirvel, Kalaiselvi; Thirumalairaj, Brindha; Jaganathan, Mallika
    The corrosion inhibition properties of 2,6-diphenylpiperidin-4-one (DPP) (1A) and 2,6-diphenyldihydro-2H-thiopyran-4(3H)-one (DPDT) (1B) for mild steel in 1 M phosphoric acid were studied using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopic techniques. The effect of temperature on the corrosion behavior of mild steel has been examined in the temperature range 303 - 328 K. The inhibition efficiency increases with increasing inhibitor concentration but decreases with increasing temperature. Potentiodynamic polarization studies indicated the mixed nature of inhibitors. The adsorption of the inhibitors on mild steel surface obeyed the Langmuir adsorption isotherms. The density functional theory (DFT) at the B3LYP/6- 31G (d) basis set level was performed on 1A and 1B to investigate the correlation between molecular structure and the corresponding inhibition efficiency (%). The quantum chemical parameters such as EHOMO, ELUMO, the energy gap (E), hardness (η), softness (S), dipole moment (µ), electron affinity (A), ionization potential (I), the absolute electronegativity (χ), the fraction of electron transferred (N), electrophilicity index (ω), the back-donation (EBack-donation) and Mulliken population analysis have been calculated.
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    XRF Analysis of Heavy Metals for Surface Soil of Qarun Lake and Wadi El Rayan in Faiyum, Egypt
    (Scientific Research, 2013-07) El-Bahi, Samia M.; Sroor, Amany T.; Arhoma, Najat F.; Darwish, Saher M.
    The environmental pollution with some heavy metals for twenty four surface soil samples collected from Qarun Lake and Wadi El Rayan region in Faiyum, Egypt utilizing X-ray fluorescence (XRF) spectroscopy was measured. The concentrations of 13 elements Cr, Ni, Cu, Zn, Zr, Rb, Y, Ba, Pb, Sr, Ga, V and Nb were determined. The elemental concentrations were compared with the normal values and other studies in different locations from the world. The correlation between elements appears that pollution inside the investigated lake and Wadi result from different sources of contamination present inside them. The results establish a database reference of radioactivity background levels around these regions.
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    Comparative Study on Heavy Metals Biosorption by Different Types of Bacteria
    (Scientific Research, 2013-07) Gelagutashvili, Eteri
    Biosorption of Cd(II), Ag(I) and Au(III) by cyanobacteria Spirulina platensis, of Au(II)—by Streptomyces spp. 19H, and of Cr(VI) and Cr(III)—by Arthrobacter species was studied by using the dialysis and atomic absorption analysis under various conditions. In particular, the impact of the following parameters on biosorption was studied: pH (for Ag, Cd, Au), living and non-living cells (for Cr), heavy metal valence (for Cr), homogenized and non-homogenized cells (for Au), Zn(II) ions (on Cr(VI)—Arthrobacter species). It was shown that biosorption efficiency of Cr(III), Cr(VI), Cd(II), Au(III) and Ag(I) ions is likely to depend on the type of bacteria used as well as on the conditions under which the uptake processes proceeded. It was shown that metal removal by microorganisms was influenced by physicalchemical parameters. The pH value of 7.0 was optimum for the removal of Ag(I) and Cd(II) by Spirulina platensis. At a low pH value of 5.5, Au (III) was by test algae more efficiently than Cd(II) and Ag(I).
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    Assessment of Heavy Metals Immobilization in Artificially Contaminated Soils Using Some Local Amendments
    (Scientific Research, 2013-07) Abdel-Kader, Noha H.; Shahin, Reda R.; Khater, Hasan A.
    Three alluvial soil samples with different textures were artificially polluted with chloride solutions of Cd, Pb, Co and chromate solution for Cr. The aqua-regia extracted concentration ranges in the artificially polluted soils were 1134 - 1489 mg·kg−1 for Pb, 854 - 938 mg·kg−1 for Cr, 166 - 346 mg·kg−1 for Co and 44 - 54 mg·kg−1 for Cd. The aqua-regia extracted metals were the highest in the spiked clay soil due to its high adsorption capacity. Rock phosphate (PR), limestone (LS) and Portland-cement (Cem) were mixed with the spiked soils at 1% and 2% rates (w/w) and incubated at 30 C for 2, 7, 14, 30, 60, 150 and 360 days. The extracted DTPA metals significantly decreased with different magnitudes with increasing the incubation period accompanied by increases in both pH and EC. The data showed that cement (Cem) treatment dropped the DTPA-Pb from @ 1000 to @ 400 mg·kg−1 in all the studied soils (60% decrease) in the first 2 months while it gradually decreased from 400 to 200 mg·kg−1 (20% decrease) in the next 10 months. Limestone (LS) and rock phosphate (PR) materials were relatively less effective in lowering DTPA-Pb after 12 months of incubation. The data showed also that cement (Cem) treatment was the most effective one in lowering DTPA-Cd by @ 60% as compared to the un-amended soils after 12 months of soil incubation. Extractable DTPA-Co and Cr showed consistent decreases with time down to nearly 50% of un-amended soils due to the effect of the added amendments after 12 months of incubation with superior reductions for the cement treatment in all the investigated soils. The statistical analysis confirmed that in all the studied metals and treatment, cement treatment (Cem) was significantly the most effective in lowering the DTPA extracted metals as indicated from LSD test. It was found that up to 73% and 57% of the applied Pb and Cd, respectively, were fixed by only 1% cement. However, the present study showed that from the practical and economic points of view, that 1% Cement was the best treatment to immobilize Pb and Cd from all the artificially polluted soils.
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    Heavy Metal Contaminated Food Crops Irrigated with Wastewater in Peri Urban Areas, Zambia
    (Scientific Research, 2013-07) Kapungwe, Evaristo Mwaba
    Studies on peri urban farming in Zambia have not adequately tackled the issues pertaining to heavy metal contaminated wastewater irrigation farming. The study investigated heavy metal contamination of water, soils and crops at two peri urban areas in Zambia. Two study sites were New Farm Extension in Mufulira Town in the Copperbelt Province and Chilumba Gardens in Kafue Town in Lusaka Province. The heavy metals investigated were lead, copper, cobalt, nickel and chromium. These heavy metals were found to be higher than acceptable limits in wastewater used to irrigate crops and there are potential human health risks associated with consumption of heavy metal contaminated food crops which have implications on the livelihoods of people. Samples of water, soil and crops were collected and analysed for lead (Pb), copper (Cu), chromium (Cr), cobalt (Co) and nickel (Ni) using the Atomic Absorption Spectrometer (AAS). The data on heavy metals was analysed using mean, standard error and T-test. The results indicated that the levels of heavy metals in wastewater, soil and food crops were above acceptable limits at two study sites. It can be concluded that there was heavy metal contamination of wastewater, soil and food crops at the two peri-urban areas in Zambia. The study highlighted the actual levels of heavy metal contaminant uptake in food crops consumed by the peri urban population. The information from this study can be used by the relevant authorities to develop appropriate measures for monitoring and control of heavy metal contamination in wastewater irrigation farming systems in peri urban areas in Zambia.
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    A Novel Technique for Determination of Flow Characteristics of Blast Furnace Slag
    (Scientific Research, 2012-06) Dash, Supratik; Mohanty, Nachiketa; Mohanty, Upendra K.; Sarkar, Smarajit
    A study of flow characteristics of blast furnace slag helps determine its softening and flow (liquid-mobility) temperatures. The slag with a narrow difference between the two temperatures is termed a “Short Slag”. Its formation ensures higher rates of slag-metal reactions with the trickle of the slag soon after its formation exposing fresh mass for faster reactions, the trickling slag, creating fresh interfaces facilitating slag-metal exchanges. In the present work, a novel technique is adopted to determine the flow characteristics of blast furnace slag obtained from different industrial blast furnaces. It is seen that the results so obtained agree very closely with the values obtained from adopting conventional methods of determining the liquidus temperature using “slag atlas”. It is observed that under the range of compositions studied a high C/S ratio combined with a high MgO content in the slag is beneficial to the B.F. process as it renders a “short slag”.
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    Enhancing Mar and Abrasion Resistance of Acrylic Hard Coatings with Soft Base Layer
    (Scientific Research, 2016-01) Chouwatat, Patcharida; Kotaki, Masaya; Yokohama, Atsushi
    Mar and abrasion resistance were investigated by a progressive load scratch test and steel wool abrasion test, respectively. Two acrylic coating systems including trimethylolpropane triacrylate (TMPTA) and pentaerythritol triacrylate (PETA) were prepared. A soft base layer was introduced as an intermediate layer between two different types of top layer and poly (methyl methacrylate) (PMMA) substrate to demonstrate the effect of soft base layer on mar and abrasion resistance. Abrasion damage on the coating surface was found to be less severe, when the soft base layer was incorporated into the coating systems. The reduction in scratch coefficient of friction (SCOF) and surface roughness was also observed. The results suggested that mar and abrasion resistance was greatly influenced by the presence of soft base layer, although different top layers were used. Moreover, it was found that abrasion resistance was further improved as the thicker soft base layer was applied.
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    Effect of Molecular Weight and Molecular Distribution on Skin Structure and Shear Strength Distribution near the Surface of Thin-Wall Injection Molded Polypropylene
    (Scientific Research, 2016-01) Maeda, Keisuke; Yamada, Koji; Yamada, Kazushi; Kotaki, Masaya; Nishimura, Hiroyuki
    In this study, the relationship between skin structure and shear strength distribution of thin-wall injection molded polypropylene (PP) molded at different molecular weight and molecular distribution was investigated. Skin-core structure, cross-sectional morphology, crystallinity, crystal orientation, crystal morphology and molecular orientation were evaluated by using polarized optical microscope, differential scanning calorimeter, X-ray spectroscopic analyzer and laser Raman spectroscopy, respectively, while the shear strength distribution was investigated using a micro cutting method called SAICAS (Surface And Interfacial Cutting Analysis System). The results indicated that the difference of molecular weight and molecular weight distribution showed own skin layer thickness. Especially, high molecular weight sample showed thicker layer of the lamellar orientation and molecular orientation than low molecular weight sample. In addition, wide molecular distribution sample showed large crystal orientation layer.
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    Characterization of Some Hydrogels Used in Water Purification: Correlation of Swelling and Free-Volume Properties
    (Scientific Research, 2015-07) Mohsen, M.; Maziad, N. A.; Gomaa, E.; Aly, E. Hassan; Mohammed, R.
    In this study, the main objective is to develop a good chelation and ion exchange hydrogel. This hydrogel is obtained by polymerization of dimethyl amino ethyl methacrylate (DMAEMA) and acrylic acid (AAc) by gamma irradiation, for the purpose of separation of some heavy and toxic metals from water. UV spectroscopy is applied to determine the metal ion concentration before and after treatment. The FTIR spectral analysis has identified the bond structure of PAAc, DMAEMA and P (DMAEMA/AAc) hydrogels. Microstructure and nanostructure are investigated by means of SEM and positron annihilation lifetime spectroscopy (PALS) respectively. A maximum swelling percent is found for 80/20 DMAEMA/AAc at free-volume hole size and fraction of 97 Ǻ3 and 3.4% respectively. The P (DMAEMA/AAc) and PAAc hydrogels have been applied for Cu+2, Co+2 and Ni+2 removals from aqueous solutions, and the factors affecting the adsorption capacity are determined. The adsorption capacity of P (DMAEMA/AAc) is found to be higher than the corresponding ones PAAc. Its experimental results showed that, the maximum adsorption of P (DMAEMA/AAc) after 24 h occurs at pH 7 with concentration of 250 ppm for Ni+2 ions and at pH 5 with concentration of 40 ppm for Cu+2 and Co+2 ions. The adsorption affinity of P (DMAEMA/AAc) hydrogel at different treatment contact times is in the following order Ni > Cu > Co. However, the order becomes Co > Ni > Cu by the variation of the pH of the metal ion solution; the variation of its concentration leads to a different order of Cu > Co > Ni.
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    High Performance Oil Resistant Rubber
    (Scientific Research, 2012-10) Khalaf, A. I.; Yehia, A. A.; Ismail, M. N.; El-Sabbagh, H.
    Blending of polymers has gained much interest due to the fact that, it can be used to produce new polymeric materials with specific properties suitable for some special applications. The blends from acrylonitrile butadiene rubber (NBR), chloroprene rubber (CR) and polyvinyl chloride (PVC) has been designed for products working in contact with oils. The characteristics of the designed blends either binary blends (NBR/PVC or PVC/CR) or ternary blends (NBR/ PVC/CR) were investigated by rheological properties, mechanical analysis and swelling in oil and toluene. It was found that the incorporation of PVC in the blend compositions leads to the decrease in degree of swelling, the penetration rate and the average diffusion coefficient. On the other hand the ultimate tensile strength (UTS), the hardness and strain energy were increased. This was attributed to the plastic nature of PVC, beside its additional behavior as filler. The crosslinking density in the blend vulcanizates under investigations was determined by Flory-Rehner and Mooney-Rivlin [Stress/Strain] equations. The higher values of crosslinking density determined by Mooney-Rivlin can be attributed to the additional physical crosslinks (e.g. entanglements etc), beside the chemical crosslinks determined by swelling in toluene. This study showed that NBR/PVC blends are characterized with high performance oil resistant, which can be recommended to automotive industry.
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    Investigation into Failure in Mining Wire Ropes—Effect of Crystallinity
    (Scientific Research, 2013-04) Devasahayam, Sheila; Sahajwalla, Veena; Sng, Michael
    A range of blends of polypropylene-polyethylene are investigated for their mechanical performances. These speciality polymer blends are chemically designed to suit high modulus/high load bearing mining wire rope applications subjected to continued bending and tensile stresses and fluctuating loads and are exposed to extreme weather conditions. In this paper we study the influence of different parameters on the performance of the wire ropes: chemistry of polymer, crystallinity of the polymer matrix, and the morphology. The FTIR and SEM studies revealed that the high fraction of polypropylene in polypropylene-polyethylene matrix lead to early failure as a result of incompatibility and phase segregation and high spherulite sizes of the polymer matrix.
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    Improving Functional Characteristics of Wool and Some Synthetic Fibres
    (Scientific Research, 2011-10) Allam, O. G.
    The present article reviews recent developments in different treatments that confer functional characteristics on wool and some synthetic fibers such as acrylic, polyamide and polyester of these functionalities mention is made of shrinkage-resistance, felt proofing, ant pilling, antimicrobial, surface properties (hydrophilic, soil -resistance, water and oil-repellency), self-cleaning, anti odor and flame retardant. The article also illustrates nanotechnology applications to improve and / or to induce some of these properties. Improvement of these properties can give the fibres an important position between the textile fibres which make them more convenient in different uses.
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    Corrosive Behavior and Physic-Chemical Characterization of Filtration Tanks
    (Scientific Research, 2017-11) Casanova-del-Angel, Francisco
    Most drinkable water supplied to the public in Mexico City comes from deep wells which extract water from the subsoil. Before being distributed, it is treated in steel filtration tanks. This water must be subject to evaluation through physic-chemical and bacteriological analyses in order to determine its quality. However, doubts always remain over the influence of the components of this water on the corrosive behavior of the filtration tanks. In light of this, this article studies the physic-chemical characterization values of water and presents the results. This has also enabled the analysis of the corrosion speed of filtration tanks components, boilers and water-cooled systems, where incrustations in pipes, obstructions and loss of heat transfer efficiency occur, rendering drinkable water bad tasting and, after some time, causing pitting corrosion although this type of corrosion only causes serious problems in the long term.
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    Updated Definition of the Three Solvent Descriptors Related to the Van der Waals Forces in Solutions
    (Scientific Research, 2018-02) Laffort, Paul
    Innovative viewpoint on the older topic of the van der Waals forces, is of interesting and significant issue to be concerned in both the fields related to the fundamental investigation and thus valuable in guiding the new physiochemical phenomena and processes for both academic research and practical applications. The intermolecular Van der Waals forces involved in solutions have been recently deeply reconsidered as far as the solute side is concerned. More precisely, the solute descriptors (or parameters) experimentally established, have been accurately related to molecular features of a Simplified Molecular Topology. In the present study, an equivalent result is reached on the solvent side. Both experimental parameters have been obtained simultaneously in previous Gas Liquid Chromatographic studies for 121 Volatile Organic Compounds and 11 liquid stationary phases, via an original Multiplicative Matrix Analysis. In that experimental step, five groups of forces were identified, two of hydrogen bonding and three of Van der Waals: 1) dispersion (London), 2) orientation or polarity strictly speaking (Keesom), and 3) induction-polarizability (Debye). At this stage, an attempt of characterization the solvent parameters via the SMT procedure has been limited to those related to the Van der Waals forces, those related to the hydrogen bonding being for now left aside.
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    Simplified Step-by-Step Nonlinear Static Program Investigating Equilibrium Conditions of Electrons in Atom and Ionization Energies: Case Study on Argon
    (Scientific Research, 2018-05) Papadopoulos, Panagis G.; Koutitas, Christopher G.; Dimitropoulos, Yannis N.; Aifantis, Elias C.
    For investigation of equilibrium conditions of electrons in an atom, and Ionization Energies of Elements, a simplified deterministic static model is proposed. The electrons are initially uniformly and sparsely arranged on the outer surface of nucleus. Then, by taking into account the nucleus-electron interaction (attractive and repulsive) and the mutual electron-electron repulsions, and by a simple step-by-step nonlinear static analysis program, all the electrons are found to equilibrate on the outer surface of the same sphere, which is concentric and larger than nucleus. In a second stage, starting from an equilibrium sphere of electrons, one of the electrons is subjected to gradual forced removal, radially and outwards with respect to nucleus. Within each removal step, the produced work increment is determined and the increments are summed. When no more significant attraction is exerted by nucleus to removed electron, the total work gives the Ionization Energy. After removing of single electron, the remaining electrons fall on a lower shell, that is, they equilibrate on the outer surface of a smaller concentric sphere. For nucleus-electron interaction, an L-J (Lennard-Jones) type curve, attractive and repulsive, is adopted. When the parameter of this curve is n > 1.0, the Ionization Energy exhibits an upper bound. As parameter n increases from 1.0 up to 2.0, the attractive potential of L-J curve is gradually weakened. The proposed model is applied on Argon. It is observed that, as the number of electrons increases, the radius of equilibrium sphere increases, too, whereas the attractive nucleus-electron potential is reduced; thus the Ionization Energy is reduced, too. Particularly, as the number of electrons and the radius of equilibrium sphere exceed some critical values, the above two last quantities exhibit abrupt falls. A regular polyhedron is revealed, which can accommodate Elements up to atomic number Z = 146, that is 28 more than Z = 118 of existing last Element, as guide for initial locations of electrons in the above first program.
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    A Specific Periodic Table for Chemistry of Organic, Semi-Organic and Inorganic Elements: Compatibility with the Even-Odd Rule,the Number of Electrons and the Isoelectronicity Rule
    (Scientific Research, 2018-05) Auvert, Geoffroy
    Following the introduction of the new even-odd and isoelectronic rules and definitions affecting the understanding of electronic structure and bonds, the author has thought necessary to summarize understandings in the form of a table. The classical periodic table, a simple tool used by generations of physicists, is here extended to become a useful tool aimed specifically at chemists. In chemistry, position and number of covalent bonds of each atom are needed, as well as the exact location of charges. The table gives the number of possible bonds for each element and reveals how it is affected by charges. Additionally, the specific table indicates for each atom its isoelectronic elements and highlights the distinction between organic and inorganic elements. Discussion is led on the first two rows of the table by successfully comparing its statement with more than 50 well-known liquid and gaseous compounds.