Numerade

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Write down a multiple of 7 that is between 20 and 30

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Part 2: Detailed Analysis Questions (70 Points total) 1. (35 pts) Recently, a number of research projects have been conducted to develop opaque surfaces for passive radiative cooling of buildings. The basic concept of these surfaces is that they are highly reflecting of solar irradiation and most irradiation from Earth's atmosphere, but are highly emissive in a specific wavelength band (8–13 µm) for which the atmosphere is nearly transparent (and therefore, low-emitting). As a result, they can cool down below the local air temperature. Consider the above material developed by Raman et al. (2014, including Penn State's own Linxiao Zhu!). Its emissivities in the following wavelength bands are listed below. The band emissivities of the atmosphere are also listed in the table. Wavelength band Cooling Surface Atmosphere (µm) Emissivity Emissivity 0.3-0.75 0.90 0.30 1.0 0.05 0.20 1.0-8.0 0.05 0.50 8.0-13 0.65 0.10 13-∞ 0.95 a. (10 pts) Draw a control-volume diagram indicating the heat fluxes into and out of the cooler surface due to solar irradiation (qabs,sun), irradiation from the atmosphere (qabssky), emission (E = εσT^4), and convection with the surroundings (with heat transfer coefficient h and air temperature T). Assume that the sides and bottom of the cooler are perfectly insulated. Write an energy balance equation to represent this process at steady state conditions. b. (8 pts) Assume that the irradiation from the sun is Gsun = 800 W/m^2, and that the spectral distribution follows a black body at Tsun = 5800 K. Calculate the solar heat flux absorbed in each wavelength band and the total absorbed solar heat flux. Assume that the sky is at Tsky = 273 K. Calculate the atmospheric irradiation heat flux absorbed by the solar cooler in each wavelength band listed above, and the total absorbed heat flux from the sky (qabs,sky). c. (8 pts) Assume that the cooling surface is at Tc ≈ 285 K. Calculate the emissive power from the surface in each wavelength band and the total emission E. d. (9 pts) Finally, solve the energy balance equation to find the cooling surface temperature Tc. Assume the local ambient air temperature is T∞ = 15°C and the heat transfer coefficient is h = 5 W/m^2 K. How much cooler is the surface than the surrounding air?

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K Solve the equation and check your answer. \[ -5(6-7 x)-(1-x)=2(x-3) \] $ x= $ $ \square $ (Simplify your answer. Type an integer or a simplified fraction.)

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A particle with charge $q_1$ = +3.5 µC is located at (x=0,y=0). A second particle with charge $q_2$ = -7.4 µC is located at (x=0,y=4.00 cm), and a third charge $q_3$ = +5.4 µC is located at (x=3.00 cm,y=0). (a) In your notebook, draw a diagram of the three-charge system showing the location of the charges. (b) Calculate the potential energy of this three-charge system. PE = -6.65 J

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Calculate the pH of the solution formed when 30.0 mL of 0.25M HSeO3- is mixed with: a) 15 mL of 0.20M KOH, b) 20.0 mL of 0.25M HCl, c) 25.0 mL of 0.20M K2SeO3. Ka's for H2SeO3 are: K1= 2.7x10^-3, K2=2.5x10^-7

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Task 3: Write a C program to convert a string from upper-case characters to lower-case characters. Use the library function \texttt{strlen()} or otherwise to iterate through all string characters. Since strings in C are null-terminated character sequences, \texttt{strlen} can only determine the length of a string by stepping through the sequence until it hits a null character. Use the \texttt{clock()} function to measure program performance. Also, try the \texttt{time} command in \texttt{gcc}. a) Double, triple, and quadruple the length of the string and note the program performance. b) Suggest a method to improve the program's performance. What is the optimization method called? c) Repeat step (a) and note the program performance. d) The compiler does not move \texttt{strlen} outside the loop. Why? e) Draw an Excel plot to compare the program performance for different string lengths for original code and optimized code. Comment on the nature of the graphs.

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Consider the following algorithm. First, explain what exactly it computes. Then, use the 5 steps in the General Plan to analyze the time efficiency of the algorithm. Algorithm 1: A pseudocode of an algorithm whose time efficiency is of interest Data: a non-negative integer n Result: to be answered by you s ← 0; for i ← 1 to n do s ← s + i * i end return s (Hint: Note that this is a non-recursive algorithm. So, follow the procedure in the General Plan for non-recursive algorithms.) For each of the following recurrence relations, first, write down explicitly what sequence they represent, and then solve them. a. x(n) = 3x(n − 1) for n > 1, with the initial condition x(1) = 5 b. x(n) = x(n/2) + n, for n > 1, with the initial condition x(1) = 1 (solve for n = 2^k)

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Weygandt, Accounting Principles, 12e Problem 9-2A Information related to Mingenback Company for 2017 is summarized below. Total credit sales Accounts receivable at December 31 Bad debts written off $\hspace{1cm}2,550,000$ $\hspace{1cm}848,000$ $\hspace{1cm}32,000$ (a) What amount of bad debt expense will Mingenback Company report if it uses the direct write-off method of accounting for bad debts? (b) Assume that Mingenback Company estimates its bad debt expense to be 2% of credit sales. What amount of bad debt expense will Mingenback record if it has an Allowance for Doubtful Accounts credit balance of $\hspace{1cm}3,700$? $\hspace{1cm}32000$ $\hspace{1cm}76500$ (c) Assume that Mingenback Company estimates its bad debt expense based on 5% of accounts receivable. What amount of bad debt expense will Mingenback record if it has an Allowance for Doubtful Accounts credit balance of $\hspace{1cm}2,500$? $ (d) Assume that Mingenback Company estimates its bad debt expense based on 5% of accounts receivable. What amount of bad debt expense will Mingenback record if it has an Allowance for Doubtful Accounts debit balance of $\hspace{1cm}2,500$? $

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4.1 The following gas-phase homogeneous reactions were carried out in a piston flow reactor at atmospheric pressure and 800 C. $C_6H_5CH_3 + H_2 \rightarrow C_6H_6 + CH_4$ Under the reaction conditions, the rate equation of the reaction is as follows: $r = 1.5C_T C_H^{0.5}, mol/l.s$ Concentrations of Cr and Ch in the formula are alpha extraction and hydrogen, respectively. mol/l, The molar ratio of toluene to hydrogen is equal to 1. If the diameter of the reactor is 50 mm, the length of the reactor with the final conversion of toluene of 95% is calculated.

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2. Calculate the fugacity of each component for a binary mixture containing 20 mol%\nethylene (1) and 80 mol% carbon monoxide (2) at 130°C and 4.00 MPa by the\following methods:\(a) Assume the mixture to be an ideal gas.\(b) Assume the mixture to be an ideal solution with the volumes of the pure gas given\by:\$Z = 1 + \frac{BP}{RT}$\and the virial coefficients $B_{11} = -1.1$, $B_{22} = 9.7$, $B_{12} = +10$ (Units are in cm³/gmole).\(c) Use the second virial coefficients predicted by the generalized correlation for B.

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linda u.