Stresses exerted by brain tumors on neighboring normal brain tissue can cause se
ID: 163194 • Letter: S
Question
Stresses exerted by brain tumors on neighboring normal brain tissue can cause serious complications. To estimate these stresses, consider a simple model for a growing brain tumor. Bars constrained between the rigid sides of the skull represent the tumor (elastic modulus E_1) and the brain (elastic modulus E_2). At time t = 0. the lengths of the tumor and brain are L_1 and L_2, respectively, and the bars have equal cross-sectional areas A. Suppose tumor growth is represented by a thermal strain Element_ T. In terms of Element_ T, compute the stress in the brain due to the growing tumor. For a given Element_ T. what is the length of the tumor? Assume Element_ T = a(l - exp(-bt)), where t is time and a and b are constants, and consider the following parameter values: L_1 = 1 cm L_2 = 19 cm E_2 = 25 kPa a = 5 b = 0.08 day^-1 Because benign tumors usually are softer than malignant tumors, it is interesting to explore the effects of tumor stiffness on stress and strain. On one graph, plot tumor length vs. time (0 lessthanorequalto t lessthanorequalto 100 days) for E_1 = 5, 25, 50 kPa. On a second graph, plot brain stress vs. time (0 lessthanorequalto t lessthanorequalto 100 days) for the same values of E_1.Explanation / Answer
1. thermal strss means it is accrodancce with temperature in directly propotional to the tempeature so when it enhanced the expansion of the tumor also be directed accroding to thermal activity, it means due to the growth of the tumor normal cell of the brain will found the supressed conditiion or the nutrion which is required for the growth will deflict dut to higher consumption of tummor cell in accrodance with the temperature.
2. it can not be predicted,
3. the eqation only correlates with the constant a and b there is laking of lenth relation in accrodance with thermal sensitivity, corelation should established before going to manuplate the thermal sensitivity in termas of length so in above problem laking of corelation with length. so graphical presentationcan not be possible. for that formula should be appropriate.