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3 years ago

Difference between a scientists and an engineer

Engineering

1 answer:

UNO [17]3 years ago

5 0

Answer:

Scientists observe the world, while engineers focus on creating. While both fields do involve observation and analysis, engineering mainly deals with creating and working on already existing creations, while scientists work with things in nature.

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Chegg Discuss why stress-strain behavior of material is critical than just the ultimate strength of the material. What propertie

DanielleElmas [232]

Answer:

Throughout the clarification section elsewhere here, the definition of the concern is mentioned.

Explanation:

The stress-strain curve provides designers with a long list of critical parameters that are needed for utility development. Including capacity, longevity, elasticity, apparent viscosity, tension electricity, resilience, as well as flexural strength, a load-pressure assignment gave us several mechanical households at a certain point of operation. It also assists in manufacturing.
During which the overarching force can inform us about the maximum energy either workload the substance will experience, which could also be inferred within the action of the stress-strain. The dynamic properties can be seen by pre maximum activity because it will be before even the maximum yield intensity as well as the posted maximum would display plastic behavior however after the peak becomes achieved, the natural frequencies continue to decline.

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3 years ago

Define the following terms: data, database, DBMS, database system, database catalog, program-data independence, user view, DBA,

nalin [4]

Answer:

data - Any form of value in a column of a table in a relational database.

DBMS - Short for Database management system, which is a software that can be used to create, manipulate and view databases, e.g. MS SQL Server.

database system - Same as DBMS.

database catalog - Place where the metadata of a Database including its tables, users etc. exists, e.g. date created, size, number of columns etc. Also known as Data Dictionary.

program-data independence - Program-data independence refers to the design of keeping different levels of database (external, logical and physical) separate and loosely coupled from each other, for easier maintenance or modification work.

DBA - Short for Database Administrator, person responsible for maintaining the database. Its main responsibility is to keep the data clean and safe i.e. data doesn't contain wrong or invalid data, and is safe from viruses and is backed up.

end user - Anyone who is not directly interacting with a database, but through some software, like website or mobile application.

persistent object - An object of a class in a program, that interacts with the underlying database and is responsible for manipulating the database, the program is connected to.

transaction-processing system - A transaction process system is part of a software, responsible for making sure critical business transactions, like crediting or debiting money, either goes through cleanly or doesn't at all.

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4 years ago

In successive an object moves from start position, then moves 1ft, 4ft and 8ft. This is an example of a. non-uniform motion b. u

Nikolay [14]

Answer:Non-uniform motion

Explanation:

This is an example of Non-uniform motion because unequal distance traveled by an object in equal interval of time is termed as Non-Uniform motion and here also the distance traveled by object is 1 ft ,4 ft and 8 ft which is different from each other.

In Uniform motion distance traveled is equal in equal interval of time .

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3 years ago

Air initially at 120 psia and 500o F is expanded by an adiabatic turbine to 15 psia and 200o F. Assuming air can be treated as a

Goshia [24]

Answer:

a. Wa = 73.14 Btu/lbm

b. Sgen = 0.05042 Btu/lbm °R

c. Isentropic efficiency is 70.76%

d. Minimum specific work for compressor W = -146.2698 Btu/lbm [It is negative because work is being done on the compressor]

Explanation:

Complete question is as follows;

Air initially at 120 psia and 500oF is expanded by an adiabatic turbine to 15 psia and 200oF. Assuming air can be treated as an ideal gas and has variable specific heat.

a) Determine the specific work output of the actual turbine (Btu/lbm).

b) Determine the amount of specific entropy generation during the irreversible process (Btu/lbm R).

c) Determine the isentropic efficiency of this turbine (%).

d) Suppose the turbine now operates as an ideal compressor (reversible and adiabatic) where the initial pressure is 15 psia, the initial temperature is 200 oF, and the ideal exit state is 120 psia. What is the minimum specific work the compressor will be required to operate (Btu/lbm)?

solution;

Please check attachment for complete solution and step by step explanation

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4 years ago

A counter-flow double-piped heat exchange is to heat water from 20oC to 80oC at a rate of 1.2 kg/s. The heating is to be accompl

lawyer [7]

Answer:

110 m or 11,000 cm

Explanation:

let mass flow rate for cold and hot fluid = Mc and Mh respectively
let specific heat for cold and hot fluid = Cpc and Cph respectively
let heat capacity rate for cold and hot fluid = Cc and Ch respectively

Mc = 1.2 kg/s and Mh = 2 kg/s

Cpc = 4.18 kj/kg °c and Cph = 4.31 kj/kg °c

Using effectiveness-NUT method

First, we need to determine heat capacity rate for cold and hot fluid, and determine the dimensionless heat capacity rate

Cc = Mc × Cpc = 1.2 kg/s × 4.18 kj/kg °c = 5.016 kW/°c

Ch = Mh × Cph = 2 kg/s × 4.31 kj/kg °c = 8.62 kW/°c

From the result above cold fluid heat capacity rate is smaller

Dimensionless heat capacity rate, C = minimum capacity/maximum capacity

C= Cmin/Cmax

C = 5.016/8.62 = 0.582

.2 Second, we determine the maximum heat transfer rate, Qmax

Qmax = Cmin (Inlet Temp. of hot fluid - Inlet Temp. of cold fluid)

Qmax = (5.016 kW/°c)(160 - 20) °c

Qmax = (5.016 kW/°c)(140) °c = 702.24 kW

.3 Third, we determine the actual heat transfer rate, Q

Q = Cmin (outlet Temp. of cold fluid - inlet Temp. of cold fluid)

Q = (5.016 kW/°c)(80 - 20) °c

Qmax = (5.016 kW/°c)(60) °c = 303.66 kW

.4 Fourth, we determine Effectiveness of the heat exchanger, ε

ε = Q/Qmax

ε = 303.66 kW/702.24 kW

ε = 0.432

.5 Fifth, using appropriate effective relation for double pipe counter flow to determine NTU for the heat exchanger

NTU = $\\ \frac{1}{C-1} ln(\frac{ε-1}{εc -1} )$

NTU = $\frac{1}{0.582-1} ln(\frac{0.432 -1}{0.432 X 0.582 -1} )$

NTU = 0.661

.6 sixth, we determine Heat Exchanger surface area, As

From the question, the overall heat transfer coefficient U = 640 W/m²

As = $\frac{NTU C{min} }{U}$

As = $\frac{0.661 x 5016 W. °c }{640 W/m²}$

As = 5.18 m²

.7 Finally, we determine the length of the heat exchanger, L

L = $\frac{As}{\pi D}$

L = $\frac{5.18 m² }{\pi (0.015 m)}$

L= 109.91 m

L ≅ 110 m = 11,000 cm

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3 years ago