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500-Year Records Demonstrating a Sharp Increase in Intensities of Three Natural Hazards at Multiple Spatiotemporal Scales in China
Get PDFChina has experienced frequent natural disasters, including droughts, floods, and heavy snowfall. This study discusses the temporal-spatial patterns in the country since 1500. The intensity of drought in Henan and Inner Mongolia was higher than that in Guizhou and Qinghai, while little difference in flood intensity was observed among these provinces. The intensity of snow disasters in Qinghai was much higher. Except for the slightly decreasing drought trend in Henan, the three natural disasters showed a significant increase over time. Drought disasters in Guizhou, Henan, and Qinghai showed few seasonal differences, whereas those in Inner Mongolia mostly occurred in winter and spring. Floods were concentrated during the summer, while snow disasters occurred mainly during winter and spring. According to the Mann–Kendall (M–K) test, the seasonal differences in disaster trends in Guizhou, Henan, and Qinghai were unclear and similar to the overall trend. However, the disaster trends in Inner Mongolia showed seasonal differences. The spatial distribution of natural disasters in Guizhou and Henan were similar, and their changing trends were extremely scattered, while in Inner Mongolia and Qinghai, they were clustered. The spatial distribution of disaster intensity had few seasonal differences and was similar to the overall distribution. However, when considering the spatial distribution of disaster trends by season, seasonal differences were evident. This study has provided an earlier signal on how to prevent and mitigate natural disasters based on 500 years' tempo-spatial pattern, and the measures on how to improve the management practices of natural hazards under climate change were also suggested
Revitalizing Urban Interfaces through Historical Spaces: An Exemplification from the Renovation of Pukou Railway Station Area, Nanjing, China
Get PDFThis research delves into the significance and methodological approaches concerning the conservation and regeneration of historical facilities and spaces in contemporary urban environments through the lens of the conservation and regeneration project of the Pukou Railway Station Historic District in Nanjing. The study underscores the imperative of respecting, protecting, and revitalizing historical facilities and spaces. The refurbishment of old facilities, employing the most apt technologies and methods, accomplished a commendable balance between economic investment and efficiency. Respecting all historical textures and contexts is foundational to the preservation of the historical appearance of districts. The project, through the refurbishment of historical buildings and cautious design of new constructions, ensured a harmonious coexistence of old and new elements, thereby enhancing the cultural essence of the historical district architecture. The conservation and regeneration project of the Pukou Railway Station Historic District in Nanjing offers a beneficial case on managing historical facilities and spaces, showcasing how, through rational technical measures and respect for historical context, historical spaces can be revitalized, providing rich cultural and spatial resources for modern cities
Priming Bean Seedlings to Boost Natural Plant Defenses Against Common Bacterial Wilt: Salicylic Acid Responses to Chemical Primers (Part 1)
Get PDFThis greenhouse study evaluated the effects of two chemical inducers for priming kidney bean seedlings against a bacterial wilt disease. This study's central premise was that chlorine dioxide's oxidant properties would mimic the signaling properties of radical oxygen species, thereby initiating a cascade of molecular plant defenses, including the synthesis of salicylic acid (SA). This signaling agent then initiates a cascade of pre-defense activities to provide a more rapid and robust natural defense against pathogen attacks. This factorial study included two levels for a foliar chlorine dioxide treatment and two for a bacterial wilt inoculation treatment. The two plant response variables were free and conjugated salicylic acid levels sampled in leaf tissue over two collection dates. Half of the 96 plants were inoculated with a bacterial culture that causes common bean wilt disease. Leaf tissue was harvested 17 to 32 h and 960 h after the wilt inoculation to determine the temporal dynamics of SA due to chemical treatments. Also, PCR tests were used to verify wilt presence in the inoculated plants. Inoculation of the wilt disease did not affect free SA when leaf tissue was sampled from 17 to 32 h. after wilt inoculation. However, chlorine dioxide applied at 400 mg/l and sampled at 20 h after inoculation resulted in a 15-fold increase in free SA over the control. Also, chlorine dioxide applied at 400 mg/l with leaf tissue sampled at 26 h after inoculation resulted in a 33-fold increase in conjugate SA levels compared to the control plants.
Leaf tissue sampled at 960 h after the inoculation showed no free SA differences among the chemical treatments. However, the inoculated plant had a 15.9-fold increase in free SA compared to the non-inoculated plants. The priming effect on kidney bean seedlings using a single chlorine dioxide foliage application temporarily increased free and conjugate SA. The free and conjugate SA levels for the non-inoculated plants returned to baseline levels when sampled at 960 h. These results indicate that primed plants elevate SA up to several weeks with a slow decline back to baseline levels. Stem injection of the bacterial wilt bypassed the immunity mechanisms present in leaves, which significantly increased the wilt injury levels. Stem injection negated much of the foliar defenses, which overshadowed the priming effects of the chemical treatments on plant immunity and foliar defenses. The second leaf sampling on newly formed leaves reveals elevated SA levels in the inoculated plants but not in the non-inoculated plants
Numerical Investigation on Flow-Field Characteristics towards Removal of Free-Water by A Separator with Coalescing Plates
Get PDFThe produced water-containing polymer brings new challenges to oil-water separation in oilfield production, yet separators with coalescing plates to remove free water have been playing an active role. In this paper, the flow-field characteristics of polymer-laden produced water in a separator with coalescing plates are analyzed using computerized mathematical methods to investigate the effects with a water content of 55%, 70%, and 85%, flow rate of 3500 m3/d, 4800 m3/d, and 6000 m3/d, and duration time of 20 min, 40 min, and 60 min on flow-field properties and separating efficiency are studied. The results show that the separating efficiency is positively correlated with water content and duration time, and duration time has the greatest improvement to the separating efficiency, but the enhancement of flow rate may reduce the separating efficiency. It is also observed that the separation efficiency of free-water reached 70.9% and the water content at the oil outlet of the separator reached 20.4% at a duration time of 60 min, when the contained polymer concentration and water content in the oil-water mixture are 500 mg/L and 70%, respectively
A Review on Fundamentals and Capturing Petroleum Fluid Hysteresis Through Experiments
Get PDFHysteresis is proven to have a significant role in petroleum fluids and other disciplines for better understanding and evaluation. This shows a need to be explicit about precisely what is meant by the word "hysteresis." For a long time, the term hysteresis has been used and has attracted the attention of most researchers and investigators. Despite its common usage, hysteresis is used in different disciplines to mean different things. Thus, hysteresis has many definitions depending on the book or paper's area of interest. While various definitions of the term 'hysteresis' have been suggested, this paper will focus on the definition in the oil and gas industry. Hysteretic impacts petroleum fluids either positively or negatively. Therefore, accurately estimating fluid properties curves is vital in evaluating hydrocarbon recovery processes. This paper addresses and discusses a comprehensive review of the hysteresis of different petroleum fluid properties and their applications. This paper reviews many fluid properties of hysteresis and investigates them experimentally. Numerous laboratory studies in hysteresis are present in the literature and critically reviewed and highlighted in this research. This paper aims to review the experimental processes of fluid hysteresis extensively. To satisfy this aim, this paper offers insights into and explanations for experiments that have been used in fluid hysteresis. The outcomes highlight some missing concepts of the existing models and experimental processes for fluid hysteresis. Furthermore, this paper tracks the current development of hysteresis and gives insight into the future trends in the application of hysteresis
Visualization Experiments of Radial-Rotating Oscillating Heat Pipe Filled with Methanol
Get PDFOscillating heat pipes (OHP) have highly efficient heat transfer capability. Some researchers have applied OHPs to cutting tools and rotating machines by embedding tubular OHPs in machines or by making flow channels on metal plates. Most studies are on heat transfer performance, and there are few studies on the heat transfer behavior of radial-rotating oscillating heat pipes (RR-OHP) under operating conditions. This paper conducted the visualization test of an RR-OHP filled with methanol by studying the flow patterns and motion modes at rotation speed (0-860 rpm) and heat flux (20000-40000 W/m2). When the heat flux is increased from 20000 W/m2 to 40000 W/m2, the flow patterns include flowless, slug flow, annular flow, and churn flow, and the motion modes contain oscillatory motion, cyclic motion, unilateral boiling, and bilateral boiling. The distribution map of the flow patterns and motion modes with the centrifugal acceleration and the heat flux was plotted, which shows the evolution of the flow patterns and the transformation of the motion modes of the RR-OHP, and elucidates the effect of the centrifugal acceleration and the heat flux on the flow patterns and motion modes
Editorial: Effective Tools for Low-Grade Thermal Energy Storage and Utilization
Get PDFLow-grade thermal energy, such as industrial waste heat, geothermal energy, and solar thermal energy, has the potential to be a valuable resource in contributing to energy conservation and improving energy efficiency. Unfortunately, much of this energy remains untapped, leading to increased environmental pollution without any benefits to production processes. The effective storage and utilization of low-grade thermal energy can significantly improve energy efficiency and reduce carbon emissions. This special issue aims to provide a platform for researchers to share their latest findings and advancements in low-grade thermal energy storage and utilization and promote the development and implementation of innovative technologies and policies in this area
Analysis of Functional and Neutral Differential Equations via Lyapunov Functionals
Get PDFWe employ Lyapunov types functions and functionals and obtain sufficient conditions that guarantee the boundedness and the exponential decay of solutions, stability and exponential stability of the zero solution in nonlinear delay and neutral differential systems. The theory is illustrated with several examples.
2000 Mathematics Subject Classification: Primary 39A13, 39A23; Secondary 34K4
Enzymatic Treatment of Cotton Fabric for Desizing
Get PDFThe possibility of softening the conditions of biochemical treatment to remove the sizing agent from the surface of the fibers in the preparation of cotton fabric for dyeing has been studied. The efficiency of the α-amylase enzyme was evaluated by the amount of sugars reduced in the modifying solution, as well as by the capillarity of the samples of the treated fabrics. The enzyme used is active towards starch starting from a low concentration (0.02 g/l) and low temperature (32°C). The effect of enzyme concentration from 0.02 to 6.0 g/l, solution pH from 4.5 to 8.5, temperature from 32 to 60°C on the amount of sugars in the solution after enzymatic treatment, and fabric capillarity was determined. Almost complete removal of sizing from the surface of fibers of the original fabric was achieved under moderate and mild processing conditions: α-amylase concentration 1.0÷5.0 g/l, pH=6.0÷7.0, temperature 50-55°C. Based on the dependence of the logarithm of the reaction rate on the reciprocal temperature, the activation energy of the desizing reaction was calculated, which turned out to be equal to E = 17.5 kJ/mol. The low activation energy shows that the desizing process is carried out under energetically favorable conditions with moderate heating. The surface morphology of treated and untreated samples of cotton fabric was studied by scanning electron microscopy. The removal of the adhesive substance from the surface of the fibers, the separation of individual fibers, and the smoothing of the fabric surface after treatment with an amylase solution were recorded
Thermal-Economic Analysis of an Organic Rankine Cycle System with Direct Evaporative Condenser
Get PDFThe organic Rankine cycle (ORC) system for power generation has proven to be an effective technology for low-temperature waste heat utilization. Accurate prediction and comprehensive comparison of system performance under different conditions are necessary for the development and application of suitable ORC configurations. This paper proposed an organic Rankine cycle (ORC) system using a direct evaporative condenser to realize performance enhancement and analyzed its dynamic performance based on the actual climatic condition, which is beneficial for the performance optimization of this system. This study begins with an introduction to the thermal economics model of the proposed system and evaluates the performance of the system based on the 3E (energy, exergy, economy) analysis method. Secondly, four candidate working fluids were compared and analyzed, leading to the selection of R142b as the best working fluid for the proposed system. Finally, the dynamic performance of the proposed system using the working fluid of R142b was analyzed based on the hourly environment temperature. The result showed that the net thermos-electric conversion efficiency of the system was negatively correlated with the ambient wet-bulb temperature. The annual average exergy efficiency of the system is about 65.79%, and the average exergy loss of the heat absorption unit, evaporative condenser, pump, and expander account for 61.07%, 6.92%, 2.99%, and 29.01% of the exergy loss of the system respectively. In the case 8760 h of operation per year, the payback period of the proposed ORC system using direct evaporative condenser is about 2.14 years