Assessment of rehabilitation strategies for lakes affected by anthropogenic and climatic changes: A case study of the Urmia Lake, Iran

Over the last three decades,more than half of the world's large lakes and wetlands have experienced significant shrinkage,primarily due to climate change and extensive water consumption for agriculture and other human needs.The desiccation of lakes leads to severe environmental,economic,and social repercussions.Urmia Lake,located in northwestern Iran and representing a vital natural ecosystem,has experienced a volume reduction of over 90.0%.Our research evaluated diverse water management strategies within the Urmia Lake basin and prospects of inter-basin water transfers.This study focused on strategies to safeguard the environmental water rights of the Urmia Lake by utilizing the modeling and simulating(MODSIM)model.The model simulated changes in the lake's water volume under various scenarios.These included diverting water from incoming rivers,cutting agricultural water use by 40.0%,releasing dam water in non-agricultural seasons,treated wastewater utilization,and inter-basin transfers.Analytical hierarchy process(AHP)was utilized to analyze the simulation results.Expert opinions with AHP analysis,acted as a multi-criteria decision-making tool to evaluate the simulation and determine the optimal water supply source priority for the Urmia Lake.Our findings underscore the critical importance of reducing agricultural water consumption as the foremost step in preserving the lake.Following this,inter-basin water transfers are suggested,with a detailed consideration of the inherent challenges and limitations faced by the source watersheds.It is imperative to conduct assessments on the impacts of these transfers on the downstream users and the potential environmental risks,advocating for a diplomatic and cooperative approach with adjacent country.This study also aims to forecast the volumes of water that can be transferred under different climatic conditions—drought,normal,and wet years—to inform strategic water management planning for the Urmia Lake.According to our projection,implementing the strategic scenarios outlined could significantly augment the lake's level and volume,potentially by 3.57×109–9.38×109 m3 over the coming 10 a and 3.57×109–10.70×109 m3 in the subsequent 15 a.

Proposal of Landscape Space Transfer Index and Changes of Landscape Area Based on Transfer Matrix——With Yutian County in Xinjiang as a Study Case

The most significant changes of landscape in a certain period are landscape area changes and spatial changes of landscape patches.Based on transfer matrix and total amount change of landscape area,landscape space transfer index and landscape area change index were established,and then applied to analyze plain oasis and desert in Yutian County,Xinjiang Uyghur Nationality Autonomous Region,the results showed that landscape space transfer in this region was drastic,but total landscape area changed only slightly,thus space transfer index was much higher than area change index,which indicated that landscapes in arid area were given with particular spatial undulant features and sensitivity,while man-made landscapes(artificial oasis) are stable and expanding to some extent.With landscape space transfer index as the comprehensive indicator,space transfer intensity of landscape within a certain period can be demonstrated,which is favorable for the comparison of landscape change intensity among different types and within different periods,in addition,some macroscopic change features of landscapes can also be reflected by comprehensively analyzing landscape space transfer index and landscape area change index.

Heat transfer and parametric studies of an encapsulated phase change material based cool thermal energy storage system

This work investigates the transient behaviour of a phase change material based cool thermal energy storage (CTES) system comprised of a cylindrical storage tank filled with encapsulated phase change materials (PCMs) in spherical container integrated with an ethylene glycol chiller plant. A simulation program was developed to evaluate the temperature histories of the heat transfer fluid (HTF) and the phase change material at any axial location during the charging period. The results of the model were validated by comparison with experimental results of temperature profiles of HTF and PCM. The model was also used to investigate the effect of porosity, Stanton number, Stefan number and Peclet number on CTES system performance. The results showed that increase in porosity contributes to a higher rate of energy storage. However, for a given geometry and heat transfer coefficient, the mass of PCM charged in the unit decreases as the increase in porosity. The St number as well as the Ste number is also influential in the performance of the unit. The model is a convenient and more suitable method to determine the heat transfer characteristics of CTES system. The results reported are much useful for designing CTES system.

Experimental study of the mass transfer behavior of carbon dioxide absorption into ternary phase change solution in a packed tower

Phase change absorbents for CO_(2)are of great interest because they are expected to greatly reduce the heat energy consumption during the regeneration process.Compared with other phase change absorbents,monoethanolamine(MEA)-sulfolane-water is inexpensive and has a fast absorption rate.It is one of the most promising solvents for large-scale industrial applications.Therefore,this study investigates the mass transfer performance of this phase change system in the process of CO_(2)absorption in a packed tower.By comparing the phase change absorbent and the ordinary absorbent,it is concluded that the use of MEA/sulfolane phase change absorbent has significantly improved mass transfer efficiency compared to a single MEA absorbent at the same concentration.In the 4 mol·L^(-1)MEA/5 mol·L^(-1)sulfolane system,the CO_(2)loading of the upper liquid phase after phase separation is almost zero,while the volume of the lower liquid phase sent to the desorption operation is about half of the total volume of the absorbent,which greatly reduces the energy consumption.This study also investigates the influence of operating parameters such as lean CO_(2)loading,gas and liquid flow rates,CO_(2)partial pressure,and temperature on the volumetric mass transfer coefficient(K_(G)α_(V)).The research shows that K_(G)α_(V) increases with increasing liquid flow rate and decreases with the increase of lean CO_(2)loading and CO_(2)partial pressure,while the inert gas flow rate and temperature have little effect on K_(G)α_(V).In addition,based on the principle of phase change absorption,a predictive equation for the K_(G)α_(V) of MEA-sulfolane in the packed tower was established.The K_(G)α_(V) obtained from the experiment is consistent with the model prediction,and the absolute average deviation(AAD)is 7.8%.

Effect of different heat transfer fluids on discharging performance of phase change material included cylindrical container during forced convection

In the present work,effects of various heat transfer fluids on the discharging performance of a phase change material(PCM) included cylindrical container are numerically assessed during forced convection.The heat transfer fluid air,hydrogen,water and nanofluid with alumina particles are used and the the geometric variation of the PCM embedded region is also considered.The finite element method is used as the solver.Dynamic features of heat exchange with various phases are explored for different heat transfer fluid types,Reynolds number(between 100 and 300) and PCM embedded region geometric variation(h_(x)between 0.01 d_(1) and 0.65 d_(1),hybetween 0.1 h_(1) and 0.4 h_(1)).It is observed that discharging time is significantly influenced by the heat transfer fluid type while full phase transition time for air is obtained as more than 10 times when hydrogen is utilized as heat transfer fluid.The best performance is achieved with nanofluid.When the PCM integrated region size is reduced,discharging time is generally reduced while due to the form of the geometry,vortex formation is established in the PCM region.This results in performance degeneration at the highest radius and height of the inner cylinder.Discharging time increases by about 12% when radius of the inner cylinder is increased from h_(x)=0.35 d_(1) to h_(x)=0.45 d_(1).Dynamic features of PCM temperature and liquid fraction are affected with Reynolds number while discharging time is reduced by about 48% when configurations with the lowest and highest Reynolds number are compared.

Numerical study on freezing-thawing phase change heat transfer in biological tissue embedded with two cryoprobes

A two-dimensional model for freezing and thawing phase change heat transfer in biological tissue embedded with two cryoprobes was established.In this model,the blood vessels were considered as tree-like branched fractal network,and the effective flow rate and effective thermal conductivity of blood were obtained by fractal method.The temperature distribution and ice crystal growth process in biological tissue embedded with two cryoprobes during freezing-thawing process were numerically simulated.The results show that the growth velocity of ice crystal in freezing process from 200 to 400 s is more rapid than that from 400 to 600 s. Thawing process of frozen tissue occurs in the regions around cryoprobes tips and tissue boundary simultaneously,and the phase interfaces are close to each other until ice crystal melts completely.The distance of two cryoprobes has a more profound effect on the temperature distribution in freezing process at 400 s than at 800 s.

Heat transfer performance testing of a new type of phase change heat sink for high power light emitting diode

In view of the limitations of solid metal heat sink in the heat dissipation of high power light emitting diode （LED）, a kind of miniaturized phase change heat sink is developed for high power LED packaging. First, the fabrication process of miniaturized phase change heat sink is investigated, upon which all parts of the heat sink are fabricated including main-body and end-cover of the heat sink, the formation of three-dimensional boiling structures at the evaporation end, the sintering of the wick, and the encapsulation of high power LED phase change heat sink. Subsequently, with the assistance of the developed testing system, heat transfer performance of the heat sink is tested under the condition of natural convection, upon which the influence of thermal load and working medium on the heat transfer performance is investigated. Finally, the heat transfer performance of the developed miniaturized phase change heat sink is compared with that of metal solid heat sink. Results show that the developed miniaturized phase change heat sink presents much better heat transfer performance over traditional metal solid heat sink, and is suitable for the packaging of high power LED.

Heat Transfer Characteristics of Work Fluid Including Phase Change Material That Flow into Heating Surface from Narrow Path

Use of the low temperature (less than 100°C) energy contributes to effective use of heat resources. The cost recovery by power generation is difficult by using an existing system (the binary cycle or the thermoelectric conversion element), because the initial investment is large. The final purpose of this research is development of the low temperature difference drive engine supposing use in a hot-springs resort as a power source for electric power generation. In order that a traveler may look at and delight a motion of an engine, it is made to drive at low-speed number of rotations. An engine cycle of this study is aimed at the development of Stirling cycle engine which can maintain high efficiency in small size. This kind of engine has simple structure;it brings low cost, and it is easy to perform maintenance. However, it is difficult to obtain enough output by this type of engine, because of its low temperature difference. This paper deals with the heat transfer characteristic that the working fluid including a phase change material flows into the heating surface from the narrow path. In order to increase the amount of the heat transmission, Diethylether is added to the working fluid. Diethylether is selected as a phase change material (PCM) that has the boiling point which exists between the heat source of high temperature and low temperature. The parameters of the experiment are additive amount of PCM, rotational speed of the displacer piston and temperature of heat transfer surface. It is shown that it is possible to make exchange of heat amount increase by adding phase change material. The result of this research shows the optimal condition of the difference in temperature in heat processing, number of revolutions, and addition concentration of PCM.

Exact analytical solution to three-dimensional phase change heat transfer problems in biological tissues subject to freezing

Analytically solving a three-dimensional （3-D） bioheat transfer problem with phase change during a freezing process is extremely difficult but theoretically important. The moving heat source model and the Green function method are introduced to deal with the cryopreservation process of in vitro biomaterials. Exact solutions for the 3-D temperature transients of tissues under various boundary conditions, such as totally convective cooling, totally fixed temperature cooling and a hybrid between them on tissue surfaces, are obtained. Furthermore, the cryosurgical process in living tissues subject to freezing by a single or multiple cryoprobes is also analytically solved. A closed-form analytical solution to the bioheat phase change process is derived by considering contributions from blood perfusion heat transfer, metabolic heat generation, and heat sink of a cryoprobe. The present method is expected to have significant value for analytically solving complex bioheat transfer problems with phase change.

Investigation of Coulomb stress changes in south Tibet(central Himalayas) due to the 25th April 2015 M_W 7.8 Nepal earthquake using a Coulomb stress transfer model

After Mw 7.8 Nepal earthquake occurred, the rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. We present the calculations of the coseismic stress changes that resulted from the 25th April event using models of regional faults designed according to south Tibet-Nepal structure, and show that some indicative significant stress increases. We calculate static stress changes caused by the displacement of a fault on which dislocations happen and an earthquake occurs. A Mw 7.3 earthquake broke on 12 May at a distance of - 130 km SEE of the Mw 7.8 earthquake, whose focus roughly located on high Coulomb stress change （CSC） site. Aftershocks （first 15 days after the mainshock） are associated with stress increase zone caused by the main rupture. We set receiver faults with specified strikes, dips, and rakes, on which the stresses imparted by the source fault are resolved. Four group normal faults to the north of the Nepal earthquake seismogenic fault were set as receiver faults and variant results followed. We provide a discussion on Coulomb stress transfer for the seismogenic fault, which is useful to identify potential future rupture zones.

Inter-Basin Water Transfer Projects and Climate Change: The Role of Allocation Protocols in Economic Efficiency of the Project. Case Study: Dez to Qomrood Inter-Basin Water Transmission Project (Iran)

Nowadays, there is a growing emphasis on Inter-basin water transfer projects as costly activities with ambiguous effects on environment, society and economy. Since the concept of climate change was in its embryonic phase before 1990’s, the majority of these projects planned before that period have not considered the effect of long term variation of water resources. In all of these numerous operational and under-construction projects, an intelligent selection of the best water transmission protocol, can help the governments to optimize their expenditures on these projects ,and also can help water resources managers to face climate change effects wisely. In this paper as a case study, Dez to Qomrood inter-basin water transfer project is considered to evaluate the efficiency of three different protocols in long term. The effect of climate change has been forecasted via a wide range of GCMs (Global Circulation Model) in order to calculate the change of flow in the basin's area with different climate scenarios. After these calculation, a water allocation model has been used to evaluate which of these three water transmission protocols (Proportional Allocation (PA), Fix Upstream allocation (FU), and Fix Downstream allocation (FD)) is the most efficient logic switch economically in a framework including both upstream and downstream stakeholders. As the final result, it can be inferred that Fix Downstream allocation (FD) protocol can supply more population especially with urban water for a fix expense and also is the most adapted protocol with future global change, at least in the first round of sustainability assessment.

Paraffin–CaCl_(2)·6H_(2)O dosage effects on the strength and heat transfer characteristics of cemented tailings backfill

The challenge of high temperatures in deep mining remains harmful to the health of workers and their production efficiency The addition of phase change materials (PCMs) to filling slurry and the use of the cold storage function of these materials to reduce downhole temperatures is an effective approach to alleviate the aforementioned problem.Paraffin–CaCl_(2)·6H_(2)O composite PCM was prepared in the laboratory.The composition,phase change latent heat,thermal conductivity,and cemented tailing backfill (CTB) compressive strength of the new material were studied.The heat transfer characteristics and endothermic effect of the PCM were simulated using Fluent software.The results showed the following:(1) The new paraffin–CaCl_(2)·6H_(2)O composite PCM improved the thermal conductivity of native paraffin while avoiding the water solubility of CaCl_(2)·6H_(2)O.(2) The calculation formula of the thermal conductivity of CaCl_(2)·6H_(2)O combined with paraffin was deduced,and the reasons were explained in principle.(3) The“enthalpy–mass scale model”was applied to calculate the phase change latent heat of nonreactive composite PCMs.(4)The addition of the paraffin–CaCl_(2)·6H_(2)O composite PCM reduced the CTB strength but increased its heat absorption capacity.This research can give a theoretical foundation for the use of heat storage backfill in green mines.

Evaluation of Characteristics of Phase Change Heat Transfer in Ultrafine Cryoprobe

To reduce the invasiveness of cryosurgery, a miniaturized cryoprobe is necessary. The authors have developed an ultrafine cryoprobe for realizing low-invasive cryosurgery by local freezing. The objectives of this study are to estimate the heat transfer coefficient and investigate the characteristics of the phase change heat transfer in the ultrafine cryoprobe. This cryoprobe has a double-tube structure consisting of two stainless steel microtubes. The outer diameter of the cryoprobe was 550 μm. The alternative Freon HFC-23, which has a boiling point of ?82?C at 0.1 MPa, was used as a refrigerant. To evaluate the characteristics of boiling flow in the cryoprobe, the heat transfer coefficient was estimated. The derived heat transfer coefficient was higher than that obtained from the conventional correlation. Additionally, a bubble expansion model was introduced to evaluate the heat transfer mode of the phase change flow in the ultrafine cryoprobe. This model can estimate the liquid film thickness during the expansion of a single bubble in a microchannel. The experimentally measured wall superheat was much lower than that obtained from the model. Therefore, this result also implied that the heat transfer mode in the ultrafine cryoprobe should be nucleate boiling.

Comparative Heat Transfer Data for Solid-Liquid Phase Change of D-Mannitol and Adipic Acid

The goal of this work was to measure the heat transfer rates from thermofluid, Therminol 66, to two phase change materials, D-mannitol and adipic acid. It concerns the determination of heat transfer coefficients for the design of a concentrated solar energy plant requiring PCM thermal energy storage and is part of a wider set of experiments, where several PCMs were tested. An experimental installation was used with a cylindrical vessel with three tubes disposed almost horizontally (5°inclination), containing the phase change material, around which the thermal fluid flowed almost perpendicular to the tubes. The experimental installation allowed to recreate heating and cooling cycles. In order to evaluate the influence of the flow on the rate at which the heating and cooling processes took place, tests were performed at different thermofluid mass flow rates, concluding that there is no great influence, since the thermal resistance inside the tubes is much higher than on the outside. D-mannitol and adipic acid, present different phase change temperatures, 164°C for D-mannitol and 152°C for adipic acid. The average heat transfer coefficient, during the phase change process, was of 340 W/(m2K) for D-mannitol and 1320 W/(m2K) for adipic acid.

Lattice Boltzmann simulation of phase change and heat transfer characteristics in the multi-layer deposition

The metal droplets deposition method(MDDM)is a rapid prototyping technology,implemented via metallurgy bonding within droplets.The anisotropy of heat transfer and re-melting is caused by an asymmetric deposition process.A lattice Boltzmann method(LBM)model is established to predict the heat transfer and phase change in the multi-layer deposition.The prediction model is verified by the experimental temperature profiles in existing literature.The monitoring points are set to compare the temperature profiles,and decoupling analyze the heat transfer mechanism in different positions.The negative relationships between the re-molten volume of the temperature difference,as well as the influence of the dispositive position and the relative position of the adjacent component are observed and analyzed under the heat conduction.This work is helpful to choose the appropriate temperature conditions and the optimal dispositive method.

Simplified Correlation Equations of Heat Transfer Coefficient during Phase Change for Flow inside Tubes

In this work, the easy to use, simple and direct equations were formulated and tested. These equations can be used to calculate the mean values of the heat transfer coefficients of inside tube flow during phase change. Analytical and experimental methods were used to correlate these equations. Two different forms were used, one for evaporation case and the other for condensation case. Carbon dioxide, CO2, was used as case study. Correlated values of the mean heat transfer coefficients （hcor,.） were compared with the experimental results （he^e） and with other published result, a good agreement was noticed. The resulted correlations can be used to simplify the design and performance studies of both condensers and evaporators.

Fabrication and testing of phase change heat sink for high power LED

A novel phase change heat sink was fabricated for packaging cooling of high power light emitting diode （LED）. 3D structures as enhanced boiling structure in the evaporation surface were composed of a spiral micro-groove along circumferential direction and radial micro-grooves which were processed by ploughing-extrusion （P-E） and stamping, respectively. Meanwhile, the cycle power of refrigerant was supplied by wick of sintered copper powder on internal surface of phase change heat sink. Operational characteristics were tested under different heat loads and refrigerants. The experimental results show that phase change heat sink is provided with a good heat transfer capability and the temperature of phase change heat sink reaches 86.8 ℃ under input power of 10 W LED at ambient temperature of 20 ℃.

Effect of Source-sink Change on Photosynthesis and Yield of Wheat

[Objective] The paper aims to explore the influences of source sink change of wheat at different densities on wheat yield.[Method] 225 （D1） and 320 plant/m2（D2） were adopted,then cutting flag leaf （L1）,the second last leaf （L2）,removing upper part of spike （L3） and controlling （CK） were used to conduct field experiment.[Result] The results showed that both of the two densities of wheat＇s 1 000-grain weight and grain filling rate after anthesis in a decreasing order of L3〉CK〉L2〉L1,and the grain weight per spike and dry matter amount translated after anthesis turned to be CK〉L2〉L1 〉L3.[Conclusion].Both of leaf-cutting and spikelet removing decreased the grain weight per spike and dry matter amount translated after anthesis.Removing upper part of spike increased wheat＇s 1 000-grain weight.But the decreasing of the sink and dry matter amount translated contributed to the decreasing of the yield of wheat.

Impact of Fin Arrangement on Heat Transfer and Melting Characteristics of Phase Change Material

Present work investigates the heat transfer and melting behaviour of phase change material(PCM) in six enclosures(enclosure-1 to 6) filled with paraffin wax.Proposed enclosures are equipped with distinct arrangements of the fins while keeping the fin's surface area equal in each case.Comparative analysis has been presented to recognize the suitable fin arrangements that facilitate improved heat transfer and melting rate of the PCM.Left wall of the enclosure is maintained isothermal for the temperature values 335 K,350 K and 365 K.Dimensionless length of the enclosure including fins is ranging between 0 and 1.Results have been illustrated through the estimation of important performance parameters such as energy absorbing capacity,melting rate,enhancement ratio,and Nusselt number.It has been found that melting time(to melt 100% of the PCM) is 60.5%less in enclosure-2(with two fins of equal length) as compared to the enclosure-1,having no fins.Keeping the fin surface area equal,if the longer fin is placed below the shorter fin(enclosure-3),melting time is further decreased by 14.1% as compared to enclosure-2.However,among all the configurations,enclosure-6 with wire-mesh fin structure exhibits minimum melting time which is 68.4% less as compared to the enclosure-1.Based on the findings,it may be concluded that fins are the main driving agent in the enclosure to transfer the heat from heated wall to the PCM.Proper design and positioning of the fins improve the heat transfer rate followed by melting of the PCM in the entire area of the enclosure.Evolution of the favourable vortices and natural convection current in the enclosure accelerate the melting phenomenon and help to reduce charging time.

Phase change analysis of an underwater glider propelled by the ocean's thermal energy

The phase change characteristic of the power source of an underwater glider propelled by the ocean＇s thermal energy is the key factor in glider attitude control. A numerical model has been established based on the enthalpy method to analyze the phase change heat transfer process under convective boundary conditions. Phase change is not an isothermal process, but one that occurs at a range of temperature. The total melting time of the material is very sensitive to the surrounding temperature. When the temperature of the surroundings decreases 8 degrees, the total melting time increases 1.8 times. But variations in surrounding temperature have little effect on the initial temperature of phase change, and the slope of the temperature time history curve remains the same. However, the temperature at which phase change is completed decreases significantly. Our research shows that the phase change process is also affected by container size, boundary conditions, and the power source＇s cross sectional area. Materials stored in 3 cylindrical containers with a diameter of 38ram needed the shortest phase change time. Our conclusions should be helpful in effective design of underwater glider power systems.