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A selective and sensitive new reversed-phase method was developed and validated by using Waters Acquity UHPLC system coupled with Waters Micromass Quattro PremierXE (MS/MS) to identify and quantify the genotoxic impurity 2-(2-chloroethoxy) ethanol at trace level (∼2.0 ppm) in quetiapine fumarate. The method used positive ion electrospray ionization with a multiple reaction monitoring detection mode using ACE3 C18(100 mm × 4.6 mm × 3.0 µm) column. For analysis, an isocratic program was developed using 0.01 M ammonium acetate in Milli-Q water (mobile phase A) and methanol (mobile phase B) in 20:80v/v ratio. Elution of 2-(2-chloroethoxy) ethanol was monitored using triple quadrupole mass spectrometer with an injection volume of 10 μl, a column oven temperature of 40 °C, an auto-sampler temperature of 15 °C, and flow rate of 0.5 mL/min. The retention time of 2-(2-chloroethoxy) ethanol was observed at 2.38 min. The LOQ and LOD were determined at concentrations of 0.235 ppm and 0.070 ppm respectively. The correlation coefficient R2 was 0.9983 and the percent recoveries of method range from 98.1% to 114.0%. The method was successfully validated according to International Council for Harmonization requirements (ICH Q2(R1) and ICH M7(R1)) for genotoxic impurities. The method was sensitive, selective, accurate and precise and therefore can be used for identification and quantification of genotoxic impurity 2-(2-chloroethoxy) ethanol in quetiapine fumarate. [ABSTRACT FROM AUTHOR]

The Corid-19 pandemic has adversely affected all the fields in the w'orld including education. During this epidemic it is noticed that the majority of young learners lost their basic literacy and numeracy skills. IIi order to identify the standards of the students who are studying II to X classes in all the Primary. Upper Primary and Secondary schools functioning under Government management. the Government of Andhra Pradesh has conducted a Baseline assessment survey on 22nd and 26th July 2022 by employing the Oral and Written tools recommended by Pratham Foundation. The foundation annually assess the country-wise academic standards of students and publishes its results in the form of Annual Status of Education Report (ASER). The researchers collected the baseline assessment results of the Mathematics subject of Class VI from the AP Model Schools and KGBVs. From the results, 60 VI class students who are in the level of 'Not having Basic Numeracy Skills' were considered the studys sample. To bring the sample-s standard to the next level of learning for ensuring Foundational Numeracy. the researchers followed the Jigsaw Method of Cooperative learning strategy for 40 instructional hours. The investigators developed Lessoii transcripts and Achievement tests in Mathematics for both pre and post-test levels. Both the pre and post-test results were analysed by employing Mean. SD. Paired sample t-test and Correlation. The results indicate that Jigsaw Cooperative learning strategy has effectively improved the Foundational numeracy levels (Mathematical academic standards) of VI class students. [ABSTRACT FROM AUTHOR]

In the present work, the effect of Al content (0, 3, 5, 10, 15 wt-%) on the microstructure, mechanical and wear properties of Cu was systematically studied. Interestingly, the core–shell microstructure was observed in the Cu–Al alloys or Al bronzes with different layers of α-Cu, and intermetallic phases. The Cu–Al alloys displayed good compressive yield strength of 174–653 MPa, in particular, the Cu samples with Al (upto 10 wt-%) did not show fracture upto strain of 40%. Abrasion wear was the predominant wear mechanism in pure Cu and Cu–Al alloys after sliding against SiC. The Al addition to Cu drastically decreased the wear rate (198 ×10−3 to 3.8 ×10−3 mm3 N–1m–1) of Cu–Al alloys. The present work demonstrates the advantage of the addition of (5–10 wt-%) Al to Cu in achieving good combination of mechanical and wear properties of Cu–Al alloys. [ABSTRACT FROM AUTHOR]

[Display omitted] • All the Cu samples could be densified to more than 92.16% • The microstructure of hot-pressed Cu-Al (mixed) alloys exhibited core-rim structure. • The conductivity of Cu varied between 97.0% and 12.3% IACS. The present work elucidates the effect of powder processing conditions (milling/mixing) and conductive alloying element (Al: aluminium) and ceramic (ZrB 2 : zirconium diboride) reinforcement addition on the densification, microstructure and electrical conductivity of copper (Cu) processed via hot pressing route. Disregard of alloying element/reinforcement/content or powders preparation method, the density of Cu materials varied between 92.16 and 99.76% ρ th (theoretical density) after hot pressing at a low temperature of 500 °C. In case of Cu-Al alloys, the powder processing method significantly influenced its microstructure and conductivity. Particularly the Cu-Al alloys processed using mixed powders consisted of various phases Cu, α-Cu, γ 1 (Cu 9 Al 4), δ (Cu 3 Al 2), ζ 1 (Cu 4 Al 3), η 2 (CuAl) and θ (CuAl 2) and the Cu alloys prepared using milled powders composed of either only α-Cu or α-Cu and γ 1 (Cu 9 Al 4) phases (depending on the Al content). Whereas, only Cu and ZrB 2 phases were observed with the Cu-ZrB 2 composites processed using either milled or mixed powers. In case of Cu-Al alloys, the hardness (0.88–3.41 GPa) and strength (540.30–1120.18 MPa) of Cu increased with the addition of Al. Interestingly, the hardness (0.88–2.55 GPa) and strength (508.50–970.60 MPa) of Cu increased upto 5 wt% ZrB 2 and then they lowered with further addition of ZrB 2. In particular, the hardness and strength of Cu-ZrB 2 composites are lower than Cu-Al alloys reflecting the effectiveness of solid solution strengthening in the Cu alloys as compared to dispersion strengthening mechanism in Cu composite. The pure Cu prepared using milled powders exhibited low conductivity (75.70% IACS) than Cu processed using as-received/un-milled powders (97.00% IACS). Also, the Cu-ZrB 2 composites measured with better electrical conductivity than Cu-Al alloys. Depending on the milling conditions and alloying/reinforcement amount, the conductivity of Cu-ZrB 2 composites varied between 44.10 and 88.70% IACS. [ABSTRACT FROM AUTHOR]

The present work investigates the effect of (0–10 wt%) ZrB 2 reinforcement on densification, mechanical, tribological and electrical properties of Cu. The consolidation of Cu–ZrB 2 samples was carried out using a hot press (temperature: 500 °C, pressure: 500 MPa, time: 30 min, vacuum pressure: 1.3 × 10-2 mbar). The bulk density of the hot-pressed Cu composites decreased from 8.84 g/cc to 8.16 g/cc and the relative density of samples lowered from 98.6% to 92.1% with the addition of ZrB 2. The incorporation of hard ZrB 2 (up to 10 wt%) improved the hardness of Cu (1.32–2.55 GPa). However, the yield strength and compressive strength of Cu composites increased up to 5 wt% ZrB 2 , and further addition of ZrB 2 lowered its strength. The yield strength of Cu samples varied from 602 to 672 MPa and the compressive strength between ~834 and 971 MPa. On the other hand, the coefficient of friction (COF) (from 0.49 to 0.18) and wear rate (from 49.3 × 10-3 mm3/Nm to 9.1 × 10-3 mm3/Nm) of Cu–ZrB 2 samples considerably decreased with the addition of ZrB 2. Significantly low wear was observed with Cu-10 wt% ZrB 2 (Cu-10Z) samples, which is 5.41 times less than pure Cu. As far as the wear mechanisms are concerned, in pure Cu, continuous chips (wear debris) were formed during sliding wear by plowing. Whereas the major amount of material loss was occurred due to the plowing mechanism with discontinuous and short chip formation for Cu–ZrB 2 composites. The electrical conductivity of Cu–ZrB 2 samples decreased from 75.7% IACS to 44.1% IACS. In particular, Cu with ZrB 2 (up to 3 wt%) could retain the conductivity of 66.8% IACS. This study reveals that the addition of ZrB 2 (up to 3 wt%) is advantageous to have a good combination of properties for Cu. [ABSTRACT FROM AUTHOR]

The present work explores the effect of aluminium (Al: 0, 3, 5, 10 & 15 wt%) addition on wear behaviour of copper (Cu). The Cu-Al alloys were fabricated via mechanical alloying and high-pressure hot press. In fact, high-pressure processes are beneficial as they result in obtaining fine microstructure and property enhancement. Depending on the amount of Al, the microstructure of hot pressed samples (Cu with Al up to 5 wt%) consisted of copper-rich solid solution phase (Cu 0.92 Al 0.08) and the presence of both Cu 0.78 Al 0.22 and Cu 9 Al 4 intermetallic phases for Cu containing high amount of Al (≥10 wt%). The relative density of Cu-Al alloys varied between ∼95 and 98% and the hardness of Cu enhanced significantly from 1.32 to 6.16 GPa with Al content. The coefficient of friction (COF) (0.54 to 0.16) and wear rate (18.26 × 10−5 to 0.92 × 10−5 mm3/N-m) of Cu decreased with the addition of Al. A transition in wear mechanisms of Cu was observed with Al. In case of pure copper, adhesion was the major wear mechanism. Adhesion and tribo-oxidation controlled the wear of Cu alloyed with Al (up to 5 wt%). Oxide layer formation influenced the wear of Cu-10Al, while abrasion was the predominant wear mechanism for Cu-15Al. These results clearly indicate the advantage of large amount of Al addition to achieve better wear resistance of Cu. • Highly dense Cu-Al alloys were processed via powder metallurgy. • The hardness Cu enhanced significantly from 1.32 to 6.16 GPa with Al addition. • Both COF and wear rate of Cu decreased with the addition of Al. • Adhesion was the major mechanism for pure copper. • Adhesion and third body wear (wear debris/oxide layer) controls the wear of Cu alloyed with Al (up to 10 wt%). • Abrasion was the predominant wear mechanism for Cu-15wt% Al. [ABSTRACT FROM AUTHOR]

• Relatively higher density was achieved for hot pressed Cu and Cu-15Al alloy. • The hardness of Cu was significantly improved with the addition of Al. • Drastic reduction in corrosion of Cu with addition of 15 wt% Al. • The formation of protective layer improved corrosion resistance of Cu-15Al alloy. Higher density of 98.66 and 94.60% ρ th (theoretical density) was achieved for hot pressed Cu and Cu-15Al alloy, respectively. The microstructure of Cu-15Al alloy consists of α (Cu 0.78 Al 0.22) and γ 2 (Cu 9 Al 4) phases. The hardness of Cu was significantly improved (from 1.32 to 6.03 GPa) with the addition of Al. Drastic reduction in corrosion of Cu-15Al (1.6 mpy) when compared to pure Cu (20.7 mpy) was noticed despite the low densification of Cu-Al. The higher impedance of Cu-15Al alloy corroborates the formation of protective layer. This work demonstrates the efficacy of high amount of Al in improving corrosion resistance of Cu. [ABSTRACT FROM AUTHOR]

In the present work, hot press of Cu-15 wt% Al alloys was carried out in a vacuum environment at a sintering temperature of 500 °C for 30 min with varying pressure (100-500 MPa) to densify the alloys. Both the density and hardness of Cu alloys were significantly increased with increasing the hot press pressure. A maximum density of ~ 94.5% ρth (theoretical density) and microhardness of ~ 6.2 GPa was achieved for Cu-Al alloy after hot press at 500 °C with 500 MPa pressure application. The XRD, SEM-EDS analysis confirms the presence of solid solution α (Cu0.78Al0.22) and γ (Cu9Al4) inermetallic phases in the sintered samples. Maximum hardness of 7.88 GPa and elastic modulus of 177.35 GPa was measured for Cu-Al alloy using nano-indentation test. It must be noted that so far in the literature a maximum hardness of 4.9 GPa was reported for Cu-based materials. The alloy was also measured with a moderately high compressive yield strength (1019 MPa), compressive strength (1106 MPa), and a reasonable amount of strain (6.6%). The wear tests revealed that the Cu-15 Al alloy hot pressed at 500 MPa pressure can exhibit better wear properties. Low coefficient of friction (COF) of 0.15 and wear rate of 0.71 × 10−5 mm3/N-m was observed at a sliding speed of 0.25 m/s and high COF of 0.20 and wear rate of 4.33 × 10−5 mm3/N-m were noted with further increasing the sliding speed (1.25 m/s). Further microstructural characterization of worn surfaces reveals abrasion wear as the major dominant wear mechanism. The present work clearly demonstrates the use of a high amount of hot press pressure in achieving good sinter density for Cu-15 wt% Al alloys with superior hardness, better wear and compressive strength properties. [ABSTRACT FROM AUTHOR]

A new transition-metal-free, sodium metaperiodate (NaIO4)-mediated direct oxidation of methylarenes and benzylic bromides to the corresponding aromatic carboxylic acids is described. Under the same reaction conditions, benzylic alcohols are selectively oxidized to afford the corresponding aldehydes in good yields without undergoing overoxidation. Unprecedentedly, oxidation of benzyl bromide, toluene, or benzyl alcohol with NaIO4 underwent nuclear bromination followed by oxidation to give 4-bromobenzoic acid in 60–79% yields. [ABSTRACT FROM AUTHOR]

This constitutes the first crystallographic observation of hydrated Cu(II) ion retaining up to its third hydration layer which, along with the chair form water hexamer, builds up a unique water-cation layer. Moreover, an unprecedented supramolecular honeycomb network of [Cu(phen)3]2+units templated by Anderson polyoxometallate units occupy the intervening spaces between successive water layers. Complex 1is a rare example of parallel interpenetration of a 2D π–π network and a 3D pillar-layered hydrogen bonded network. [ABSTRACT FROM AUTHOR]

The effect of ZrB 2 (1, 3, 5, 10 wt%) reinforcement on two-body abrasion wear properties of Cu was studied using pin-on-disc wear tester. The relative density of Cu–ZrB 2 composites varied in the range between 96.0 and 99.7%, and in particular, relative density of copper was lowered with the addition of ZrB 2. Among all the composites, Cu–10ZrB 2 showed maximum hardness (1.25 GPa) and yield strength (261 MPa). However, the improvement of mechanical properties of Cu with ZrB 2 was marginal. On the other hand, the ZrB 2 addition significantly affected the wear properties of Cu. The steady-state coefficient of friction (COF) of Cu was reduced from 0.56 to 0.16 with the addition of ZrB 2. Pure Cu exhibited a high wear coefficient (17.33 × 10−2) due to its softness and high ductile nature. The abrasive wear resistance of Cu was considerably improved with the addition of ZrB 2 (up to 3 wt%) by resisting the cutting forces of SiC abrasives (counterbody). A low wear coefficient of 2.4 × 10−2 was evident for Cu–3ZrB 2 composites and the wear was reduced by 7.33 times compared to pure Cu. Further addition of ZrB 2 reinforcement lowered wear resistance of Cu composites. Nevertheless, the wear resistance of Cu composites was substantially better than pure Cu. The wear mechanisms were proposed based on microstructural analysis of worn surfaces of Cu–ZrB 2 composites, SiC emery paper (counterbody) and wear debris. The present study demonstrates the advantage of selecting ZrB 2 as reinforcement in improving the abrasion wear resistance of Cu. • The relative density of Cu–ZrB 2 composites varied in between 96.0 and 99.7%. • Cu–10ZrB 2 showed maximum hardness (1.25 GPa) and yield strength (261 MPa). • With the addition of ZrB 2 , the COF of Cu was reduced from 0.56 to 0.16. • Pure copper was measured with high wear coefficient (17.33 × 10−2). • Low wear coefficient (2.4 × 10−2) was evident for Cu–3ZrB 2 composites. [ABSTRACT FROM AUTHOR]

Organic molecules with the possibility of logic operations are highly useful building blocks for the development of molecule-based “intelligent” devices for information processing applications. We have designed herein a very simple bio-friendly chemosensor (LC) equipped with a rhodamine fluorophore moiety. This probe showed a chromo-fluorescence response profile for Al3+but a colorimetric response for Cu2+metal. The absorption responses of LCcaused by these metal ions along with the “OFF–ON–OFF” fluorescence behavior of an LC–Al3+complex towards EDTA were employed for the development of a three-input and one output combinatorial molecular system. Interactions of the mentioned metal ions with LCin controlled sequential experiments gave fluorescence responses, enabling us to fabricate a ‘key-pad-logic’ function. So, a single molecular system performing such multiple ‘Boolean’ operations not only simplifies the complexity of a chemical driven ‘Intelligence’ device but also enriches the security of such a device against information invasion due to the sequence controlled sensor–analyte interactions and may find potential applications in biocompatible molecular logic platforms. [ABSTRACT FROM AUTHOR]

Trans-1, [HNEt3][CoIII(LSe)2]·H2O and cis-1, [HNEt3][CoIII(LSe)2]·3H2O have been synthesized and characterized by single-crystal X-ray studies. The counter ion Et3NH+plays a crucial role in the crystal packing leading to the formation of two distinctly different supramolecular assemblies in the two complexes. In trans-1, Co-bisphenolate units and triethylamine molecules are arranged in a linear fashion leading to a supramolecular columnar assembly along the crystallographic a-axis. In this assembly, triethylammonium ions are sandwiched between successive Co-bisphenolate units and act as gluing agents joining Co-bisphenolate units on either side through C–Hπ interactions. In sharp contrast to trans-1, Co-bisphenolate units and triethylammonium ions in cis-1are arranged in a helical supramolecular assembly through similar C-Hπ interactions along the crystallographic b-axis. The SeSe van der Waals interactions may be responsible for the predominant occurrence of the cis- isomer. The cyclic voltammetric studies showed quasi-reversible waves for the cobalt(iii) → cobalt(ii) reductions with E1/2= 0.635 and 0.628 V vs.Ag/AgCl for cis-1(at ∼5 °C) and trans-1(at ∼ 25 °C), respectively. DFT calculations show that the trans-form is the thermodynamic product with higher stability than the cis- one, which is consistent with the variable temperature 1H NMR studies [ABSTRACT FROM AUTHOR]