ItemAccidental Freezing of the Tongue to Metal PolesGurzo, Mike; Ho, Jeremy; Lally, Sean; Selig, Mike (2000-01-10T19:06:12Z)In an attempt to verify the age-old claim that your tongue will freeze to a metal pole and become stuck if you decide to lick it in the midst of winter, we have modeled tongue contact with a cold metal surface using finite-element analysis techniques. After varying ambient temperatures, we have concluded that accidental tongue-freezing is not a myth, and below -5 deg. C the tongue will freeze before it can be removed. An accompanying sensitivity analysis showed that variations in contact area, metal properties, and the convection coefficients do not significantly change this conclusion. Our simulation has opened the possibility for further study of the accidental freezing process, including the modeling of methods to remove the tongue once it is stuck. ItemCold Therapy Analysis in Structurally Damaged TissueLai, Sherry; Pottle, Bill; Schlesinger, Nicole; Lee, Jeff S. (2000-01-10T19:04:08Z)For our project, we conducted an analysis of cold therapy for structurally damaged tissue. Our intent was to determine the ideal conditions of temperature and time of cold therapy needed to most effectively treat a bruise. To do this, we devised a model of damaged tissue via GAMBIT and FIDAP and exposed this tissue to cold therapy at varying temperatures and times. We created a function to assess effectiveness of treatment which was dependent on the depth of penetration at 34 deg. C (ideal temperature for treated tissue) and the depth of penetration of 5 deg. C(temperature at which vasodilation occurs in order for the body to maintain homeostasis). The significance of this effectiveness value is that it is an indication of how effectively we have reduced blood flow in and surrounding the damaged tissue layers. A high effectiveness value translates into significantly reduced blood flow which mitigates the extent of damage. The applications of our findings could be put towards devising an ice pack/gel pack which is maintained at an appropriate temperature and left on an injury for an appropriate time. ItemFrostbite in Ithaca: A Walk to Riley-RobbAridgides, Lynn; Avrin, Becky; Smith, Chris (2000-01-10T19:01:02Z)Frostbite occurs when body tissues freeze after being exposed to extreme cold and wind. It?s most likely to occur on body extremities ? fingers, nose, ears, and toes ? areas far from the warm body core and exposed to the elements. We have modeled tissue freezing in a finger in order to predict combinations of wind speed and temperature likely to lead to frostbite. Our model incorporates different tissue layers in the finger, sources of heat, transient properties, and heat transfer through convection and conduction. Such a model is valuable because it accurately predicts the existence and extent of tissue freezing. The model uses two tissue layers in the finger because of their disparaging material properties. It also contains a region attached to the finger to simulate heat flux from the hand to the finger. Heat generation was ignored, and heat transfer to the finger from blood flow was accounted for by a source term. The model is axi-symmetric, with radial heat flow into the finger. The edges of the finger have a convection boundary condition, and the region attached to the finger was perfectly insulated. The far edge of the region attached to the finger was set to a constant temperature equal to average body temperature. Each simulation was performed for a time span of thirty minutes for each set of ambient conditions. We then noted whether or not the conditions were conducive to frostbite. A sensitivity analysis was performed to ensure that the solutions converged. ItemHeat and Moisture Transport in the Nasal CavityBahr, Douglas; Tyler, John Poe; Weinert, Peter; Egan, John (2000-01-10T18:59:21Z)The intake of air into the lungs is obviously a vital process for the survival of humans, and the conditioning of this air from ambient to alveolar is a necessity accomplished primarily in the nasal cavity. The human nose is capable of taking in air of nearly all conditions (hot, cold, dry, moist) and properly maintaining the required equilibrium. Increased awareness of nasal diseases, the use of drugs to aid in breathing, and surgeries (cosmetic and medical) have placed a premium on the understanding of the dynamics of the heat and water vapor transport phenomenon. This report takes a two-dimensional cross section and models flow past the inferior turbinate, producing velocity, temperature and water vapor profiles for normal breathing conditions and shows a control when the turbinate is not present. The results show that the turbinate (concha) is vital for processing the air to alveolar conditions. The results obtained at the exit match those in previous literature -- nearly saturated and near body temperature air leaves the cavity when the concha is present. However, the air is considerably closer to ambient conditions when turbinate is not present. ItemCryogenic Freezing of the Entire Prostate GlandEhrenberg, Morton; Flynn, Terence; Seth, Rajeev; Thompson, Glenn; Yi, Jason (2000-01-10T18:57:02Z)The goal of this study was to model cryogenic freezing of the entire prostate, using five cryoprobes, while minimizing damage to the surrounding tissue. A 3-D model was attempted, but failed due to time constraints; therefore, a 2-D model was constructed. It was determined that probe placement was the key factor in minimizing the time required to freeze the prostate and the extent of damage to the surrounding tissue. Varying probe temperature between -180 deg. and -195 deg.C had little affect on these results. We also increased the temperature of the center probe outside of the range currently used for this procedure. This decreased the frozen area below the prostate where the rectum is located. ItemThermal Burning and Its Effects on Human SkinCampbell, Mike; Goodman, Joshua; Millis, Carrie; Rasmussen, Jessica (2000-01-10T18:52:08Z)The objective of this paper is to model thermal burning due to application of a heat source, in the form of a cylindrical disc, through the three distinct layers of human skin, the epidermis, dermis and subcutaneous fat. The temperature of the disc was varied from 50 to 80 degrees Celsius, and was applied for 20 seconds. After the disc was removed, the exposed skin experienced natural convection at ambient air temperature. Metabolic heat generation and blood perfusion in the dermis were taken into consideration. We modeled heat conduction in the skin, tissue damage as a function of time and temperature, and finally, we determined that metabolic heat generation and blood perfusion heat were negligible. The following report introduces our problem, discusses the methods used to generate results and the results obtained, and finally presents our major conclusions and recommendations. ItemProstate Cryosurgery with Various Numbers of ProbesChow, Brian; Lau, Ingar; Neidrauer, Mike; Park, Jennifer (2000-01-10T18:49:56Z)Cryosurgery is an increasingly popular way to treat prostate cancer. This process includes inserting one or more probes directly into the prostate to freeze the whole tissue and kill the cancer cells. The number of probes is a determining factor for the effectiveness of the procedure. In our project, we varied the number of probes to see how much of the prostate is frozen in twenty minutes. We used an argon cryogen system with probe temperature of -150oC. Using FIDAP to model the freezing of the prostate, we looked at the temperature data of nodes 2 cm away from the center of the prostate after 20 minutes. For the 1 probe model, the average temperature of the tissue was 25.76 deg C, for the 3 probe the average was 1.05 deg C and for the 5 probe, -16.97 deg C. From these results, it is evident that 1 probe is insufficient for prostate freezing since the temperature only went from 35oC to 25oC in twenty minutes, a mere 10 degree change. Even three probes will be inefficient for prostate freezing since it was twenty degrees away from reaching the optimal temperature of -20oC. We recommend using 5 probes for prostate freezing and looking into using even more probes for more time-efficient freezing. A colder cryogen would also lead to faster cooling. Our model used an argon system; liquid nitrogen with temperature -196oC could be a better alternative. ItemHeart CryopreservationFoote, Stacey; Gaines, Carmen; Levine, Jacob; Pecak, Garry; Saikkonen, Kelly (2000-01-10T16:55:05Z)Heart disease affects many people and heart transplants are becoming more common. Limited shelf life is a major hindrance to the success of heart transplants. Cryopreservation opens an avenue for increasing shelf life. Our goal in this study was to model the preservation of a heart using finite element software to determine the time needed to sufficiently cool the heart and to compare the average temperature to the maximum temperature of the heart. We found a range of minimum times varying with material properties of the heart. We concluded that computer simulation can be used to approximate the minimum time needed to reach a desired maximum temperature. We also found that average temperature of the heart during cooling was not an accurate approximation of the maximum temperature. ItemThermal Effects of Laser Eye Correction on the CorneaChen, Chih Hao; Chen, Diana; Chow, Kim Foo; Hui, JenYee; Lo, Darrick (2000-01-10T16:47:20Z)Eye laser surgery such as Photo Refractive Kerotectomy (PRK) has been the most recent technology towards correcting vision disorders. However, 20/20 vision is not guaranteed and side effects are possible. By measuring the properties of the patient's cornea, the surgeon can customize the laser surgery procedure for more accurate results. Using GAMBIT and FIDAP, two dimensional (2D) design simulations of the cornea in contact with a laser beam were used to determine the optimal surgical time for laser eye correction. Three dimensional (3D) simulations were designed for an off center laser and four coupled lasers in contact with the cornea. Results indicated a directly proportional relationship between corneal density and conductivity with ablation time. An indirect relationship existed between laser power and time for ablation. Design simulations indicated a longer ablation time compared with centered lasers, but can be useful for specific vision disorders such as hyperopia.