Sudden Temperature Changes Research Articles

Winter desiccation of dwarf pine (Pinus mugo Turra) needles in the area of Belmeken Dam

In the summer of 2018, browning and drying of the needles on the dwarf pine (Pinus mugo Turra) formations in the vicinity of the dam Belmeken (Rila Mt.) were found. The damages were concentrated mainly in the southern part of the plants and affect the young needles on the tops of the shoots. During the route survey conducted in 2019, almost complete recovery of the affected plants was observed. Symptoms of drying were found only on single bushes. Studies and laboratory analyses gave reason to conclude, that the drying was due to adverse weather conditions in the winter of 2017-2018, when there was significantly less than normal rainfall, and sudden temperature changes and extremes were found. Established in the dry needles, fungi of the genera Lophodermium, Hendersonia and Neofusicoccum can be characterized as weak parasites, manifested secondarily, or as endophytes, which under physiological stress due to changes in certain environmental factors can become latent pathogens, worsening the condition of dwarf pine.

The Time-Dependent Response of a Two-Basin Ocean to a Sudden Surface Temperature Change

Abstract Building on previous work using single-basin models, we here explore the time-dependent response of the Atlantic meridional overturning circulation (AMOC) to a sudden global temperature change in a two-basin ocean–ice model. We find that the previously identified mechanisms remain qualitatively useful to explain the transient and the long-term time-mean responses of the AMOC in our simulations. Specifically, we find an initial weakening of the AMOC in response to warming (and vice versa for cooling), controlled by the mid-depth meridional temperature contrast across the Atlantic basin. The long-term mean response instead is controlled primarily by changes in the abyssal stratification within the basin. In contrast to previous studies we find that for small-amplitude surface temperature changes, the equilibrium AMOC is almost unchanged, as the abyssal stratification remains similar due to a substantial compensation between the effects of salinity and temperature changes. The temperature-driven stratification change results from the differential warming/cooling between North Atlantic Deep Water and Antarctic Bottom Water, while the salinity change is driven by changes in Antarctic sea ice formation. Another distinct feature of our simulations is the emergence of AMOC variability in the much colder and much warmer climates. We discuss how this variability is related to variations in deep-ocean heat content, surface salinity, and sea ice in the deep convective regions, both in the North Atlantic and in the Southern Ocean, and its potential relevance to past and future climates.

The Influence of Environmental Factors on the Quality of GPR Data: The Borre Monitoring Project

The Borre Monitoring Project investigated how environmental factors, in particular, precipitation and soil moisture variation as well as different soil and sediment types, affect the quality of GPR data collected for archaeological purposes. To study these questions, regular GPR surveys were conducted over a period of 14 months across a test area covering a hall building at the Iron and Viking Age site of Borre in Norway. In order to obtain in situ measurements of environmental factors relevant for electromagnetic wave propagation including volumetric water content, bulk electrical conductivity, ground temperature, and precipitation, three monitoring stations were erected at the test site. Soil and sediment samples taken from the profiles at the respective monitoring stations were analysed to gain a basic description of their physical and chemical properties. Twelve GPR surveys were conducted roughly once a month between August 2016 and September 2017 and the results clearly indicated differences in the quality of the data collected. To better understand the underlying causes for this variation, GPR data were compared against and integrated with the in situ measurements gathered using the monitoring stations. The results of this analysis emphasised the benefit of dry conditions, which, if prevailing over a longer period of time, proved to generate GPR data of the highest quality. Seasonality could not be attested; instead, data quality was governed by small-scale weather patterns, where the time and intensity of rainfall events prior to the surveys as well as sudden changes in air temperature played a decisive role. While the results of this study are only valid for sites with similar settings such as Borre, they emphasise the importance of considering the environmental factors during all stages of a GPR survey and highlight the need for further studies investigating other settings.

The success of the bloom-forming cyanobacteria Planktothrix: Genotypes variability supports variable responses to light and temperature stress

Cyanobacterial blooms can modify the dynamic of aquatic ecosystems and have harmful consequences for human activities. Moreover, cyanobacteria can produce a variety of cyanotoxins, including microcystins, but little is known about the role of environmental factors on the prevalence of microcystin producers in the cyanobacterial bloom dynamics. This study aimed to better understand the success of Planktothrix in various environments by unveiling the variety of strategies governing cell responses to sudden changes in light intensity and temperature. The cellular responses (photosynthesis, photoprotection, heat shock response and metabolites synthesis) of four Planktothrix strains to high-light or high-temperature were studied, focusing on how distinct ecotypes (red- or green-pigmented) and microcystin production capability affect cyanobacteria's ability to cope with such abiotic stimuli. Our results showed that high-light and high-temperature impact different cellular processes and that Planktothrix responses are heterogeneous, specific to each strain and thus, to genotype. The ability of cyanobacteria to cope with sudden increase in light intensity and temperature was not related to red- or green-pigmented ecotype or microcystin production capability. According to our results, microcystin producers do not cope better to high-light or high-temperature and microcystin content does not increase in response to such stresses.

An Optimal Linear Quadratic Regulator in Closed Loop with Boost Converter for Current Photovoltaic Application

In this paper, a steady-state output power oscillation problem is overcome using the indirect control mode based-Perturb and Observe (P&O) implementation algorithm. This can be ensured through controlling the duty cycle input of the DC-DC boost converter using the proposed Linear Quadratic Regulator (LQR) controller. Their parameters are optimized using the Grasshopper Optimization Algorithm (GOA) where a good tracking behavior of a desired Maximum Power Point (MPP) can be guaranteed for various sudden changes in weather conditions such as absolute temperature and solar irradiance. The desired performances and robustness of the closed-loop system can be achieved by the two following stages. In the first stage, the standard P&O algorithm based-direct control mode generates a reference current perturbation using both existing electrical power and measured PV current. Accordingly, a current error perturbation is provided through the discrepancy between reference and measured currents. In the second stage, the previous current error provided in the inner control-loop is mitigated as much as possible using the stabilized LQR controller. The current control-loop problem is addressed with a detailed analysis technique of averaging and linearization, in which the linearization of actual PV-boost converter system around the desired MPP allows determining the corresponding linear plant-model. This leads to well optimize the LQR controller parameters. The performance and robustness provided by the P&O algorithm based-indirect duty cycle control are shown for sudden changes in solar irradiance and absolute temperature as well as in a wide variation of the resistive load.

Handling Load Uncertainty during On-Peak Time via Dual ESS and LSTM with Load Data Augmentation

This paper proposes a scheduling method of dual ESSs (Energy Storage Systems) for the purpose of reducing the peak load when there are sudden loads or generation changes during the on-peak time. The first ESS is scheduled once a day based on a day-ahead load prediction, and the second ESS is scheduled every 15 min during on-peak time based on a short-term load prediction by LSTM (Long Short-Term Memory). Special attention is paid to training the LSTM for the short-term load prediction by using the augmented past load data which is generated by adding possible uncertainties to the past load and temperature data. Based on the load forecast, optimization problems for the scheduling are formulated. The proposed scheduling method is validated using load and temperature data from a real building. In other words, when the proposed method is applied to the real building energy data in the case study, it not only shaves the peak load during on-peak time interval effectively but also results in lower electricity price although there are sudden load or temperature changes during the time interval.

Impact of temperature changes to the adhesion strength of molar tubes: an in vitro study

BackgroundThe main purpose of this was to determine study adhesion strength of molar tubes bonding with a composite adhesive after exposure to a sudden change in temperature (thermal cycles).MethodsThe study sample consisted of 40 recently extracted human first permanent molars, which were randomly divided into two groups of 20: group 1 was the experimental group (affected by thermal cycles), and group 2 was the control group. Molar tubes were bonded with a light-cure tube adhesive. The experimental group teeth were dipped 2,000 times in saline at 5 °C and at 55 °C. The control group were immersed in 37 °C saline. Molar tubes for both groups were removed with an adapted Mecmesim Multitesters 2.5—I, and the data were recorded with EMPEROR software. ANOVA was used to calculate and compare the results.ResultsIn the experimental group of the teeth, the maximum force was obtained at 94.2 N and the lowest force was 19.69 N. In the control group of the teeth, the maximum force was obtained at 159.1 N and the lowest force was 28.1 N. In the experimental group, the mean debonding force (59.12 N) was statically significantly smaller than in the control group (79.88 N), p = 0.0345. The forces in the control group were by 1.35 times greater than those in the experimental group.ConclusionsThe forces of the adhesion of molar tubes to the tooth surface were reduced after exposure to a sudden change in temperature (thermal cycles). The results were significantly different between the experimental group and the control group.

Temperature-Induced Environmental Chain Reaction in Marine Sedimentation and Its Impact on Manila Clam Ruditapes philippinarum

Marine Heatwaves (MHWs) events have been increasing, causing severe impacts on marine ecosystems and aquaculture. In this study, the effects of temperature on changes in sediment dissolved oxygen (DO) and hydrogen sulfide (H2S) concentrations and their effects on the behavioral and physiological responses of a bivalve were investigated by simulating different sudden summer temperature change conditions. The results showed that temperature was an important factor affecting DO consumption and H2S release in sediments, and sediment type also played a key role. At higher temperatures, DO was consumed more rapidly and H2S release increased in sediments, and the DO was consumed and H2S released in sandy sediments was less than in silty sand sediments. The response of Manila clam’s exercise behavior under environmental pressure was also rapid. The excavation index of the Manila clam decreased with the DO consumption, indicating that the Manila clam could alter its burial depth and move toward the sediment-water interface when stressed. Compared with phenol oxidases (PO) activity being activated under experimental conditions, succinate concentrations only increased slightly at 32°C, and did not surpass the threshold indicative of anaerobic metabolism. However, when toxic substances such as H2S start to accumulate, they may damage the immune system and tissues of the Manila clam, thereby affecting its future survival. Therefore, when temperatures are high for long periods in summer, it is necessary to take timely action to prevent and guard against harm caused by DO and H2S to aquaculture organisms.

On the dynamically arrested states of equilibrium and non-equilibrium gels: a comprehensive Brownian dynamics study

In this work a systematic study over a wide number of final thermodynamic states for two gel-forming liquids was performed. Such two kind of gel formers are distinguished by their specific interparticle interaction potential. We explored several thermodynamic states determining the thermodynamic, structural and dynamic properties of both liquids after a sudden temperature change. The thermodynamic analysis allows to identify that the liquid with short range attraction and long range repulsion lacks of a stable gas–liquid phase separation liquid, in contrast with the liquid with short range attractions. Thus, although for some thermodynamic states the structural behavior, measured by the static structure factor, is similar to and characteristic of the gel phase, for the short range attractive fluid the gel phase is a consequence of a spinodal decomposition process. In contrast, gelation in the short range attraction and long range repulsion liquid is not due to a phase separation. We also analyze the similarities and differences of the dynamic behavior of both systems through the analysis of the mean square displacement, the self part of the intermediate scattering function, the diffusion coefficient and the α relaxation time. Finally, using one of the main results of the non-equilibrium self-consistent generalized Langevin equation theory (NE-SCGLE), we determine the dynamic arrest phase diagram in the volume fraction and temperature (φ vs T) plane.

Understanding the flash flood event of 7th February 2021 in Rishi Ganga basin, Central Himalaya using remote sensing technique

On 7th February 2021, a sudden flash flood in the Rishi and Dhauli Ganga rivers in Uttarakhand Himalaya killed 80 people and left 124 people missing. Two hydropower projects were completely destroyed. The flash flood was caused by an avalanche and debris flow. In the present study, spatio-temporal variation in dynamics of glaciers and meteorological parameters including precipitation, land surface temperature etc. was investigated. The study also indicates tectonic correlation with high velocity in the region. A significant change in the climatic conditions just before the flashflood event was observed. Snow cover trend indicates heavy snowfall precipitation followed by abrupt escalation in the difference between diurnal temperatures in the Tapovan valley. Our findings suggest that a sudden temperature change couple of days before caused rapid glacier melt. The melt water moved down along the pre-existing joint/fracture plane, causing the wedge to fail and a flash flood to occur. It is envisioned that the recent change in weather conditions in the region is the primary cause of this event. The steep, narrow river valley increases the kinetic energy of the river, causing even more devastation in its lower reaches. Due to climate change, the Himalayan glaciers have melted rapidly over the last century, expanding the size of glacier lakes and depositing massive sediments in de-glaciated areas. Based on the recent flash flood event and the previous Kedarnath tragedy, it is critical to monitor such potential glacier areas in order to avoid such unfortunate hazards in the future.

Containment Liner Plate Void Defect Detection Technique Using Phased Array Ultrasonic Testing and Acoustic Resonance Method.

The CLP (containment liner plate) of a nuclear power plant protects the internal system from the external environment and sudden changes in internal pressure or temperature, and it is a structure that blocks and protects radioactive materials leaking inside and outside in the event of a nuclear accident and is composed of a liner plate, reinforcing bars, tendons, and concrete. Recently, corrosion on the rear side of the liner plate and concrete voids has emerged as a severe defect in nuclear power plants across South Korea. Therefore, in this study, we proposed a new inspection method that a line-type inspection method applied phased array ultrasonic testing and the area inspection method applied acoustic resonance method using developed moveable tapper. The acoustic signals were signal-processed and reproduced to a mapping image following the inspection area, and with the image, it was possible to determine the type of defect. Furthermore, an automated inspection system for within the CLP was proposed.

Cyclosporine release and distribution in ophthalmic emulsions determined by pulsatile microdialysis

An in vitro release test based on pulsatile microdialysis (PMD) is presented for the purpose of measuring the release of cyclosporine from ophthalmic emulsions, along with a method to determine the drug distribution within the oil-rich globule, surfactant-rich micelle and aqueous phases of the emulsion formulation. Compositionally equivalent formulations containing 0.05% cyclosporine were prepared with similar physical parameters (globule size, viscosity, surface tension zeta potential, osmolality, pH) but made with different manufacturing conditions. Emulsions were made by ultrasonication, using different ultrasonication times (22–49 min) and temperatures (50–82 °C). Formulations were stored at room temperature (20 °C) and PMD was performed under two conditions, one in which the receiving medium temperature was 20 °C, and another in which the receiving medium temperature was 35 °C to mimic the temperature change expected when a drop of formulation is administered to the eye. The PMD release data were taken at release times of 20, 40, 60, 90, 120, 180, 300 and 600 s. All experiments showed a qualitatively similar release pattern, with a rapid initial rate of drug release (Release-1) for the first few minutes, followed by a much slower release (Release-2). In addition, imposing a sudden temperature change on the formulation was observed to affect the release, with some formulations releasing faster into receiver media at 35 °C than at 20 °C, while others released faster into 20 °C than 35 °C receiver media. The drug distribution was also calculated from PMD release data into 20 °C receiver media using a novel release kinetics model. The drug distribution varied among the formulations, with 54–77% of the cyclosporine in the oil phase of the emulsions. PMD is a promising method to evaluate how manufacturing-induced differences affect the distribution and release kinetics of cyclosporine within the emulsion formulation.

Infrared radiation quantification of rock damage and its constitutive modeling under loading

The root cause of the infrared radiation (IR) change in rock is the failure of microelements during its evolution. However, the quantified relationship between the two parameters remains unclear. This paper, therefore, presents a quantification approach to investigate the internal damage evolution of loading rock through the surface IR. Multiparameter observation experiments were conducted primarily in coal rock samples. The change in related parameters within the rock sample during the evolution of the damage was recorded. The IR noise from the reference (unloaded) samples was taken as the threshold of the sudden change in the IR temperature. Thus, the noise signal and the sudden change in IR temperature were separated through these threshold values. On this basis, a quantitative index of infrared radiation, the IR counts was adopted. It was found that there was a synchronous sudden change between the IR and Acoustic ringing counts. According to the occurrence of sudden change in the IR counts and the differential infrared radiant thermal image sequence at the corresponding time, the damaged area of the rock can be accurately determined. Taking the IR counts as the characterization parameter of the rock damage variable, the quantitative characterization method of the evolution of coal-rock damage by IR and the stress-strain constitutive model was established. The IR calculated stress (σIR) can reflect the failure process of rock transition from the linear elastic to the plastic deformation stage.

Structural, physical and mechanical changes of cement-bonded particleboards during sudden fluctuations in temperature and moisture

The paper presents research focused on behaviour of cement-bonded particleboards with modified composition during sudden changes of temperature and humidity. Four types of boards were made—one control and three modified ones. Finely ground limestone was used as a modifying component in binder. Secondary wood particles made from crushing cuttings of cement-bonded particleboards were used as chips substituent. Two sets of test specimens (1 set = 6 test specimens) were manufactured. The first set was stored in laboratory conditions. The second set was subjected to 10 cycles of sudden changes of temperature (− 20 °C to + 70 °C) and humidity in accordance with EN 321 (further in the paper referred to as “wet–frost–dry cycle”.) After each cycle, dimensions and mass of the test specimens as well as ultrasonic pulse velocity were determined. A detailed analysis of structural changes in boards during cycling was carried out by an optical microscope. After 10 wet–frost–dry cycles were completed, bending strength and modulus of elasticity in bending were determined. The analysis of test results implies a very good relation between change of ultrasonic pulse velocity and width of cracks in the area of interfacial zone between cement matrix and wood particles. This finding also corresponds with dimensional and volumetric changes of the boards. Dependence of bending strength and modulus of elasticity in bending on composition of boards is apparent. Positive influence of secondary spruce chips on dimensional changes of cement-bonded particleboards caused by sudden changes of temperature and humidity was proved. Finely ground limestone contributes to more resistant structure of boards which leads to improved bending properties. Adverse conditions had more considerable influence on bending strength (decrease by 21% to 26%) than on modulus of elasticity in bending (decrease by 12% to 19%).

TEST SYSTEM TO VERIFY THERMAL SHOCK RESISTANCE

The article presents the method and the prototype system to verify the resistance of technological objects to environmental impacts in the form of increased or decreased temperatures or sudden temperature changes (i.e. thermal shocks), developed in accordance with the following PN-EN 60068 standard requirements as regards environmental testing: PN-EN 60068-2-1:2009 – Test A: Cold [7]; PN-EN 60068- 2-2:2009 – Test B: Dry heat [8]; and PN-EN 60068-2-14:2009 – Test N: Change of temperature [9]. The developed solution is also aligned with the testing procedure requirements applicable to military equipment tests [12]. The system is mainly designed for testing prototype technological devices subject to significant changes in the temperature of the environment in which they operate, including thermal shocks; it also enables periodic quality checks of manufactured goods [1, 2]. With the developed system the following may be tested: the operation of individual mechanisms; the shape stability and resistance [10]; the resistance to damage; as well as the operability of electronic systems [3]. The flexible method of programming tests used in the system enables the performance of both normative and non-standard tests, depending on the requirements of the research to be carried out. The article describes the system design process, its architecture, structure, and operation, as well as the prototype verification test results. The validated prototype test system was incorporated into the structure of the laboratory for the identification and verification of technical safety of industrial and special-purpose applications under environmental conditions established at the Łukasiewicz Research Network – Institute for Sustainable Technologies (Łukasiewicz–ITEE).

Research of the modernized intake system of the gasoline engine

Problem. In recent years, Ukraine has seen a sharp decline in ambient temperature, especially in the winter. Accordingly, this has a negative impact on the performance of car engines (difficult to start and prolonged warm-up), as the lion's share of private sector cars are parked in open areas and are subject to sudden temperature and humidity changes. Therefore, to partially solve this problem, our attention was focused on the air lines of the intake system of the gasoline engine, as this system is easily accessible and does not require significant design changes for its modernization. Goal. The purpose of the work is to ensure the ease of starting the gasoline engine and reduce the time to warm up. Methodology. Operation of the car in the conditions of the lowered temperatures, essentially promotes deterioration of its fuel economy. The basis of such a negative process of fuel consumption is incomplete combustion of the working mixture. And this is the deterioration of spraying and evaporation of fuel and increasing the duration of engine warm-up. At such low ambient temperatures, the effective operation of the car in a garage depends significantly on the method of its preparation (which should at a minimum cost of fuel and energy resources to ensure rapid and reliable engine start and accelerated warm-up). We decided to obtain thermal energy to heat the inlet air at no additional cost. This is the installation of a gasoline engine with a spark ignition of the incandescent coil in the intake air line, which will receive power from the battery. Such modernization of the system does not require major design changes and significant financial investments Unresolved issues remain to assess the effectiveness of the process of heating the air entering the combustion chamber of the engine to create a working mixture. It should be noted that the optimal heating of the engines is most appropriate to carry out (ie heating the coolant and oil in the engine lubrication system) not to the temperature of the operating thermal mode, but to the temperature that ensures its reliable start. Results. The scheme of connection of a heater of intake air in an onboard electric network of the car is presented. The results of the heat balance of the studied gasoline engine (using cold and heated air flow) during its heating are obtained. The optimum temperature of the warmed-up engine at which further economical operation of the car is possible is established. Originality. This spiral heater was first used to heat the intake air charge during the start-up and warm-up of a gasoline engine. Practical value. The developed heating equipment can be used for both gasoline and diesel internal combustion engines. It should be switched on only during engine start-up and warm-up.

Experimental Investigation on the Energy Properties and Failure Process of Thermal Shock Treated Sandstone Subjected to Coupled Dynamic and Static Loads

Thermal shock (TS) is known as the process where fractures are generated when rocks go through sudden temperature changes. In the field of deep rock engineering, the rock mass can be subjected to the TS process in various circumstances. To study the influence of TS on the mechanical behaviors of rock, sandstone specimens are heated at different high temperatures and three cooling methods (stove cooling, air cooling, and freezer cooling) are adopted to provide different cooling rates. The coupled dynamic and static loading tests are performed on the heated sandstone through a modified split Hopkinson pressure bar (SHPB) system. The influence of heating level and cooling rate on the dynamic compressive strength, energy dissipations, and fracturing characteristics is investigated based on the experimental data. The development of the microcracks of the sandstone specimens after the experiment is analyzed utilizing a scanning electron microscope (SEM). The extent of the development of the microcracks serves to explain the variation pattern of the mechanical responses and energy dissipations of the specimens obtained from the loading test. The findings of this study are valuable for practices in rock engineering involving high temperature and fast cooling.

ПОДБОР И АНАЛИЗ СЫРЬЕВЫХ КОМПОНЕНТОВ ДЛЯ ЗАЩИТНОГО И ДЕКОРАТИВНОГО СЛОЯ КОМПОЗИЦИОННОГО МАТЕРИАЛА

With modern housing construction, the cost of finishing work has increased significantly. The development of protective and decorative coatings is necessary, with architectural and artistic advantages and high performance properties with a slight increase in cost. It is necessary to develop a high-quality multilayer monolithic composite with a high degree of adhesion of functional layers to each other. Glass industry waste of various fractions and coloring salts of metals are proposed to be used for a decorative layer, which allows to obtain an almost unlimited color gamut of the coating during plasma chemical modification. The choice of application of high-alumina refractory and alumina cement in the protective layer is justified due to their high thermal resistance to sudden temperature changes. Compositions of a protective layer based on binders and a decorative layer using crushed colored container glass and coloring metal salts moistened with a 5% aqueous solution of liquid glass have been proposed, which makes it possible to significantly expand the raw material base for obtaining functional coatings on concrete. The melt heating temperature and the kinetics of its cooling are determined in order to identify rational rates and duration of high-temperature treatment for further coating creation. Rational rates of plasma processing of composite material for the formation of coatings of various textures are revealed

A novel three-dimensional numerical model to simulate heat transfer inside a double U-tube borehole with two independent circuits

In this paper, a three-dimensional numerical model is developed to investigate the transient heat transfer inside a double U-tube borehole with two independent circuits. The thermal resistance and capacity approach is applied to develop this model. Moreover, a new thermal network is proposed based on experimental data for a double U-tube borehole with two independent circuits. In this model, the axial heat conduction and thermal capacities of the grout and fluid carriers are taken into account. Besides, based on the experimental data, the grout inside the borehole for each layer is divided into five zones. The accuracy of the proposed model is investigated with the available experimental data and a fully three-dimensional unsteady CFD model. The suggested model is examined in two modes of long- and short-time simulations. The temperature and mass flow rate of inlet fluids are constant for long-time simulations. Moreover, two modes of variable fluid inlet temperature and variable fluid mass flow rates are considered for the short-time simulation to examine the accuracy of the proposed model against sudden changes of temperature and mass flow rate of the inlet fluids. Also, the proposed model is compared against the existing analytical and numerical models to investigate the heat transfer inside a double U-tube borehole with two independent circuits. Based on the results, it is found that the accuracy of the developed model is higher than the existing models.

Precise control over tunable translucency and hysteresis of thermo-responsive hydrogel for customized smart windows

In view of global warming and following fossil energy consumption caused by the using of heavy-loaded air conditioners, smart windows, which can intelligently regulate solar radiation, became a highly anticipated strategy to slow down the pressure. As most of the traditional hydrogel-based smart windows abruptly switch between transparent and opaque making a sudden change in temperature and light, we established a poly-N-isopropylacrylamide (PNIPAM) thermo-responsive hydrogel system with additional cross-linking of chitosan and Al3+, which exhibited a smooth thermo-response during heating and a novel recovery hysteresis during cooling. By enabling additional gentle transition in translucency, we are able to retain a comfortable indoor temperature/lightness balance during an increase in outdoor temperature, in avoidance of sudden indoor darkness at elevated temperature. By enabling additional control in the thermo-response hysteresis, this methodology provides a solution to continuously shield the dazzling afternoon sunshine until a comfortable outdoor temperature is reached. And the response degree and response temperature can be adjusted by the contents of chitosan and Al3+, respectively, so that the material can be customized personally. Moreover, we discovered that the hydrogel-based smart window system constructed by this methodology bears notably enhanced strength, toughness and conductivity, making it a comprehensively promising candidate for customizable smart windows.