151 research outputs found
Analytic modeling of a high temperature thermoelectric module for wireless sensors
A novel high temperature thermoelectric module with thermoelectric materials never before combined in a module is currently researched. The module placement in the cooling channels of a jet engine where the cold side will be cooled by high flow cooling air (550 degrees C) and the hot side will be at the wall (800 degrees C). The aim of the project is to drastically reduce the length of the wires by replacing wired sensors with wireless sensors and power these (3-10mW) with thermoelectric harvesters. To optimize the design for the temperature range and the environment an analytic model was constructed. Using known models for this purpose was not possible for this project, as many of the models have too many assumptions, e.g. that the temperature gradient is relatively low, that thick electrodes with very low resistance can be used, that the heat transfer through the base plates are perfect or that the aim of the design is to maximize the efficiency. The analytical model in this paper is a combination of several known models with the aim to examine what materials to use in this specific environment to achieve the highest possible specific power (mW/g)
Approximate non-linear model predictive control with safety-augmented neural networks
Model predictive control (MPC) achieves stability and constraint satisfaction
for general nonlinear systems, but requires computationally expensive online
optimization. This paper studies approximations of such MPC controllers via
neural networks (NNs) to achieve fast online evaluation. We propose safety
augmentation that yields deterministic guarantees for convergence and
constraint satisfaction despite approximation inaccuracies. We approximate the
entire input sequence of the MPC with NNs, which allows us to verify online if
it is a feasible solution to the MPC problem. We replace the NN solution by a
safe candidate based on standard MPC techniques whenever it is infeasible or
has worse cost. Our method requires a single evaluation of the NN and forward
integration of the input sequence online, which is fast to compute on
resource-constrained systems. The proposed control framework is illustrated on
three non-linear MPC benchmarks of different complexity, demonstrating
computational speedups orders of magnitudes higher than online optimization. In
the examples, we achieve deterministic safety through the safety-augmented NNs,
where naive NN implementation fails
Modelling and experimental verification of more efficient power harvesting by coupled piezoelectric cantilevers
A new piezoelectric energy harvester design is proposed in order to achieve a wider bandwidth without compromising energy conversion efficiency. By coupling two cantilevers where the tip of the bottom one is attached to the base of the upper one, the simulated harvester will have a wider bandwidth and higher power output compared with two simulated single tuned single cantilevers. This is a compact design, using only half the area compared to two parallel single cantilevers at the price of a small increase in height. The measured coupled harvester has approximately 1.7 times higher energy output than the combination of two measured tuned single cantilevers achieved by a coupling with less mechanical damping. With an improved coupling the power output is increased to 2.3 times higher than two single tuned cantilevers
Simulation of a Novel Bridge MEMS-PZT Energy Harvester for Tire Pressure System
Self-powering is becoming an important issue for autonomous sensor systems. By having an on-the-go power source the life span increases in comparison to a limited battery source. In this paper, simulation of an innovative design for a piezoelectric energy harvester for Tire Pressure Measurement System (TPMS) is presented. The MEMS-based thin-film PZT harvester structure is in the form of a bridge with a big central seismic mass and multiple electrodes. This design takes the advantage of the S-profile bending and a short beam length to concentrate the piezoelectric effect in a small segment along the beam and maximize the power output for a given displacement. From simulation in Comsol Multiphysics, the 9mm x 5mm bridge, seismic mass of 8.7mg and resonance frequency of 615Hz, generates 1 mu W by mechanical pulses excitation equivalent to driving at 60 km/h (roughly 180G)
Generating stable molecules using imitation and reinforcement learning
Chemical space is routinely explored by machine learning methods to discover interesting molecules, before time-consuming experimental synthesizing is attempted. However, these methods often rely on a graph representation, ignoring 3D information necessary for determining the stability of the molecules. We propose a reinforcement learning (RL) approach for generating molecules in Cartesian coordinates allowing for quantum chemical prediction of the stability. To improve sample-efficiency we learn basic chemical rules from imitation learning (IL) on the GDB-11 database to create an initial model applicable for all stoichiometries. We then deploy multiple copies of the model conditioned on a specific stoichiometry in a RL setting. The models correctly identify low energy molecules in the database and produce novel isomers not found in the training set. Finally, we apply the model to larger molecules to show how RL further refines the IL model in domains far from the training data
Favorable impact of long-term exercise on disease symptoms in pediatric patients with inflammatory bowel disease
Evidence is growing that both short- and long-term physical exercise have the potential to positively impact on the physiological system related to inflammatory indices, though, such patterns are unknown for pediatric patients with Inflammatory Bowel Disease (IBD). The aim of the present intervention study was to investigate the influence of a single bout and chronic moderate-intensity exercise on IBD-related inflammatory indices and exercise capacity among pediatric individuals with IBD and healthy controls.; Twenty-one pediatric patients with IBD, split into a "remission-group" (IBD-RE; n = 14) and an "active disease group" (IBD-AD; n = 7), were compared to 23 age matched healthy controls (HC). All participants completed a single bout of exercise at baseline and an 8-week exercise intervention. Before and after the single bout of exercise IBD-related inflammatory indices (erythrocyte sedimentation rate (ESR), albumin, C-reactive protein (CRP), cortisol, hemoglobin, hematocrit, thrombocytes and leukocytes) were assessed.; At baseline, after a single bout of exercise, inflammation (albumin, hemoglobin, erythrocytes, hematocrit and leukocytes) increased in all three groups IBD-AD, IBD-RE and HC. CRP and thrombocytes were only elevated in IBD-AD and IBD-RE, compared to HC. After a longer-term exercise intervention, ESR, CRP and thrombocytes significantly decreased in all groups. The longer-term exercise intervention did not decrease acute immunopathologic responses after a single bout of exercise, compared to baseline.; Whereas a single bout of exercise increases albumin, erythrocytes and leukocytes, longer-term moderate-intensity exercise reduced inflammatory markers in pediatric patients with IBD. Children and teenagers with IBD should be encouraged to engage in regular moderate-intensity exercise activities, as such activities may contribute to inflammation suppression and improved disease management
Π€ΡΠΎΡΠΈΠ΄Π½Π°Ρ ΡΠ΅Ρ Π½ΠΎΠ»ΠΎΠ³ΠΈΡ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ ΡΠΈΡΠ°Π½ΠΎΠ²ΡΡ ΠΏΠΎΡΠΎΡΠΊΠΎΠ²
ΠΠ±ΠΎΡΠ½ΠΎΠ²Π°Π½Π° Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΡΡΡ ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΠΈ Π½ΠΎΠ²ΠΎΠΉ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΏΠ΅ΡΠ΅ΡΠ°Π±ΠΎΡΠΊΠΈ ΡΠΈΡΠ°Π½ΡΠΎΠ΄Π΅ΡΠΆΠ°ΡΠΈΡ
ΠΊΠΎΠ½ΡΠ΅Π½ΡΡΠ°ΡΠΎΠ². ΠΡΠΏΠΎΠ»Π½Π΅Π½ΠΎ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠ΅ ΠΏΡΠΎΡΠ΅ΡΡΠ° ΡΡΠΎΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΡΡΠΈΠ»ΠΎΠ²ΠΎΠ³ΠΎ ΠΊΠΎΠ½ΡΠ΅Π½ΡΡΠ°ΡΠ° ΡΠ»Π΅ΠΌΠ΅Π½ΡΠ½ΡΠΌ ΡΡΠΎΡΠΎΠΌ. ΠΠΏΠΈΡΠ°Π½Ρ ΠΏΡΠΎΡΠ΅ΡΡΡ, ΠΏΡΠΎΡΠ΅ΠΊΠ°ΡΡΠΈΠ΅ ΠΏΡΠΈ ΡΠ»Π΅ΠΊΡΡΠΎΠ»ΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠΌ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΠΈ ΡΠΈΡΠ°Π½ΠΎΠ²ΡΡ
ΠΏΠΎΡΠΎΡΠΊΠΎΠ² Π²ΠΎ ΡΡΠΎΡΠΈΠ΄Π½ΡΡ
ΡΠ°ΡΠΏΠ»Π°Π²Π°Ρ
TiF4. ΠΠ»Ρ ΠΎΡΠΌΡΠ²ΠΊΠΈ ΠΎΡ ΠΏΡΠΈΠΌΠ΅ΡΠ΅ΠΉ ΠΊΠ°ΡΠΎΠ΄Π½ΠΎΠ³ΠΎ ΠΎΡΠ°Π΄ΠΊΠ° ΠΏΡΠ΅Π΄Π»ΠΎΠΆΠ΅Π½ΠΎ Π΄Π²Π΅ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΠΈ β Π² ΡΠΌΠ΅ΡΠΈ Π½Π΅ΠΎΡΠ³Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΡ
ΠΊΠΈΡΠ»ΠΎΡ ΠΈ Π±Π΅Π·Π²ΠΎΠ΄Π½ΡΠΌ HF; ΠΏΠΎΠΊΠ°Π·Π°Π½Ρ ΠΏΡΠ΅ΠΈΠΌΡΡΠ΅ΡΡΠ²Π° ΠΎΡΠΌΡΠ²ΠΊΠΈ HF; ΡΠΎΠ΄Π΅ΡΠΆΠ°Π½ΠΈΠ΅ ΠΏΡΠΈΠΌΠ΅ΡΠ΅ΠΉ Π² ΠΏΠΎΡΠΎΡΠΊΠ΅ ΡΠΈΡΠ°Π½Π°, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΠΎΠΌ ΠΎΡΠΌΡΠ²ΠΊΠΎΠΉ Π² Π±Π΅Π·Π²ΠΎΠ΄Π½ΠΎΠΌ HF Π½Π΅ΡΠΊΠΎΠ»ΡΠΊΠΎ Π½ΠΈΠΆΠ΅, ΡΠ΅ΠΌ ΠΏΡΠΈ "ΠΊΠΈΡΠ»ΠΎΡΠ½ΠΎΠΉ" ΠΎΡΠΌΡΠ²ΠΊΠ΅. ΠΡΠΈ ΠΏΡΠΎΠΌΡΡΠ»Π΅Π½Π½ΠΎΠΌ ΠΎΡΡΡΠ΅ΡΡΠ²Π»Π΅Π½ΠΈΠΈ ΠΏΡΠΎΡΠ΅ΡΡΠ° HF ΡΠ΅ΡΠΈΡΠΊΡΠ»ΠΈΡΡΠ΅Ρ Π² ΡΡ
Π΅ΠΌΠ΅, ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°Ρ ΡΠΊΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΡΡ Π±Π΅Π·ΠΎΠΏΠ°ΡΠ½ΠΎΡΡΡ ΠΈ Π½ΠΈΠ·ΠΊΡΡ ΡΠ΅Π±Π΅ΡΡΠΎΠΈΠΌΠΎΡΡΡ Ti.The brief review of industrial technologies of processing the titanium containing concentrates has been carried out. The research of the fluorination process of rutile concentrates with element fluorine was carried out. The processes occurring during the electrolysis of titanic powders from fluoride fusions, from TiF4, are described. In order to wash off impurities of cathode deposit, two techniques were proposed - in a mixture of inorganic acids and anhydrous HF; advantages of washing off with HF are shown; the impurity content in the titanium powder obtained by washing off in anhydrous HF is slightly lower than at "acid" washing off. In the industrial process implementation HF recycles tin a circuit that ensures environmental safety of production and low production cost of obtained Ti
Π Π°Π·ΡΠ°Π±ΠΎΡΠΊΠ° ΡΠ΅Ρ Π½ΠΎΠ»ΠΎΠ³ΠΈΠΈ ΠΈΠ·Π³ΠΎΡΠΎΠ²Π»Π΅Π½ΠΈΡ Π΄Π΅ΡΠ°Π»ΠΈ Β«Π‘Π΅Π΄Π»ΠΎΒ»
ΠΡΠΏΡΡΠΊΠ½Π°Ρ ΠΊΠ²Π°Π»ΠΈΡΠΈΠΊΠ°ΡΠΈΠΎΠ½Π½Π°Ρ ΡΠ°Π±ΠΎΡΠ° Π²ΠΊΠ»ΡΡΠ°Π΅Ρ Π² ΡΠ΅Π±Ρ ΠΏΡΠΎΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΠ΅ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΏΡΠΎΡΠ΅ΡΡΠ° ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ Π΄Π΅ΡΠ°Π»ΠΈ "Π‘Π΅Π΄Π»ΠΎ" ΠΈ ΡΠΎΠ΄Π΅ΡΠΆΠΈΡ: Π°Π½Π°Π»ΠΈΠ· ΡΠ΅ΡΡΠ΅ΠΆΠ° ΠΈ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ½ΠΎΡΡΠΈ Π΄Π΅ΡΠ°Π»ΠΈ; ΡΠΏΠΎΡΠΎΠ± ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΈΡ Π·Π°Π³ΠΎΡΠΎΠ²ΠΊΠΈ; ΡΠ°ΡΡΠ΅Ρ ΠΏΡΠΈΠΏΡΡΠΊΠΎΠ² Π½Π° ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΡ; ΡΠ°Π·ΡΠ°Π±ΠΎΡΠΊΡ ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΏΡΠΎΡΠ΅ΡΡΠ°, Π²ΡΠ±ΠΎΡ ΠΈ ΡΠ°ΡΡΠ΅Ρ ΡΠ΅ΠΆΠΈΠΌΠΎΠ² ΡΠ΅Π·Π°Π½ΠΈΡ; ΡΠ°Π·ΠΌΠ΅ΡΠ½ΡΠΉ Π°Π½Π°Π»ΠΈΠ· ΡΠ΅Ρ
Π½ΠΎΠ»ΠΎΠ³ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΏΡΠΎΡΠ΅ΡΡΠ°.Final qualifying work includes the design of the technological process of processing details in the "Saddle" and contains: an analysis of drawing and technology details; method of harvesting; calculation of allowances for processing; the design process, the selection and calculation of cutting conditions; dimensional analysis process
ΠΠ½Π΅Π΄ΡΠ΅Π½ΠΈΠ΅ ΠΎΡΠ³Π°Π½ΠΈΠ·Π°ΡΠΈΠΎΠ½Π½ΡΡ ΠΈΠ½Π½ΠΎΠ²Π°ΡΠΈΠΉ Π² ΠΎΠ±ΡΡΡΡΠΎΠΉΡΡΠ²Π΅ ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡΡ Π½Π΅ΡΡΠ΅Π³Π°Π·ΠΎΠ²ΠΎΠΉ ΠΎΡΡΠ°ΡΠ»ΠΈ
ΠΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡΠ° Π·Π°Π½ΠΈΠΌΠ°Π΅Ρ ΠΎΠ΄Π½Ρ ΠΈΠ· Π²Π°ΠΆΠ½Π΅ΠΉΡΠΈΡ
Π΄ΠΎΠ»ΠΆΠ½ΠΎΡΡΠ΅ΠΉ Π² ΠΎΡΠ³Π°Π½ΠΈΠ·Π°ΡΠΈΠΈ, ΠΏΡΠΈ Π³ΡΠ°ΠΌΠΎΡΠ½ΠΎΠΉ ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡΠ΅: ΠΎΡΠ³Π°Π½ΠΈΠ·Π°ΡΠΈΡ Π½Π΅ΡΡΡ Π·Π½Π°ΡΠΈΡΠ΅Π»ΡΠ½ΠΎ ΠΌΠ΅Π½ΡΡΠ΅ ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΡΡΠ²Π΅Π½Π½ΡΡ
ΠΏΠΎΡΠ΅ΡΡ. ΠΡ ΡΠ°ΡΡΠΌΠΎΡΡΠΈΠΌ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ Π²Π½Π΅Π΄ΡΠ΅Π½ΠΈΡ ΠΈΠ½Π½ΠΎΠ²Π°ΡΠΈΠΉ Π² ΠΎΡΠ³Π°Π½ΠΈΠ·Π°ΡΠΈΠΎΠ½Π½ΡΡ Π΄Π΅ΡΡΠ΅Π»ΡΠ½ΠΎΡΡΡ Π² ΠΎΠ±ΡΡΡΡΠΎΠΉΡΡΠ²Π΅ ΠΈΠ½ΡΡΠ°ΡΡΡΡΠΊΡΡΡΡ Π½Π΅ΡΡΠ΅Π³Π°Π·ΠΎΠ²ΠΎΠΉ ΠΎΡΡΠ°ΡΠ»ΠΈ.Infrastructure occupies one of the most important positions in the organization, with a competent infrastructure: the organization suffers significantly less production losses. We will consider the possibility of introducing innovations in organizational activities in arranging the infrastructure of the oil and gas industry
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