LoRa (or LoRaWAN) is by far the best known representative of narrowband communication systems designed for the Internet of Things. As a system dedicated specifically for long-range operations, it ...possesses a considerable processing gain for the energetic link budget improvement and a remarkable immunity to multipath and interference. The paper describes outcomes of measurement campaigns during which the LoRa performance was tested against these two factors, that is, a heavy-multipath propagation and a controlled, variable interference generated, respectively, in a reverberation chamber and an anechoic chamber. Results allow quantitative appraisal of the system behavior under these harsh conditions with respect to LoRa’s three major configurable parameters: the spreading factor, bandwidth, and code rate. They also allow dividing LoRa configurational space into three distinct sensitivity regions: in the white region it is immune to both interference and multipath propagation, in the light-grey region it is only immune to the multipath phenomenon but sensitive to interference, and in the dark grey region LoRa is vulnerable to both phenomena.
Weightless and SigFox are both narrowband communication systems designed for the Internet of Things, along with some other counterparts such as LoRa (Long Range) and narrowband Internet of Things ...(NB-IoT). As systems dedicated specifically for long-range operations, they possess considerable processing gain for energetic link budget improvement and a remarkable immunity to interference. The paper describes outcomes of a measurement campaign during which the Weightless and SigFox performance was tested against variable interference, generated in an anechoic chamber. Results allow the quantitative appraisal of the system behavior under these harsh conditions with respect to different operational modes of the two investigated IoT systems. The outcomes are then investigated with respect to an intentional radio jammer attempting to block a base station (BS) operation by directly radiating an interfering signal towards it. An Interference Margin is proposed for a quantitative expression of a system’s resilience to jamming. This margin, calculated for all available configuration settings, allows the clear assessment of which combination of a system’s operational parameters does and which does not provide immunity to this type of radio attack.
In order to increase the quality of the products manufactured by injection molding, RTC technology can be used to achieve higher mold temperatures. As a result, the path of the injected melt can be ...extended, allowing the production of parts with more complex shapes and greater length. Induction heating allows heating only selected forming surfaces of the mold which increases the speed and efficiency of the process. This paper presents the concept of a detachable inductor integrated with sliders to enable the application of this technology in an injection mold with sliders, along with the theoretical model used to perform the tests. First, the effect of the magnetic concentrator shape on the process was analyzed. This was followed by a simulation study of the influence of process parameters: heating time, frequency, and electric current. An extensive analysis of the test results of the temperature distribution on the insert allowed for the selection of parameter sets that would enable obtaining the desired surface temperature without a major increase in process time. The results of simulation studies confirm the possible applications and present the range of parameters for obtaining the optimal process.
Precise localization is considered one of the most salient features of Industry 4.0 manufacturing facilities. For this reason, multiple solutions have already been proposed. The method presented in ...this paper entails the use of double-band radio and optical technologies for near-real-time location tracking and remote reporting, with a final tracking accuracy of 0.5 meters. To preserve low-energy operations, the system infrastructure part is deployed on passive radio-frequency identification (RFID) tags, whereas the part installed on tracked assets implements energy-saving mechanisms. The system was deployed in an automotive production plant which allowed us to draw practical remarks on such aspects as the separation of onboard Ultra High Frequency (UHF) antennas; proper electromagnetic isolation of radio modules to prevent signal blocking; the placement and mechanical securing of RFID tags on the floor; as well as how to implement procedures to decrease the duty cycle, allowing for a trade-off between system sensitivity and energetic efficiency.
The article presents the power consumptions measurements performed for three wireless routers operating in IEEE 802.11n standard. A typical consumer-class device Asus RTAC66U was chosen, an ...operator-class Gateworks Laguna GW2387 and a router built based on the Raspberry Pi3 platform. The aim of experiments was to test the influence of the beacon interframe interval, a client association (joining) in the network and the transmission itself, on the lifetime of battery-powered devices. Theoretical calculations were also performed for the influence of the analyzed scenarios on the battery-powered devices.
The use of selective induction heating of molding surfaces allows for better filling of molding cavities and has a positive effect on the properties of molded products. This is particularly important ...in the production of parts that include flexible hinges, which are thin plastic layers connecting two or more parts of the product. By using hinges, it is possible to expand the use of injection molding products and their capabilities. They are widely used in the production of parts for the electrical engineering industry and for packaging Fast Moving Consumer Goods (FMCG). The use of hinges also entails specific reductions in wall thickness. Increases in the shear rate can be expected, which can lead to the degradation of polymers and deterioration of mechanical properties of materials. This paper investigates injection molded flexible hinge parts manufactured with selective induction heating to improve their properties. To verify the efficiency of reduction of material degradation due to high shear rates, open/close tests of elastic hinges were performed. The linear relation between the number of cycles the hinges can withstand, mold temperature and injection time was identified, where mold temperature was the more significant factor.
•Analytical efficiency model considering power losses in meshing and bearings.•Convergence of the results obtained by calculations and by testing the prototype.•High efficiency of the transmission at ...nominal load (90–96%).•Power loses in rolling bearings are several times greater than in meshing.
The aim of the article is to investigate the efficiency of the novel eccentric rolling transmission, which is a simplification of the cycloidal reducer, with parallel but not overlapping shaft axes. In this paper, a kinematic and load distribution analysis are presented with a view to determining the forces and rotational speeds necessary for efficiency calculation. The developed efficiency model involved power losses in rolling bearings, at meshing, as well as churning and windage power losses. For the verification, a transmission prototype with a 10:1 gear ratio and a dedicated test stand were designed and built. The results of the research showed that most substantial power losses occurred in the bearings and were several times greater than the losses associated with friction between the active surfaces of its main components. The transmission efficiency improved with increasing load and decreased with increasing rotational speed, reaching a maximum of 96% at nominal torque. The proposed model allows predicting the efficiency of the transmission at the stage of its design, which can further facilitate the optimization of the transmission parameters considering expected operational conditions.
A systematic study of global properties of superheavy nuclei in the framework of macroscopic-microscopic method is performed. Equilibrium deformations, masses, quadrupole moments, radii, shell ...energies, fission barriers and half-lives are calculated using the following macroscopic models: Myers-Swiatecki liquid drop, droplet, Yukawa-plus-exponential, and Lublin-Strasbourg drop. Shell and pairing energies are calculated in Woods-Saxon potential with a universal set of parameters. The analysis covers a wide range of even-even superheavy nuclei from Z=100 to 122. Magic and semimagic numbers occurring in this region are indicated and their influence on the observables is discussed. The strongest shell effects appear at proton number Z=114 and at neutron number N=184. Deformed shell closures are found at N=152 and 162. Spontaneous fission half-lives are calculated in a dynamical approach where the full minimization of the action integral in a three-dimensional deformation space of {beta} deformations is performed. The fission half-lives obtained this way are two orders of magnitude smaller than the ones resulting from static calculations. The agreement of theoretical results and experimental data is satisfying.
Fusion – fission probabilities in the synthesis of heaviest elements are discussed in the context of the latest experimental reports. Cross sections for superheavy nuclei are evaluated using the ...“Fusion by Diffusion” (FBD) model. Predictive power of this approach is shown for experimentally known Lv and Og isotopes and predictions given for Z = 119, 120. Ground state and saddle point properties as masses, shell corrections, pairing energies, and deformations necessary for cross-section estimations are calculated systematically within the multidimensional microscopic-macroscopic method based on the deformed Woods-Saxon single-particle potential. In the frame of the FBD approach predictions for production of elements heavier than Z = 118 are not too optimistic. For this reason, and because of high instability of superheavy nuclei, we comment on some structure effects, connected with the K-isomerism phenomenon which could lead to a significant increase in the stability of these systems.
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