Search for variability in Newton’s constant using local gravitational acceleration measurements

In a recent work, Dai [1] searched for a variability in Newton’s constant G using the IGETS based gravitational acceleration measurements. However, this analysis, obtained from χ 2 minimization, did not incorporate the errors in the gravitational acceleration measurements. We carry out a similar search with one major improvement, wherein we incorporate these aforementioned errors. To model any possible variation in the gravitational acceleration, we fit the data to four models: a constant value, two sinusoidal models, and finally, a linear model for the variation of gravitational acceleration. We find that none of the four models provides a good fit to the data, showing that there is no evidence for a periodicity or a linear temporal variation in the acceleration measurements. We then redid these analyses after accounting for an unknown intrinsic scatter. After this, we find that although a constant model is still favored over the sinusoidal models, the linear variation for G is marginally preferred over a constant value, using information theory-based methods.

Structural analysis on the basis of effect of molybdenum on the Pr2O3 doped lead borate glasses series-II

This paper explains the role of molybdenum on the structural analysis of the investigated rare earth ion Pr3+ doped, lead borate (75 PbO — [25 – (x+y)]B2O3—yMoO3—xPr2O3) glass matrix has been discussed using the relation between Tg and structural parameters like average cross-link density ( n ¯ c ), average stretching force constant (F) and the number of bonds per unit volume (nb). Densities, molar volume have been measured as a function of MoO3 content. Linear variation in density and in the molar volume has been observed and is credited to the role of MoO3 in the investigated glasses. Based on the properties like good stability and bond strength, investigated glasses possibly suitable for the design of optoelectronic devices.

Azetidinium Lead Halide Ruddlesden–Popper Phases

A family of Ruddlesden–Popper (n = 1) layered perovskite-related phases, Az2PbClxBr4−x with composition 0 ≤ x ≤ 4 were obtained using mechanosynthesis. These compounds are isostructural with K2NiF4 and therefore adopt the idealised n = 1 Ruddlesden–Popper structure. A linear variation in unit cell volume as a function of anion average radius is observed. A tunable bandgap is achieved, ranging from 2.81 to 3.43 eV, and the bandgap varies in a second-order polynomial relationship with the halide composition.

Pressure fluctuation study in the stages of a multistage pump at best efficiency points under various operating speeds

The interaction between the rotor and stator is a major source of high amplitude pressure fluctuation and flow-induced vibration in multistage centrifugal pumps. The pressure fluctuation is detrimental to the reliable operation of pumps. The sensitivity of vibration is severe if the number of stages is more. In the present experimental study, a vertical multistage centrifugal submersible pump is used to measure the pressure fluctuation level at Best Efficiency Points (BEP) and to determine the influence of stage and operating speed on pressure fluctuation. For this purpose, pressure fluctuation signals were captured at the delivery side of the pump at BEP at various speed settings. The characteristics of pressure fluctuation at BEP at various operating speeds were studied with the help of spectra, i.e., in the frequency domain. The amplitude variation of pressure fluctuation with harmonics of vane passing frequency at stages were studied. Results have indicated that variation of pressure fluctuation with stage and speed exhibited a non-linear variation. In addition, such a pressure fluctuation study will be helpful to modify the design to obtain a uniform pressure distribution in the stages of a multistage pump.

Azetidinium lead halide Ruddlesden-Popper phases

A family of Ruddlesden-Popper (n = 1) layered perovskite-related phases, Az2PbClxBr4-x with composition 0 ≤ x ≤ 4 were obtained using mechanosynthesis. A linear variation in unit cell volume as a function of anion average radius is observed. A tunable bandgap is achieved, ranging from 2.81 to 3.43 eV, and the bandgap varies in a second order polynomial relationship with the halide composition.

Biochemical blood values of ewes in the first month of lactation and their relation to milk productivity

Milk productivity and a set of biochemical blood parameters characterizing the metabolic status were studied in suck-ling semi-fine-fleece wool-and-meat ewes of the first month of lactation (n = 80) of the experimental herd of L. A. Kaneva farm in the Ust-Tsilemsky district of Komi Republic. The ewes with lambs were kept in the same room in similar conditions of keeping and feeding. To characterize the metabolic type, all controlled ewes were divided into three groups depending on the level of their milk productivity. There was no significant linear variation of the metabolites during the transition from group to group. As a result of studying the associations between milking capacity and biochemical parameters of blood serum within the groups, in high-milking ewes of group 3, statistically significant correlations were found with the level of urea (r = -0.47, P < 0.05), and the activity of alkaline phosphatase (r = 0.40, P < 0.05), as well as not reliable, but relatively high coefficient with glucose (r = 0.36, P > 0.05). As a result of combining urea, alkaline phosphatase (AP) and glucose into one complex index – AP*glucose/urea, it was possible to increase significantly the correlation coefficient with milking capacity to 0.61 at P < 0.001. The obtained results indicate that high-milking ewes have metabolic features developed as the result of the body's adaptation to intensive lactation activity. These features are expressed in the interrelated fluctuation of three metabolites – urea, AP and glucose. It is assumed that urea indicates more efficient assimilation of nitrogen of the diet with an increase in milk productivity, intense inclusion of amino groups into metabolic processes necessary for the synthesis of milk proteins. Glucose and alkaline phosphatase indicate an increase in the intensity of cellular metabolism.

Progressive Polytypism and Bandgap Tuning in Azetidinium Lead Halide Perovskites

<div><div><div><p>Mixed halide azetidinium lead perovskites AzPbBr_3-<i>x</i>X<i>_x</i> (X = Cl or I) were obtained by mechanosynthesis. With varying halide composition from Cl- to Br- to I-; the chloride and bromide analogs both form in the hexagonal 6H polytype while the iodide adopts the 9R polytype. An intermediate 4H polytype is observed for mixed Br/I compositions. Overall the structure progresses from 6H to 4H to 9R perovskite polytype with varying halide composition. Rietveld refinement of the powder X-ray diffraction patterns revealed a linear variation in unit cell volume as a function of the average radius of the anion, which is not only observed within the solid solution of each polytype (according to Vegard’s law) but extends uniformly across all three polytypes. This is correlated with a progressive (linear) tuning of the bandgap from 3.41 to 2.00 eV. Regardless of halide, the family of azetidinium halide perovskite polytypes are highly stable, with no discernible change in properties over more than 6 months under ambient conditions</p></div></div></div>

Progressive Polytypism and Bandgap Tuning in Azetidinium Lead Halide Perovskites

<div><div><div><p>Mixed halide azetidinium lead perovskites AzPbBr_3-<i>x</i>X<i>_x</i> (X = Cl or I) were obtained by mechanosynthesis. With varying halide composition from Cl- to Br- to I-; the chloride and bromide analogs both form in the hexagonal 6H polytype while the iodide adopts the 9R polytype. An intermediate 4H polytype is observed for mixed Br/I compositions. Overall the structure progresses from 6H to 4H to 9R perovskite polytype with varying halide composition. Rietveld refinement of the powder X-ray diffraction patterns revealed a linear variation in unit cell volume as a function of the average radius of the anion, which is not only observed within the solid solution of each polytype (according to Vegard’s law) but extends uniformly across all three polytypes. This is correlated with a progressive (linear) tuning of the bandgap from 3.41 to 2.00 eV. Regardless of halide, the family of azetidinium halide perovskite polytypes are highly stable, with no discernible change in properties over more than 6 months under ambient conditions</p></div></div></div>

Digital imaging of the oil permeation mechanism in an oleophobic textile

Resistance of military clothing to oil permeation is important for effective protection against chemical warfare. In this paper, while a military textile is rendered oleophobic (oil contact angle ≈ 120°) through plasma-assisted deposition of perfluorodecyl acrylate (PFAC8), permeation of the textile by silicon oil is observed. Using high-definition digital imaging, we study the oil permeation dynamics, rationalize the permeation with a plausible mechanism and identify the threshold textile pore size for prevention of the permeation. We find that oil permeates defects of PFAC8 textiles. Our data suggests a linear variation for oil permeation volume ΔV with time t and implies a gravity-driving permeation mechanism. The mechanism comprises three stages involving merging and propagation of oil–yarn contact lines. The threshold pore size dm scales with σ/ P, where σ is the oil surface tension and P is the hydrostatic head exerted by the oil drop. The paper indicates the importance of an undamaged textile structure to ‘robust’ oil resistance.