Research of Sensor Systems in Temperature Changes. The Main Directions of Application of Sensor Systems in Internet of Things Systems

Direction included in the technology of "Internet of Things" to analyze the working of sensor systems in extreme areas, that is the properties and features of embedded control systems based on them, to identify the main problems of operation and features of sensors in smart - systems. The article considers the main types of sensors used in smart systems, the main alignments used in the design and creation of systems based on them, and experimentally evaluates the dependence of the speed of sound on air temperature.Сенсорні системи розглядаються як такі, що можуть входити до складу інтегрованих об’єднань, з метою оптимізації та модернізації охоронних функцій. Такий підхід знаходить свою застосування у сучасних смарт – системах. Розглянуто напрямок, що входить до технології «Інтернет речей» з метою аналізу роботи сенсорних систем в умовах екстремального використання, а саме властивості і особливості роботи вбудованих систем керування на їх основі, з метою визначення основних проблем функціонування та особливостей роботи сенсорів у вбудованих системах. Розглянуто основні концепції, що визначають положення технології «інтернету речей», її склад та структуру. Визначено основні різновиди датчиків, їх характерні особливості, що впливають на можливість їх застосування у різноманітних системах, що формують смарт – системи, а саме ультразвукові датчики, принцип дії яких заснований на реєстрації зміни ультразвукового поля, викликаного появою досліджуваного об’єкта або небезпеки. Вони характеризуються високою чутливістю та високим рівнем хибних спрацювань, сенсори на основі інтерференції звукових коливань, що забезпечує дуже високу чутливість при високій економічності, оскільки хвиля від випромінювача до приймача проходить через приміщення найкоротшим шляхом, а отже має найменше загасання, проте в реальних умовах ця система практично непрацездатна із-за надзвичайно високої вірогідності помилкових спрацьовувань, ультразвукові детектори наближення, що забезпечують досить високий рівень надійності системи, їх характерні структурні моделі. Визначено основні різновиди типів сповіщувачів, основними характеристиками яких є діапазон робочих відстаней, діапазон робочих частот, струм споживання, напруга живлення, час реакції сенсора, наявність або відсутність температурної компенсації, діапазон робочих температур. В статті розглянуто основні співвідношення для сенсорів, що застосовуються в смарт – системах при проектуванні та створенні об’єктів на їх основі, а саме точність вимірювання ультразвукових сенсорів та довжини звукової хвилі, та експериментально оцінено залежність швидкості звуку від температури повітря. З’ясовано, що швидкість поширення звукових хвиль знижується зі зниженням температури повітря. У разі, коли розмір перешкод і неоднорідностей в середовищі помітно перевищує довжину хвилі звуку, поширення звуку відбувається за законами геометричної акустики. Якщо ж перешкоди можна порівняти з довжиною хвилі, істотну роль починає грати дифракція хвиль, з якою пов'язано і розсіювання звуку. Дані явища слід враховувати при виборі датчиків особливо для виявлення дрібних об'єктів і нерівностей

A Transgenic Mouse Model for DNA/RNA Gene Therapy of Human β Thalassemia

TheâIVS-2-654 C→T mutation accounts for approximately 20% of â thalassemia mutation in southern  China; it causes aberrant RNA splicing and leads to â thalassemia. To provide an animal model for testing  therapies for correcting splicing defects, we have produced two lines of transgenic mice with the human â  thalassemia mutant gene. The transgenic mice carrying this mutant gene show the same aberrant splicing  as their human counterparts and provide an animal model for testing therapies to correct splicing defects  at either the RNA or DNA level.

Simultaneous Occurrence of Traveling Ionospheric Disturbances, Farley Buneman and Gradient Drift Instabilities Observed by the Zhongshan SuperDARN HF Radar

We show that Traveling Ionospheric Disturbances (TIDs) may affect the Farley Buneman Instability (FBI) and Gradient Drift Instability (GDI) echoes referred to as the Near Range Echoes (NREs) in the SuperDARN radar backscatter from the lower part of the E‐region. TIDs and NREs are observed concomitantly by the Zhongshan SuperDARN radar (69.38°S, 76.38°E) in the far and near ranges, respectively. At the moment, there is no study about the effects of TIDs on the NREs caused by the FBI using the SuperDARN radars. The GDI are more likely to occur at a lower altitude while FBI occurs at a slightly higher altitude in the lower part of the ionospheric E‐region. We use the Spearman Correlation Coefficient (SCC) to show that a part of the NREs backscatter power could be statistically explained by the MSTIDs backscatter power received by the same radar. We also investigate the simultaneous occurrence rate of the NREs and MSTIDs during the 24th solar cycle. Seasonal variability shows that MSTIDs‐NREs events over Zhongshan mostly occur in summer and equinoxes during local night and morning. The majority of these events lasted between ∼4 and ∼8 hr. Most events disappeared early in the morning. Statistics of the Spearman correlation coefficient values show that ∼9% of NRE amplitude modulation could be due to the MSTIDs. There are almost equal numbers of negative and positive Spearman correlation coefficient values. The relative velocity between the E‐region NREs and the F‐region MSTIDs switching the electric field polarities between the crests and troughs could be the cause of those equal number of the Spearman correlation coefficient values. The orientation of the ionospheric current relative to the MSTID polarization electric field may also play a significant role in the reported Spearman correlation coefficient values. We argue that in some cases, the TIDs might have been close enough to the NREs altitude to modulate them directly by transporting the plasma up and down through shear or compression

Effect of Coarse-grain and Low-grade Iron Ores on Sinter Properties

In sintering of iron ore, small particles act as a binder that joins larger particles through diffusion and melting. In order to understand the effect of gangue and structure of coarse ore on sinter properties, melt formation in three coarse-grain, low-grade iron ores was investigated. The melt fractions at the sintering temperature were estimated using the phase diagrams and melt fluidity was quantified by testing ore compacts in an infrared furnace. The result indicates that SiO2 can significantly increase the quantity and fluidity of melt during sintering, whereas the effects of Al2O3 and MgO are small. Excessive quantity and fluidity of liquid phase result in merging of micro pores, leaving large pores behind. The impact of blending three ores with a base ore on sinter structure were tested in a mini-sinter pot. The result shows that bonding and pore structure of sinter are dominantly affected by the melt behavior and pore structure of the coarse ore. Relationships between the fluidity index of sinter feed and product properties were explored, showing meaningful and predictable trends. It was demonstrated that fluidity index can be used as parameter to link sinter mix composition and sintering conditions to the properties of the produced sinter

Foxa2 attenuates steatosis and inhibits the NF-κB/IKK signaling pathway in nonalcoholic fatty liver disease

Objective Forkhead box a2 (Foxa2) is proven to be an insulin-sensitive transcriptional regulator and affects hepatic steatosis. This study aims to investigate the mechanism by which Foxa2 affects nonalcoholic fatty liver disease (NAFLD). Methods Animal and cellular models of NAFLD were constructed using high-fat diet (HFD) feeding and oleic acid (OA) stimulation, respectively. NAFLD mice received tail vein injections of either an overexpressing negative control (oe-NC) or Foxa2 (oe-Foxa2) for four weeks. HepG2 cells were transfected with oe-NC and oe-Foxa2 for 48 h before OA stimulation. Histological changes and lipid accumulation were assessed using hematoxylin-eosin staining and oil red O staining, respectively. Expression of Foxa2, NF-κB/IKK pathway proteins, lipid synthesis proteins, and fatty acid β-oxidation protein in HFD mice and OA-induced HepG2 cells was detected using western blot. Results Foxa2 expression was downregulated in HFD mice and OA-induced HepG2 cells. Foxa2 overexpression attenuated lipid accumulation and liver injury, and reduced the levels of aspartate aminotransferase, alanine aminotransferase, total cholesterol, or triglyceride in HFD mice and OA-induced HepG2 cells. Moreover, Foxa2 overexpression decreased the expression of lipid synthesis proteins and increased fatty acid β-oxidation protein expression in the liver tissues. Furthermore, overexpression of Foxa2 downregulated the expression of p-NF-κB/NF-κB and p-IKK/IKK in OA-induced HepG2 cells. Additionally, lipopolysaccharide (NF-κB/IKK pathway activator) administration reversed the downregulation of lipid synthesis proteins and the upregulation of fatty acid β-oxidation protein. Conclusion Foxa2 expression is downregulated in NAFLD. Foxa2 ameliorated hepatic steatosis and inhibited the activation of the NF-κB/IKK signaling pathway

Analysis of Human Disturbance Features in Natural Reserves and Empirical Research on Their Restoration: A Case Study of the Huangchulin Nature Reserve in Fujian Province

Nature reserves are important areas delineated to protect natural resources and the ecological environment. They have various ecological functions, such as protecting biodiversity, conserving water sources, and purifying the atmosphere. However, with the rapid development of the social economy, human disturbance in natural reserves is becoming increasingly pronounced, which has seriously damaged the initial balance of the ecosystem in the reserves. Based on the specific local conditions of the reserve, this study selects four influencing factors that are closely related to human activities, namely, land use, vegetation cover, slope and elevation as the primary evaluation indicators of human disturbance. With the support of an analytic hierarchy process and GIS technology, this study conducts a comprehensive analysis of human disturbance in the Fujian Huangchulin Nature Reserve and proposes corresponding ecological restoration measures for different disturbed areas. The results indicate that the area that is seriously and completely disturbed by human activities is primarily that around the river basin, which accounts for 25.30% of the total area. The lightly disturbed area covers the largest area, followed by the intermediately disturbed area, which accounts for 37.91% and 32.96% of the total area, respectively. The smallest area is slightly disturbed and accounts for only 3.83% of the total area. Based on the comprehensive analytical results of human disturbance and the functional zoning of the natural reserves in China, the Shitan Stream area in the Huangchulin Nature Reserve is selected as the experimental site for ecological restoration. According to the human disturbance in different sectors of the Shitan Stream area and the concept of “Mountain, Water, Forest, Field, Lake and Grass,” the ecological restoration measures of the “Four-tiered Protection System” are proposed in the experiment, which are the river system restoration, brownfield restoration, soil and water conservation, and original ecological protection areas. Natural regeneration and active restoration are then combined to be implemented in different areas, and the ecological problems of brown land pollution, water system cutoff, and soil erosion have been effectively solved, and the plant coverage increased substantially. In summary, this study shows that only by taking social, economic and ecological factors into account and establishing a sound management system can restoration work proceed smoothly and achieve more environmental benefits

Surface Functionalization of Graphene Oxide with Polymer Brushes for Improving Thermal Properties of the Polymer Matrix

In this work, polymethyl methacrylate (PMMA) and polystyrene (PS) with controlled structures would be grafted on graphene material. The hybrid materials were prepared by coating graphene oxide (GO) with polydopamine (PDA) as a reactive underlayer and reducing agent, subsequently, surface-initiated polymerization of monomers (methyl methacrylate, styrene) based on the activators regenerated electron transfer atom transfer radical polymerization (ARGET-ATRP) technique. The polymer brush-modified graphene materials were then incorporated into the PMMA or PS matrix to get polymer nanocomposites with better thermal properties. The results of Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA) demonstrated that PMMA and PS chains were successfully anchored on the surfaces of functionalized GO sheets. The influence of the grafted polymer brush-modified GO on thermal stability of PMMA and PS was investigated by a simultaneous thermal analyzer. Thermal conductivity of the polymer nanocomposite was determined by a conductive calorimeter. The results showed that thermal stability, glass transition temperature (Tg), and thermal conductivity of the polymer nanocomposites were obviously improved compared with pure PMMA or PS

Dynamic properties of throat aurora revealed by simultaneous ground and satellite observations

Throat aurora is defined as south-north aligned auroral arcs equatorward of the dayside cusp aurora and was suggested to be the results of cold magnetospheric plasma interaction with magnetopause reconnection, but its observational properties have not yet been well established. In this paper we carefully examine a sequence of throat auroras observed over Svalbard on 27 December 2003. Observations from 630.0 nm [OI] show that poleward moving throat auroras frequently show brightening followed by dimming in auroral intensity, and sometimes, the brightening throat aurora is a precursor of poleward moving auroral forms. Simultaneous all-sky images and HF radar backscatter observations along geomagnetic meridian show that the throat aurora brightening is drifting with ionospheric E × B convection and is colocated with enhanced spectral width poleward of the convection reversal boundary (CRB), while its dimming tends to be in the vicinity of the CRB. This leads us to propose that the throat aurora brightening and dimming may be on the open and closed field lines, respectively. Particle data from NOAA 16 confirm that the dimming throat aurora is associated with precipitation of magnetosheath-like particles mixed with magnetospheric ions (>30 keV), which is characteristic of the low-latitude boundary layer. For particle data from Defense Meteorological Satellite Program F16, we notice that the dimming throat aurora is associated with lower fluxes of magnetosheath-like electrons accompanied with magnetospheric electrons, which is most likely on closed field lines. The dynamic properties of throat aurora presented in this paper are thus important to understand its generation mechanisms

Dynamic properties of throat aurora revealed by simultaneous ground and satellite observations

Throat aurora is defined as south-north aligned auroral arcs equatorward of the dayside cusp aurora and was suggested to be the results of cold magnetospheric plasma interaction with magnetopause reconnection, but its observational properties have not yet been well established. In this paper we carefully examine a sequence of throat auroras observed over Svalbard on 27 December 2003. Observations from 630.0 nm [OI] show that poleward moving throat auroras frequently show brightening followed by dimming in auroral intensity, and sometimes, the brightening throat aurora is a precursor of poleward moving auroral forms. Simultaneous all-sky images and HF radar backscatter observations along geomagnetic meridian show that the throat aurora brightening is drifting with ionospheric E × B convection and is colocated with enhanced spectral width poleward of the convection reversal boundary (CRB), while its dimming tends to be in the vicinity of the CRB. This leads us to propose that the throat aurora brightening and dimming may be on the open and closed field lines, respectively. Particle data from NOAA 16 confirm that the dimming throat aurora is associated with precipitation of magnetosheath-like particles mixed with magnetospheric ions (>30 keV), which is characteristic of the low-latitude boundary layer. For particle data from Defense Meteorological Satellite Program F16, we notice that the dimming throat aurora is associated with lower fluxes of magnetosheath-like electrons accompanied with magnetospheric electrons, which is most likely on closed field lines. The dynamic properties of throat aurora presented in this paper are thus important to understand its generation mechanisms. © 2017 American Geophysical Unio

Design and Optimization of a Soil-Covering Device for a Corn No-Till Planter

Aiming to solve the problems of easy generation of clods, poor soil fluidity and poor soil-covering effect in the no-tillage seeding operation mode, this study has designed a soil-covering device with a soil-closing function for the chisel-type furrow opener of a corn no-tillage planter. Theoretical analysis and design of the soil dividing plate and the soil-covering disc were carried out, and the key parameters were determined. Then, the soil-covering device with soil-closing function and the soil movement model was constructed in Altair EDEM, and the spatial soil particle mobility was analyzed. The numerical simulation method was combined with the center plane composite response test scheme to carry out the simulation test, and the optimal working parameter combination was obtained. The operating speed was 6.35 km·h−1, the inclination angle of the soil-covering disc was 60°, the opening angle of the soil-covering disc was 70°, and the inclination angle of the soil dividing plate was 40°. A comparative test of the soil-covering effect and performance was carried out, and the results showed that the designed device was better than the traditional soil-covering device in terms of the consistency of soil-covering thickness and the stability of seed position deviation. The relative errors of the soil bin experiment results and the simulation optimization results for the cover soil thickness and seed position deviation were 5.7% and 11.1%, respectively. The operation effect of the designed soil-covering device with soil-closing function meets the requirements of soil covering under no-tillage conditions and provides a basis for the research and development of soil-covering suppression technology and devices under no-tillage seeding mode