Магнитно-импульсное деформирование сплава TiNi: эксперимент и расчет

Magnetic-pulse loading methods have been known since the 80s of the XX century and, as a rule, are used to determine the laws of destruction of materials under the action of pressure pulses with a duration of several microseconds. A modified scheme of a magnetic-pulse setup for high strain rate uniaxial tension is used in this work. The application of the scheme with the possibility of experimental measurement of the strain accumulation time and strain rate is shown on samples of TiNi alloy. The paper presents the results of finite element modeling and analytical description. Both approaches have demonstrated good agreement between the calculated residual strain and experimental results, even on samples of TiNi alloy with a specific stress-strain diagram. The analytical solution showed good qualitative agreement in assessing the strain accumulation time. On the basis of the analytical solution, an assessment of the capabilities of the magnetic-pulse loading method for uniaxial high strain rate tension is presented.

Hydrocarbon Charging and Accumulation in the Permian Reservoirs of the Wumaying Buried Hill, Huanghua Depression, Bohai Bay Basin, China

The Wumaying buried hill experienced multi-stage tectonic movements, which resulted in a complicated and unclear nature of the hydrocarbon accumulation process. To solve these problems, in this study—based on the structural evolution and burial–thermal history of the strata, using petrology, fluid inclusion microthermometry, geochemical analysis of oil and gas, Laser Raman spectrum, and fluorescence spectrum—the history of hydrocarbon charging was revealed, and the differences in hydrocarbon charging of different wells was clarified. The results indicate that the only source for Permian oil and gas reservoirs are Carboniferous–Permian coal-measure source rocks in the Wumaying buried hill. There are three periods of hydrocarbon charging. Under the channeling of faults and micro cracks, low-mature oil and gas accumulation was formed in the first period, and the accumulation time was 112–93 Ma. In the late Cretaceous, a large-scale uplift exposed and damaged the reservoirs, and part of the petroleum was converted into bitumen. In the middle–late Paleogene, the subsidence of strata caused the coal-measure to expel mature oil and gas, and the accumulation time of mature oil and gas was 34–24 Ma. Since the Neogene, natural gas and high-mature oil have been expelled due to the large subsidence entering the reservoir under the channeling of active faults; the accumulation time was 11–0 Ma. The microfractures of Permian reservoirs in the Wumaying buried hill are the main storage spaces of hydrocarbons, and the fractured reservoirs should be explored in the future. The first period of charging was too small and the second period was large enough in the WS1 well, resulting in only a late period of charging in this well.

Biosynthesis of α-Fe2O3-CdO Nanocomposites for Electrochemical Detection of Chloridazon Herbicide

Biosynthesised α-Fe2O3-CdO electrochemical nanosensor attained from Coriandrum sativum leaves extract and fabricated on the screen-printed electrode to detect chloridazon (CLZ) herbicide in agricultural food samples. Scanning electron microscopy, energy dispersive x-ray analysis, X-ray diffraction spectroscopy, cyclic voltammetry, and differential pulse voltammetry were used to investigate the α-Fe2O3-CdO electrochemical nanosensor. The optimization factors of the effect of pH, accumulation time, accumulation potential, and foreign substances were elevated. The α-Fe2O3-CdO/SPE electrochemical nanosensor shows the significant voltammetric response for the CLZ detection. Foreign substances did not considerably influence pesticide detection. Dynamic linear CLZ plot for a standard solution of CLZ was obtained in the concentration range of 0.1 to 36.00 µg⸳mL-1 (R=0.995) with a limit of detection 0.059 µg⸳mL-1 and a quantification limit of 0.179 µg⸳mL-1. The proposed electrochemical nanosensor was used to detect CLZ in agricultural food samples and agreeable recovery results.

Optimization of Liquid Accumulation and Gas Injection Duration in Intermitter for Maximizing Production: Case Study

Gas lift is the process of injecting gas into the tubing at a predetermined depth in order to lift the crude oil to the surface. Gas lift is applied to a well when the reservoir pressure falls to such a level that it does not produce without application of external energy. There are mainly two types of gas lift which are Continuous and Intermittent gas lift. This paper deals with the theoretical determination of relationship between liquid accumulation and gas injection duration in an intermittent gas lift well and how this knowledge can be combined with the experience of Engineers to maximize the production of a well. In order to find the relationship between the given durations, a simple mathematical approach with the assumption that the gas injection time is independent of liquid accumulation time is followed. We, then apply various tools of mathematics such as the principles of maxima and minima, Leibnitz theorem, definition of the slope of a line etc. to finally prove the interdependence of liquid accumulation and gas injection time at which the well can produce at its maximum capacity. This interdependence is plotted on a separate graph with the given times on two axis. This curve represents the values at which the reservoir inflow is maximised and hence another curve representing the tubing outflow is drawn on the same graph to intersect the former curve at the optimum value of liquid accumulation and gas injection time. The paper also discusses the physical significance of the cases in which the two curves do not intersect and its possible solutions which vary in accordance with the experience of engineers and conditions of well. Our mathematical calculation led to an astonishing result that the interdependence between the two given durations is elegant and can be easily found without the use of computer in a very short interval of time. The result indicated that if a tangent is drawn from a point representing gas injection time to the graph of accumulation height versus time, it touches the graph at the value of liquid accumulation time at which the production of well is maximized. This novel approach to determine the value of time in an intermitter or time cycle controller in an intermittent well can be proved to be a boon for gas lift optimizers who would otherwise spend a large part of the time in setting the value on hit and trial basis. The graphical method can determine the optimum value in a shorter interval of time and with greater accuracy saving companies from extra man-hours and unscientific approach to optimizing any intermittent gas lift well.

Copper Film Modified Glassy Carbon Electrode and Copper Film with Carbon Nanotubes Modified Screen-Printed Electrode for the Cd(II) Determination

A copper film modified glassy carbon electrode (CuF/GCE) and a novel copper film with carbon nanotubes modified screen-printed electrode (CuF/CN/SPE) for anodic stripping voltammetric measurement of ultratrace levels of Cd(II) are presented. During the development of the research procedure, several main parameters were investigated and optimized. The optimal electroanalytical performance of the working electrodes was achieved in electrolyte 0.1 M HCl and 2 × 10−4 M Cu(II). The copper film modified glassy carbon electrode exhibited operation in the presence of dissolved oxygen with a calculated limit of detection of 1.7 × 10−10 M and 210 s accumulation time, repeatability with RSD of 4.2% (n = 5). In the case of copper film with carbon nanotubes modified screen-printed electrode limit of detection amounted 1.3 × 10−10 M for accumulation time of 210 s and with RSD of 4.5% (n = 5). The calibration curve has a linear range in the tested concentration of 5 × 10−10–5 × 10−7 M (r = 0.999) for CuF/GCE and 3 × 10−10–3 × 10−7 M (r = 0.999) for CuF/CN/SPE with 210 s accumulation time in both cases. The used electrodes enable trace determination of cadmium in different environmental water samples containing organic matrix. The validation of the proposed procedures was carried out through analysis certified reference materials: TM-25.5, SPS-SW1, and SPS-WW1.

Theoretical Foundations Development of Space Adaptive Video Information Systems Synthesis

The main provisions and principles of the synthesis of adaptive video information systems designed for recording and analyzing images of dynamic scenes at the stages of long-range detection of artificial space objects, ballistic and controlled approach to them in the middle and near zone of cooperation are considered. Based on the principle of dominant information, it is shown that the basis for the development of methods and algorithms for processing video information in on-board surveillance systems is the joint adaptive processing of video information in photo-detector matrices and in digital processors in order to maximize the quality of information issued to the consumer by suppressing background and noise information by adaptive hysteresis control of the frame frequency, frame resolution and signal accumulation time in the photodetector matrix, as well as the use of parametric neural network detectors-classifiers.

Cumulative Serum Uric Acid and Its Time Course Are Associated With Risk of Myocardial Infarction and All‐Cause Mortality

Background Serum uric acid (SUA) has been demonstrated as a risk factor for myocardial infarction (MI) and all‐cause mortality; however, the impact of cumulative SUA (cumSUA) remains unclear. We aimed to investigate the association of cumSUA with MI risk and all‐cause mortality, and to further explore the effects of SUA accumulation time course. Methods and Results The study enrolled 53 463 participants without a history of MI, and these participants underwent 3 examinations during 2006 to 2010. cumSUA from baseline to the third examination was calculated, multiplying mean values between consecutive examinations by time intervals between visits. Cox models estimated hazard ratios (HRs) and 95% CIs of MI and all‐cause mortality for cumSUA quartiles, hyperuricemia exposure duration, and SUA accumulation time course. During a median follow‐up of 7.04 years, 476 incident MIs and 2692 deaths occurred. In the fully adjusted model, a higher MI risk was observed in the highest cumSUA quartile (HR, 1.48; 95% CI, 1.10–1.99), in participants with longer hyperuricemia exposure duration (HR, 1.71; 95% CI, 1.06–2.73), and in participants with cumSUA≥median and a negative slope (HR, 1.58; 95% CI, 1.18–2.11). Similar associations persisted for all‐cause mortality. Conclusions The risk of MI and all‐cause mortality increased with higher cumSUA and was affected by the SUA accumulation time course. Early SUA accumulation contributed more to MI risk and all‐cause mortality than later SUA accumulation with the same overall cumulative exposure, emphasizing the importance of optimal SUA control early in life.

Voltammetric Determination of Amoxicillin Using a Reduced Graphite Oxide Nanosheet Electrode

A reduced graphite oxide nanosheet electrode (RGOnS) was prepared as a sensor for amoxicillin (AMX) detection, an antibiotic commonly used in the livestock farm, by the square-wave adsorptive stripping voltammetry technique. Graphite oxide with nanosheet shape was produced from a graphite electrode by a chronoamperometry process at 5 V and then an electrochemical reduction process was carried out to form RGOnS with restored long-range conjugated networks and better conductivity. The electrodes were characterized by SEM, EDX, and FTIR spectroscopy. The RGOnS electrode prepared at an optimal reduction potential of −1 V for 120 s exhibits a larger electrochemical active surface area, and the obtained oxidation signal of AMX is approximately ten times higher than that of the pristine graphite electrode. The analytical conditions such as the pH of electrolyte and accumulation time were optimized. The calibration curve built under the optimal conditions provided a good linear relationship in the range of AMX concentration from 0.5–80 µM with the correlation coefficient of 0.9992. The limit of detection was calculated as 0.193 µM. Satisfactory results are obtained from the detection of the AMX in different samples using the prepared electrode.

A wearable patch for continuous analysis of thermoregulatory sweat at rest

The body naturally and continuously secretes sweat for thermoregulation during sedentary and routine activities at rates that can reflect underlying health conditions, including nerve damage, autonomic and metabolic disorders, and chronic stress. However, low secretion rates and evaporation pose challenges for collecting resting thermoregulatory sweat for non-invasive analysis of body physiology. Here we present wearable patches for continuous sweat monitoring at rest, using microfluidics to combat evaporation and enable selective monitoring of secretion rate. We integrate hydrophilic fillers for rapid sweat uptake into the sensing channel, reducing required sweat accumulation time towards real-time measurement. Along with sweat rate sensors, we integrate electrochemical sensors for pH, Cl−, and levodopa monitoring. We demonstrate patch functionality for dynamic sweat analysis related to routine activities, stress events, hypoglycemia-induced sweating, and Parkinson’s disease. By enabling sweat analysis compatible with sedentary, routine, and daily activities, these patches enable continuous, autonomous monitoring of body physiology at rest.