## Posts

### Computing & Informatics: Octal to decimal conversion

Convert an octal number to a decimal number. Give a video example of converting an octal number into a decimal number. --- Study material is available at https://amiestudycircle.com

### Computing & Informatics: Binary number to decimal number

Give an example to convert a binary number to a decimal number. Give a video example to convert a binary number to a decimal number. --- Study material is available at https://amiestudycircle.com

### Design and Manufacturing: Selected short answer questions from AMIE exams (Summer 2017 to Summer 2020)

Write briefly about mould wash. Mould wash: A coating applied in liquid form to walls of a mould cavity. What is adaptive control? Adaptive control: Adaptive control is a set of techniques that permit to adjust the value of control parameters in real-time, permitting to monitor controlled variables even if plant parameters are unknown or if they change. This control is a special kind of non-lineal control, and the process can be split into two timelines: rapid time (feedback loop) and slow time (variation of control parameters, which affects automation). What do you understand by the term machinability index? The machinability index is used to compare the machinability of different materials in the various cutting process. It is an attempt to quantify the relative machinability of a different material. What is tack weld? Tack Welding is basically a temporary weld performed during the Fitting of a part. This is done to ensure dimensional stability before actual Welding starts. Normally

### Study Tip: Flow state technique

Try working at a ratio of 90:20 .  90 minutes of work before taking a 20-minute break.  This will create a "FIOW STATE" resting your brain just enough so it's fresh for the next 90 minutes.

### Mine Ventilation & Environmental Hazards: Selected Short Answer Questions from AMIE Exams

What are the major sources of noise in underground mining, highlighting the permissible levels of noise in those? The ambient noise level of the underground mining area is affected by the operation of the cutting machines, tub/conveyor movement and blasting of the coal. The movement of coaling machines and transport units-conveyor, tubs and transfer points caused audible noise which becomes disturbing underground because of the poor absorption by the walls. Classify mine fires. Fires underground can be classified into two broad groups, open and concealed fires. Open fires occur in airways, faces and other openings that form part of the active ventilation system of the mine and, hence, affect the quality of the mine airflows quickly and directly.  As the term might imply, open fires are often accompanied by flaming combustion because of the availability of oxygen and offer the possibility of a direct attack by fire fighting teams. Conversely, concealed fires occur in areas that are diff

### Question from Material Science (Summer 2019) AMIE Exam

At room temperature, the electrical conductivity of PbS is 25  ( Ω .m) -1 , whereas the electron and hole mobilities are 0.06 and 0.02  m 2 /V.s, respectively. Calculate the intrinsic carrier concentration for PbS at room temperature. (AMIE, Material Science, Summer 2019) Solution $\begin{array}{l}\sigma = 25{(\Omega m)^{ - 1}}\\{\mu _e} = 0.06{m^2}/Vs\\{\mu _h} = 0.02{m^2}/Vs\end{array}$ In the intrinsic region $n = p = {n_i}$ So, $\sigma = {n_i}\left| e \right|({\mu _e} + {\mu _h})$ $\therefore {n_i} = \frac{\sigma }{{\left| e \right|({\mu _e} + {\mu _h})}} = \frac{{25}}{{1.6x{{10}^{ - 19}}(0.06 + 0.02)}} = 1.95x{10^{21}}{m^{ - 3}}$ Study material for AMIE Exams

### A numerical from Material Science (Summer 2019 AMIE Question paper)

Find the equilibrium concentration of vacancies in aluminium at 300 K and 900 K. Given  ΔH f  = 68 kJ/mol (AMIE, Material Science, Summer 2019, 10 marks) Solution At 300 K $\frac{{{N_v}}}{N} = \exp \left( {\frac{{68x{{10}^3}\Delta {H_f}}}{{8.314x300}}} \right) = \exp ( - 27.26) = 1.45\,x\,{10^{ - 12}}$