73 research outputs found

    Molecular and Crystal Structure of the Bis(Acetato)-Bis(4- Methyl-1h-Pyrazole)-Zinc(Ii)

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    Due to the low CO2 emission of geopolymers compared to Portland cement, interest in their use as binding cement has increased in recent years. The main goal of this research is to relate the green and sustainable characteristics to the good mechanical and chemical properties of fly ashbased geopolymers. For those purposes, samples of different ratios of fly ash (FA) and metakaolin (MK) were prepared. Mineralogical characterization of the geopolymer samples conducted using X-ray powder diffraction (XRD) showed that in the geopolymer synthesis reaction new amorphous phase was formed. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) confirmed characteristic bands of Si-O and O-Si-O groups at 1045 cm–1 . Compressive strength analysis revealed that the optimal ratio of FA and MK is 50:50 and exhibits the highest value, while X-ray photoelectron spectroscopy (XPS) analysis revealed the total reduction of carbon content in the alkali activated geopolymer with optimal stoichiometry 50:50. The results of this research indicates the possibility to obtain a geopolymer material with almost complete absence of carbon, which implies further application as a material with very high environmental potential and zero carbon emission.distorted tetrahedral environment. Different pattern of non-bonding interactions involving chemically equivalent ligands influence the overall shape of the complex molecule. This is evident in different mutual position of the pyrazolyl and acetato ligands, which is associated with different hydrogen bonds. Two neighboring complex molecules forms hydrogen bonded dimer. There are no significant intermolecular contacts between dimmer

    Performance of Tomato with Organic Manures in Plastic Tunnel

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    Tomato is one of the most demanded vegetable with increasing trend of commercial cultivation in Nepal. As it is the heavy feeder crop thus soil nutrient management has been always challenging. Since, in modern world organic production has been favored by consumers for many reasons thus we aimed to compare the efficacy of various compost, mineral fertilizers and their combinations in tomato production and soil productivity. For the purpose a field experiment in plastic tunnel was carried out in Horticulture Research Division, Khumaltar in two consecutive years (2014 and 2015). Srijana, a popular tomato hybrid among commercial producers, was purposively selected. Eight treatments (control, recommended doses of chemical fertilizers, compost 15 t ha-1 + cattle urine, compost 10 t ha-1 + cattle urine, compost 12.5 t ha-1 + cattle urine, compost 15 t ha-1 + 1/4 recommended dose of chemical fertilizers, compost 10 t ha-1 + ¾ recommended dose of chemical fertilizer and compost 12.5 t ha-1 + 1/2 recommended dose of chemical fertilizer) were laid out in randomized complete block design and replicated thrice. The result showed significant (p < 0.05) positive correlation between the plant height and yield of tomato. The treatment with compost dose of 12.5 t ha-1 with half dose of recommended dose of chemical fertilizers produced the highest incremental yield (85% increment) over other treatments followed by compost 15 t ha-1 with cattle urine. Addition of soil organic carbon, soil nitrogen, soil potassium by the increasing level of compost though not significant, but increment in carbon content, nitrogen content and potassium content of soil observed in successive years. For commercial producer at plastic tunnel, compost at the rate 12.5 t ha-1 with half dose of recommended level of chemical fertilizer (100:90:40 kg N:P:K ha-1) is recommended to apply in field, while for organic producer, application of 15 tha-1 compost with fermented cattle urine is recommended

    Heteronuclear {TbxEu1-x} furoate 1D polymers presenting luminiscent properties and SMM behavior

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    We report the synthesis, crystal structure and photo-magnetic properties of novel Tb/Eu polymeric complexes of general formula {TbxEu1−x(α-fur)3(H2O)3}n, supported by 2-furancarboxilic acid: the homonuclear Tb(III) complex {Tb} (1), four heterodinuclear complexes, {Tb0.8Eu0.2} (2), {Tb0.7Eu0.3} (3), {Tb0.3Eu0.7} (4), and {Tb0.1Eu0.9} (5), and the homonuclear Eu(III)-only complex {Eu} (6). X-ray diffraction experiments show that the α-furoate ligands, acting in bridging mode, consolidate the 1D polymeric chains along the c-axis. Luminescence studies show the sensitization capability of the furoic acid ligand. Color tuning from green to red can be successfully achieved through the heterodinuclear strategy. We have measured Eu emission by direct excitation at the resonant 7F0 → 5L6 (395 nm), and indirectly, by excitation of the non-resonant wavelength (280 nm) which provokes ligand → Tb → Eu energy transfer. Besides, ac susceptibility measurements under varying frequencies and temperatures reveal that mixed {TbxEu1−x} complexes exhibit field-induced slow relaxation dynamics, with extremely slow relaxation times, owing to direct processes affected by the bottleneck effect. Thus, the {TbxEu1−x} complexes represent interesting low-dimensional multifunctional materials combining both luminescent and SMM magnetic properties

    Antiferromagnetic single-chain magnet slow relaxation in the {Tb(α-fur)3}n polymer with non-Kramers ions

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    We report the synthesis, crystal structure and magnetic properties of a new molecular complex based on a Tb(iii) ion supported by 2-furancarboxylic molecules: {Tb(α-fur)(HO)} (α-fur = CHOCOO). Two slightly different Tb sites (A and B) exist depending on the position of one of the dangling ligands. Ab initio calculations predict that, for both sites, the magnetic ground state is highly anisotropic (g∗ = 17.8) and consists of a quasi-doublet with a small gap, well isolated from the next excited state. The α-fur ligand forms 1D polymeric chains of Tb ions of the same type (either A or B) running along the c-axis. The crystal structure is formed by the supramolecular stacking along the a-axis of 2D layers containing parallel chains of the same type. Static magnetization and heat capacity measurements show that, magnetically, the system can be modeled as an ensemble of Ising chains of non-Kramers Tb ions with effective spin S∗ = 1/2, antiferromagnetically (AF) coupled by a weak intrachain interaction (J∗/k = -0.135 K). At very low temperatures, the static susceptibility reflects the presence of a 2-4% concentration of defects in the chains. Ac susceptibility measurements at H = 0 performed down to mK temperatures have enabled us to observe the slow relaxation of magnetization through two different pathways. They are assigned to Single-Chain-Magnet (SCM) behavior in two different types of AF chains (A and B), triggered by the existence of defects breaking the chains into segments with short-range order. At temperatures below 0.1 K this mechanism is replaced by individual relaxation of the ions through direct processes. Under the application of a magnetic field the system slowly relaxes by two distinct direct processes, strongly affected by a phonon bottleneck effect.This work has been financed by MECOM Projects MAT11/23791 and MAT11/27233-C02-02, MAT2015-68204-R, MAT2014-53921-R, DGA IMANA E34 and MOLCHIP E98 Projects. Consolider Nanoselect (CSD2007-00041) and by a grant of the Ministry of National Education, CNCS – UEFISCDI, project number PN-II-ID-PCE-2012-4-0261. D. P. thanks the Alexander von Humboldt (AvH) Foundation for financial support.Peer Reviewe

    Heteronuclear {TbxEu1-x} furoate 1D polymers presenting luminescent properties and SMM behavior

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    We report the synthesis, crystal structure and photo-magnetic properties of novel Tb/Eu polymeric complexes of general formula {TbxEu1-x(a-fur)3(H2O)3}n, supported by 2-furancarboxilic acid: the homonuclear Tb(iii) complex {Tb} (1), four heterodinuclear complexes, {Tb0.8Eu0.2} (2), {Tb0.7Eu0.3} (3), {Tb0.3Eu0.7} (4), and {Tb0.1Eu0.9} (5), and the homonuclear Eu(iii)-only complex {Eu} (6). X-ray diffraction experiments show that the a-furoate ligands, acting in bridging mode, consolidate the 1D polymeric chains along the c-axis. Luminescence studies show the sensitization capability of the furoic acid ligand. Color tuning from green to red can be successfully achieved through the heterodinuclear strategy. We have measured Eu emission by direct excitation at the resonant 7F0 ¿ 5L6 (395 nm), and indirectly, by excitation of the non-resonant wavelength (280 nm) which provokes ligand ¿ Tb ¿ Eu energy transfer. Besides, ac susceptibility measurements under varying frequencies and temperatures reveal that mixed {TbxEu1-x} complexes exhibit field-induced slow relaxation dynamics, with extremely slow relaxation times, owing to direct processes affected by the bottleneck effect. Thus, the {TbxEu1-x} complexes represent interesting low-dimensional multifunctional materials combining both luminescent and SMM magnetic properties

    Heteronuclear {TbxEu1−x} furoate 1D polymers presenting luminescent properties and SMM behavior

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    We report the synthesis, crystal structure and photo-magnetic properties of novel Tb/Eu polymeric complexes of general formula {TbxEu1−x(α-fur)3(H2O)3}n, supported by 2-furancarboxilic acid: the homonuclear Tb(III) complex {Tb} (1), four heterodinuclear complexes, {Tb0.8Eu0.2} (2), {Tb0.7Eu0.3} (3), {Tb0.3Eu0.7} (4), and {Tb0.1Eu0.9} (5), and the homonuclear Eu(III)-only complex {Eu} (6). X-ray diffraction experiments show that the α-furoate ligands, acting in bridging mode, consolidate the 1D polymeric chains along the c-axis. Luminescence studies show the sensitization capability of the furoic acid ligand. Color tuning from green to red can be successfully achieved through the heterodinuclear strategy. We have measured Eu emission by direct excitation at the resonant 7F0 → 5L6 (395 nm), and indirectly, by excitation of the non-resonant wavelength (280 nm) which provokes ligand → Tb → Eu energy transfer. Besides, ac susceptibility measurements under varying frequencies and temperatures reveal that mixed {TbxEu1−x} complexes exhibit field-induced slow relaxation dynamics, with extremely slow relaxation times, owing to direct processes affected by the bottleneck effect. Thus, the {TbxEu1−x} complexes represent interesting low-dimensional multifunctional materials combining both luminescent and SMM magnetic properties

    Efficacy of postural awareness by booklet on back pain among the sweet makers

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    Background: The purpose of the study was to identify the efficacy of postural awareness by a booklet on back pain among sweet makers. Objective was to explore socio-demographic (age, gender, educational status, occupation) characteristics of sweet-makers with back pain. To compare the rating of pain intensity before and after postural awareness by a booklet with the back pain of sweet-makers. Methods: This study was conducted by pre-test post-test experimental study in which a total of 25 sweet-makers were selected with back pain from January 2021 to December 2022. Data were collected by using the functional rating index questionnaire to evaluate the activity of daily living and pain measured by the visual analogue scale questionnaire. Statistical package for the social sciences (SPSS) was used for data analysis. Results: In this study, the results showed significant improvement in the reduction of back pain and increase functional activities of daily living by postural awareness with an educational booklet among sweet-makers. The NPRS score in pair sample t-test before and after 15 days of postural awareness by booklet was the level of significant 0.000123, the mean of 0.640±0.700. The pattern of pain before and after 15 days of postural awareness by booklet was the level significant 0.042896 when the mean difference was -0.160±0.374. The referred pain before and after 15 days of postural awareness by booklet was 0.000032 level significant where the mean difference was -0.520±0.510. Conclusions: The result of this study suggests that postural awareness through a booklet on back pain was effective and it also improves activities of daily living among sweet-makers.

    High relaxation barrier in neodymium furoate-based field-induced SMMs

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    Two new neodymium molecular magnets of formula {[Nd(α-fur)3(H2O)2]·DMF}n (1) and {[Nd0.065La0.935(α-fur)3(H2O)2]}n (2), α-fur = C4H3OCOO, have been synthesized. In (1) the furoate ligands, in bidentate bridging mode, consolidate zig-zag chains running along the a-direction. Compound (2) is a magnetically diluted complex of a polymeric chain along the b-axis. Heat capacity, dc magnetization and ac susceptibility measurements have been performed from 1.8 K up to room temperature. Ab initio calculations yielded the gyromagnetic factors gx* = 0.52, gy* = 1.03, gz* = 4.41 for (1) and gx* = 1.35, gy* = 1.98, gz* = 3.88 for (2), and predicted energy gaps of Δ/kB = 125.5 K (1) and Δ/kB = 58.8 K (2). Heat capacity and magnetometry measurements agree with these predictions, and confirm the non-negligible transversal anisotropy of the Kramers doublet ground state. A weak intrachain antiferromagnetic interaction J′/kB = −3.15 × 10−3 K was found for (1). No slow relaxation is observed at H = 0, attributed to the sizable transverse anisotropy component, and/or dipolar or exchange interactions enhancing the quantum tunnelling probability. Under an external applied field as small as 80 Oe, two slow relaxation processes appear: above 3 K the first relaxation mechanism is associated to a combination of Orbach process, with a sizeable activation energy U/kB = 121 K at 1.2 kOe for (1), Raman and direct processes; the second, slowest relaxation mechanism is associated to a direct process, affected by phonon-bottleneck effect. For complex (2) a smaller U/kB = 61 K at 1.2 kOe is found, together with larger g*-transversal terms, and the low-frequency process is quenched. The reported complexes represent rare polymeric Nd single-ion magnets exhibiting high activation energies among the scarce Nd(III) family
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