The authors have no acknowledgements.

Caution: There are two poisonous chemicals, methanol and ethylene glycol, used in these experiments. Methanol can be metabolized in the human body to generate formaldehyde and then to formic acid or formate salt. These substances are poisonous to the central nervous system and may even cause death. Ethylene glycol can be oxidized to glycolic acid, which can then turn into oxalic acid. This can cause kidney failure and death. Do not drink these chemicals. Consult a doctor immediately if an accident occurs.
1. The Cooling System
NOTE: It is very difficult to keep the brine at -18 &#176;C or so when the ambient temperature is roughly at room temperature. It is important that the tanks storing the ethylene glycol and brine are well-insulated and of a reasonable size to avoid excess electricity consumption and to ensure optimal system performance. It is recommended that the tank size does not exceed 30 L.
<ol>
	<li>Prepare the secondary cooling fluid
	<ol>
		<li>Pour 1 L of ethylene glycol into the secondary cooling tank, Tank A (Base: 400 mm &#215; 200 mm, Height: 350 mm). Add roughly 0.6-0.65 L (600-650 g) of water to Tank A.</li>
		<li>Repeat step 1.1.1 several times until there is enough fluid in Tank A (25 L).</li>
		<li>Stir the fluid so that the fluid is homogeneous.</li>
		<li>Switch on the two pumps in Tank A to the full-capacity setting (2,500 L/h). Make sure that all bubbles trapped in the heat exchangers and pipes are released.</li>
		<li>Switch off the pump to observe if all the bubbles are released. If not, repeat step 1.1.4.</li>
	</ol>
	</li>
	<li>Preparation of the brine 
	NOTE: In this example, 22 wt% brine is prepared. If other concentrations are needed, the mass of salt added should also be changed accordingly. The reference brine concentration and density values can be found on Page D-257 of the 64th Edition (1983) of the CRC Handbook of Chemistry and Physics46.
	<ol>
		<li>Add 4 kg of water into a 5-L plastic beaker.</li>
		<li>Measure 1 kg of NaCl salt on an electronic scale and pour this salt into the beaker with the water.</li>
		<li>Stir the mixture until the solution is clear (i.e., there are no salt particles or water bubbles visible in the solution).</li>
		<li>Take a sample, ~10 mL, of the solution using a 10-mL syringe.</li>
		<li>Inject the fluid into the U-tube density meter.</li>
		<li>Check for air bubbles in the tube. If there are any, inject more fluid to push them out.</li>
		<li>Press &#34;Quick Settings&#34; and select &#34;Density Temperature.&#34; Type in 20 &#176;C and press &#34;OK.&#34; The density meter will now measure the fluid density at this temperature.</li>
		<li>Press start and wait for the result.</li>
		<li>Compare the density reading with 1164.00 kg/m3.</li>
		<li>Add more salt if the reading is below the comparison density. Add water if otherwise.</li>
		<li>Repeat steps 1.2.3-1.2.10 until the fluid density is correct (1164.00 kg/m3).</li>
		<li>Pour this solution into a larger container, Container A.</li>
		<li>Use steps 1.2.1-1.2.12 to make 35-40 L of brine and put Container A into a chest freezer at -40 &#176;C. Keep the brine there for 48-72 h, until its temperature reaches -19.18 &#176;C (freezing point of this 22 wt% brine).</li>
	</ol>
	</li>
</ol>
2. Preparation of the Ice for the Injecting and Washing Water
<ol>
	<li>Prepare ice for the injecting water
	<ol>
		<li>Pour 1 L of water into a small container (200 &#215; 200 &#215; 50 mm).</li>
		<li>Repeat step 2.1.1 with another container and place the two containers in the chest freezer at -40 &#176;C.</li>
		<li>Keep them in the freezer for 10 h or more to ensure that all of the water is frozen.</li>
	</ol>
	</li>
	<li>Prepare the washing water&#39;s ice shell
	<ol>
		<li>Fill a 5-L beaker with 5 L of water.</li>
		<li>Fill a 2-L beaker with 2 L of water.</li>
		<li>Place both beakers into the chest freezer at -40 &#176;C for 8-10 h so that there is a thick shell of ice wrapping around unfrozen water.</li>
		<li>Use a high-velocity water jet at a speed of 3-5 m/s from the tap to open up a 3-cm diameter hole at the top of the ice shell.</li>
		<li>Drain the water inside the ice shell.</li>
		<li>Put the two beakers back in the freezer.</li>
		<li>If the mass of the ice shell does not reach 3 kg and 1 kg for the two beakers, respectively, repeat steps 2.2.1-2.2.5, but keep the beakers in the freezer longer in step 2.2.3. The two beakers should now be able to contain 2 L and 1 L of water, respectively.</li>
	</ol>
	</li>
</ol>
3. Water Introduction Position and the Rheology Control Experiment
<ol>
	<li>Introduce water at the brine surface
	<ol>
		<li>Decant 2 L of 22 wt% cold brine from Container A into the aluminum bucket of the ice cream maker and switch on the cooling unit.</li>
		<li>Measure the temperature of the brine with a thermometer/thermocouple (either K-Type or T-type are suitable). Carry on the experiment if the brine is -15 &#176;C or lower.</li>
		<li>Fill up the 100-mL glass syringe with tap water at room temperature. Attach a 2-mm internal diameter, 1-mm thick, and 1-m long silicone tube to the tip of the syringe.</li>
		<li>Place the syringe at a specific position such that there is a head between the water in the syringe and the exit of the silicone tube. The hydrostatic pressure will squeeze the water out of the tube.</li>
		<li>Submerge a certain length of the silicone tube, typically 70 cm, into the brine.</li>
		<li>Adjust the relative position between the syringe and the tube exit so that the hydrostatic pressure is great enough to allow water to leave the syringe. If the tube is blocked, increase the head by elevating the syringe to a higher vertical position, until the hydrostatic pressure can overcome the shear stress within the tube.</li>
		<li>Keep the tube exit roughly 1 cm or less above the brine surface.</li>
		<li>Adjust the length of submerged tube and the syringe height to control the water&#39;s outlet let temperature and flow rate in order to determine how much ice can be made or how much mixing occurs at the brine surface. The freezing phenomenon should now be observed at the brine surface. See Reference 45 for further direction.</li>
	</ol>
	</li>
	<li>Introduce water through the brine
	<ol>
		<li>Repeat steps 3.1.1-3.1.6.</li>
		<li>Keep the tube exit inside the brine, preferably at the bottom of the container.</li>
		<li>Adjust the length of the submerged tube and the syringe height.</li>
		<li>Adjust the angle of the tube exit to control the rheology of the flow.</li>
		<li>Repeat steps 3.2.3-3.2.4 to find the best coupled flow rheology and flow rate that can produce the most ice.</li>
	</ol>
	</li>
</ol>
4. Ice Production, Collection, and Measurement
<ol>
	<li>Make ice
	<ol>
		<li>If there are bubbles in the pipes, switch on the two pumps inside Tank A to release the bubbles out of the glycol circulation system, and then switch off the pumps.</li>
		<li>Switch on the three refrigeration units and let them run for 10-16 h to cool down the ethylene glycol solutions.</li>
		<li>Measure the ethylene glycol solution with a thermometer/thermocouple. The glycol temperature should be at about -25 &#176;C.</li>
		<li>Measure the temperature of the brine in Container A to make sure it is at -19 &#176;C before proceeding to step 4.1.5.</li>
		<li>Fill the brine tank, Tank B, with roughly 30 L of brine from Container A and switch on the two pumps in Tank A.</li>
		<li>Measure the temperature of the glycol in Tank A. If it is colder than -19 &#176;C, switch off one or more cooling units to prevent the precipitation of ice particles outside the heat exchangers in Tank B. If the temperature is warmer than the expected brine temperature, turn on all three cooling units. Carry out the experiment at -17 &#176;C to -19 &#176;C.</li>
		<li>Place the two premade blocks of ice from step 2.1 into the insulated 5-L beaker, Container B, and pour roughly 3 L of water into the beaker.</li>
		<li>Measure the water temperature and keep it at 2 &#176;C by stirring the mixture between experiments if the temperature rises.</li>
		<li>Fill the glass syringe with 100 mL of the 2 &#176;C water.</li>
		<li>Apply 5-10 mL of methanol to the glass window of Tank B to stop condensation and the formation of ice.</li>
		<li>Inject the water into the brine by adjusting the relative position between the syringe and the tube&#39;s exit so that there is a constant hydrostatic pressure and thus a constant flow rate. About 70 cm of the silicone tube should be submerged in the brine. Adjust the angle of injection to 0&#176; so that the initial water velocity in the upward direction is 0 m/s. 
		NOTE: The syringe can be either hand-held or clamped to a stand. Hand-held is more appropriate when the brine temperature is colder, because it takes more time to adjust a stand, and ice may block the tube. Keep the flow rheology consistent throughout the experiment by ensuring a constant flow rate and injection angle (0&#176;) and by keeping the freezing frontier roughly 3 cm above the tube exit. Do not let the flow enter the region where it starts to turn turbulent47. See Reference 45 for further direction.</li>
		<li>Collect the ice as described in steps 4.2 and 4.3. Repeat steps 4.1.8 - 4.1.11 at different brine temperatures.</li>
	</ol>
	</li>
	<li>Collect the produced ice and estimate how much ice is produced (dry collection)
	<ol>
		<li>Put a container (200 &#215; 200 &#215; 50 mm) on the scale and zero the reading by pressing the &#34;Turn On&#34; button.</li>
		<li>Use the sieve to scoop out the ice and shake off the brine.</li>
		<li>Put this ice in the container. Measure the mass of the ice using the scale.</li>
		<li>After the ice is melted, use the 10-mL syringe to take a sample. Inject this sample of liquid into the density meter.</li>
		<li>Perform steps 1.2.6-1.2.9.</li>
		<li>Record the density reading.</li>
		<li>Calculate the net water mass from its density (i.e., the mass of water converted into ice) using the following formula: 
		<img alt="Equation" src="/files/ftp_upload/55014/55014eq1.jpg" /> 
		where <img alt="Equation" src="/files/ftp_upload/55014/55014eq2.jpg" /> is the brine concentration by wt% and <img alt="Equation" src="/files/ftp_upload/55014/55014eq3.jpg" /> and <img alt="Equation" src="/files/ftp_upload/55014/55014eq4.jpg" /> are the masses of salt and water, respectively.</li>
	</ol>
	</li>
	<li>Collect the produced ice and estimate how much ice is produced (wet collection)
	<ol>
		<li>Fill the 5-L beaker with an ice shell (step 2.2) and room-temperature tap water. Put it back into the freezer at -40 &#176;C.</li>
		<li>Decant the water with the ice shell from the 5-L beaker into a 2-L beaker when its temperature is at 0 &#176;C. Fill up the 5-L beaker. Keep both beakers in the freezer.</li>
		<li>Scoop out the ice produced in steps 4.1.8 and 4.1.9 and pour 200-500 mL of water from the 2-L beaker onto the ice to wash it. Do not shake the sieve before applying the 0 &#176;C water.</li>
		<li>Shake off the fluid in the sieve.</li>
		<li>Repeat steps 4.2.2-4.2.7.</li>
	</ol>
	</li>
</ol>

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Res. 75, 583-597 (1970).</li><li>Wettlaufer, J. S., Worster, M. G., Huppert, H. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Natural+convection+during+solidification+of+an+alloy+from+above+with+application+to+the+evolution+of+sea+ice.">Natural convection during solidification of an alloy from above with application to the evolution of sea ice.</a> J. Fluid Mech. 344, 291-316 (1997).</li><li>Paige, R. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Stalactite+Growth+beneath+Sea+Ice.">Stalactite Growth beneath Sea Ice.</a> Science. 167, 171-172 (1970).</li><li>Dayton, P. K., Martin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Observations+of+ice+stalactites+in+McMurdo+Sound,+Antarctica.">Observations of ice stalactites in McMurdo Sound, Antarctica.</a> J. Geophys. Res. 76, 1595-1599 (1971).</li><li>Eide, L. I., Martin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+formation+of+brine+drainage+features+in+young+sea+ice.">The formation of brine drainage features in young sea ice.</a> J. Glaciol. 14, 137-154 (1975).</li><li>Martin, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+stalactites:+comparison+of+a+laminar+flow+theory+with+experiment.">Ice stalactites: comparison of a laminar flow theory with experiment.</a> J. Fluid Mech. 63, 51-79 (1974).</li><li>Jeffs, K., Attenborough, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Frozen Planet: Episode 5 'Winter'. , (2011).</li><li>Fothergill, A., Berlowitz, V., Attenborough, D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ch.+Winter:+Life+closes+down.">Ch. Winter: Life closes down.</a> in Frozen Planet: A World Beyond Imagination. , (2011).</li><li>Yun, X., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Ice+formation+in+the+subcooled+brine+environment.">Ice formation in the subcooled brine environment.</a> Int. J. Heat Mass Transfer. 95, 198-205 (2016).</li><li>Weast, R. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> CRC Handbook of Chemistry and Physics. 64, 257-258 (1983).</li><li>Bejan, A., Lage, J. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+Prandtl+Number+Effect+on+the+Transition+in+Natural+Convection+Along+a+Vertical+Surface.">The Prandtl Number Effect on the Transition in Natural Convection Along a Vertical Surface.</a> J. Heat Transfer. 112, 787-790 (1990).</li></ol>

The authors have nothing to disclose.

The process of ice generation using brine as a secondary refrigerant involves the combination of heat and mass transfer. If the heat transfer is greater, then ice forms before the water has the chance to mix with the bulk fluid. It was observed that when there is a relative movement between the introduced water and the quiescent bulk brine (i.e., injecting water within the brine), the flow helps the heat transfer and encourages ice to form rapidly. However, when there is too much turbulence in the flow, no ice c...

Ice slurries are extensively used in industry, and one particularly successful application is the ice-pigging technology1,2. In comparison to the conventional foam and solid pig, the ice pig can travel through complex topologies over a long distance because of the lubrication effect of the liquid phase and the elevation of its freezing point as some of the ice crystals melt3,4,5. Even if the pig gets stuck, one can simply wait for the ice slurries to melt and resume the cleaning process later. This method of pipe cleaning is cheap and easy to use.
The ice fraction plays a key role in the performance of the ice pig. To measure the ice fraction, one can use a cafeti&#232;re (French press) to determine if the ice slurry is thick enough6,7. A high cafeti&#232;re ice fraction, typically 80%, is required when carrying out ice pigging. Recent research on online ice fraction detection showed that both electromagnetic and ultrasonic waves are suitable for the job8,9,10,11.
The ice pig is usually made by a scraped-surface ice maker from a 5 wt% NaCl solution (brine). It is also the primary way of making ice slurries in industry. This type of ice maker freezes water or brine onto a cold metallic surface, typically a smooth 316 steel surface and then cyclically shears the ice particles off. The liquid-to-metal interfaces are very complex and are affected by a broad range of factors that are essential to ice making12. The interface between non-metal and water can be very different, and one especially interesting example is Kaolinite. The Kaolinite-water interface is special because there is not a favorable ice structure adjacent to the solid&#39;s surface, but rather a layer of amphoteric substrate fluid that encourages the ice-like hydrogen-bonded clusters to form on top of it13,14. Another way of producing the ice pig requires crushing the premade ice blocks while high-concentration brine is added simultaneously. For this method, the refrigeration system can run at a much higher evaporating temperature because no freezing point depressant (FPD) is added prior to the formation of ice; it is hence considered more efficient due to the lowered compression ratio and lessened power for a given cooling duty15,16,17.
There are two other ice production methods: producing ice from supercooled water and putting refrigerant and water in direct contact18,19. The supercooling method involves disturbing the metastable supercooled water to generate ice nucleation and growth. The biggest problem for this method is the unwanted ice formation that can block the system. The direct contact method is considered not suitable for ice pigging because neither refrigerant nor lubrication oil are wanted in the final ice product.
The formation of ice requires heat and mass transfer due to the latent heat of fusion generated in the process. It was first discovered by Osborn Reynolds in 1874 that the transportation of heat and mass in gases are strongly coupled and can be expressed in similar mathematical formulae20. This work formed the pioneering paper on the subject of momentum, heat, and mass transfer in fluids and was reprinted several times21,22. This subject was then studied by a number of others, from both analytical and empirical approaches, for gases, liquids, and molten metal23,24,25,26,27,28,29,30,31,32,33. Aside from the heat and mass transfer, the fluid needs nucleation sites where dendritic ice growth can develop. A modern insight into the growth of ice crystals uses Constructal Law, developed by Adrian Bejan, to explain why ice grows in this way34,35,36.
The ice formation in brine is very different from that in pure water due to the existence of salt. First of all, salt changes the thermodynamics of the fluid and depresses its freezing point. Secondly, salt cannot dissolve in the ice matrix (except for hydrohalite, which can only form when the temperature reaches the eutectic point), and it is rejected to the bulk fluid when ice starts to grow. The rejection of salt was discovered in both sea ice and ice studied in the lab37,38. Since the rejected high-concentration brine is at a temperature well below the freezing point of sea water, as it descends, ice grows at the interface between the flowing brine and the quiescent bulk fluid. These ice stalactites, also named brinicles, were first discovered in McMurdo Sound, Antarctica and were studied experimentally39,40,41,42. In 2011, BBC filmed the formation of brinicles in its Frozen Planet series43,44.
In our lab, it was discovered that by reversing the flowing and quiescent fluids when water is introduced to a bath of cold brine, the water may transform into ice under the correct conditions45. It was found that the location where the water is introduced, flow rheology, and brine temperature and concentration are all key factors influencing how much ice can be produced. The overall goal of this study is to investigate if an ice maker can be developed through this mechanism to generate ice slurries, considering that the elevated evaporator temperature and the high rate of liquid-to-liquid heat transfer can enhance the efficiency of energy usage. This article shares key aspects of the experiment.

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ice generation and the heat and mass transfer phenomena of introducing water to a cold bath of brine

We demonstrate a method for the study of the heat and mass transfer and of the freezing phenomena in a subcooled brine environment. Our experiment showed that, under the proper conditions, ice can be produced when water is introduced to a bath of cold brine. To make ice form, in addition to having the brine and water mix, the rate of heat transfer must bypass that of mass transfer. When water is introduced in the form of tiny droplets to the brine surface, the mode of heat and mass transfer is by diffusion. The buoyancy stops water from mixing with the brine underneath, but as the ice grows thicker, it slows down the rate of heat transfer, making ice more difficult to grow as a result. When water is introduced inside the brine in the form of a flow, a number of factors are found to influence how much ice can form. Brine temperature and concentration, which are the driving forces of heat and mass transfer, respectively, can affect the water-to-ice conversion ratio; lower bath temperatures and brine concentrations encourage more ice to form. The flow rheology, which can directly affect both the heat and mass transfer coefficients, is also a key factor. In addition, the flow rheology changes the area of contact of the flow with the bulk fluid.

Figure 1 compares the effects of water introduced at the brine surface to water injected through the brine. In the &#34;ice-cap&#34; scenario, the formed ice is solid because the water did not mix much with the bulk fluid. The temperature and density difference between the two fluids generates buoyancy force on the water and prevents them from mixing. Both fluids are static (i.e., the heat transfer is much greater than that of the mass; Sc &#8776; 500, Pr &#8776;...

Watch this Scientific Journal Video about Ice Generation and the Heat and Mass Transfer Phenomena of Introducing Water to a Cold Bath of Brine at JoVE.com

Ice Generation and the Heat and Mass Transfer Phenomena of Introducing Water to a Cold Bath of Brine

Here, we present a protocol to demonstrate the generation of ice when water is introduced to a cold bath of brine, as a secondary refrigerant, at a range of temperatures well below the freezing point of water. It can be used as an alternative way of producing ice for industry.

We demonstrate a method for the study of the heat and mass transfer and of the freezing phenomena in a subcooled brine environment. Our experiment showed ...

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Temperature and Heat

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13.8K Views.  University of Bristol. Here, we present a protocol to demonstrate the generation of ice when water is introduced to a cold bath of brine, as a secondary refrigerant, at a range of temperatures well below the freezing point of water. It can be used as an alternative way of producing ice for industry.

Video: Ice Generation and the Heat and Mass Transfer Phenomena of Introducing Water to a Cold Bath of Brine

Reservoir Condition Pore-scale Imaging of Multiple Fluid Phases Using X-ray Microtomography

X-ray microtomography was used to image, at a resolution of 6.6 &#181;m, the pore-scale arrangement of residual carbon dioxide ganglia in the pore-space of a carbonate rock at pressures and temperatures representative of typical formations used for CO2 storage. Chemical equilibrium between the CO2, brine and rock phases was maintained using a high pressure high temperature reactor, replicating conditions far away from the injection site. Fluid flow was controlled using high pressure high temperature syringe pumps. To maintain representative in-situ conditions within the micro-CT scanner a carbon fiber high pressure micro-CT coreholder was used. Diffusive CO2 exchange across the confining sleeve from the pore-space of the rock to the confining fluid was prevented by surrounding the core with a triple wrap of aluminum foil. Reconstructed brine contrast was modeled using a polychromatic x-ray source, and brine composition was chosen to maximize the three phase contrast between the two fluids and the rock. Flexible flow lines were used to reduce forces on the sample during image acquisition, potentially causing unwanted sample motion, a major shortcoming in previous techniques. An internal thermocouple, placed directly adjacent to the rock core, coupled with an external flexible heating wrap and a PID controller was used to maintain a constant temperature within the flow cell. Substantial amounts of CO2 were trapped, with a residual saturation of 0.203 &#177; 0.013, and the sizes of larger volume ganglia obey power law distributions, consistent with percolation theory.

We present a methodology for the imaging of multiple fluid phases at reservoir conditions by the use of x-ray microtomography. We show some representative results of capillary trapping in a carbonate rock sample.

X-ray microtomography was used to image, at a resolution of 6.6 &#181;m, the pore-scale arrangement of residual carbon dioxide ganglia in the pore-space ...

Experimental System of Solar Adsorption Refrigeration with Concentrated Collector

To improve the performance of solar adsorption refrigeration, an experimental system with a solar concentration collector was set up and investigated. The main components of the system were the adsorbent bed, the condenser, the evaporator, the cooling sub-system, and the solar collector. In the first step of the experiment, the vapor-saturated bed was heated by the solar radiation under closed conditions, which caused the bed temperature and pressure to increase. When the bed pressure became high enough, the bed was switched to connect to the condenser, thus water vapor flowed continually from the bed to the condenser to be liquefied. Next, the bed needed to cool down after the desorption. In the solar-shielded condition, achieved by aluminum foil, the circulating water loop was opened to the bed. With the water continually circulating in the bed, the stored heat in the bed was took out and the bed pressure decreased accordingly. When the bed pressure dropped below the saturation pressure at the evaporation temperature, the valve to the evaporator was opened. A mass of water vapor rushed into the bed and was adsorbed by the zeolite material. With the massive vaporization of the water in the evaporator, the refrigeration effect was generated finally. The experimental result has revealed that both the COP (coefficient of the performance of the system) and the SCP (specific cooling power of the system) of the SAPO-34 zeolite was greater than that of the ZSM-5 zeolite, no matter whether the adsorption time was longer or shorter. The system of the SAPO-34 zeolite generated a maximum COP of 0.169.

With solar energy as the driving force, a novel adsorption refrigeration system has been developed and experimentally investigated. Water vapor and zeolite formed the working pair of the adsorption system. This manuscript describes the setup of the experimental rig, the operation procedure, and the important results.

To improve the performance of solar adsorption refrigeration, an experimental system with a solar concentration collector was set up and investigated. The ...

Environment

Dynamic Pore-scale Reservoir-condition Imaging of Reaction in Carbonates Using Synchrotron Fast Tomography

Underground storage permanence is a major concern for carbon capture and storage. Pumping CO2 into carbonate reservoirs has the potential to dissolve geologic seals and allow CO2 to escape. However, the dissolution processes at reservoir conditions are poorly understood. Thus, time-resolved experiments are needed to observe and predict the nature and rate of dissolution at the pore scale. Synchrotron fast tomography is a method of taking high-resolution time-resolved images of complex pore structures much more quickly than traditional &#181;-CT. The Diamond Lightsource Pink Beam was used to dynamically image dissolution of limestone in the presence of CO2-saturated brine at reservoir conditions. 100 scans were taken at a 6.1 &#181;m resolution over a period of 2 hours. The images were segmented and the porosity and permeability were measured using image analysis and network extraction. Porosity increased uniformly along the length of the sample; however, the rate of increase of both porosity and permeability slowed at later times.

Synchrotron fast tomography was used to dynamically image dissolution of limestone in the presence of CO2-saturated brine at reservoir conditions. 100 scans were taken at a 6.1 &#181;m resolution over a period of 2 h.

Underground storage permanence is a major concern for carbon capture and storage. Pumping CO2 into carbonate reservoirs has the potential to dissolve ...

Measuring Electrical Conductivity to Study the Formation of Brines Under Martian Conditions

This paper describes a protocol to design experiments to study the formation of brines under Martian conditions and monitor the process with electrical conductivity measurements. We used the Engineering Qualification Model (EQM) of Habitability: Brines, Irradiation, and Temperature (HABIT)/ExoMars 2022 instrument for the experiment setup but we provide a brief account of constructing a simple and inexpensive electrical conductivity measurement setup. The protocol serves to calibrate the electrical conductivity measurements of the salt deliquescence into brine in a simulated Martian environment. The Martian conditions of temperature (-70 &#176;C to 20 &#176;C), relative humidity (0% to 100%) and pressure (7 - 8 mbar) with carbon-dioxide atmosphere were simulated in the SpaceQ Mars simulation chamber, a facility at the Lule&#229; University of Technology, Sweden. The hydrate form of the known amount of salt accommodated between a pair of electrodes and thus the electrical conductivity measured depends predominantly on its water content and the temperature and relative humidity of the system. Electrical conductivity measurements were carried out at 1 Hz while exposing salts to a continuously increasing relative humidity (to force transitioning through various hydrates) at different Martian temperatures. For demonstration, a day-night cycle at Oxia Planum, Mars (the landing site of ExoMars 2022 mission) was recreated.

The objective of the protocol is to monitor the hydration of salts and the brine formation process. Electrical conductivity is used as the measurement technique. The experiments are performed in a simulated Martian environment of temperature, relative humidity and carbon-dioxide atmosphere.

This paper describes a protocol to design experiments to study the formation of brines under Martian conditions and monitor the process with electrical ...

Chemistry

A Microfluidic Approach for the Study of Ice and Clathrate Hydrate Crystallization

An accurate mechanistic description of water crystallization is challenging and requires a few key elements: superb temperature control to allow the formation of single microscopic crystals and a suitable microscopy system coupled to the cold stage. The method described herein adds another important feature that includes exchanging solutions around ice and clathrate hydrate crystals. The described system comprises a combination of unique and home-developed instruments, including microfluidics, high-resolution cold stages, and fluorescence microscopy. The cold stage was designed for microfluidic devices and allows for the formation of micron-sized ice/hydrate crystals inside microfluidic channels and the exchange of solutions around them. The temperature resolution and stability of the cold stage is one millikelvin, which is crucial for controlling the growth of these small crystals. This diverse system is used to study the different processes of ice and hydrate crystallization and the mechanism by which the growth of these crystals is inhibited. The protocol describes how to prepare microfluidic devices, how to grow and control microscopic crystals in the microfluidic channels, and how the utilization of the flow of liquids around ice/hydrate crystals affords new insights into the crystallization of water.

The present protocol describes the crystallization of microscopic ice crystals and clathrate hydrates in microfluidic devices, enabling liquid exchange around the formed crystals. This provides unparalleled possibilities to examine the crystallization process and binding mechanisms of the inhibitors.

An accurate mechanistic description of water crystallization is challenging and requires a few key elements: superb temperature control to allow the ...

Non-invasive Assessments of Subjective and Objective Recovery Characteristics Following an Exhaustive Jump Protocol

Fast recovery after strenuous exercise is important in sports and is often studied via cryotherapy applications. Cryotherapy has a significant vasoconstrictive effect, which seems to be the leading factor in its effectiveness. The resulting enhanced recovery can be measured by using both objective and subjective parameters. Two commonly measured subjective characteristics of recovery are delayed-onset muscle soreness (DOMS) and ratings of perceived exertion (RPE). Two important objective recovery characteristics are countermovement jump (CMJ) performance and peak power output (PPO). Here, we provide a detailed protocol to induce muscular exhaustion of the frontal thighs with a self-paced, 3 x 30 countermovement jump protocol (30-s rest between each set). This randomized controlled trial protocol explains how to perform local cryotherapy cuff application (+ 8 &#176;C for 20 min) and thermoneutral cuff application (+ 32 &#176;C for 20 min) on both thighs as two possible post-exercise recovery modalities. Finally, we provide a non-invasive protocol to measure the effects of these two recovery modalities on subjective (i.e., DOMS of both frontal thighs and RPE) and objective recovery (i.e., CMJ and PPO) characteristics 24, 48, and 72 h post-application. The advantage of this method is that it provides a tool for researchers or coaches to induce muscular exhaustion, without using any expensive devices; to implement local cooling strategies; and to measure both subjective and objective recovery, without using invasive methods. Limitations of this protocol are that the 30 s rest period between sets is very short, and the cardiovascular demand is very high. Future studies may find the assessment of maximum voluntary contractions to be a more sensitive assessment of muscular exhaustion compared to CMJs.

This protocol describes the procedure for non-invasive recovery assessments during a 72 h recovery period. This protocol induces muscular exhaustion of the frontal thighs using countermovement jumps and uses either local cold-cuff or thermoneutral-cuff application as a recovery modality.

Fast recovery after strenuous exercise is important in sports and is often studied via cryotherapy applications. Cryotherapy has a significant ...

Medicine

Experimental Multiscale Methodology for Predicting Material Fouling Resistance

The buildup of fouling deposits in energy systems degrades their ability to transfer heat, reducing efficiency and causing operational issues such as localized corrosion. Each application presents its own challenges. In nuclear power generation, the buildup of CRUD (Chalk River Unidentified Deposits) induces unique, negative effects ranging from reduced heat transfer, to axial power shifting, to CRUD-induced localized corrosion (CILC), the last of which can cause sudden fuel failure. Knowledge of why CRUD forms and how to prevent its adhesion to nuclear fuel rods represents a major step towards eliminating it. This paper demonstrates a methodology to ascertain which materials may resist CRUD adhesion, thereby preventing its initiation and growth. It presents experiments targeted at multiple length scales: pool boiling (macroscale), which simulates CRUD initiation processes in a nuclear reactor, and atomic force microscope (AFM) force spectroscopy (microscale), which yields quantitative measurements of the adhesion between CRUD constituents and candidate CRUD-resistant materials. Early data from both sets of experiments show some correlation, suggesting that AFM force spectroscopy (AFM-FS) may be used to pre-screen materials for fouling resistance. So far, it appears that CRUD constituents adhere well to oxides, while carbides show both greatly reduced adhesion and no adherent CRUD in pool boiling experiments. The relationship between the AFM-FS measurements and the growth of CRUD in the pool boiling experiments may provide insight into the possible factors affecting fouling in nuclear reactors, eventually leading to its elimination.

Fouling, or corrosion product deposition, plagues numerous fields of energy production. At its core is adhesion between dissimilar materials. Understanding and controlling adhesion could reduce or eliminate fouling. This paper demonstrates pool boiling experiments (macroscale) and atomic force microscope force-spectroscopy measurements (microscale), which when in agreement, indicate fouling-resistance.

The buildup of fouling deposits in energy systems degrades their ability to transfer heat, reducing efficiency and causing operational issues such as ...

Biology

Conducting Reactions Below Room Temperature

Source: Laboratory of Dr. Dana Lashley - College of William and Mary
Demonstration by: Matt Smith
When new bonds are formed in the course of a chemical reaction, it requires that the involved species (atoms or molecules) come in very close proximity and collide into one another. The collisions between these species are more frequent and effective the higher the speed at which these molecules are moving. A widely used rule of thumb, which has its roots in the Arrhenius equation1, states that raising the temperature by 10 K will approximately double the rate of a reaction, and raising the temperature by 20 K will quadruple the rate:
(1) <img alt="Equation 1" src="/files/ftp_upload/10224/10224eq1.jpg" />
Equation (1) is often found in its logarithmic form:
(2) <img alt="Equation 2" src="/files/ftp_upload/10224/10224eq2.jpg" />
where k is the rate of the chemical reaction, A is the frequency factor (relating to frequency of molecular collisions), Ea is the activation energy required for the reaction, R is the ideal gas constant, and T is the temperature at which the reaction is taking place.
A higher temperature therefore means a reaction is completed much faster. Nonetheless, in some cases it is desirable to carry out reactions at low temperatures, in spite of the lowering effect on the rate of the reaction. A few scenarios in this regard are elaborated upon further below.
When it is useful to run a reaction below room temperature, chemists use cooling baths to maintain a certain temperature or temperature range. Reactions are cooled down to a desired temperature by placing the reaction flask inside an appropriate cooling bath. The reagents in the reaction never come in direct contact with the chemicals in the cooling bath. The cooling bath may consist of a single cryogenic (cooling) component (such as ice, dry ice, or liquid nitrogen) or may be a mixture of the cryogenic component with a certain solvent and/or an additive salt. The purpose of the solvent is to effectively transfer temperature of the cooling agent to the reaction flask, and the purpose of the additive is to lower (or depress) the freezing point of the mixture. (Note that it is possible for a substance to be both a solvent and an additive.)

Source: Laboratory of Dr. Dana Lashley - College of William and Mary
Demonstration by: Matt Smith
When new bonds are formed in the course of a chemical ...

JoVE Science Education

Organic Chemistry

Quenching and Boiling

Source: Alexander S Rattner, Sanjay Adhikari, and Mahdi Nabil; Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, University Park, PA
Controlled heating followed by rapid cooling is an important element of many materials processing applications. This heat-treating procedure can increase material hardness, which is important for cutting tools or surfaces in high wear environments. The rapid cooling stage is called quenching, and is often performed by immersing materials in a fluid bath (often water or oil). Quenching heat transfer can occur due to forced convection - when the action of rapidly moving material through coolant drives the heat transfer process, and due to free convection - when the reduced density of hot fluid near the material surface causes buoyancy-driven circulation and heat transfer. At high material temperatures, the coolant can boil, leading to increased heat transfer effectiveness. However, when extremely hot materials are quenched, they can be blanketed in relatively low thermal conductivity coolant vapor, leading to poor heat transfer.
In this experiment, quenching heat transfer will be measured for a heated copper cylinder, which is representative of small heat-treated parts. The transient sample temperature profile will be measured during quenching and compared with theoretical results for free convection heat transfer. Boiling phenomena will also be investigated qualitatively.

Quenching, Boiling, Convection and Nusselt Number

Source: Alexander S Rattner, Sanjay Adhikari, and Mahdi Nabil; Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, ...

Mechanical Engineering

Working with Hot and Cold Sources

Source: Robert M. Rioux &amp; Suprita Jharimune, Pennsylvania State University, University Park, PA
Working with extreme temperatures, both high and low, is an integral part of many laboratory operations. For many, mentioning a laboratory instantly evokes the mental picture of a Bunsen burner. Bunsen burners and hot plates are used extensively in small and large operations in research laboratories and industries, thus making it necessary for all users to be aware of their safe handling procedures. Hot plates and Bunsen burners are high temperature heat sources, while low temperatures are obtained using dry ice and cryogenic liquids, such as liquid nitrogen. Both dry ice and liquid nitrogen can pose significant hazards to the user if not handled carefully.

Working with Extreme Temperatures: Hot and Cold Sources

Source: Robert M. Rioux &amp; Suprita Jharimune, Pennsylvania State University, University Park, PA
Working with extreme temperatures, both high and low, ...