Here are some spectrograms (with sound) that show what is happening:see a spectral movie with sound here (WMV) or sound only here (WAV) or a still imagehere (JPG) ... and anothersee a spectral movie with sound here (WMV) or sound only here (WAV) or a still imagehere (JPG) Filling a cup with waterThis one simply shows you how the sound changes as you fill the cup with cold water, tapping as you go:see a spectral movie with sound here (WMV) or sound only here (WAV) or a still imagehere (JPG) many thanks to my assistants Sandy (age 10) and Eloise (age 8) for helping me with these experimentsAlkaseltza in cold waterThis is a useful experiment to do if you don't have access to hot water, or if you're working with young kidswhere you don't want to risk scalding accidents.see a spectral movie with sound here (WMV) or sound only here (WAV) or a still imagehere (JPG) Explanation:Air is more soluble in cold water than in hot water. Cold water out of the tap has lots of dissolved air. When you heat it up in the microwave the air-in-water solution becomes supersaturated. Adding sugar (or any granular material) very quickly nucleates lots of tiny air bubbles out of solution.Now, water has a density of around 1000kg/m3 and the presence of tiny air bubbles doesn't change this much. But its stiffness (or better, the Bulk Modulus)is around 10^9 GPa, whereas it drops to about 10^5 GPa with only 0.01% of its volume taken up by air bubbles (these are round figures for illustration). This massive reduction in stiffness causes some of the vibration modes of the water-filled coffee cup to drop in frequency. But as the bubbles rise to the surface thenthe volume fraction of air drops below 0.01% and the frequency goes back to "normal".A fuller explanation can be found under the heading "The hot chocolate effect" in the American Journal of Physics -- May 1982 -- Volume 50, Issue 5, pp. 398-404and there is a nice acoustic holography image of the vibrating walls of a coffee cup done at the Physics Department, Northern Illinois Universityand there's more on the "cheap instant coffee effect" here Back to Vibration Topics Gyroscopes and Boomerangs: go to Hugh Hunt's gyro and boomerang page Dynamics Videos: go to Hugh Hunt's movies page and for other stuff: go to Hugh Hunt's Cambridge University home page
Double chocolate muffins. But not just any double chocolate muffins. These are made with orange blossom water, yogurt, and olive oil for a rich flavor and moist texture. They are chocolatey, soft, and utterly delicious. Each bite provides a distant taste of the orange blossom just to remind you it is there. I like the depth of the extra-virgin olive oil, but feel free to use mild olive oil or another oil of your choice if you prefer. That being said, these muffins will be sure to fulfill your indulgence cravings. They are also especially perfect with a hot cup of jasmine tea.
Chocolate Water WAV
1 cup all-purpose flour1/4 teaspoon salt1/2 teaspoon baking soda1/2 cup cocoa powder, (sifted)1/2 teaspoon espresso powder, optional1/2 cup plus 4 tablespoons semi-sweet chocolate chips, divided1 cup sugar1/4 cup olive oil1 large egg1/2 cup plain yogurt or sour cream2/3 cups whole milk1/2 teaspoon vanillaZest of 1/2 an orange
5. Pour the batter into the muffin tin so that it is almost full. Top with the remaining 4 tablespoons of chocolate chips. Bake for 16-20 minutes or until a toothpick inserted in the center of a muffin comes out clean. Let cool for for at least 10 minutes before transferring to a baking rack to cool completely.
Water hammer can occur when an open valve suddenly closes, causing the water to slam into it, or when a pump suddenly shuts down and the flow reverses direction back to the pump. Since water is incompressible, the impact of the water results in a shock wave that propagates at the speed of sound between the valve and the next elbow in the piping system or within the column of water after the pump.
Repeated water hammer may also cause significant damage to pumps, existing valves, and instruments, lead to the catastrophic failure of gasketed joints and expansion joints, and affect the integrity of pipe walls and welded joints.
As you can see, it is essential that immediate action is taken at the initial signs of water hammer. Failing to do so will ultimately result in system wide damage, and may spread beyond the flow system to other equipment or facility infrastructure.
One of the main contributors of water hammer can be the choice of check valve type. Valve types, such as swing, tilting disc or piston style check valves, depend on gravity and the reversal of flow to return the valves to the closed position. This causes water to slam into the valve mechanism, creating a pressure wave that propagates through the piping system.
Silent or spring-assisted check valves, on the other hand, are fitted with an internal spring that silently moves the valve into closed position before flow reversal, thereby reducing or eliminating the possibility of water hammer.
Air chambers are also an effective water hammer solution. These systems consist of a short segment of pipe, usually in the form of a tee-fitting, with an empty/air-filled chamber that serves as a cushion (shock absorber) for the water to expand when it changes direction suddenly. This reduces the magnitude of shock that would otherwise be directed towards the pipeline.
Water hammer can have costly and devastating effects on pipelines and piping systems. DFT Inc. offers a broad range of valve solutions that lessen or eliminate the probability of water hammer and the issues it causes, extending the service life of equipment and reducing long-term repair and maintenance costs. Be sure to specify DFT for all your check valve needs. Request a quote or contact us for more information.
A six mile round trip hike in required to get to The Wave. Since there is no trail to The Wave you should be able to use a map and compass or GPS to help with navigation. The BLM provides a map with your permit and instructions on getting to The Wave, and there are a small number of cairns on the way. Over the past five years five people have died on the way to/from The Wave. If you are not sure about your navigation skills I strongly suggest you hike in with a guide or a friend with these skills. Do not go alone. If you use a GPS be sure to mark the Wirepass trailhead and other key points along the route. Stay with your party. Four of the five fatalities were heat related, so if you go in the warmer months bring plenty of water, at least four liters, and preferably more.
I used to believe these were the worst months to go to The Wave. I now believe they are reasonably good, if you are prepared and can stand the heat. Average daily high temperature at the Wave is 101 ºF in July and there is little shade. If you go in July do not plan to be out all day. Either go in the morning when temperatures and cloud cover are lower, or go in mid afternoon if the weather looks cooperative. In 2013 there were three heat related fatalities at the Wave, and there was another heat related death in 2018. Go prepared. If you plan to stay the whole day you will need to find shade. A space blanket can help, you need to elevate it with hiking sticks, rocks, bushes, ... A good place to find natural shade is on Toprock at the Alcove. Finally bring at least one gallon of water per person in July and August. You will need it. I have seen recommendations of nine liters per person per day when temperatures are this high! Keep water inside your pack so it stays cooler, and bring some of it in the for of ice. There is a good possibility of afternoon thunderstorms or even hail. Mornings are cooler, often clear, and have little wind. It's likely you can get a good photograph in the morning, and if the weather cooperates you may get a great one in the afternoon! With luck there will be water at the Wave or in the water pockets south of The Wave. Water pockets won't last long given the average July August temperatures though. If there are water pockets look for tadpoles and tadpole shrimp. If there's a lot of water you may even hear toads croaking! (males calling for females). Permits, though still difficult, are easier to get than during the peak months.
The first stop on the loop hike is The Wave. The Wave gets good light about an hour after sunrise, before then parts of it are in shadow. It takes about 90 minutes to hike from the Wirepass trailhead to The Wave. Most people start their hike very early in the day and end up leaving when they run out of energy, usually before best light. If you have the stamina to stay out 10-15 hours begin hiking at dawn; otherwise I suggest you start your hike later. Do not start hiking too late as shadows start to hit the south wall of The Wave before mid-day. After shooting The Wave explore the area around it for an hour or two. There are usually some nice water pools 150 yards southeast of The Wave. Ginger Rock is a good subject mid-day. It can be found about 200 yards north of The Wave.
This image is best about an hour after sunrise when the south wall is in light, and the side walls are in shadow. A few hours later the side walls are partially lit and the image suffers. Water is often found at the entrance to The Wave, especially in summer. Only a little water is needed to get a good photo, even one inch will do. Shoot close to ground level to emphasize the little rocks in the water, with a wide angle to normal lens. Both vertical and horizontal compositions work.
I've updated the Bryce Canyon gallery with many new images of the canyon in winter. Images were shot from the rim trail between Sunrise and Sunset Points. I've also included images of the Arches Trail near Losee Canyon just outside the park and of Tropic Ditch Falls. It runs year round. Tropic Ditch Falls is a man-made waterfall created when Mormon pioneers diverted water from the East Fork of the Sevier River to irrigate their fields near the town of Tropic. The colorful rocks surrounding the fall are magnificent, and there are several photogenic arches in the area. Be careful should you climb up to the arches. Small stones on the "trail" make the go treacherous. 2ff7e9595c
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