Sustainable synthesis of cyclic carbonates from bio‐based polyether polyol: the structure characterization,rheological behaviour and thermal properties

The cycloaddition of CO₂ to epoxides represents a green efficient method to form bis(cyclic carbonate)s. The main purpose of the work reported in this paper was to examine the effect of the gas flow rate (20, 40, 60 and 100 mL min^–1) during carbonation on the conversion yield, chemical structure, rheological behaviour and thermal properties of the prepared compounds. A series of new bis(cyclic carbonate)s was obtained from bio‐based polyether polyol. The syntheses were performed in the absence of toxic solvents and the process did not require the use of elevated pressure. The progressive structural changes and the presence of characteristic chemical groups were monitored by attenuated total reflection Fourier transform infrared spectroscopy. The characterization of the structure by ¹H NMR and ¹³C NMR also confirmed the formation of cyclic carbonate moieties. The non‐Newtonian behaviour and the optimal mathematical model (Herschel–Bulkley) were verified by rheological measurements. The materials obtained could be used as a chemical intermediate to synthesize advanced materials based upon polyurethanes without using isocyanates. © 2019 Society of Chemical Industry     

Effect of Acute Sprint Exercise on Myokines and Food Intake Hormones in Young Healthy Men

Physical exercise is known to influence hormonal mediators of appetite, but the effect of short-term maximal intensity exercise on plasma levels of appetite hormones and cytokines has been little studied. We investigated the effect of a 30 s Wingate Test, followed by a postprandial period, on appetite sensations, food intake, and appetite hormones. Twenty-six physically active young males rated their subjective feelings of hunger, prospective food consumption, and fatigue on visual analogue scales at baseline, after exercise was completed, and during the postprandial period. Blood samples were obtained for the measurement of nesfatin-1, ghrelin, leptin, insulin, pancreatic polypeptide (PP), human growth factor (hGH) and cytokine interleukin-6 (IL-6), irisin and plasma lactate concentrations, at 30 min before exercise, immediately (210 s) after exercise, and 30 min following a meal and at corresponding times in control sedentary males without ad libitum meal intake, respectively. Appetite perceptions and food intake were decreased in response to exercise. Plasma levels of irisin, IL-6, lactate, nesfatin-1 and ghrelin was increased after exercise and then it was returned to postprandial/control period in both groups. A significant rise in plasma insulin, hGH and PP levels after exercise was observed while meal intake potentiated this response. In conclusion, an acute short-term fatiguing exercise can transiently suppress hunger sensations and food intake in humans. We postulate that this physiological response involves exercise-induced alterations in plasma hormones and the release of myokines such as irisin and IL-6, and supports the notion of existence of the skeletal muscle–brain–gut axis. Nevertheless, the detailed relationship between acute exercise releasing myokines, appetite sensations and impairment of this axis leading to several diseases should be further examined.     

电弧炉粉尘等温还原的动力学研究

为使还原条件与实际电弧炉生产相接近,在等温条件下对电弧炉粉尘球团的还原过程动力学进行了研究。电弧炉粉尘与还原剂碳和粘接剂石灰均匀混合后制粒,经干燥后将球闭置于恒定温度的加热炉中,利用电子称定时对球团重量进行检测。金属还原率的计算中,考虑了球团的失重、铅和锌在高温下挥发。经研究,电弧炉粉尘的还原分为二个阶段,还原初期由化学反应控制而还原后期由扩散控制,并建立了每一阶段的还原动力学方程,确定了有关的动力学参数表观活化能和频率因子。     

Relaxation processes and intermolecular interactions in PVME hydrogels in sub-zero temperatures: Glass transition and pre-melting of ice

The phase transition observed by various methods in poly(vinyl methyl ether)/water systems at around 18 °C has been assigned by some investigators to the pre-melting of water and by others to a glass transition of the polymer. In this study, broadband dielectric spectroscopy and temperature modulated differential scanning calorimetry were used to identify this transition in radiationally crosslinked poly(vinyl methyl ether) hydrogels, as well as to analyse sub-zero relaxation processes in such a three-phase (polymer/ice/liquid water) system. The process at 18 °C was related to the pre-melting of water induced by the segmental motions of the polymer; however, it was seen to be one transition due to the cooperative motions of both compounds. The atypical (two regimes) temperature dependence of the segmental motion process was observed and was related to confinement of the polymer chains between ice clusters below approximately ?24 °C; furthermore, the main dielectric process of hexagonal ice was identified and a Maxwell-Wagner effect was observed.     

Teaching Multibody Dynamics at Warsaw University of Technology

The paper concerns the usage of the method of multibody systems (MBS) in teaching students at the Warsaw University of Technology. Research results from the MBS discipline are being used in several ways. Large-scale computer software is being used to illustrate lecture material, some MBS research results are included in lecture topics and independent courses are taught, based directly on MBS research. During senior courses, advanced software is also used as a computational tool as well as an integral part of Virtual Prototyping. The paper presents also several examples of student projects created with MBS.     

Inverse Analysis of Axisymmetrical Compression of HSLA Steel

The objective of the present work is to further explore the problem of selection of the flow stress function which will give the best agreement with experiments for a wide range of the Zener‐Hollomon parameter. Analysis of various flow stress functions was performed, with particular emphasis on the Zerilli‐Armstrong model. Inverse analysis was successfully applied to identify the flow stress model for microalloyed steels deformed in ferrite, two‐phase and austenite regions. Inverse method is applied to interpret the results of the axisymmetrical compression tests performed for HSLA steel samples on a Gleeble 3800 and Split Hopkinson Pressure Bar. Sensitivity analysis is performed based on local and global methods. The objective of the sensitivity analysis in the present study is the evaluation to what extent the selected coefficients in the rheological model influence the result of simulations. In the considered tests this result is represented by two dependent variables, the load and the shape of the sample (barrelling). It is confirmed that the Zerilli‐Armstrong equations should be applied at very high strain rates. Physical meaning is an advantage of this model. Difficulties with identification are the main disadvantage.     

A certain class of starlike functions

This paper presents a new class of functions analytic in the open unit disc, and closely related to the class of starlike functions. Besides being an introduction to this field, it provides an interesting connections defined class with well known classes. The paper deals with several ideas and techniques used in geometric function theory. The order of starlikeness in the class of convex functions of negative order is also considered here.     

Integrated Data Management for a Fleet of Search‐and‐rescue Robots

Search‐and‐rescue operations have recently been confronted with the introduction of robotic tools that assist the human search‐and‐rescue workers in their dangerous but life‐saving job of searching for human survivors after major catastrophes. However, the world of search and rescue is highly reliant on strict procedures for the transfer of messages, alarms, data, and command and control over the deployed assets. The introduction of robotic tools into this world causes an important structural change in this procedural toolchain. Moreover, the introduction of search‐and‐rescue robots acting as data gatherers could potentially lead to an information overload toward the human search‐and‐rescue workers, if the data acquired by these robotic tools are not managed in an intelligent way. With that in mind, we present in this paper an integrated data combination and data management architecture that is able to accommodate real‐time data gathered by a fleet of robotic vehicles on a crisis site, and we present and publish these data in a way that is easy to understand by end‐users. In the scope of this paper, a fleet of unmanned ground and aerial search‐and‐rescue vehicles is considered, developed within the scope of the European ICARUS project. As a first step toward the integrated data‐management methodology, the different robotic systems require an interoperable framework in order to pass data from one to another and toward the unified command and control station. As a second step, a data fusion methodology will be presented, combining the data acquired by the different heterogenic robotic systems. The computation needed for this process is done in a novel mobile data center and then (as a third step) published in a software as a service (SaaS) model. The SaaS model helps in providing access to robotic data over ubiquitous Ethernet connections. As a final step, we show how the presented data‐management architecture allows for reusing recorded exercises with real robots and rescue teams for training purposes and teaching search‐and‐rescue personnel how to handle the different robotic tools. The system was validated in two experiments. First, in the controlled environment of a military testing base, a fleet of unmanned ground and aerial vehicles was deployed in an earthquake‐response scenario. The data gathered by the different interoperable robotic systems were combined by a novel mobile data center and presented to the end‐user public. Second, an unmanned aerial system was deployed on an actual mission with an international relief team to help with the relief operations after major flooding in Bosnia in the spring of 2014. Due to the nature of the event (floods), no ground vehicles were deployed here, but all data acquired by the aerial system (mainly three‐dimensional maps) were stored in the ICARUS data center, where they were securely published for authorized personnel all over the world. This mission (which is, to our knowledge, the first recorded deployment of an unmanned aerial system by an official governmental international search‐and‐rescue team in another country) proved also the concept of the procedural integration of the ICARUS data management system into the existing procedural toolchain of the search and rescue workers, and this in an international context (deployment from Belgium to Bosnia). The feedback received from the search‐and‐rescue personnel on both validation exercises was highly positive, proving that the ICARUS data management system can efficiently increase the situational awareness of the search‐and‐rescue personnel.