Compute diffusion coefficients for the interdiffusion of carbon in both (a) α-iron (BCC) and (b) γ-iron (FCC) at 875˚C. Assume that D0 for the interdiffusion of carbon in α-iron and in γ-iron are 1.1 × 10-6 and 2.3 × 10-5 m2/s, respectively, and that Qd are 80 and 148 kJ/mol, respectively. (a) m2/s (b) m2/s

Calculate the value of D at 636°C for the diffusion of some species in a metal for which the values of D₀ and Q_d are 5.9 × 10^-5 m²/s and 167 kJ/mol, respectively.

The activation energy for the diffusion of atomic species A in metal B is 113 kJ/mol. Calculate the diffusion coefficient at 859°C, given that the value of D at 1190°C is 7.3 × 10^-11 m²/s.

Determine the carburizing time necessary to achieve a carbon concentration of 0.50 wt% at a position 3.3 mm into an iron-carbon alloy that initially contains 0.18 wt% C. The surface concentration is to be maintained at 1.1 wt% C, and the treatment is to be conducted at 1050°C. Assume that D0 = 3.1 × 10-5 m2/s and Qd = 120 kJ/mol. The following table may be useful.

An iron-carbon alloy initially containing 0.227 wt% C is exposed to an oxygen-rich and virtually carbon-free atmosphere at 1080°C. Under these circumstances the carbon diffuses from the alloy and reacts at the surface with the oxygen in the atmosphere; that is, the carbon concentration at the surface position is maintained essentially at 0.0 wt% C. At what position will the carbon concentration be 0.170 wt% after a 9 h treatment? The value of D at 1080°C is 1.9 × 10^-10 m²/s.

Nitrogen from a gaseous phase is to be diffused into pure iron at 700°C. If the surface concentration is maintained at 0.19 wt% N, what will be the concentration (in weight percent) 2.3 mm from the surface after 7.5 h? The diffusion coefficient for nitrogen in iron at 700°C is 1.2 × 10^-10 m²/s.

describe a synchro self shifting (SSS) clutch and how it operates

The following are some maintenance strategies:

1. Breakdown (DEFECT /REACTIVE) Maintenance;

2. Preventive Maintenance;

3. Predictive Maintenance ;

4. Project Maintenance;

5. Proactive Maintenance

Provide a brief description of each of these strategies, then give examples of where each strategy would work best in real business and why you say so.

Please solve this question as soon as possible as it is part of an assignment that I have to submitt within 10 hours. Thank you.

Maximizar P=2x+3y+5z

Sujeto a: x+2y+3z ≤ 12

               x-3y+2z ≤ 10

                x ≥ 0, y ≥ 0, z ≥ 0

Maximize P=2x+3y+5z

Subject to:

x+2y+3z ≤ 12

x-3y+2z ≤ 10

                x ≥ 0, y ≥ 0, z ≥ 0

What is the typical impact energy value of the material for 3 different heat treatments (any). Put some microstructures and discuss the impact energy differences . For alluminium 6061

There are ten (10) basic principles of designing economical production. One of them
is utilising special process characteristics. Discuss about this characteristic and
provide one (1) example to support your explanation. Provide sketching when it is
possible in order to support your explanation.

Discuss three (3) key elements of Design for Manufacture (DFM). Elaborate for each
of them.

A power plant operates on a regenerative vapor power cycle with one open feedwater heater. Steam enters the first turbine stage at 12 MPa, 560°C and expands to 1 MPa, where some of the steam is extracted and diverted to the open feedwater heater operating at 1 MPa. The remaining steam expands through the second turbine stage to the condenser pressure of 50 kPa. Saturated liquid exits the open feedwater heater at 1 MPa. The net power output for the cycle is 330 MW. Assume that both turbine stages and both pumps have an isentropic efficiency of 90%.


Determine:

(a) the percent cycle thermal efficiency.

(b) the mass flow rate into the first turbine stage, in kg/s.

(c) the rate of entropy production in the open feedwater heater, in kW/K.

Develop a simple MIS (Management Information System) that consists of a simple database (a text file). The system manages to dynamically input record/data into the database. The data from the database can be sorted, searched and updated. User also should be able to add new records/data, remove any data and etc.
Here are some ideas of MIS that can be developed:
1. Hotel reservation system.
2. Students management system.
3. Payroll management system.
4. Bus/Railway/Plane ticketing system.
5. Clinic record management system.

Reflect a triangle whose vertices are ?(2, 3), ?(6, 3) and ?(4, 8) about the line ? = 3? + 4. Determine the final coordinates of the triangle. Sketch the initial and final positions

A gourmet coffee shop in downtown Vancouver uses a Periodic Inventory System and is open 200 days a year. They sell on an average 75 pounds of KONA coffee beams a day. (Demand can be assumed to be distributed normally with a standard deviation of 15 lbs. per day.) After (fix cost = $16 per order), beans are always shipped from Hawaii within exactly 4 days. Per-pound annual holding costs for the beans are $3 and the cycle service level established by management is 98%. a. What is the economic order quantity (EOQ) for Kona coffee beans? b. Determine the Periodic Review Interval? c. What level of safety stock is required? d. What is the Target Inventory Level that is required to achieve these results? e. What are the total annual holding costs of stock for Kona coffee beans? f. What are the total annual ordering costs for Kona coffee beans? g. At the time the inventory was taken, the on hand was 300 lbs with the schedule receipts at 250 lbs with no back order. How much should the company order?