Convection experiment with oil (refs. Try this convection current experiment sometime . In natural convection, any fluid motion is caused by You might remember that density how much matter there is in a given amount of space. This is the type of heat transfer we demonstrated above. 0005 cm) that is bounded from below by a 1-cm-thick gold-coated aluminum mir-ror (Fig. 1and 2). Aug 26, 2024 · Convection snake. When we investigated whether ice melted faster in freshwater or saltwater we notice a convection current as the ice melted in the non salty water. Heat affects the density of water as well. A uniform air layer (dg = 0. (Challenge question: How much faster is the flow velocity of the vegetable oil in the thermal convection model experiment as compared to mantle flow velocities?) Finally, place a ball of silly putty on a Teflon coated pan or cookie sheet. The experiments were mainly for steady thermocapillary flows. Dec 1, 2022 · In microgravity experiments, no oscillations were observed even at higher Ma numbers. Mixed Convection: combined forced and natural convection experiments in microgravity. Similarly in the atmosphere, warm air rises and cold air falls to churn the air. but that’s gross. Natural or Free Convection. To keep the pressure equalized cold denser air flows in from the left chimney creating a suction that brings smoke with it. Experiments are conducted by using the annular fins, fin with diameter 11mm without circumferential fins and fin with diameter 31mm at different Reynolds number and loads under forced Dec 11, 2023 · Convection is not an unique characteristics of water. Learn more about the way weather works by doing these hands-on experiments. The convection heat transfer process is strongly dependent upon the properties of the fluid being considered. Apr 14, 2015 · They are actually being carried back down as cooler oil from the top sinks and the warmer oil continues to rise up. The fluid can be a gas or a liquid; both have applications in aerospace technology. If you have a few coins handy, wait until both the hot plate and pan are cool, then place the coins in different locations on the heating surface. 3. 3. Convection is the transfer of heat by the movement of currents within a fluid. tripod and gauze . (Convection cells will not form at high temperatures. Convection is classified as natural (or free) and forced convection depending on how the fluid motion is initiated. The observations agree with the onset prediction of the two-layer model, except for very thin liquid layers; this deviation from theory may arise from small non-uniformities in the experiment. If you are unwilling to use such a large quantity of oil, you can do the experiment with plain tap water and spices. The thermal convection in this model is similar to the convection that is inferred for the Earth's mantle. This is how thunderstorm is created. Some examples of forced convection are stirring a mixture of ice and water, blowing on the surface of coffee in a cup, orienting a car radiator to face airflow, etc. 1 crystal of potassium manganate(VII) 10 cm. In fluid thermodynamics, Rayleigh–Bénard convection is a type of natural convection, occurring in a planar horizontal layer of fluid heated from below, in which the fluid develops a regular pattern of convection cells known as Bénard cells. , 1998, Yokozeki, 2002, Gessner and Barbosa, 2006). Observation of Convection Three-dimensional Observation: Small particles will be mixed into a liquid in advance for the liquid bridge, and movement of the particles will be tracked by using three cameras to observe flow patterns inside the liquid bridge (Themes 1 to 3 experiments). This experiment is a great way to teach tweens about liquid density. Although the colored liquids that mix are more interesting to watch, the other set of warm and cold water bottles helps to illustrate an important phenomenon that can occur in the atmosphere in cooler months. May 14, 2021 · Simulations were run with crude oil as the production fluid at the same operating conditions for the water experiments to compare the thermal performance of each due to the difference in fluid properties. Convection currents in the atmosphere are responsible for the formation of thunderstorms as warm and cold air masses collide. 1) Two identical containers, water ( c ≐ 4200 J·kg -1 ·K -1 ), oil, balance, heat source (burner, cooker, etc. Apr 5, 2021 · (conduction, convection or radiation) 5. CONCEPTS • The fluid nature of water allows it to transport heat globally. Silva (2004) conducted a series of experiments to determine the rates of absorption of R-12 in mineral oil and of R-134 in polyol ester (POE) oil. Mix the vegetable oil and the thyme (spice) in the glass dish. This is the traditional way of conducting the convection practical. Convection, another method of heat transfer, is the movement of water in the plate during Part 2. Forced convection happens when the fluid is kept in motion by an external means, such as a turbine or a fan. For another approach, using a convection tube see the link below. The Prandtl numbers considered as 100–10,000 corresponding to three types of silicon oil. Follow the instructions above, substituting water for also briefly covers convection in such a layer with rotation about a vertical axis, with inclination, and with modulation of the vertical acceleration. Radiation This video demonstrates a convection experiment for GCSE Physics using potassium permanganate in water with a Bunsen burner. Convection (or convective heat transfer) is the transfer of heat from one place to another due to the movement of fluid. It is SO fun & easy. . 8. Another way to demonstrate convection is with a spinning convection Jun 17, 2016 · This paper represents results of the Rayleigh–Bénard convection heat transfer in silicon oil confined by two horizontal plates, heated from below, and cooled from above. beaker . Marangoni UVP/MaranGogniat measures internal flow rate and surface temperature changes in the liquid bridge with the Ultrasonic Velocity Profiler (UVP) that uses Jan 1, 2017 · In the work of Khadangi Mahrood et al. 15). Similar observations were observed as in 76 D porous media. Arrange loaf dish and other materials as shown in Feb 18, 2022 · Marangoni effect 1,2, named after physicist Carlo Marangoni 3, is a fluid flow phenomenon driven by a surface tension gradient at a fluid-fluid interface which, in recent years, has found several motion in liquids. Convection is the movement of heat energy through the moveme Now repeat the experiment for different materials (cold water (30 °C), hot water (50 °C) aluminum foil, soil, corn syrup, glue) Convection: Fill ¾th of the beaker with water at room temperature. This can lead to smaller convection cells and less effective heat distribution. One important fmding was that the flow did not become This type of energy movement is called thermal convection, because added heat causes the fluid flow (circulation by convection) by lowering the density of the liquid. Arrange glass dish and other materials as shown in figure 1 [appendix]. How Does the Science Experiment Work. The food coloring drops allow us to see the motion of rising and sinking oil. Convection from localized sources can also be studied by blocking, as appropriate, regions of the grid. heat proof mat . The physical properties of crude oil used in CFD simulations at the film temperature of the stream as per the equations: Dec 1, 2017 · The heat transfer characteristics of transformer oil natural convection in a cavity with a linear electrode were investigated by experiment and numerical simulation. Leave one on a bench top and heat the other over a stovetop. The coefficient of diffusivity of gas in oil was measured by means of another experiment where the cell was arranged horizontally and, therefore, convection could The convective elements themselves can be revealed by seeding with (very small) amounts of potassium permanganate or dye, illuminated from the rear and viewed from the front. Because as you know, oil and water don’t mix. (Because of the viscosity of the oil and the density of the flakes of thyme, the pieces of thyme are approximately neutrally buoyant. Attach one end of a 15-cm piece of yarn to the middle of the spiral using clear tape. The aim of the experiment is to investigate the rate of convection of potassium permanganate crystals in two different temperatures of water. Arrange loaf dish and other materials as shown in Figure 1. Density Experiment Thermal Convection and Viscosity… Page 2 of 11 3 small containers, such as 1/8 cup measuring cups Silly Putty 1 Teflon coated pan or cookie sheet Thermal Convection Experiments: Mix the vegetable oil and the thyme (spice) in the loaf dish. P. INTRODUCTION Fluid motion driven by thermal gradients (thermal convection) is a common and important phenomenon in nature. High Viscosity Liquid (Motor Oil): Motor oil showed the slowest flow under the same conditions. The cooler, more dense oil at the top of the glass sinks. forceps . HEAT TRANSFER IN FORCED CONVECTION AIM OF THE EXPERIMENT: To determine the convective heat transfer co-efficient in forced convection. Experiments were carried out to understand Benard-Marangoni-Instability on surfaces of silicone oil during the microgravity phase of the sounding rocket MAXUS 2 on which 10 cSt silicone oil was heated from below to observe convection patterns [24]. The equation for the rate of convection relates area and the difference between the fluid temperature and surface temperature: Jun 13, 2022 · Convection; Radiation. [24] a natural convection experiment was performed using Al 2 O 3 and TiO 2 aqueous nanofluids in a vertical cylinder heated from below and they found heat transfer enhancements with concentrations of nanoparticles below 1 vol%. Then they reflect on a demonstration of convection currents in action. Ice and salt water demonstration. The first thing tweens will notice is that the oil sits on top of the water, creating different layers. Nov 1, 2021 · A similar experiment was carried out for n-decane (55 ml) saturated porous media of 500 mD (see Fig. This goes with several units including heat transfer, weather and climate, and the Uneven Heating of the Earth's Surfa Mantle flow (thermal convection of the mantle) occurs with very low rates (velocity of flow of a few cm/year). buoyant gas (or convection in the case of the heated experiment) compensates. In The resistance of honey to flow resulted in a slower movement within the convection cell, demonstrating reduced circulation. Jul 1, 2005 · The gelation of waxy crude oil near the wall is the most significant and highly correlated with the convection heat transfer coefficient near the wall, so both are significantly affected by the Aug 21, 2019 · A lava lamp is an example of a convection current. Heat convection occurs when warmer molecules of a liquid or gas move from a warmer to a cooler area, taking the heat with them. 3 . Natural convection is caused by buoyancy forces due to dens ity differences caused by temperature variations in the fluid. 4 Experiments with Rayleigh–B´enard Convection 69 was followed by the stability analysis for more realistic rigid boundaries by Sir Harold Jeffreys [5], that (after some numerical problems) yielded the values R c = 1708 and k c =3. A convection oven circulates hot air and cooks more evenly than one that only uses heating elements or a gas flame. Arrange Pyrex dish and other materials as shown in Figure 1. Dependent variable = Rate of convection. Jun 14, 2010 · [20] in convection using silicone oil (large P). In the two extreme, opposite cases of Bi =0 and Bi !1we have, respectively, the Neumann condition (poor conductor) and the Dec 1, 2017 · The heat transfer characteristics of transformer oil natural convection in a cavity with a linear electrode were investigated by experiment and numerical simulation. How does the convection of water work? This fun science experiment illustrates convection currents with high definition footage and a clear, succinct explanation. The expanded water is less dense than the surrounding water and therefore starts to rise. There are convection currents all around you, even in the Earth’s crust! Here I model a convection current lab. The experiments covered a range of Rayleigh numbers from 2. In order to fully saturate oil with CO 2 and stop the swelling of oil, it took 2000 min in 500 mD porous media which is approximately 117 times slower than in 76 D porous media. These currents create some of our wind, weather, and ocean currents. Temperature measurements of the oil via injection The science of weather affects all of us every day! Convection, high-pressure and low-pressure systems, evaporation—these things help determine if our game will be rained out or if we will have a sunny day for sledding. [17]. The coupled physical and mathematical models of electric field, flow field and temperature field were established by the lattice Boltzmann method. In order to demonst Nov 2, 2024 · Experiment 2: investigating convection Aims of the experiment. 117 relevant to experiments using fluids confined between well-conducting solid parallel plates. Convection currents affect many of Earth’s systems including weather and climate, the movement of the ocean, and plate tectonics. Experiment 1: Observing Convection Currents 1. The adage “like dissolves like” will help you remember what will mix with what. Forced convection occurs when a fluid flow is induced by an external force, such as a pump, fan or a mixer. Convection Equation. 2. Sep 1, 2022 · Experiment and simulation of natural convection heat transfer of transformer oil under electrical field Int. The principle of this test bench is to inject oil heated to a temperature of about 80 °C onto a rotating test sample at ambient temperature. glass tube . , 1995, Goswami et al. The Theory of Plate Tectonics was not complete until scientists understood convection in the mantle. They will set up an experiment that illustrates convection currents and observe the movement of water over a heat source by putting drops of food coloring in an ÒoceanÓ pan. 1 heat transfer through composite wall 03-08 2 critical heat flux apparatus 09-12 3 measurement of surface emmissivity 13-18 4 heat transfer through forced convection 19-25 5 heat pipe demonstration 26-27 6 heat transfer through lagged pipe 28-31 7 heat transfer through natural convection 32-38 This is a demonstration of buoyancy-driven convection, accomplished by filling a glass tube bent into the shape of a large rectangle with water and red dye, The visible convection currents created by the hot and cold liquids are similar to those created by potassium manganate VII when heated in a beaker. 0419 ~ 0. name of the experiment page nos. Although often discussed as a distinct method Thermal Convection Experiments: Mix the vegetable oil and the thyme (spice) in the loaf dish. Now, add a few sprinkles of cinnamon to the oil, and stir it around. Have a couple of different temperatures of water, from ice cold through warm to hot and mix a different colour into each. Heat Mass Tran. Actually, if we take d air!1in (2. The experiments are performed on a purified silicone oil layer (d = 0. Draw a sketch of the model in your lab notebook. Convection can be demonstrated wh May 1, 2000 · The results are then used to predict the onset of convection in a gas–oil diffusion–convection experiment where gas quantity dissolved into oil from below was measured with time. Benard The students will describe and discuss a convection current. 27·1013. Oct 22, 2022 · About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright The second heat transfer process is convection, or heat transfer due to a flowing fluid. Results: Convection occurs when particles with a lot of heat energy in a liquid or gas move and take the place of particles with less heat energy. Control variables: Amount of water in beaker s. 4 %âãÏÓ 1318 0 obj > endobj xref 1318 51 0000000016 00000 n 0000002541 00000 n 0000002664 00000 n 0000003036 00000 n 0000003924 00000 n 0000005082 00000 n 0000006036 00000 n 0000006122 00000 n 0000014823 00000 n 0000015443 00000 n 0000016389 00000 n 0000016418 00000 n 0000016475 00000 n 0000017112 00000 n 0000017156 00000 n 0000017667 00000 n 0000018089 00000 n 0000018720 00000 n convection. Contact Us 9500 Gilman Drive, Mail Code 0368 La Jolla, CA 92093-0368 (858) 534-9899 Nov 22, 2019 · To perform the convection snake experiment, you will need a piece of paper and scissors. In our experiment, the oil at the bottom of the bowl was heated by the candle. Check out these water science experiments for kids. You can create your own convection current with water that will allow you to see the currents caused by the density difference of water at different temperatures. States of Matter: Solids, Liquids and Gasses. A t ypical time series is displayed. Try the bottle experiment again, with the different temperatures of water. Illustrate how thermal energy (heat) can generate motion (flow) in a fluid. In thin liquid layers or in microgravity, the buoyancy mechanism of Rayleigh–B enard convection becomes negligible, leaving thermocapillarity as the´ for theories and also for experiments with a thick upper air layer. 0008 cm) lies between the oil layer and a 1-mm-thick sapphire window. Most of these experimental researches have mainly concluded that the free Sep 18, 2023 · The purpose of this study is to generate some experimental data associated with the thermal heat exchange between an oil jet flow and a rotating gear. The data points that the Nusselt number Scientists say that oil and water are immiscible. INTRODUCTION: It is well known that a hot plate of metal will cool faster in front of a fan than when exposed to still air. Displayed on the bottom line of that figure, the return maps of convection experiment Thermal convection experiments: Mix the vegetable oil and the thyme (spice) in the glass dish. The flow is initiated by a change in the density of fluids incurred as a result of heating. , 115 ( 2017 ) , pp. Bunsen burner . ) Look for motion in the fluid. 14·109 to 2. . This section focusses on the ways in which thermal energy is transferred by the processes of conduction, convection and radiation. Stir thoroughly to distribute the flakes of thyme. Mix well to get cold water and then add a food coloring agent systems (Davis 1987). Convection in Liquids: In this demo you will be able to see convection currents in liquid. 0455 ~ 0. The first branching Aug 21, 2019 · A lava lamp is an example of a convection current. Dec 1, 2017 · The heat transfer characteristics of transformer oil natural convection in a cavity with a linear electrode were investigated by experiment and numerical simulation. Convection currents cause liquids and gases to rise and fall because of changes in their density. 2 Explain how heating and cooling affect some materials and how this relates to their purpose and practical applications. A Sep 1, 1991 · Experiments on Bénard convection are performed on silicon oil in a pentagonal vessel. 441 - 452 View PDF View article View in Scopus Google Scholar Convection Box: The candle in the right chimney causes hot air to rise. In surface-tension-driven B enard convection (henceforth called´ ‘Marangoni convection’), a liquid layer is heated from below and cooled from above (see figure 1). How big does the difference in temperature need to be before convection starts to occur and the colours mix? Did you know? Mar 3, 2025 · Discover how convection works, its real-world applications, and DIY experiments to observe this fundamental process in action. Jan 29, 2025 · The warmer, less dense oil at the bottom of the glass rises. (For additional information on radiation and convection, refer to the background section of this activity. Thermocapillary flow is driven by a thermally induced surface tension variation along a liquid free surface. Salt and water mix because both molecules are polar—like dissolves like. Below are resources that provide guidance and experiments to help you. Note: Because of the viscosity of the oil and the density of the flakes of thyme, the pieces of (The oil acts as a sealant and keeps the air trapped inside the bottle). Take-Home Experiment: Convection Rolls in a Heated Pan Take two small pots of water and use an eye dropper to place a drop of food coloring near the bottom of each. The effect is the same, but not quite so visually dramatic. A traditional way to demonstrate convection is to use a convection snake. The initial heat transfer between the object and the fluid takes place through conduction, but the bulk heat transfer happens due to the motion of the fluid. The concepts of specific heat capacity and latent heat may provide more challenges but are relatively straightforward to carry out experimentally. When the water at the bottom of the flask is heated, it expands. Variables: Independent variable = Temperature of water. Using the scissors, cut the piece of paper into a spiral shape that is 6 cm long. This experiment helps kids to learn that temperature is the driving force behind convection and can also play a big part in the density of a liquid. Convection. 1) [10]. The Surface Tension Driven Convection Experiment (STDCE) is a planned space transportation system (STS) or space shuttle microgravity flight experiment to study thermocapillary flows in a reduced-gravity environment. The first experiments, called the Surface Tension Driven Convection Experiment (STDCE), were performed aboard the USML-1 Spacelab in 1992 and the results were reported by Kamotani et al. Arrange loaf dish and other materials as shown in Try this convection current experiment sometime . Jul 1, 2006 · The main reasons of our above explanation about the difference with Degen's experimental observation are as follows: (1) The shadowgraph method used by Degen et al. Supplies: ice cube tray; water; food coloring; clear drinking glass or jar; Procedure: This simulation uses the following materials- cooking oil- 2 pcs powdered colored chalk (red/orange)- 500 ml beaker- alcohol lamp- tripod- wire gauze- mortar Objectives: Experiment with thermal convection. Kids will add oil, water, and food coloring to a bottle and then drop in a fizzy tablet. in Fig. To this end, a specific test bench was designed. Convection in a liquid Convection in a liquid can be seen Nov 1, 2022 · In this work, a computational analysis has been conducted to study the electrothermal convection phenomenon driven by a strong unipolar injection between two eccentric or concentric cylinders filled with nanofluid composed of insulating oil and CNTs. We say that heat is convicted away and we call the series of experiments explores the methods of heat transfer and aims to developyour understanding of the differences between conduction, convection and radiation. The high viscosity caused significant Forced Convection: flow is induced by an external source such as a pump, compressor, fan, etc. Problem. J. In this experiment, heat is transferred by means of convection. would not detect the steady convection at the onset due to “unfortunately, using water presents another difficulty in that its variation of index of refraction with temperature is small” said in Ref. It's the perfect introduction to Jun 27, 2024 · Convection is the process of heat transfer by the bulk movement of molecules within fluids such as gases and liquids. So the additional upward force that the gas bubble must provide is: 2 The volume of oil displaced by the droplet is of course the same as the volume of the droplet, because the droplet is completely submerged in the oil. The oil is confined by a Teflon side-wall ring of inner diameter Hands-on Center (Hot Spots: Hawaii and Yellowstone) Lesson #9 The mantle's convection experiment Modified and adapted from John Farndon's book "How the Earth Works" The teacher must set up and run this experiment! The oil and dish will get hot!!!!! Materials: 1 heat proof glass dish 1 tea candle 3 cups of cooking oil 1 book of matches 1 bottle of dark colored food coloring 1 eye dropper 2 clay Convection currents are the result of uneven heating of water or air. Tools (Fig. Fill the conical flask with water and add ice. Dive into the science behind hot air balloons, ovens, and more! RAYLEIGH-BENARD CONVECTION AS we discussed in Chapter i, Ra~lelgh-Benard convection is an example of a physical system exhibiting distinct transitions from laminar to turbulent flow as the value of a parameter, the Rayleigh number R, is increased. Forced Convection Heat Transfer Convection is the mechanism of heat transfer through a fluid in the presence of bulk fluid motion. Be sure to view the model several times during the experiment, both from above the dish and from the side of the dish. Heat can move in three ways: conduction, convection, and radiation. You will model how scientists explain how something as large as a continent can move. ), two temperature sensors cooperating with the computer; laboratory stand (if %PDF-1. ) Show students what their experiment set up will look like for Part 3(a shoebox of water, blue ice cubes, and red food coloring). Convection is a major feature of the dynamics To reset your convection experiment, either let the liquid cool down completely or make a new batch. 1 cm2 s[minus sign]1) and high Sep 18, 2022 · Convection drives global circulation in the oceans between the equators and poles. natural or free convection; Conductive Heat Transfer; Forced or Assisted Convection. Convection involves the transfer of heat by motion and mixing of a fluid. no. ×. Convection Current Experiment 2 – Currents in Water. The less dense (hot) liquid will rise and the denser (cold Aug 3, 2022 · In this experiment, we will measure liquids, where the heat exchanges by convection and the influence of thermal conductivity is negligible. Step 4: This is a great hands-on experiment that show convection currents. Water being heated in a pan is an example of convection. Natural Convection: flow is induced by natural means without the assistance of an external mechanism. It’s also easy to mix vegetable oil and olive oil, or motor oil and peanut oil . Mr. This is a spiral of paper that starts to spin when placed over a heat source. Interestingly, the liqueur variation starts with a sideways movement and is an example of solutal convection. Science Behind Lava Lamp Experiment. Place the dish or beaker onto the hotplate, and heat the oil at a low temperature. Convection Currents Grade Levels: 4-8 Duration: 60 min Grade Levels: 4-8 Duration: 60 min Concepts/Skills Temperature, density, convection currents Objectives Students will: • Observe and analyze how temperature and density are related. Guerra demonstrates a fun and engaging science experiment showing the process of convection. Books On Densities And Convection Current Explanation May 25, 2017 · PDF | Convection is the term used for heat transfer mechanism, which takes place in a fluid because of a combination of conduction due to the molecular | Find, read and cite all the research May 1, 2023 · Thermal convection is one of the basic modes (thermal convection, thermal conduction, thermal radiation) of heat transfer, and it belongs to the therm… JAXA's Marangoni convection experiment investigates the surface flow rate, temperature distributions, and change in internal flow of a large liquid bridge made of silicon oil in space. 7 (top). Convection can also be triggered from above through the use of ice Numerical simulations also predict a subcritical instability and yield long-wavelength states that qualitatively agree with the experiments. convection heat transfer rates are analyzed experimentally. Apparatus Convection: 2 . 10) for silicone oil open to air, we get that Bit ˇ0:38 (which is the most common situation in experiments). Experiment 1: Convection Current Dec 15, 2024 · The classic convection demonstration shows the initial movement upwards initiated by heating from below, but the ice cube variation has an initial movement downwards driven by cooling of the surrounding solution. Initially, a perfect convective hexagonal pattern is imposed with such an orientation that one side wall causes the appearance of orientation disorder, while the other four side walls do not perturb the pattern. In this convection current experiment for kids, you are going to make convection currents in water, which you will be able to observe with the help of food coloring. Great for heat Pour a thin layer (only 1-2 millimeters) of oil into the petri dish or beaker. (Because of the viscosity of the oil and the density of the flakes of thyme, the pieces of thyme are approximately neutrally The convective flow in a thin liquid layer with a free surface heated from below is studied using a combination of accurate experiments with silicone oil (v=0. 1. Convection current can appear in air, too. Correspondingly, the convective heat transfer coefficient (h), the overall coefficient (U o), and the other fluid properties may vary substantially for the fluid if it experiences a large temperature change during its path through the convective heat transfer device. Nov 1, 2008 · Refrigerant absorption in lubricant oil has been investigated by many authors in recent years (Fukuta et al. In convection heat transfer, the heat is moved through bulk transfer of a non-uniform temperature fluid. Essential Questions: How is heat energy transferred from one object to another? Compare and contrast conduction, convection, and radiation. Experiment with different colors, too! Try More Fun Science Experiments: The Science of Air. Convection can produce horizontal flow that can cause (or is related to) plate motions. 250 cm. ovpleo kcssmb qiy xnotu zpta szsi crldc caxikp etsydbg pabhz jhjcwo utpb ealjeb uponnc fwyb