what is the enthalpy of formation for c4h8??????????????

A converging nozzle feeds an insulated square duct (L = 224 ft, W = H = 8.0 in, f = 0.02) with air flowing steadily at 7200 lbm/min. The inlet stagnation temperature and stagnation pressure are respectively equal to 116 deg F and 190 psia. Calculate the exit Mach number, exit pressure, exit stagnation pressure and exit stagnation temperature. Ans. 0.67, 70.2 psia, 94.9 psia, 116 deg F.

# Heat Transfer,

Why the ratio of (thermal resistance of conduction)/(thermal resistance of convection) must be less than .1 for a system to lumped.

Why is there this grinding teeth in automatic car system? Is it bad fuel, choice of oil, engine and gear meeting point, bad/faulty gear/transmission system

As speed increases in an engine with throttle body fuel injection, does the temperature of the air-fuel mixture at the intake manifold exit increase or decrease? Explain what parameters affect your answer.

A technician has learned all techniques and skills for material processing. But he has never learned material science. Now he wants to find a material that its weight is as light as aluminum and its tensile strength is as high as steel. So he comes to TTU for instruction. You, as an instructor, need to explain to him what material he can select, and what procedure/s he should undertake to approach the goal with minimal explanation (as brief as possible) on the reason/mechanism related to your suggestion.

2. Needs Assessment for Coastal Tool Rental

Kathleen Marsh is a recent community college graduate who plans to open an equipment and tool rental store in the next few months. The store will target do-it-yourselfers who need gardening and home improvement implements that may be too expensive to purchase for a limited project.

Although this is her first real venture as an entrepreneur, Kathleen worked in a tool rental shop during high school and college. Kathleen’s store, Coastal Tool Rental, will be in a new shopping center. Kathleen chose the location because a sizable community of family homes is nearby and because no major competition is located in the area, which is about 15 miles from the nearest large town. She has arranged to rent 2500 square feet of space in the shopping center. She has located a wholesaler who can provide her with a start-up inventory of common garden and home improvement implements. The wholesaler can also serve as a supplier for new and replacement tools, equipment, and consumables.

Kathleen majored in small business management, but she also took a number of computer- related courses as electives—including some classes on programming and on using word processing, spreadsheet, and database applications. Kathleen plans to purchase a desktop computer for use in her small business venture, but her start-up money and time are limited.

Kathleen is considering the following four options to keep track of equipment rentals:

1. A manual system of file cards for each piece of equipment and each customer

2. A computer-based system she would build using a spreadsheet or database application

3. A computer-based option she would program herself

4. An off-the-shelf software package designed for equipment renta

She has asked for your help to determine the feasibility of each of these options. Complete the following:

# First, prepare a list of interview questions for Kathleen that would help you make a recommendation to her.

# After you have a list of potential questions to ask in an interview, compare your questions with those of three classmates or coworkers. Work with your group to create one merged list of questions for Kathleen. Organize the questions under several main categories.

# When you have completed the list of interview questions, your instructor will provide you with Kathleen’s responses to several questions from an interview with her. Based on her responses, complete the following:

Briefly describe the pros and cons of the four options Kathleen is considering.

Based on what you know of Kathleen’s situation, which of the four options would you recommend to her? Explain your reasoning.

In order to implement one of these options, Coastal Tools Rental would need data on each rental item and each customer. List the fields you think Coastal would need to include in either a record for each rental tool or a record for each customer.

The purpose of this problem is to use graphic user interface (GUI) to interactively store grades in a text file, rather than adding them manually to a script. Follow these steps to complete the program:

Step 1. Use a question dialog box and ask the user “Do you want to run this Program?” with two options for “yes” and “no”. If the user’s answer is “yes”, go to the next step, otherwise, go to Step 6.

Step 2. Create a file using fopen command to store the data.

Step 3. Use a while loop and create an input dialog box similar to that of Figure 1 inside the loop.

Step 4. Every time that the users enters the values, check whether the grade is -1 or not. If the grade is not -1, store the name, student ID, and grade in one line in the file using fprintf command. If the Student ID was shorter or longer than 7 digits, an error dialog box should appear and give an appropriate error message and display a fresh input dialog box. If the entry was correct, make sure to separate the data at each line by using horizontal tabs (this can be done by typing \t in the fprintf argument). Remember that the output of an input dialog box is a cellular array and you have to convert it into a string (by using curled brackets to access a specific element of the input dialog result) before storing it in a file.

Step 5. Close the file.

Step 6. Output a message using a message dialog box indicating that the problem is terminated. If you would like to use strcmp function, you may.

Step 7. Write the same code in a way that it stores the data in an Excel spreadsheet with proper formatting

It is observed that polycrystalline chromium has a higher tensile strength than single crystalline chromium. Propose a reason for this difference in tensile strength

3.A simple Rankine cycle uses water as the working fluid. The boiler operates at 6000 kPa and the condenser at 50 kPa. At the entrance to the turbine, the temperature is 450°C. The isentropic efficiency of the turbine is 90 percent, pressure and pump losses are negligible, and the water leaving the condenser is subcooled by 6.3°C. The boiler is sized for a mass flow rate of 20 kg/s. Determine (a) the rate at which heat is added in the boiler, (15 points) (b)the power required to operate the pumps, (15 points) (c) the net power produced by the cycle, and the thermal efficiency

Problem 9

In a design where weight is a critical factor, such as in a space shuttle frame, and specific yield strength, specific elastic modulus, and specific fracture toughness are of equal importance, using the above table, Calculate to show which of the materials Inconel Al-7075, 4340 steel, Mg-ZK61A, or Ti-8Al-1Mo-1V in the above table, is the best material choice?

The uniform pole of length 5 m and mass M = 94.2 kg is placed against the supporting surfaces shown. If the coefficient of static friction at both A and B is 0.25. Determine the maximum angle theta (in degrees) at which the pole can be placed before it begins to slip.

Use knowledge of engineering science and mathematics to predict some key performance metrics of the caravan (weight, cost of manufarure, acceleration etc)