manufacturing silicone stopper for balloon tag assembly

Optimizing Balloon Tag Assembly to Recover Sensor Fish and Live Fish

Hydropower is a significant renewable energy resource worldwide. In the United States, hydropower contributes an estimated 38% or 274 TWh of electricity generated from renewable sources1 and has the potential to add approximately 460 TWh per year2. However, as hydropower development increases, concerns about fish injury and mortality during hydraulic passage have become paramount3. Various mechanisms contribute to fish injuries during passage, including rapid decompression (barotrauma), shear stress, turbulence, strikes, cavitation, and grinding4. Although these injury mechanisms may not have an immediate impact on the overall condition of the fish, they can render them more vulnerable to diseases, fungal infections, parasites, and predation5. Additionally, direct physical injuries resulting from collisions with turbines or other hydraulic structures can lead to significant mortality, emphasizing the importance of mitigating these risks in hydropower development.
One of the most common methods for evaluating fish passage conditions is releasing Sensor Fish and live fish through hydraulic structures6,7. The Sensor Fish is an autonomous device designed to study the physical conditions that fish experience during passage through hydraulic structures, including turbines, spillways, and dam bypass alternatives8,9. Equipped with a 3D accelerometer, 3D gyroscope, temperature sensor, and pressure sensor9, the Sensor Fish provides valuable data on fish passage conditions.
Balloon tags, which are self-inflating balloons attached externally to Sensor Fish and live fish, assist in their recovery after passing through hydraulic structures. The balloon tags consist of dissolvable capsules filled with gas-generating chemicals (e.g., oxalic acid and sodium bicarbonate), a silicone stopper, and a fishing line. Prior to deployment, water is injected through the silicone stopper into the balloon. The water dissolves the vegetable-based capsules, triggering a chemical reaction that produces gas&#160;inflating the balloon. In this neutralization reaction, sodium bicarbonate, a weak base, and oxalic acid, a weak acid, react to form carbon dioxide, water, and sodium oxalate10. The chemical reaction is provided below:
2NaHCO3+ H2C2O4 &#8594; 2CO2 + 2H2O + Na2C2O4
The inflated balloon increases the buoyancy of the Sensor Fish and live fish, enabling them to float on&#160;the water surface for easier recovery.
The number of balloon tags required to achieve flotation and facilitate the retrieval of a sample (e.g., Sensor Fish or live fish) may vary based on the volume and mass characteristics of the sample. The duration of balloon tag inflation can be adjusted by injecting water at different temperatures. Colder water will increase the inflation time, while warmer water will decrease it. Balloon tags have been successfully employed in various locations, including the Farmers Screen, a unique horizontal, flat-plate fish and debris screen structure in Hood River, Oregon11, and a Francis turbine at Nam Ngum Dam in the Lao People&#39;s Democratic Republic12. Another commercially available balloon tag example is the Hi-Z Turb&#39;N Tag13,14. The Hi-Z Turb&#39;N Tag allows inflation time to be adjusted between 2 min and 60 min, depending on the injected water temperature13. This technology has been used in fish studies at many field sites, including studies involving Chinook salmon smolts released at Rocky Reach Dam on the Columbia River and juvenile American shad at Hadley Falls Dam on the Connecticut River15,16. Both technologies utilize acid-base&#160;chemical reactions to inflate the balloon tags for recovery.
This method offers cost-effectiveness and simplicity in manufacturing, with an estimated material cost of only $0.50 per balloon. As described here, the manufacturing process is easy to follow, making balloon tag production accessible to anyone.

Author Spotlight: Developing Cost-Effective and Customizable Balloon Tags for Fish Passage Studies 

Balloon Tag Manufacturing Technique for Sensor Fish and Live Fish Recovery

This research focuses on developing and evaluating cost-effective balloon tags for fish passage studies and hydraulic structures. Our aim is to assess the effectiveness of different balloon tag configurations for the recovery of sensor fish and live fish after they pass through these hydraulic structures. The balloon tag protocol we developed offer a cost effectiveness, customizability, and adjustable inflation times.It is a low-cost solution for large scale studies with limited budgets. It helps to understand the impact of hydraulic structures on fish and can be tailored to different species and environments. We have developed a cost-effective balloon tag manufacturing process.This will enhance our understanding of balloon tag performances under different conditions, enabling tailored testing and facilitating environmental impact assessments for developing and operating fish-friendly hydropower systems.

Watch this Scientific Journal Video about Manufacturing Silicone Stopper for Balloon Tag Assembly at JoVE.com

Manufacturing Silicone Stopper for Balloon Tag Assembly

To begin, mix both commercial silicone mold material components in a mixing cup, maintaining a one-to-one weight ratio. Stir thoroughly with a disposable spoon for about five minutes until the mixture becomes uniform in appearance. Then position the 3D-printed mold plate fitted with packing tape over a sheet of paper.Pour the silicone mixture into each stopper hole, ensuring all the holes are filled. Using a rubber squeegee, spread the silicone evenly into each stopper hole before clearing any leftover silicone. Leave the rubber stoppers to dry for four hours.Once the stoppers have fully cured as indicated by the complete drying and hardening of the silicone mixture, take off the tape from the back of the mold plate and pull the stoppers out of the mold. Finally, clean any surplus silicone attached to the stoppers.

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160 Views.  Pacific Northwest National Laboratory. To begin, mix both commercial silicone mold material components in a mixing cup, maintaining a one-to-one weight ratio. Stir thoroughly with a disposable spoon for about five minutes until the mixture becomes uniform in appearance. Then position the 3D-printed mold plate fitted with packing tape over a sheet of paper.Pour the silicone mixture into each stopper hole, ensuring all the holes are filled. Using a rubber squeegee, spread the silicone evenly into each stopper hole before clea...

Video: Manufacturing Silicone Stopper for Balloon Tag Assembly

Fish may experience injuries and mortality when they pass through hydraulic conveyances at hydropower dams, even if these conveyances are designed to be fish-friendly, such as downstream bypass systems, modified spillways&#160;and turbines. The main methods used to study fish passage conditions in hydraulic structures involve direct, in situ testing using Sensor Fish technology and live fish. Sensor Fish data helps identify physical stressors and their locations in the fish passage environment, while live fish are assessed for injuries and mortality. Balloon tags, which are self-inflating balloons attached externally to Sensor Fish and live fish, aid in their recovery after passing through hydraulic structures.
This article focuses on the development of balloon tags with varying numbers of dissolvable, vegetable-based capsules containing a mixture of oxalic acid, sodium bicarbonate powders, and water at two different temperatures. Our research determined that balloon tags with three capsules, injected with 5 mL of water at 18.3 &#176;C, consistently achieved the desired balloon volume. These tags had a mean inflation volume of 114 cm3 with a standard deviation of 1.2 cm3. Among the balloon tags injected with water at 18.3 &#176;C, it was observed that the two-capsule balloon tags took the longest time to reach full inflation. In addition, the four-capsule balloon tags demonstrated a faster inflation start time, while the three-capsule balloon tags demonstrated a faster deflation start time. Overall, this approach proves to be effective for validating the performance of new technologies, improving turbine design, and making operational decisions to enhance fish passage conditions. It serves as a valuable tool for research and field evaluations, aiding in the refinement of both the design and operation of hydraulic structures.

A protocol is presented for designing and manufacturing balloon tags to recover Sensor Fish and live fish, allowing assessment of their physical condition and biological performance in hydraulic structures. The method optimizes balloon tag performance by considering factors such as balloon volume, inflation/deflation times, component selection, and the characteristics of the injected water.

Fish may experience injuries and mortality when they pass through hydraulic conveyances at hydropower dams, even if these conveyances are designed to be ...

Acid/Base Encapsulation for Balloon Tag Assembly

To begin, in a mixing cup, combine oxalic acid and sodium bicarbonate, maintaining a weight ratio of one to two. If the acid-based powder mix becomes crystalline, grind it into a fine powder using a mortar and pestle. To fill the capsules using a semi-automatic capsule filling machine, place the cap sheet on a clean, dry surface.Align the encapsulation sheet over the cap sheet. Separate the capsule tops and bottoms unless using pre-separated capsules. Pour the capsule tops into the encapsulation sheet and shake the sheet gently in a circular motion to fill the holes with the tops.Collect the leftover capsule tops in a clean cup. Detach the encapsulation sheet from the completely filled cap sheet and keep the cap sheet aside. Identify and flip the capsule tops that are upside down.Next, place the body or bottom sheet on a clean, dry, flat surface. Fix the encapsulation sheet to the bottom sheet and secure the alignment with the black pegs. Pour the cap bottoms onto the encapsulation sheet and shake as described previously to fill all the holes.Then pour off the excess capsule bottoms from the sheet. Remove the encapsulation sheet from the filled bottom sheet. Flip any capsule bottoms found upside down.Now, disperse the acid base powder mixture onto the filled bottom sheet. Using a plastic spreader, fill the capsule bottoms with the powder. After positioning the filled cap sheet on a flat surface, mount the middle sheet on its top.Invert the cap sheet affixed to the middle sheet on the filled bottom sheet, ensuring a proper mutual alignment. Press gently, but equally on all sides of the cap sheet to join and fit the tops and bottoms of the capsules. Then remove the cap sheet and the middle sheet from the bottom sheet, leaving the capsule tops and bottoms joined.Check each capsule to ensure its top and bottom are fitted tightly. If not, manually press and tighten the top and bottom together. Finally, transfer the filled capsules to an airtight sealable container.

Balloon Tag Assembly and Attachment to Sensor Fish Caps

To begin the balloon tag assembly, carefully insert the piercing tool into the silicone stopper. Then insert the piercing tool attached to the stopper into a 15 gauge syringe needle. After that, remove the piercing tool from the silicone stopper leaving only the needle embedded in the stopper.Cut a six inch piece from a 50 pound fishing line. Insert the fishing line piece into the silicone stopper through the 15 gauge needle. While holding the stopper and the fishing line together, carefully retract the needle from the stopper leaving the fishing line inside the stopper.Next, insert two acid-based powder filled capsules into a latex balloon. Using a rubber band expansion tool like a castration band plier, gently expand the balloon opening. Then carefully insert one silicone stopper into the balloon opening, making sure to keep the two ends of the fishing line outside the balloon.Place two O-rings onto the rubber band expansion tool and expand them. Push the neck of the latex balloon through the two expanded O-rings. Carefully pull the two O-rings away from the rubber band expansion tool leaving them tightly wrapped around the balloon's neck centered on the stopper.Insert one end of the fishing line through one of the small holes in the sensor fish cap and pull it through the large hole at the center. Tie both ends of the fishing line together leaving a 0.5 to one inch gap from the top of the cap to the balloon base. Keep the extra fishing line attached as cutting it too close to a knot might cause it to untie.Studying the average inflation time for balloon tags with different volumes of water at two different temperatures revealed that full inflation occurred faster when using water at 18.3 degrees Celsius as compared to 12.7 degrees Celsius. A slower dissolution of the capsules at lower temperatures caused delayed inflation. Among the tested conditions, the three capsule balloon tags injected with five milliliters of water at 18.3 degrees Celsius exhibited consistent size with a mean volume of 114 cubic centimeters.At 18.3 degrees Celsius, the four capsule balloon tags demonstrated a faster inflation start time. However, the full inflation times for the two capsule and four capsule balloon tags were nearly identical. The three capsule balloon tag began deflating first followed by the four capsule, and finally, the two capsule balloon tags.

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Manufacturing Silicone Stopper for Balloon Tag Assembly