Comparing audio- and video-delivered instructions in dispatcher-assisted cardiopulmonary resuscitation with drone-delivered automatic external defibrillator: a mixed methods simulation study

This study compared first responders’ cardiopulmonary resuscitation (CPR) performance when a dispatcher provides audio instructions only and when both audio and video instructions are given. In the simulation, an automatic external defibrillator (AED) was delivered via drone in response to a cardiac arrest occurring outside a hospital setting. Participants’ qualitative experiences were also explored.An exploratory sequential mixed methods design was used. AEDs were delivered to college students via drone with one group receiving both audio and video instructions and the other receiving audio-only instruction, and differences in CPR performance and accuracy were compared. After completion, focus group interview data were collected and analyzed. Video-based instruction was found to be more effective in the number of chest compressions (p < 0.01), chest compression rate (p < 0.01), and chest compression interruptions (p < 0.01). The accuracy of the video group for the chest compression region was high (p = 0.05). Participants’ experiences were divided into three categories: “unfamiliar but beneficial experience,” “met helper during a desperate and embarrassing situation,” and “diverse views on drone use.” Our results lay the groundwork for a development plan for providing emergency medical services using drones, as well as the preparation of guidelines for dispatchers on the provision of video instructions.

What Solar–Terrestrial Link Researchers Should Know about Interplanetary Drivers

One of the most promising methods of research in solar–terrestrial physics is the comparison of the responses of the magnetosphere–ionosphere–atmosphere system to various types of interplanetary disturbances (so-called “interplanetary drivers”). Numerous studies have shown that different types of drivers result in different reactions of the system for identical variations in the interplanetary magnetic field. In particular, the sheaths—compression regions before fast interplanetary CMEs (ICMEs)—have higher efficiency in terms of the generation of magnetic storms than ICMEs. The growing popularity of this method of research is accompanied by the growth of incorrect methodological approaches in such studies. These errors can be divided into four main classes: (i) using incorrect data with the identification of driver types published in other studies; (ii) using incorrect methods to identify the types of drivers and, as a result, misclassify the causes of magnetospheric-ionospheric disturbances; (iii) ignoring a frequent case with a complex, composite, nature of the driver (the presence of a sequence of several simple drivers) and matching the system response with only one of the drivers; for example, a magnetic storm is often generated by a sheath in front of ICME, although the authors consider these events to be a so-called “CME-induced” storm, rather than a “sheath-induced” storm; (iv) ignoring the compression regions before the fast CME in the case when there is no interplanetary shock (IS) in front of the compression region (“sheath without IS” or the so-called “lost driver”), although this type of driver generates about 10% of moderate and large magnetic storms. Possible ways of solving this problem are discussed.

Influence of the cross-sectional shape and length of the compressible sections on the characteristics of a linear peristaltic pump

In the overview part of the work, the most common existing designs of pumps of the peristaltic principle of operation, as well as the main areas of their application, are briefly presented. The main part of the work is devoted to the study of the influence on the operation of a peristaltic pump with a linearly arranged tube of the shape of the cross-section of the tube in the region of the compressible sections, as well as the ratio of the sizes of the release elements periodically compressing the pump tube in the transverse direction. The studies were carried out through numerical experiments in the STAR-CCM + program, which is based on the control volume method. As a result of the carried out calculations, it was found that the use of protrusions on the inner surface of the tube gives a positive effect if the protrusions have a special curvilinear shape with a smooth transition near the inner surface of the tube, and the increase in the generated pressure and feed is greater if the protrusions are present only in the compression region tube with the first squeeze element. In this case, the discharge angle of the pump characteristic changes so that a positive effect is not observed in the region of small values of the generated pressure. The study of the influence of different ratios of the lengths of the compressible sections of the tube on the flow and pressure created by the pump showed that for the incomplete compression of the pump tube investigated in the work, the use of squeeze elements of the same length is favorable. Both for a tube without protrusions and for a tube with protrusions, the use of a second squeeze element of greater or lesser length than the length of the remaining squeeze elements with the same total length of all three compressible sections leads to an increase in leakage when the tube is not fully compressed, and thus reduces the pump flow.

Characterisation of Hybrid Carbon Glass Fiber Reinforced Polymer (C/GFRP) of Balanced Cross Ply and Quasi Isotropic under Tensile and Flexural Loading

This study is performed to characterize composite material of hybrid carbon glass reinforced polymer (C/GFRP) of two (2) types; namely balanced cross ply and quasi isotropic subjected to tensile and flexural loading. The mechanical testing performed on the hybrid composite as per ASTM standard and aimed to extract the mechanical properties related to tensile and flexural. The failure modes associated with the rupture of the composites/hybrid composites samples under tensile and three-point bending were assessed via JEOL 6010 Plus Scanning Electron Microscopy (SEM) instrument. The combination of GFRP lay-up at 0° at tensile side, GFRP lay-up 90° at compression side and ±45° lay-up of CFRP at shear/compression region enable the hybrid composite cross ply 8 to record the highest flexural strength. The substitution of 0° GFRP with 0° layup CFRP together with layup of 90° GFRP in hybrid composite cross ply 4, matrix/resin dominated layup acts as stress reliever in compression region during flexural loading taking place. This has induced to the increase of flexural strength, which observed to improve its original constituent of cross ply 2 (balanced cross ply GFRP). The factor of layup GFRP at transverse direction has enabled hybrid composite to possess a higher tensile modulus and to record considerably high tensile strength. The role of GFRP layup in enhancing the strain to failure in tensile and its role as a reliever in improving flexural strength during flexural loading has been tested and justified in this experiment.

A critical look at studying the interplanetary drivers of the magnetospheric disturbances

&lt;p&gt;Although the main types of solar wind (the so-called interplanetary drivers), which may contain the southward component of the interplanetary magnetic field (Bz &lt;0) and cause disturbances in the magnetosphere, have long been known, it has only recently been discovered that different types of drivers cause a different reaction of the magnetosphere for identical field variations (Borovsky and Denton,2006, Yermolaev et al., 2013). This discovery led to a significant increase in the number of investigations studying the response of the magnetosphere-ionosphere system to various drivers. At the same time, the number of incorrect approaches in this direction of research has increased. These errors can be attributed to 4 large classes. (1) First class includes works whose authors uncritically reacted to previously published works and use incorrect results to identify types of drivers. (2) Some authors independently incorrectly identified driver types. (3) Very often, authors associate the perturbation of the magnetosphere-ionosphere system caused by a complex driver (a sequence of single drivers) with one of the drivers, ignoring the complex nature. For example, a magnetic storm is often caused by a compression region Sheath in front of an interplanetary CME (ICME), but the authors consider the ICME to be a cause of disturbance, not Sheath. (4) Finally, there is a &amp;#8220;lost driver&amp;#8221; of magnetospheric disturbances: some authors simply do not consider the Sheath compression region before ICME if there is no interplanetary shock (IS) before Sheath, although this type of driver, &amp;#8220;Sheath without IS&amp;#8221;, generates about 10% of moderate and strong geomagnetic storms (Yermolaev et al., 2017, 2020). These errors lead to numerous mistakes and incorrect conclusions.&lt;br&gt;The work is supported by the RFFI grant 19-02-00177&amp;#1072;.&amp;#160;&lt;/p&gt;&lt;p&gt;References&lt;br&gt;Borovsky, J. E., and M. H. Denton (2006), Differences between CME&amp;#8208;driven storms and CIR&amp;#8208;driven storms, J. Geophys. Res., 111, A07S08, doi:10.1029/2005JA011447&lt;/p&gt;&lt;p&gt;Yermolaev, Y. I., N. S. Nikolaeva, I. G. Lodkina, and M. Y. Yermolaev (2012), Geoeffectiveness and efficiency of CIR, sheath, and ICME in generation of magnetic storms, J. Geophys. Res., 117, A00L07, doi:10.1029/2011JA017139&lt;/p&gt;&lt;p&gt;&lt;br&gt;Yermolaev, Y.I., Lodkina, I.G., Nikolaeva, N.S. et al. (2017), Some problems of identifying types of large-scale solar wind and their role in the physics of the magnetosphere, Cosmic Res. 55: 178. https://doi.org/10.1134/S0010952517030029&lt;/p&gt;&lt;p&gt;Yermolaev, Y.I., Lodkina, I.G., et al. (2020), Some problems of identifying types of large-scale solar wind and their role in the physics of the magnetosphere. 4. Lost driver, Cosmic Res. 59, in press&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;

The application of the elastic tube with the specific cross section form in the linear peristaltic pump

The article presents a study of the tube form influence on performance of the peristaltic pump with the linearly placed tube and several pushers squeezing it in the transverse direction. The coupled numerical simulation of fluid flow and solid domain deformation was carried out using the software, based on the finite volume method. The cross sections with surface protrusions of two different types are considered for numerical simulation. The simulation results have shown that protrusions without a smooth transition at the tube walls reduce the compression ratio of the tube and therefore yield the flow rate reduce. Protrusions with s smooth transition at the tube walls on the contrary increase the flow rate in a high pressure range. Higher flow rate and pressure values achieved in the case of surface protrusions placed in the first compression region of the tube only. Comparison of pump characteristic curves shows that the use of tube surface protrusions can significantly increase the energy efficiency of the pump.

THEORETICAL SOLUTION TO THE PROBLEM OF THE PROPAGATION OF STRESSES IN SOILS WHEN EXPOSED TO AXISYMMETRIC RADIAL EFFECTIVE STRESSES

The article discusses issues related to the determination of radial and tangential stresses in the well in the presence of gravitational pressure of the soil mass. The basis is the well-known theoretical solutions of the axisymmetric problem of a thick-walled pipe, namely, the Lame solution. The action of two pressures is considered: the internal pressure р 1 and the external р 2, uniformly distributed over the inner and outer surfaces of the hollow cylinder. As a result of theoretical studies, it was found that the use of the elasticity theory equation to determine radial and tangential stresses in a well with an internal effective pressure s r = р 1, leads to its slow horizontal decrease, which is not observed in practice. The authors proposed solutions that make it possible to obtain closer values of s r for soils. It was also experimentally proved that the value of the active compression region for soil wells with internal effective pressure р 1 is almost two times higher than the value obtained for stamp tests in half-space conditions. The authors obtained mathematical expressions of the strength and stability of wells from gravitational loads of soil.

Динамика оптических и физиологических свойств кожи человека in vivo в процессе ее компрессии

The results of the study of dynamics of the optical and physiological properties of the human skin in vivo when applying and removing external mechanical compression based on the analysis of temporal changes in the diffuse reflectance spectra of human skin in the range of 400–2000 nm are presented. In the spectrum range 500–600 nm (hemoglobin absorption areas), the temporal dynamics of the skin reflectance coefficients show that skin compression leads to an exponential decrease in the blood content in the skin, while the average time for displacing blood from the compression region is about 4–5 min. After the compression is relieved, the blood filling of the skin is restored exponentially during a time of about 30 s. In the spectral range 700–2000 nm, the peculiarity of the skin reflectance coefficients after skin compression is applied is their monotonic decrease according to a two-exponential law with characteristic times of the order of 10 s and several minutes, which can be caused by the displacement of free and bound water from the compression region.