Journal articles on the topic 'Resonant column apparatu'

The resonant column test includes torsional and flexural modes that can be used to obtain reduction curves for the shear modulus and Young’s modulus of the soil, respectively. When the resonant column test is performed under flexural mode, Young’s modulus is calculated mainly using the measured resonant frequency following the formula proposed by Cascante et al. However, this formula does not consider the rotational inertia effect of the electromagnetic drive disk of the resonant column apparatus and thus may inaccurately calculate Young’s modulus. In this study, the formula was modified by considering the rotational inertia effect of the electromagnetic drive disk, and its accuracy was verified by using three aluminum calibration rods with different diameters as a dummy specimen for the resonant tests in flexural and torsional modes.

For resonant column tests conducted in the flexure mode of excitation, a new methodology has been proposed to find the elastic modulus and associated axial strain of a cylindrical sample. The proposed method is an improvement over the existing one, and it does not require the assumption of either the mode shape or zero bending moment condition at the top of the sample. A stepwise procedure is given to perform the necessary calculations. From a number of resonant column experiments on aluminum bars and dry sand samples, it has been observed that the present method as compared with the one available in literature provides approximately (i) 5.9%–7.3% higher values of the elastic modulus and (ii) 6.5%–7.3% higher values of the associated axial strains.

In this study a resonant column apparatus was used to obtain the shear modulus and damping ratio of the waste granular rubber and cement soil mixtures. Specimens were tested for different rubber contents and confining pressures. Experiments show that with the rubber increased, the damping ratio of the rubber and cement soil mixtures increases, dynamic modulus decreases. When the confining pressure increases, the shear modulus of rubber and cement soil mixtures increase gradualy, damping ratio increase slightly.

The dynamic parameters of silty clay in Dujiangyan under dynamic loading are studied with RCA resonant column apparatus made in GDS Company of British with different confining pressures. The results show that: The test process can be reproducible; the maximum dynamic shear modulus and damping ratio are increasing, and the shear strain amplitude is decreasing with increasing confining pressures. The empirical formula of the dynamic parameters of silty clay in Dujiangyan vs. confining pressures is formed. The study can provide basic data for seismic dynamic response analysis of soil.

Abstract The paper concerns laboratory methods for determination of soil stiffness. Major criterion for selection of analysed equipment is range of strain in which stiffness can be reliably determined. Substantially, various configurations of triaxial apparatus are referred to i.e. with standard cell and with the modified one. Additional system for internal measurement of strain is described and rational (based on test results) for use of it is presented. As to shear wave velocity measurement as a mean to obtain initial stiffness, requirements for proper measurement and interpretation was given. Finally, an approach to determine Poisson’s ratio on the basis of combined results of cyclic triaxial and resonant column tests was presented.

ABSTRACTVarious studies have already been performed involving the whole aerial parts of Centella asiatica (L.) (Umbelliferae), commonly known as gotu kola orjalbrahmi, and thus, the present investigation has been carried out for the phytochemical study of an ethanolic extract of the aerial parts of C. asiatica.To perform this activity, the drug (1.5 kg) was exhaustively extracted in 95% ethanol using Soxhlet apparatus. The column chromatography wasperformed then for isolating the various phytoconstituents using the solvents of increasing polarity from petroleum ether to methanol. The isolatedcompounds were structurally elucidated using various spectral data analysis, i.e. infrared,1H nuclear magnetic resonance (NMR),13C NMR, and positiveion fast atom bombardment mass spectrometry. One of the isolated compounds was characterized as n-heptacosanyl oleate.Keywords: Whole aerial parts, Centella asiatica, Soxhlet, Column, Heptacosanyl oleate.

Abstract The paper presents a selected aspect of the determining the initial soil shear modulus value on the research example in resonant column – torsional shear apparatus (RC / TS). There are presented the significance of the initial value of shear modulus in design of offshore wind power plant foundations and the importance of its variability in the function of cyclical shear strains of soil related to the impact of sea and atmosphere on the designed structures. Based on the conducted analyses, a new methodology for interpreting the TS test results of soil has been proposed. It allows estimating the values of the shear modulus in the full range of shear strains occurring in issues closely related to the design and construction work of offshore wind power plant foundations.

The present paper describes a measurement technique for phase-separated velocity profile measurements in the two-phase bubbly flow. The Ultrasonic Velocity Profiler (UVP) method which is nonintrusive measurement, is applied to obtain an instantaneous velocity profile of liquid and bubble separately by using only one resonant frequency. To achieve this target, developed algorithm, which can decompose frequency component of the Doppler signal affected by liquid and bubble, is applied in the UVP system to obtain and separate instantaneous velocity profile of both phases. For confirming the applicability of modified measurement system, the developed UVP was used for the measurement of the velocity profile in bubbly flow on vertical pipe flow apparatus, the measurement accuracy was validated by UVP Original and Particle Image Velocimetry (PIV) method. Finally, the UVP was applied to experiment for observing velocity distribution of both phases in a bubble column.

In this paper, bender elements are used as sensors to measure the damping ratio of soil by the spectral-ratio method. The results of numerical and physical experiments suggest that adequate measurement precision can be achieved by reducing the two types of inherent biases arising from (i) the near-field effect and (ii) the different transfer functions of the two receiver bender elements. The first bias can be avoided by setting sensors to r1/λ ≥ 2.0 and r1/r2 ≥ 2.0, where r1 and r2 are the distances between the source and the first and second receivers, respectively; and λ is the wavelength. The second bias can be minimized by modifying the original spectral-ratio method to accommodate the self-healing technique. The damping ratios, measured by this modified method, obtained from the experiment conducted in a tailor-made, true-triaxial apparatus are very similar to those obtained from resonant column tests under the same state of stress.Key words: bender element, damping ratio, spectral-ratio method, near-field effect, true-triaxial apparatus.

Abstract This article deals with the question of theoretical description of behaviour of a single pile rested in a layered soil medium. Particular attention is paid to soil modulus which is used in calculation method for pile load-settlement curve. A brief analysis of the results obtained by laboratory tests to assess soil modulus and its nonlinear variability has been presented. The results of tests have been used in triaxial apparatus and resonant column/torsional shear device. There have also been presented the results of load-settlement calculation for a single pile under axial load with implementation of different models of soil modulus degradation. On this basis, possibilities of using particular kinds of laboratory tests in calculation procedure of foundation settlement have been presented as well as further developments of them.

Abstract Investigating the stress state of a sample-standard column in forced-oscillation apparatus is critical to clearly quantify measurement credibility, offering insights into revealing intrinsic frequency-dependent elastic characteristics of a rock sample. To investigate the effects of the jointing condition, the location of strain gauges and device resonance on the stress state of a sample-standard column, we experiment with a typical forced-oscillation setup numerically and experimentally at frequencies of 2–800 Hz. Overall, the numerical model captures the primary features of the forced-oscillation device, which makes the simulated data fit well with the measured results. Meanwhile, based on the configuration of the sample-standard column with variable static friction in jointing contacts, the simulated results also indicate that mechanical contacts of the sample-standard-vibrator assembly lead to stress concentration, resulting in coordinate-dependent strains on both the sample and standard. Additionally, strain magnitude is also frequency-dependent, causing a relatively large measurement error on the elasticity of the sample at higher frequencies. Ultimately, numerical results not only optimize measurement workflow but also create a solid foundation for the interpretation of measured data.

This research investigates the performance of an assembly micro-atomizer under single-fluid and twin-fluid operational conditions of micro-encapsulation process. Alginate and CaCl2 aqueous solution are used as the membrane material and hardening agent, respectively. The high speed images were taken to investigate the formation processes of the microcapsules. Results showed that the formation of the microcapsules depends on the instability modes of the liquid column including asymmetry mode, helical mode, sinusoidal mode and spray developing mode as Reynolds number was increased from 221 to 2210. Excitation at resonance frequency of 2.18 kHz of this system resulted in the production of uniform-sized microcapsules. Moreover, SMD equal to 20 μm can be achieved in low GLR under twin-fluid atomization process. It is not easy to achieve by commercial apparatus.

Extraction of dyes from walnut using Soxhlet apparatus has been studied. The color components extracted and isolated from walnut shells were characterized by column chromatography, thin layer chromatography (TLC), nuclear magnetic resonance (NMR), mass spectroscopy (MS), and infrared (IR) techniques. Natural dye extract obtained from the walnut was used in dyeing polyamide fabrics with different mordants. The dyed fabrics were evaluated for antibacterial activity against pathogenic strains of Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) bacteria. As such, the relationship between antibacterial activity and dye concentration is investigated. Durability of antibacterial activity to laundering is also discussed. Results indicate that the polyamide dyed with walnut displayed excellent antibacterial activity in the presence of ferric sulfate, cupric sulfate, and potassium aluminum sulfate and exhibited good and durable fastness properties.

Determination of liquefaction potential of sands in laboratory; dynamic three axial, hollow cylindrical torsional shear, resonance column, bender elements and cyclic simple shear tests are used. In this study, the effect of sample size on the determination of liquefaction energy of sandy soils in cyclic simple shear test apparatus was investigated. Uniform clean sea sand was used in the study. The cell inner diameter in which the samples to be tested is placed is 50 mm. Samples were prepared three different sizes with a length/diameter (H/D) ratio of 1, 0.5 and 0.25 and four varied relative densities (Dr: 40%, 50%, 60% and 70%). The samples were subjected to 1D cyclic loading at a frequency of 0.1 Hz under 100 kPa vertical stress and 50 kPa pore pressure. Each experiment was repeated 3 times, with equivalent or closer results considered significant. According to the test results, the liquefaction energy values per volume (J/m3) of the samples of different sizes are different from each other.

Solid-state 13C nuclear magnetic resonance (NMR) spectroscopy was used in this work to analyze the physical and chemical properties of plasma blacks and carbon deposits produced by thermal cracking of natural gas using different types of plasma reactors. In a typical configuration with a double-chamber reactor, N2 or Ar was injected as plasma working gas in the first chamber and natural gas was injected in the second chamber, inside the arc column. The solid residue was collected at different points throughout the plasma apparatus and analyzed by 13C solid-state NMR spectroscopy, using either cross polarization (CP) or direct polarization (DP), combined with magic angle spinning (MAS). The 13C CP/MAS NMR spectra of a number of plasma blacks produced in the N2 plasma reactor showed two resonance bands, broadly identified as associated with aromatic and aliphatic groups, with indication of the presence of oxygen- and nitrogen-containing groups in the aliphatic region of the spectrum. In contrast to DP experiments, only a small fraction of 13C nuclei in the plasma blacks are effectively cross-polarized from nearby 1H nuclei and are thus observed in spectra recorded with CP. 13C NMR spectra are thus useful to distinguish between different types of carbon species in plasma blacks and allow a selective study of groups spatially close to hydrogen in the material.

The construction sector is currently struggling with the reuse of waste originating from the demolition and modernization of buildings and roads. Furthermore, old buildings are gradually being replaced by new structures. This brings a significant increase of concrete debris to waste landfills. To prevent this, many studies on the possibilities of recycling concrete, known as recycled concrete aggregate (RCA), have been done. To broaden the applicability of reused concrete, an understanding of its properties and engineering behavior is required. A difficulty in sustainable, proper management of RCA is the shortage of appropriate test results necessary to assess its utility. For this reason, in the present study, the physical, deformation, and stiffness properties of RCA with gravely grain distribution were analyzed carefully in the geotechnical laboratory. To examine the mentioned properties, an extensive experimental program was planned, which included the following studies: granulometric analysis, Proctor and oedometer tests, as well as resonant column tests. The obtained research results show that RCA has lower values of deformation and stiffness parameters than natural aggregates. However, after applying in oedometer apparatus repetitive cycles of loading/unloading/reloading, some significant improvement in the values of the parameters studied was noticed, most likely due to susceptibility to static compaction. Moreover, some critical reduction in the range of linear response of RCA to dynamic loading was observed.

Flavonoids are secondary metabolites providing Ultraviolet-visible (UV) spectroscopy protection and color in almost all terrestrial plants and fruits. They have a fused ring system consisting of an aromatic ring and a benzopyran ring with a phenyl substituent. As their biological activities have an impact on human health, they serve as target molecules in the development of new drugs. The objective of this research was to study the antioxidant activity and chemical analysis of the luteoline fromCentaurea behenL. (Compositae family). The aerial parts of powdered and driedC. behenwere extracted with methanol (MeOH) in a Soxhlet apparatus over a period of 2 days. The concentrated total extract was extracted with petroleum ether, diethylether, and methanol. From the methanol extract of the aerial parts ofC. behen, the flavonoid derivative (luteoline) was identified. The aerial parts’ extract demonstrated effective antioxidant activity measured in terms of half-maximal inhibitory concentration (IC50). The product extract has been isolated by UV, column chromatography (CC), and preparative high-performance liquid chromatography (HPLC). The structures involved were elucidated by1H and13C nuclear magnetic resonance (NMR) and heteronuclear multiple-bond correlation (HMBC) spectra. The compound identified had not been reported in previous studies ofC. behenL.

Determining the geomechanical properties of hydrate-bearing sands (HBS), such as strength and stiffness, are critical for evaluating the potential for the economic and safe recovery of methane gas from HBS reservoirs. To date, results from numerous independent laboratory studies on synthesized HBS have shown that strength and stiffness are largely influenced by hydrate saturation, the method adopted for hydrate formation, and to a lesser extent, the confining stresses applied during testing. However, a significant scatter is observed in the data even when these conditions are similar. These include recent studies on natural HBS where sands with larger particle size distribution (PSD) exhibited higher strengths despite lower hydrate saturation. To investigate the impact of PSD, and the role that specific hydrate formation conditions might impose, on the strength and stiffness of HBS, a series of laboratory tests were carried out on sand specimens formed with different particle size distributions and utilizing different approaches for forming gas saturated HBS. The laboratory apparatus included a resonant column drive head to measure the small-strain stiffness of the specimen during hydrate formation, and subsequent drained compressional shearing to capture the stress-strain response of the HBS. Results indicate that the PSD significantly affects both the stiffness evolution (during hydrate formation) and peak strength at failure after formation compared to the effect of the methodology adopted for hydrate formation. These observations improve our understanding of the geomechanical behavior of laboratory-synthesized HBS and allow more robust relationships to be developed between them and natural HBS. This may aid in the development of economic and safe methane gas production methods to help realize the energy resource potential of HBS reservoirs.

AbstractThe problem is a continuation of the research conducted at the University of Warmia and Mazury in Olsztyn, Institute of Building Engineering. It concerns the development of methods for the interpretation of the shear modulus measurements based on the tests conducted on a torsional shear (TS) apparatus. The issue has significant importance in determining the deformation parameters, essential to perform numerical simulations of the interaction between a geotechnical structure and the subsoil. The purpose of this study was to conduct a comparative analysis of the various methods of interpretation of research results based on direct and reverse analysis, as well as automated classification of the first cycle of the relationship between the shear stress and the shear strain components obtained from the TS test. The methodology for verification of the presented interpretative methods consists in carrying out a series of laboratory tests on non-cohesive and cohesive samples of different granulation and state parameters. The course of the research includes the following steps: elaboration of the granulometric composition of several samples of soil, determination of soil index properties and execution of TS tests. Various methods of interpretation of obtained results were taken into account, in addition to conducting a comparative analysis. The study used a non-standard interpretation approach consisting of analysing one-fourth of the hysteresis loop of the first load–unload cycle of the tested samples. The obtained results confirmed the hypothesis that it is possible to estimate the degradation value of the shear modulus based on a part of the TS test results carried out under quasi-monotonic load conditions. The proposed methods of interpreting test results have confirmed their high usefulness, which is devoid of the uncertainty associated with standardised resonant column/TS testing.

One of the features of traumatic spinal cord injury in children is a high probability of the isloted form of its injury (syndrome SCIWORA – spinal cord injury without radiograph abnormality). Mobility and elasticity of the spine column in childhood explains a relatively rare incidence of its injury in young children; however, we meet a high incidence of the isolated spinal trauma in this group of patients. According to various authors, SCIWORA is more common in children under the age of 5 ~ 64%; from 6 to 12 ~ 35%; over 12 – about 20%. The relevance of the present study is explained by errors in the isolated spinal cord injury diagnostics and by the lack of clear clinical and diagnostic algorithm optimizing SCIWORA verification in this category of patients. Aim. To analyze the level of SCIWORA diagnostics in children with spinal cord injury (SCI) in a specialized surgical hospital as well as to assess reasons of misdiagnostics. Material and methods. 167 children with SCI were included into the study. They were admitted to the Clinical and Research Institute of Emergency pediatric Surgery and trauma (CRIEpSt) in 2014-2020. Depending on the time of admission, patients were divided into two groups: Group I – children who were admitted to the hospital within the first month after injury; Group II – children who were admitted later. Children aged 12.2 ± 5.0 y.o., in average. All patients were examined for their neurological status by ASIA scale; they also had radial diagnostics: computed tomography (CT) and magnetic resonance imaging (MRI). Results. The isolated spinal cord injury (SCIWORA) was revealed in 6.0% of children with SCI who were admitted to CRIEpSt in 2014 – 2020. The greater number of SCIWORA (60%) occurred as a result of road accidents and was recorded in the thoracic region (50%). Isolated the soinal cord injury occured more often in the age groups under 5 y. o. and 5 – 12 y.o. (by 40% in each age group). The severity of spinal cord injury in SCIWORA depends on the very mechanism of such damage: A – 80%, B – 20% by ASIA scale. In SCIWORA, computed tomography does not allow to fully assess SCI severity. MRI is prescribed for more precise diagnostics: to clearly visualize damages to the ligamentous apparatus and intervertebral discs; in addition to clinical findings to confirm contusion, hematomyelia, partial or complete rupture of the spinal cord; to make rehabilitation prognosis using tractography. Conclusion. The reasons for errors in the isolated spinal cord injury diagnosis in children is a result of underestimated severity of child’s condition due to his/her young age or due to the combination of SCI with severe traumatic brain injury (TBI) with a reduced state of consciousness. In case of even a slight suspicion of isolated spinal cord injury, the diagnostic algorithm in little children or in patients with reduced consciousness state should include a “head-to-toe” CT scanning and MRI examination in addition to a full-fledged neurological examination.

Isoflavones are naturally occurring compounds well-known for their beneficial role in several diseases, such as cancer and inflammation. Recently some isoflavones derivatives were reported as potent and competitive antagonists of formyl peptide receptors (FPRs) with an important role in regulating the inflammatory process. As a result of their biological activities, there is a huge interest in developing synthetic procedures to obtain isoflavones. Surprisingly, and as far as our knowledge goes, the synthetic work and full characterisation of the isoflavones described as FPR antagonists weren’t yet reported. The work herein described comprises the synthesis of two series of 2-trifluoromethyl isoflavones, including the ones described as FPR antagonists and their complete characterisation by 1D, 2D NMR techniques and high-resolution mass spectroscopy. IntroductionIsoflavones are naturally occurring compounds mainly found in soybeans, soy foods and vegetables. Chemically, they retain the typical C6C3C6 skeleton of flavonoids, consisting of two aromatic rings being linked through an oxygenated heterocycle nucleus, being isomers of flavones. They are characterised by the presence of a double bond between carbons C2 and C3 and an aromatic ring in the C3 position.1 Dietary isoflavones are well-known by their ability to act as phytoestrogens.1,2 Nevertheless, other health benefits have been attributed to this class of compounds namely, their beneficial role in cancer, such as hormone-dependent cancers, in osteoporosis, cardiovascular disease and inflammation, and several mechanisms have since been proposed to explain these activities.3 Interestingly,a series of synthetic isoflavones were recently reported as potent and competitive antagonists of formyl peptide receptors (FPRs) having an important role in the regulation of inflammatory reactions implicated in disease pathogenesis.4 Thus, the isoflavone backbone represents a promising scaffold for the development of novel FPR antagonists. As a result of their biological activity, there is a huge interest in the development of synthetic procedures to obtain isoflavones and their derivatives for structure-activity relationship studies. Surprisingly, and as far as our knowledge goes, the synthetic work and full characterisation of the synthetic isoflavones described as FPR antagonists(compounds A1, B2 and B3, figure 1), weren’t yet reported. Accordingly, the work herein described comprises the synthesis of two series of 2-trifluoromethyl isoflavones (figure 1), including the ones described as FPR antagonists and their complete characterisation by 1D and 2D NMR techniques and by high-resolution mass spectroscopy. ExperimentalMaterialsAll reagents were purchased from Sigma-Aldrich Química, S.L. and Alfa Aesar, Thermo Fisher Scientific. All solvents were pro analysis grade from Merck, Carlo Erba Reagents and Scharlab. Thin layer chromatography (TLC) was performed on pre-coated silica gel 60 F254 acquired from Merck with layer thickness of 0.2 mm. The spots were visualized under UV detection at 254 and 366 nm. Column chromatography was carried out with silica gel 60 0.040-0.063 mm acquired from Carlo-ErbaReactifs. Solvents were evaporated with a BuchiRotavapor. NMR spectroscopy 1H and 13C NMR data were acquired on a Bruker Avance III 400 NMR spectrometer operating at 400.15 MHz and 100.62 MHz, respectively. For the 1H NMR experiments, the relaxation delay was 90° pulse, spectral width of 8012 Hz and 65 K data points. In the case of the 13C NMR experiments, the corresponding parameters were 30º pulse, 24038 Hz and 65 K, respectively, and 2.0 s relaxation delay. For the Distortionless Enhancement by Polarization Transfer (DEPT) sequence, the width of the 90º pulse for 13C was 7.7 μs, and the 90º pulse for 1H was 9.8 μs; the delay 2JC, H was set to 2.0 ms. For correlation spectroscopy (COSY) and heteronuclear single quantum coherence (HSQC), the data points were set to 2 K × 256 (t2 × t1) with a relaxation delay D1 of 1.5 s. The Heteronuclear Multiple Bond Connectivity (HMBC) was acquired with data points set to 4 K × 256 (t2 × t1) and relaxation delay D1 of 1 s. Furthermore, the long-range coupling time for HMBC was set to 71 ms.The data were processed using quadratic sine-bell weighting functions in both dimensions. 1H and 13C spectra of the samples were recorded at room temperature in 5 mm outer-diameter tubes. Samples were prepared in deuterated chloroform (CDCl3). Tetramethylsilane (TMS) was used as internal reference; chemical shifts (δ) were expressed in parts per million (ppm), and coupling constants (J) were given in Hertz (Hz). The 1H and 13C chemical shifts of CDCl3 were 7.26 and 77.2 ppm, respectively. Mass spectroscopyMass spectra (MS) were carried out on a Bruker Microtof (ESI) apparatus; the data were reported as m/z (% of the relative intensity of the most important fragments). Synthesis of trifluoromethylisoflavones esters Compounds A1-A3 (Figure 1) were obtained by the cyclization of the 2-(2′-Chlorophenyl)-2′,4′-dihydroxyacetophenone, followed by its acylation with the corresponding acyl chloride, as depicted in scheme 1 (step b and c).5,6,7 Briefly, 2-(2′-Chlorophenyl)-2′,4′-dihydroxyacetophenone (1mmol) was cyclised, using trifluoroacetic anhydride (3mmol) and triethylamine (2mL). The reaction was refluxed for one hour, then poured into water, acidified (pH=3) and stirred at room temperature for another hour. The crude material was extracted with ethyl acetate (3x 10 mL). were dried over anhydrous sodium sulphate and the solvent evaporated. 7-hydroxy-3-(2-chlorophenyl)-2-(trifluoromethyl)-4H-chromen-4-one was recrystallised from ethyl acetate and obtained in a 65% yield. The acylation step was performed following the methodology described by Jayashree et al. 7: 7-hydroxy-3-(2-chlorophenyl)-2-(trifluoromethyl)-4H-chromen-4-one and (1mmol) and the corresponding acyl chloride (1.25 mmol), were dissolved in pyridine (7.5mL), and the solution refluxed for one hour (scheme 1, step c). The mixture was then cooled to room temperature and poured into water (30 mL), acidified to pH=5, and stirred at room temperature for two hours. Afterwards, the mixture was extracted with ethyl acetate (3x 10mL). The combined organic phases were dried over anhydrous sodium sulphate and the solvent evaporated under reduced pressure. The structure, chemical name, yield, and mass spectroscopy data of synthesised compounds are depicted in table I. Compounds B1-B3 (Figure 1) were obtained by the acylation of 7-hydroxy-3-(2-methoxyphenyl)-2-(trifluoromethyl)-4H-chromen-4-one with the corresponding acyl chloride, following the methodology described above and depicted in scheme 1 (step c). 7-hydroxy-3-(2-methoxyphenyl)-2-(trifluoromethyl)-4H-chromen-4-one was obtained following the procedure described in literature 8 (scheme 1, step a and b). Results and DiscussionThe complete structural characterisationof all synthesisedcompounds (A1- A3 and B1- B3) is depicted in tables II and III. The unambiguous assignment of all carbons and hydrogens was achieved by the combined expenditure of one- and two-dimensional nuclear resonance techniques. The unequivocal assignment of the NMR data for compound A1 was performed as followed: The hydrogens H-5 and H-8 of the benzopyran structure of compound A1 were readily assigned considering their splitting pattern and coupling constants (Table II). Thus, the peak at δ=8.31 ppm (d, J=8.8 Hz) was assigned to H-5 and the peak at δ=7.60 ppm (d, J=2.1 Hz) to H-8. The COSY experiment revealed an H-H interaction between these two peaks and the multiplet at δ=7.43-7.33 ppm (Figure 2), which integrated for three hydrogens. Furthermore, for this multiplet, an H-H interaction was observed with a peak at 7.52 ppm (ddd, J=0.4, 1.4, 7.9 Hz) (Figure 2). The construction of a splitting three diagram for the signal at δ=7.43-7.33 ppm enabled the identification of three hydrogens: one hydrogen at δ=7.41 ppm (H-4’, ddd, J=1.7, 7.5, 7.9 Hz), other at δ=7.39 ppm (H-6, dd, J=2.1, 8.8 Hz) and another at δ=7.35 ppm (H-5’, ddd, J=1.4, 7.4, 7.5 Hz). The COSY experiment also showed an H-H interaction between two double doublets (at δ=8.05 ppm and 7.75 ppm) with the multiplet at δ= 7.24-7.21 ppm (which integrates for two hydrogens) (Figure 2). The splitting pattern along with the coupling constants enabled the attribution of the peak at δ=8.05 ppm to H-6’’, and the peak at δ=7.75 ppm to H-4’’. Moreover, by assembling a tree diagram of the multiplet at δ= 7.24-7.21 ppm, H-5’’ and H6’ were assigned to δ=7.23 ppm. Both hydrogens showed a double doublet multiplicity. However, H6’’ showed characteristic coupling constants of a thiophene ring (J=3.8, 5.0 Hz) while H6’ presented the typical meta and orthoconstants of a phenyl ring (J=1.7, 7.4 Hz). The carbons of compound A1 were assigned using HSQC experiment and depicted in table II. The CF3 and the C-2 quaternary carbons were easily identified due to their typical coupling constants; the peak at δ= 118.9 ppm (d, J=277 Hz) was attributed to CF3, and the signal at δ= 149.4 ppm (d, J=37 Hz) was assigned as C-2. The other quaternary carbons were then assigned based on the HMBC experiment and chemical shifts with the long-range interactions summarized in Figure 3. The attribution of the quaternary carbons from the benzopyran nucleus (C-4, C-4a, C-8a, C-7) was as follows: a)The peak at δ= 175.1 ppm was assigned to C-4 due to their chemical shift and a long-range interaction with H-5; b) the long-range interaction detected between H-5 and H-8 with the peaks at δ=155.4 and 155.6 ppm allowed their attribution to C-7 and C-8a, respectively; c) a long-range interaction was detected between H-6 and the peak at δ=155.4 ppm, corroborating its assignment to C-7. Additionally, a long-range interaction of H-8 with the peak at δ=120.9 ppm was observed, which was identified as C-4a (Figure 4a). The quaternary carbons of the exocyclic phenyl ring were attributed based on the long-range correlation between the H-3’, H-4’ and H-6’ and the quaternary carbon at δ= 134.3 ppm, which was assigned to C-2’ (Figure 4b). Furthermore, the HMBC experiment showed an interaction between H-6’ and a peak at δ= 123.7 ppm, which was thus assigned as C1’. The signal at δ=159.4 ppm was assigned to carbon C-1’’ by its chemical shift and long-range interaction with H-4’’ and H-6’’. Moreover, H-4’’ and H-6’’ also showed a long-range interaction with the peak at δ=131.7 ppm, which was attributed to C-2’’ of the thiophene ring (Figure 4c). The structural assignment of compounds A2and A3 were based onthe attributions performed for compound A1.are depicted in table II. Using the same approach, the unequivocal assignment of hydrogens and carbons of the C2’-methoxyl counterparts (compounds B1-B3), was accomplished and described in table III. Nevertheless, the hydrogens of the methoxyl group were readily assigned from 1H NMR spectrum, by their chemical shift, integration and multiplicity at δ=3.77 ppm, δ=3.76 ppm and δ=3.75 ppm for compounds B1, B2 and B3, respectively. It is also important to stress that the chemical shift of exocyclic aromatic hydrogens and carbons was slightly affected by theaffected by the presence of methoxyl group at position C-2’ instead of chlorine. All the hydrogens and carbons of compounds B1- B3, with exception off C-2’, that appear with higher values of chemical shifts, suffered an upfield chemical shift, while C-2’ appears at relative to their C2’-Cl counterparts (compounds A1- A3). Table II: 1H and 13C NMR Data of Compounds A1-A3 Table I: 1H and 13C NMR Data of Compounds B1-B ConclusionsThis work describes for the first time an effective synthetic strategy to obtain trifluoromethylisoflavones derivatives, namely the ones that were described as FPR antagonists.4Theisoflavones(compounds A1-A3 and B1-B3) were synthesised in good yields and had been fully characterised by homo- and hetero-nuclear NMR and high-resolution mass spectrometry. The acquired data allowed the unambiguous identification of these compounds, providing a valuable database for the unequivocal identification of other analogue libraries. AcknowledgmentsThis work was funded by FEDER funds through the Operational Programme Competitiveness Factors-COMPETE and national funds by FCT – Foundation for Science and Technology under research grants (QUI/UI0081/2013, NORTE-01-0145-FEDER-000028 and PTDC/DTP-FTO/2433/2014). A. Gaspar (SFRH/BPD/93331/2013) grant is supported by FCT, POPH and QREN. References Szeja, W.; Grynkiewicz, G.; Rusin, A. “Isoflavones, their Glycosides and Glycoconjugates. Synthesis and Biological Activity”. Curr Org Chem. 2017, 21(3), 218-235. Vitale, DC.; Piazza, C.; Melilli, B.; Drago, F.; Salomone, S. “Isoflavones: Estrogenic activity, biological effect and bioavailability”. Eur J Drug Metab Pharmacokinet. 2013, 38, 15–25. Jie Yu, J.; Bi, XJ.; YU, B.; Chen, D. “Isoflavones: Anti-Inflammatory Benefit and Possible Caveats” 2016, 8(6), 361. Schepetkin, IA.; Kirpotina, LN.; Khlebnikov, AI.; Cheng, N.; Ye, RD. “Antagonism of human formyl peptide receptor 1 (FPR1) by chromones and related isoflavones”. 2014, 92, 627–641. Balasubramanian, S.; Nair, MG. “An Efficient “One Pot” Synthesis of Isoflavones”. Synth Commun. 2000, 30(3), 469-484. Eiffe, E.; Heaton, A.; Walker, C.; Husband, A. “2-Substituted isoflavonoidcompounds, medicaments and uses”. 2009, WO 2009003229 A1. Jayashree, BS.; Thejaswini, JC.; Nayak, Y.; Kumar, DV. “Synthesis of Novel Flavone Acyl Esters and Correlation of log P Value with Antioxidant and Antimicrobial Activity”. Chem Asian J. 2010, 22(2), 1055-1066. John NicolsonLow, J. N.; Ligia R. Gomes, L.R.; Alexandra Gaspar, A.; Borges. “Structure of 7-hydroxy-3-(2-methoxyphenyl)-2-trifluoromethyl-4H-chromen-4-one”. Acta Crystallogr E Crystallogr Commun. 2017, 73, 1130–1134.

The shear modulus and damping ratio of frozen soil are thebasic parameters of its dynamic properties and are often testedwith the dynamic triaxial apparatus. However, the resonantcolumn apparatus is more suitable for the testing at the microstrainlevel. A resonant column apparatus was here used toidentify the varying modes with negative temperature of theinitial shear modulus, modulus ratio, and damping ratio of frozensilt. Correction factor curves indicate that the temperaturehas a great effect on the shear modulus and damping ratio offrozen silt. The curves also show that, within the sensitive stage,the temperature significantly affects the modulus and damping.Within the insensitive stage, the modulus and dampingwere insensitive to the temperature. The experimental resultsand analysis given here provide support for improving seismicdesign codes and offer reasonable parameters for seismicresponse analysis in engineering construction in cold regions.

Resonant column (RC) devices have been widely used for estimating the shear modulus and damping ratio over a broad range of shear strain amplitudes. Although RCs significantly improve the assessment of soil dynamic properties, some challenges mainly associated with the calibration process still exist. This paper discusses the effect of the driving system rigidity on the measurements performed on a Hardin-type RC. It is shown that the use of a rigid connection between the soil specimen and the driving mass could significantly influence the obtained results. The findings of this study indicate that the apparatus resonant frequency of the Hardin-type RC device should be lower than the resonant frequencies likely to be measured during testing of the specimens.

Acoustic resonance is a physical phenomenon in which in-phase sound wavescombine together to produce maximum amplitude; on the other hand, out-of-phasesound waves cancel each other to produce minimum amplitude. The purpose of thisstudy is to investigate and demonstrate this phenomenon with the use of a reliabledevice. This study requires a modified resonator tube apparatus to be developed andfabricated from locally-available materials for the purpose of demonstrating resonanceand normal modes of sound waves. Air column length versus harmonic number (Lvs n) and frequency versus harmonic number (f vs n) experiments were performedtogether with open-pipe and stopped-pipe procedures. For L vs n experiments,deduced value of speed of sound is 337.79±0.94 m/s at 760 Hz for open-pipe takenat 29°C; and 357.72±9.34 m/s at 412 Hz for stopped-pipe taken at 25°C. For f vsn experiments, deduced value of speed of sound is 337.09±5.98 m/s at 2.30 m foropen-pipe taken at 25°C; and 345.92±5.55 m/s at 1.60 m for stopped-pipe takenat 30°C. Results had shown that the modified resonator tube apparatus is accurateand precise within 5% margin of error. Therefore, the apparatus is a reliable devicein demonstrating acoustic resonance phenomenon in the physics classroom setting.Keywords: Physics, Sound Waves, Resonance, Normal Modes, ExperimentalMethod, Philippines

Objective: The present study was designed with the aim of preliminary phytochemical evaluation and spectral characterization phytochemicals present in the extracts of whole plant Argyreia imbricata (Rox) Sant and Patel. Methods: The whole plant A. imbricata was collected, authenticated, and dried in the shade for powdering in mechanical grinder. The powdered plant material was extracted with Soxhlet apparatus using different solvents, and the dried extract obtained was subjected to preliminary phytochemical evaluation, and then column chromatography separation and the separated fractions were subjected to thin-layer chromatography (TLC) separation. Based on the yield in TLC, the selected compounds were subjected to carbon-13 nuclear magnetic resonance, proton NMR (1H NMR), and mass spectroscopic evaluation. Results: In the preliminary phytochemical evaluation, the presence of alkaloids, glycosides, phenolic compounds, flavonoids, carbohydrates, saponins, sterols, and terpenoids was found in different extracts. In column chromatography separation, totally 650 fractions were collected, and four compounds were isolated with the help of TLC. Among the four, two compounds were selected for spectral evaluation based on the yield obtained. The selected compounds were identified and named as, 3-ethyl-5-(hydroxymethyl) phenol and methyl 4-hydroxybenzoate with the help of spectral evaluation. Conclusion: The outcome of this study is beneficial, and further investigation in the future directed toward the detailed pharmacological screening of the extracts may give more valuable results.

To evaluate the hepatoprotective activity of different solvent extracts of Origanum majorana. The root materials were shade dried and were extracted in a soxhlet apparatus successively with ethyl acetate and methanol. The solvent was removed by the process of distillation and the crude extract was dried under vacuum. The extracts were subjected to hepatoprotective activities, the extract producing significant activity was column chromatographed. The extract was preliminarily screened using thin layer chromatography (TLC) and nuclear magnetic resonance (NMR) to know the types of compounds present in the extracts. TLC was developed in n hexane: ethyl acetate solvent systems of different polarities and then plates were visualized under Iodine vapour exposure, UV short wave 254 nm and long wave 366 nm. Plates were sprayed with a solution of visualizing reagent 10% H2SO4 in methanol followed by heating in an oven at 110°C for up to five minutes. The methanolic extracts of Origanum majorana at different doses, Silymarin and Drug vehicle were administered p.o in sodium carboxy methyl cellulose suspension. The serum was used for the estimation of various biochemical parameters like SGOT, SGPT, ALKP, TBL, CHL, TPTN and ALB. The results clearly depicted that CCl4 intoxication in normal rats elevated the serum levels of SGOT, SGPT, ALKP, TBL and CHL, where as decreased the levels of TPTN, ALB significantly when compared to control indicating acute hepatocellular damage and biliary obstruction leading to necrosis.

Aim and Objective:: Nowadays, developing effective antibiotics for bacteria control has become difficult due to increased resistance to the available medicines in the market. Essential oils have very interesting biological properties; some of their components have very powerful antiviral and antibacterial properties. Carthamus caeruleus is a plant that has antibacterial and antioxidant activity due to the presence of an acetylenic compound, Carlina oxide. The aim of this work was to provide for the first time the chemical modifications to the structure of Carlina oxide and the in-silico study of these analogues. Materials and Methods:: The essential oil of Carthamus caeruleus was extracted by steam distillation in a Clevenger-type apparatus. Carlina oxide component was separated by column chromatography. Five new analogues were synthetized and identified by spectroscopic analyses (RMN, IR and SM). Molecular docking simulation study was performed using Molecular Operating Environment software (MOE) on three enzymes of bacterial origin (Streptococcus pyogenesis and Enterococcus faecalis). Results:: Five new compounds derived from Carlina oxide were synthesized (IM8-IM12), and their structures were characterized by infrared (IR), 1H and 13C nuclear magnetic resonance (NMR). The new synthesized compounds were evaluated as mSpeB, DHFR from Enterococcus faecalis and DNA gyrase inhibitors by a docking analysis using MOE. These results show interesting ligand interactions with the three enzymes, and the best result was attributed to the complexes formed with IM9, which had the lowest score. Conclusion:: In fact, these new compounds could lead to powerful approaches for the research and development of new antibiotics.

Pharmacological features and chemical compounds derived from Solanum xanthocarpum are often investigated. S. xanthocarpum has been widely used to treat a variety of ailments as traditional medicine. Different parts of the plant are being studied to find more new uses for the herb. Xanthine oxidase inhibition is important in many vascular, renal, and bone disorders as this super enzyme causes an increase in uric acid formation and oxidative stress. With this perspective and current literature, further studies are required to be conducted to highlight new features that may be derived from the plant. This study aimed to explore the fruits of Solanum xanthocarpum for their phytochemical constituents and their xanthine oxidase inhibitory activity. Fruits from S. xanthocarpum were identified and collected. We performed alcoholic extraction in the Soxhlet apparatus and fractionation using column chromatography. Furthermore, we analyzed phytochemical properties using fingerprinting chromatography, NMR (Nuclear magnetic resonance), Mass-spectrometry, Ultraviolet (UV), and infrared (IR) spectroscopy. The NMR spectrum revealed new chemical moieties which were validated using mass spectrometry. Later on, we conducted bioassays for xanthine oxidase Inhibitory activity on individual fractions. Three new chemical compounds were discovered (Eicosa -11, 14-dienoic acid, Docosa-7, 10, 13, 16, 19-pentanoic acid, and Glyceryl Tri Palmitoleate). These compounds were fatty acids in nature. Bioassay results obtained were positive and encouraging. Our study findings provide evidence of new chemical compounds that can be derived from Solanum xanthocarpum and can be used to treat renal diseases and gout by inhibiting excessive enzyme catalyzation of xanthine oxidase. The results suggest S. xanthocarpum as a possible candidate for a new therapeutic approach.