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3 years ago

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A rigid tank whose volume is 2 m3, initially containing air at 1 bar, 295 K, is connected by a valve to a large vessel holding a

ir at 6 bar, 295 K. The valve is opened only as long as required to fill the tank with air to a pressure of 6 bar and a temperature of 350 K. Assuming the ideal gas model for the air, determine the heat transfer between the tank contents and the surroundings, in kJ

1 answer:

bazaltina [42]3 years ago

8 0

Answer:

$Q_{cv}=-339.347kJ$

Explanation:

First we calculate the mass of the aire inside the rigid tank in the initial and end moments.

$P_iV_i=m_iRT_i$ (i could be 1 for initial and 2 for the end)

State1

$1bar*|\frac{100kPa}{1}|*2=m_1*0.287*295$

$m_1=232kg$

State2

$8bar*|\frac{100kPa}{1bar}|*2=m_2*0.287*350$

$m_2=11.946$

So, the total mass of the aire entered is

$m_v=m_2-m_1\\m_v=11.946-2.362\\m_v=9.584kg$

At this point we need to obtain the properties through the tables, so

For Specific Internal energy,

$u_1=210.49kJ/kg$

For Specific enthalpy

$h_1=295.17kJ/kg$

For the second state the Specific internal Energy (6bar, 350K)

$u_2=250.02kJ/kg$

At the end we make a Energy balance, so

$U_{cv}(t)-U_{cv}(t)=Q_{cv}-W{cv}+\sum_i m_ih_i - \sum_e m_eh_e$

No work done there is here, so clearing the equation for Q

$Q_{cv} = m_2u_2-m_1u_1-h_1(m_v)$

$Q_{cv} = (11.946*250.02)-(2.362*210.49)-(295.17*9.584)$

$Q_{cv}=-339.347kJ$

The sign indicates that the tank transferred heat<em> to</em> the surroundings.

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Consider a single crystal of nickel oriented such that a tensile stress is applied along a [001] direction. If slip occurs on a

Elena L [17]

Answer:

$\mathbf{\tau_c =5.675 \ MPa}$

Explanation:

Given that:

The direction of the applied tensile stress =[001]

direction of the slip plane = [ $\bar 1$ 01]

normal to the slip plane = [111]

Now, the first thing to do is to calculate the angle between the tensile stress and the slip by using the formula:

$cos \lambda = \Big [\dfrac{d_1d_2+e_1e_2+f_1f_2}{\sqrt{(d_1^2+e_1^2+f_1^2)+(d_2^2+e_2^2+f_2^2) }} \Big]$

where;

$[d_1\ e_1 \ f_1]$ = directional indices for tensile stress

$[d_2 \ e_2 \ f_2]$ = slip direction

replacing their values;

i.e $d_1$ = 0 , $e_1$ = 0 $f_1$ = 1 & $d_2$ = -1 , $e_2$ = 0 , $f_2$ = 1

$cos \lambda = \Big [\dfrac{(0\times -1)+(0\times 0) + (1\times 1) }{\sqrt{(0^2+0^2+1^2)+((-1)^2+0^2+1^2) }} \Big]$

$cos \ \lambda = \dfrac{1}{\sqrt{2}}$

Also, to find the angle $\phi$ between the stress [001] & normal slip plane [111]

Then;

$cos \ \phi = \Big [\dfrac{d_1d_3+e_1e_3+f_1f_3}{\sqrt{(d_1^2+e_1^2+f_1^2)+(d_3^2+e_3^2+f_3^2) }} \Big]$

replacing their values;

i.e $d_1$ = 0 , $e_1$ = 0 $f_1$ = 1 & $d_3$ = 1 , $e_3$ = 1 , $f_3$ = 1

$cos \ \phi= \Big [ \dfrac{ (0 \times 1)+(0 \times 1)+(1 \times 1)} {\sqrt {(0^2+0^2+1^2)+(1^2+1^2 +1^2)} } \Big]$

$cos \phi= \dfrac{1} {\sqrt{3} }$

However, the critical resolved SS(shear stress) $\mathbf{\tau_c}$ can be computed using the formula:

$\tau_c = (\sigma )(cos \phi )(cos \lambda)$

where;

applied tensile stress $\sigma =$ 13.9 MPa

∴

$\tau_c =13.9\times ( \dfrac{1}{\sqrt{2}} )( \dfrac{1}{\sqrt{3}})$

$\mathbf{\tau_c =5.675 \ MPa}$

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3 years ago

Your manager has asked you to research and recommend a writing guide that examiners in your digital forensics company can use fo

vivado [14]

Answer:

Kindly Check the explanation

Explanation:

Report

A Report is a way to present the forensic examination result in front of judge. A report contains warrants, all affidavits issued for arrest, expenses occur during forensic test and lists of evidence. Apart from evidence a report also contains expert opinions.

Guidelines

These are the set of rules and written statement which are used to present the important information in a structured and clear format. The main motive behind to define the guidelines is to achieve standardization in the reports. It also improves the readability of the report.

Guidelines for report

Abstract:

Each report must contain an abstract of the report which gives the brief review about the report. It came at the starting of the report. The main motive behind to give abstract is to give brief about report to someone in a very less time. The size of abstract must not be more than one page.

Index:

Each report must contain an index which display's which content is available at which page of report. The content of index must be appropriate and clear so that the reader will not get confuse.

Format of report:

The formatting of report is also one of the essential parts of the guidelines. It makes the report attractive and also due to this reader not gets bored while reading the report. The guidelines regarding layout of report are as follow:

1. Use time roman font and 12 font size as a default font to explain anything in the report.

2. The explanation must be justified

3. As possible divide the long paragraph. if possible explain in points.

4. The page must have border on all sides

5. Each pages must have numbering and footer

Rules for grammar:

1. The language of the report must be simple and clear. So that everyone can understand it easily.

2. Avoid repeating same sentence or word again and again.

3. Use active instead of passive voice, in order to give importance to doer.

4. Write expressions between commas.

5. Avoid spelling mistakes in report which also make wrong impact.

6. As possible give heading or subheading to material or explanation which must be accurate.

7. Explain, new or difficult words used in the report.

8. What ever written in the report must be through the point and accurate on bases of fact.

Body of report:

The body of the report referred to as a content written inside the report. In order to write an impressive report, it must include all these things:

1. Avoid use of hypothetical question, if still hypothetical question arises it must be bases on factual evidence.

2. Add all the affidavits and warrants in the report issued for search and arrest.

3. The cost money expenses while solving the case.

4. The expert opinion which must be bases on knowledge or previously declare case results.

5. The list of people and evidence which are collected and interrogative during the investigation.

6. If investigation is further going on than write the area in which the investigation further goes on and also mention when the investigation get complete.

Forensic software used:

A short must be given about the software used in the investigation. The result generated by the software must also be pasted in that report. It is more good if attach the snap shot of the result. Add any previous case result in which the same software result is taken as evidence, in order to justify that the result generated by the software is true. Some of forensic softwares are FTK, ProDiscover, Hexworkshop. The result of these softwares must be heighted so that everyone can notice it.

Conclusion:

The conclusion must be given at the end of report to tell according him what result came after investigation. In conclusion also write on which basis the result concludes. There must be strong behind the conclusion.

References:

In Reference write all the cases, thesis, books which an investigator followed to solve the current case. In addition if they referred any internet article. They can also write the website name where that article lies. In short can say that write everything where they got an idea which is helpful in solving the case.

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Aleonysh [2.5K]

Answer:

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Explanation:

we have given 4140 steel contains 0.4% C

we know here that 4140 steel is low steel alloy , and it have low amount of chromium , manganese etc alloying element

and these elements which are present in 4140 steel they increase yield strength and ultimate strength of steel

while in 1045 steel contains 0.45 % c is plain carbon steel

and it do not contain any alloying element

so that 4140 steel contains 0.4% C having higher yield strength and ultimate strength than the 1045 steel contains 0.45% C

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