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A classification -spaces of nonconstant curvature with respect to (nonhomothetic) Lie algebras of infinitesimal projective and affine transformations is given. [ABSTRACT FROM AUTHOR]

We study five-dimensional pseudo-Riemannian h-spaces of type . Necessary and sufficient conditions are determined under which is a space of constant (zero) curvature. Nonhomothetical projective motions in of nonconstant curvature are found, homotheties and isometries of the indicated spaces are investigated. Dimensions, basis elements, and structure equations of maximal projective Lie algebras acting in of nonconstant curvature are determined. As a result, the classification of h-spaces of type by (non-homothetical) Lie algebras of infinitesimal projective and affine transformations is obtained. [ABSTRACT FROM AUTHOR]

In this article, the scientific concept, phrases and obtained scientific research results related to the formation, implementation and management of the quality management system in production enterprises are analyzed and recommendations for the evaluation of the effectiveness are developed. The quality management system is a system that summarizes many years of experience of production enterprises and adopts all the positive world practices forcing enterprises to form certain quality practices and integrates all quality concepts into its philosophy.

Comprehensive measures are being implemented aimed at ensuring the comprehensive integration of production enterprises into world markets, increasing the quality and competitiveness of manufactured products, improving the quality management system and product production processes. This article discusses the main essence of the analysis of production processes at engineering enterprises based on statistical methods and the possibility of improving the effectiveness and efficiency of processes based on the fulfillment of the requirements for them. Statistical control of processes by monitoring the description of processes and products, focusing the possibility of processes on the creation of a quality product with a uniform demand, identifies the working procedure for managing the processes of constant production technology and allows to increase the efficiency of the process possibility. Statistical process control is not about checking whether parts are in good condition or not, but about anticipating and trying to prevent the production of poor quality parts. This is done by using control charts as a predictive tool to identify potential inconsistencies.

A seventh blind test of crystal structure prediction was organized by the Cambridge Crystallographic Data Centre featuring seven target systems of varying complexity: a silicon and iodine-containing molecule, a copper coordination complex, a near-rigid molecule, a cocrystal, a polymorphic small agrochemical, a highly flexible polymorphic drug candidate, and a polymorphic morpholine salt. In this first of two parts focusing on structure generation methods, many crystal structure prediction (CSP) methods performed well for the small but flexible agrochemical compound, successfully reproducing the experimentally observed crystal structures, while few groups were successful for the systems of higher complexity. A powder X-ray diffraction (PXRD) assisted exercise demonstrated the use of CSP in successfully determining a crystal structure from a low-quality PXRD pattern. The use of CSP in the prediction of likely cocrystal stoichiometry was also explored, demonstrating multiple possible approaches. Crystallographic disorder emerged as an important theme throughout the test as both a challenge for analysis and a major achievement where two groups blindly predicted the existence of disorder for the first time. Additionally, large-scale comparisons of the sets of predicted crystal structures also showed that some methods yield sets that largely contain the same crystal structures., (open access.)

The thermodynamic stability of the furoxan ring annullated with 1,2,3,4-tetrazine 1,3-dioxide cycle was studied. Crystal structure prediction based on global energy minimization in the framework of the atom-atom potential functions method was performed for isomeric furoxano-tetrazinedioxides (FuxTDOs): [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 1,5,7-trioxide (1) and [1,2,5]oxadiazolo[3,4-e][1,2,3,4]tetrazine 1,4,6-trioxide (2). The Coulomb energy was calculated with advanced point charge models fitted with high accuracy to the molecular electrostatic potentials of these molecules. The pressure and velocity of detonation of compounds 1 and 2 were estimated using the calculated enthalpy of formation and predicted molecular crystal density, which allows us to consider these compounds as high energetic materials.

There is conflicting evidence regarding the morphology and orientation of the cervical ligament (CL) and interosseous talocalcaneal ligament (ITCL). The morphology of the CL and its relationship to the ITCL were studied to obtain an understanding of these structures. Twenty-six feet (13 left, 13 right) were obtained from formalin-fixed cadavers (14 females, four males) with the mean standard deviation (SD) age at death 80.9 (12.9) years. All measurements were made with a digital caliper. The length and width of the foot, the width and height of the talus, were measured. The talus was cut coronally to expose the ITCL and qualitative observations were noted. The mean (SD) heights and widths of the CL at the anterior, posterior, superior, and inferior points were 8.27 (2.52), 13.95 (5.96), 9.15 (2.45), and 11.90 (4.30) mm, respectively. The mean (SD) thicknesses of the CL at the superoanterior, superoposterior, inferoanterior, inferoposterior, and central points were 0.62 (0.24), 1.05 (0.30), 0.70 (0.26), 1.20 (0.34), and 0.97 (0.31) mm, respectively. The fibers of the CL are oriented at a slight superoanterior to inferoposterior angle, whereas the fibers of the ITCL are oriented in a slight superomedial to inferolateral angle. The fibers of the CL and ITCL overlap inside the tarsal sinus with the CL positioned anteriorly, which helps to distinguish the two ligaments. In this study, we identified the morphometrics of the CL and described the CL and ITCL qualitatively. These results are relevant to introducing innovative techniques for reconstructive surgery of the subtalar ligaments in order to repair, for example, subtalar instability., Competing Interests: The authors have declared that no competing interests exist.