Answer:
Cell phones emit low levels of non-ionizing radiation when in use. The type of radiation emitted by cell phones is also referred to as radio frequency (RF) energy. As stated by the National Cancer Institute, "there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans.
Explanation:
Cell phones emit low levels of non-ionizing radiation when in use. The type of radiation emitted by cell phones is also referred to as radio frequency (RF) energy. As stated by the National Cancer Institute, "there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans.
Air is contained inside a vertical piston-cylinder assembly by a piston of mass 105 kg and face area of 0.05 m2 . The mass of air inside the cylinder is 20 grams, and the air initially occupies a volume of 50 liters. The atmosphere exerts a pressure of 101.3 kPa on the top of the piston. The volume of the air slowly decreases to 0.005 m3 , while maintaining constant pressure, as the specific internal energy of the air decreases by 175 kJ/kg. Neglecting friction between the piston and the cylinder wall, determine the heat between the surroundings and the air inside the piston-cylinder assembly in kJ
Answer:
ΔQ = 1.06 KJ
Explanation:
The amount of heat transfer between the piston-cylinder system and the surrounding can easily be found by using the First Law of Thermodynamics. The first law of thermodynamics can be written as follows:
ΔQ = ΔU + W
ΔQ = mΔu + PΔV
where,
ΔQ = Heat transfer between system and surrounding = ?
Δu = specific change in internal energy of the system = - 175 KJ/kg
m = mass of air = 20 g = 0.02 kg
P = Constant Pressure = 101.3 KPa
ΔV = Change in Volume = 0.05 m³ - 0.005 m³ = 0.045 m³
Therefore,
ΔQ = (0.02 kg)(-175 KJ/kg) + (101.3 KPa)(0.045 m³)
ΔQ = -3.5 KJ + 4.56 KJ
ΔQ = 1.06 KJ
A cone-shaped part is to be fabricated using stereolithography. The radius of the cone at its base = 35 mm, and its height = 50 mm. To minimize the staircase effect, layer thickness = 0.05 mm. The diameter of the laser beam = 0.22 mm, and the beam is moved across the surface of the photopolymer at a velocity of 900 mm/s.
Required:
Compute an estimate for the time required to build the part, if 15 s are lost each layer to lower the height of the platform that holds the part. Neglect post-curing time. Setup time for the job = 25 min.
Explanation:
volume = πR²h/3
= πx35²x50/3
= 192325/3
= 64166.725
number of layers n = 50mm/0.05
n = 1000layers
average volume = 64166.725/1000
= 64.167mm³
average area = 64.167/0.05
= 1283.34mm²
average time = 1283.34/900mm x 0.22
= 6.48
6.48 + 15 seconds
= 21.48 seconds
time required = 1000x21.48
= 21480 seconds
convert to minutes
21480/60
= 358 minutes
21480/3600
= 5.967 hours
Refrigerant-134a at 1 MPa and 100 C is to be cooled to 1 MPa and 28 C in a condenser by air. The air enters at 125 kPa and 25 C with a mass flow rate of 697 kg/min and leaves at 97 kPa and 58 C. Determine the mass flow rate of the refrigerant. Assume air has a constant heat capacity determined at room temperature. Report the mass flow rate of the refrigerant in kg/min with one decimal digit, for example 95.3 or 105.6.
what is an undescribable outcome from cellphones?
Answer:
Cell phones emit low levels of non-ionizing radiation when in use. The type of radiation emitted by cell phones is also referred to as radio frequency (RF) energy. As stated by the National Cancer Institute, "there is currently no consistent evidence that non-ionizing radiation increases cancer risk in humans.
Explanation:
What’s is the answer
Silicon carbide nanowires of diameter D = 15 nm can be grown onto a solid siliconcarbide surface by carefully depositing droplets of catalyst liquid onto a flat silicon carbide substrate. Siliconcarbide nanowires grow upward from the deposited drops, and if the drops are deposited in a pattern, an array ofnanowire fins can be grown, forming a silicon carbide nano-heat sink. Consider finned and unfinned electronicspackages in which an extremely small, 10 μm × 10 μm electronics device is sandwiched between two d = 100-nm-thick silicon carbide sheets. In both cases, the coolant is a dielectric liquid at 20°C. A heat transfer coefficient of h= 1 × 10^5 W/m^2 · K exists on the top and bottom of the unfinned package and on all surfaces of the exposed siliconcarbide fins, which are each L = 300 nm long. Each nano-heat sink includes a 200 × 200 array of nanofins.
Required:
Determine the maximum allowable heat rate that can be generated by the electronic device so that its temperatureis maintained at Tt < 85°C for the unfinned and finned packages.
Answer:
For unfined package = 1.30 × 10^-3 W.
Dor fined package = 8.64 × 10^-3 W.
Explanation:
STEP ONE: The first thing to do is to determine the cross sectional area and input the value into the convectional resistance formula/equation in order to determine the heat rate for the unfined package.
Thus, Area = (dimension of the electronic device) ^2. = (10 × 10^-6)^2 m.
Convectional Resistance = (100 × 10^-9)÷ (10 × 10^-6)^2 × 490 = 2.04 K/W.
Heat transfer coefficient = 1/ (10 × 10^-7)^2 × 10^5. = 1 × 10^5 K/W.
Thus, the heat rate for the unfined package = 2{(85 - 20) ÷ (10^5 + 2.04)} = 1.30 × 10^-3 W.
STEP TWO: Determine the surface area of each fin and the prime area.
Surface area of each fin = {300 + 15/4} × 10^-9 × 10^-9 × π × 15 = 1.43 × 10^-14 m^2.
Prime area = (10^-6 × 10)^2 - (200 × 200) × π × [ ( 15 × 10^-9)^2 ÷ 4] = 9.29 × 10^-11 m^2.
STEP THREE: Determine the efficiency
G ={ [300 + 15/4) × 10^9 } × [ 4 × 10^5÷ 490 × 15 × 10^-9] = 7.09 × 10^-2.
Efficiency= tanh ( 7.09 × 10^-2) ÷ 7.09 × 10^-2 = 0.998.
Thus, the coefficient = 1 - (1.43 × 10^-14 × (200 × 200) ÷ (6.65 × 10^-10) × (1 - 0.998) = 0.99.
STEP FOUR: Determine the heat rate for the finned package.
Thermal resistance = 1/ (10^5 × 0.999 × 10^-10 × 6.65 = 1.50 × 10^4 K/W.
The heat rate for the finned package = 2 { 85 - 20} ÷ { 1.50 × 10^4 + 2.04} = 8.64 × 10^-3 W
Which of the following is most characteristic of OSHA's relationship with professional trade organizations in residential construction?
O beneficial
confrontational
competitive
awkward
Answer:
its beneficial
Explanation:
took the test
Answer:
Beneficial would be the correct answer.
Explanation:
In lighting system, why it is important to consider maintenance factor?
Answer: The maintenance factor of a lighting system reflects how much of the initial luminous flux is still available at the end of its useful life. The planned lighting engineer must compute the maintenance factor and multiply the new value of the light output by it.
Explanation:
Answer:
Explanation: A lighting system's maintenance factor indicates how much of the initial luminous flux remains available at the end of its service life. The maintenance factor must be determined by the planning lighting engineer and the new value of the luminous flux multiplied by it.
A measurement that represents where two lines, arcs, or a
line and an arc would meet is called:
Angle is defined as the measurement that represents where two lines, arcs, or a line and an arc would meet.
What is an Arc?This is defined as a smooth curve which joins two endpoints. An angle can be formed when two two lines, arcs, or a line and an arc meet.
This is why it was chosen as the most appropriate type of measurement in the scenario mentioned above.
Read more about Degree here https://brainly.com/question/25770607
what is the answer What will finally break the internet?
A hot brass plate is having its upper surface cooled by impinging jet of air at temperature of 15°C and convection heat transfer coefficient of 220 W/m^2•K. The 10-cm thick brass plate (rho = 8530 kg/m^3, cp = 380 J/kg•K, k = 110 W/m•K, and α = 33.9×10^–6 m^2/s) has a uniform initial temperature of 900°C, and the bottom surface of the plate is insulated.
Required:
Determine the temperature at the center plane of the brass plate after 3 minutes of cooling.
Answer:
809.98°C
Explanation:
STEP ONE: The first step to take in order to solve this particular Question or problem is to find or determine the Biot value.
Biot value = (heat transfer coefficient × length) ÷ thermal conductivity.
Biot value = (220 × 0.1)÷ 110 = 0.2.
Biot value = 0.2.
STEP TWO: Determine the Fourier number. Since the Biot value is greater than 0.1. Tis can be done by making use of the formula below;
Fourier number = thermal diffusivity × time ÷ (length)^2.
Fourier number = (3 × 60 × 33.9 × 10^-6)/( 0.1)^2 = 0.6102.
STEP THREE: This is the last step for the question, here we will be calculating the temperature of the center plane of the brass plate after 3 minutes.
Thus, the temperature of the center plane of the brass plane after 3 minutes = (1.00705) (0.89199) (900- 15) + 15.
= > the temperature of the center plane of the brass plane after 3 minutes = 809.98°C.
I need help with online lab
Answer:
I believe on the fist question it power rationg
if you play roblox leave user down bellow
Answer:
why dont you make friends on roblox lol might be safer
Explanation:
Answer:
yes i play roblox
Explanation:
But why are you asking this type of Question
What is troubleshooting?
creating a checklist
finding and fixing a problem
scanning for viruses
performing regular maintenance
Answer:
B. finding and fixing a problem
Explanation: is correct on edge2020
Please hit that thanks button below and mark brainliest if possible
Whose responsibility is it to provide a safe and healthy workplace?
Answer:
Under the OSH law, employers have a responsibility to provide a safe workplace. This is a short summary of key employer responsibilities: Provide a workplace free from serious recognized hazards and comply with standards, rules and regulations issued under the OSH Act.
credits to google
Explanation:
Answer:
employers
Explanation:
because they are responsible.
At time t the resultant force on a particle, of mass 250kg is (300ti-400tj)N. Initially, the particle is at the origin and is moving
with the velocity (2i-3j)m
−1
Answer:
i
Explanation:
All of these are true about aluminum EXCEPT that it:
A) has a self-healing, corrosion-resistant coating.
B) is resistant to galvanic corrosion.
C) is a nonferrous metal.
D) is easy to be initially formed.
All of the aforementioned are true characteristics and properties of aluminum except: B. is resistant to galvanic corrosion.
What is aluminum?Aluminum can be defined as a silvery white metal and it is considered to be the most abundant metal found in the Earth's crust. Also, it is represented with the chemical symbol "Al" and it has an atomic number of thirteen (13).
This ultimately implies that, aluminum is found in Group 3 on the periodic table because it has three (3) valence electrons, which are found in the outermost shell of its atomic nucleus.
The characteristics and properties of aluminum.Some of the characteristics and properties of aluminum include the following:
It has a self-healing and corrosion-resistant coating.It is a nonferrous metal.It is easy to be initially manufacture or formed.Read more on aluminum here: https://brainly.com/question/25869623
What is one advantage corporations have over other types of businesses
whats your answer Where is the strangest place you’ve urinated or defecated?
Answer:At the train station
Explanation:
Answer:
in those camping portal pottys
in software engineering how do you apply design for change?
Answer:
it is reducely very iloretable chance for a software engineer to give an end to this question
What make metal ductwork more desirable than flex duct?
Less friction loss
Less chance of restriction
More direct routes to boots
All of the above
what is the irregular past tense of hear?
Answer:
Past tense of hear = heard
In this activity, you will conduct research on a famous work of architecture from the 1800s and write a report about the work and the architect who created it. You will then create an architectural drawing.
__________________________________________________________________________
Directions and Analysis
Task 1: Researching an Architectural Work of the 1800s
Use the Internet and other available resources to conduct basic research on architecture from the 1800s. Select a building designed by a significant (influential) architect from that period, and then write a paper about the building and architect. Make sure you include the following:
About the architect
basic biographical information
education
how the architect influenced society and design
About the building/work
main materials used
structural considerations
technology and tools used during construction
Answer:
can you explain how to do this
Explanation:
Water that has evaporated returns to earth as
Answer:
rain
Explanation:
evaoration causes clouds
clouds condense and rain
Answer:
rain
Explanation:
Three groups of students are given study outlines for 6 weeks. One group studies 2 hours a night, a second group studies 1 hour a night, and the third group only studies 30 minutes. Their final exam grade will be at the end of the 6 weeks. What is the constant ?
Answer:
The constant here is the study outline
Explanation:
In scientific research, the constant variable is that part/variable of the experiment that does not change or is set not to change. Examples include temperature, environment or height.
Assuming the scenery described in this question is an experiment. All the groups presented are bound by a constant during the experiment. The constant here is the study outline. The study outline provided to the students is not going to change.
NOTE: There could be confusion as regards the answer being the final exam grade but that will be the dependent variable as that will be the outcome of the experiment while the time spent to study will be the independent variable.
Lynx eat snowshoe hares, and snowshoes hears eat plants. Which term can be applied to the lynx in this food chain example? Primary consumer predator secondary consumer
Answer:
primary consumer because YES
Answer:predator and secondary consumer
Explanation:
Clarisse is an architect. What skills will she apply to integrate her visualized solutions with other aspects such as business and industry standards? Clarisse will apply BLANK skills to integrate her visualized solutions with other aspects such as business and industry standards.
Answer:
Conceptual problem-solving skills
Explanation:
Conceptual problem-solving is a way of solving problems by applying what we know to what we do not know. For Clarisse who is an architect, the knowledge she has about visualization, and the concepts of the business world are not quite related.
So to integrate her visualization solutions to business standards, she would have to compare the two spheres of knowledge to determine how to adapt one t the other.
Answer:
Management skills
Explanation:
Bit of a shot in the dark here, but, and i quote:
"Management skills comprise planning, organizing, and coordinating a project to reach a goal. Architects apply management skills to integrate their visualized solutions with other aspects such as business and industry standards."
Hopefully this works out for ya'll.
A transparent film is to be bonded onto the top surface of a solid plate inside a heated chamber. For the bond to cure properly, a temperature of 70°C is to be maintained at the bond, between the film and the solid plate. The transparent film has a thickness of 1 mm and thermal conductivity of 0.05 W/m·K, while the solid plate is 13 mm thick and has a thermal conductivity of 1.2 W/m·K. Inside the heated chamber, the convection heat transfer coefficient is 70 W/m2·K. If the bottom surface of the solid plate is maintained at 52°C.
Required:
Determine the temperature inside the heated chamber and the surface temperature of the transparent film. Assume thermal contact resistance is negligible.
Answer:
1.) 103.23 degree centigrade
2.) 126.96 degree centigrade
Explanation:
Given that a transparent film is to be bonded onto the top surface of a solid plate inside a heated chamber. For the bond to cure properly, a temperature of 70°C is to be maintained at the bond, between the film and the solid plate. The transparent film has a thickness of 1 mm and thermal conductivity of 0.05 W/m·K, while the solid plate is 13 mm thick and has a thermal conductivity of 1.2 W/m·K. Inside the heated chamber, the convection heat transfer coefficient is 70 W/m2·K. If the bottom surface of the solid plate is maintained at 52°C.
To determine the temperature inside the heated Chamber, let us first calculate the heat transfer rate per unit area through the plate by using the formula
Heat transfer rate R = k( Tb - T2)/L
Where
k = 1.2 W/mA.K
Tb = 70 degree
T2 = 52 degree
L = 13mm = 13/1000 = 0.013m
substitute all the parameters into the formula above.
R = 1.2 x ( 70 - 52 )/ 0.013
R = 1.2 x (18/0.013)
R = 1661. 5 W/m^2
the surface temperature of the transparent film will be
Ts = Tb + (RLf/Kf)
Ts = 70 + (1661.5 x 0.001)/0.05
Ts = 70 + (1.6615)/0.05
Ts = 70 + 33.23
Ts = 103.23 degree centigrade
the temperature inside the heated Chamber will be calculated by using the formula
Ti = Ts + (R/h)
Ti = 103.23 + (1661.5/70)
Ti = 103.23 + 23.74
Ti = 126.97 degree centigrade
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Based on the results, which statement is most likely a criterion for the gaming system design? Choose the correct answer.
a. width of about 8 inches
b. ability to connect wifi
c. battery life of at least 24hrs
d. production cost of less than $40
Answer:
B
Explanation:
You need to connect to WiFi without it no multiplayer
When a current carrying coil is placed between the magnetic poles a force acts on it that causes it to rotate what can be done to make the coil rotate faster
Answer:
increase the field strengthincrease the currentdecrease the moment of inertia of the coilExplanation:
The rotation speed depends on the force applied to the coil, and on the mass (moment of inertia) of the coil. The force can be increased by ...
increasing the magnetic field strength
increasing the coil current
And the moment of inertia can be decreased by ...
making the coil lighter
making the coil more compact.
Any of these changes will increase the rotation speed.