name two prons and two cons of using sulfur dioxide as a tool of geoengineering.

In tropical regions less energy is emitted by the earth as infrared radiation than is absorbed as solar radiation averaged over the year. Explain briefly why tropical regions do not continually get warmer year after year after year.

$12 Summaries

With each word being worth 10 cents, write four $12 summaries of the reading from any four of the following chapters in Everyday Bible Study:

• 15. Observe: How to Make Accurate Observations
• 16. How to Use Multiple Translations of the Bible
• 17. How to Ask Key Questions
• 28. Interpret: How to Find the Meaning of the Bible
• 29. Correlate: How to Connect Scripture to Other Scriptures
• 30. Correlate: How to See Jesus in the Bible
• 31. Apply: How to Live Out What You Learn
• 32. How to Study the Old Testament Genres, Part 1: Law
• 33. How to Study the Old Testament Genres, Part 2: Narrative
• 34. How to Study the Old Testament Genres, Part 3: Wisdom and Poetry
• 35. How to Study the Old Testament Genres, Part 4: Prophetic Literature

This means that in this assignment you are developing four summaries of 120 words each (one for each of the four chapters you selected). You should aim to create four summaries where each summary is between 100-120 words. Each of your summaries should not exceed the 120-word or $12 limit.

Neil De Grasse Tyson said, "The good thing about science is that it works whether you believe in it or not." Describe two aspects of science and the scientific method that support this statement.

3.2. Discuss the significance of Risk Assessment as a step in developing a Disaster Risk Profile. (10)

Question 16

Item 16

(1) Space flights to other planets have long been a fixture of science fiction, and in 2017 the fiction appeared to come closer to reality when the National Aeronautics and Space Administration (NASA) announced it was prioritizing eventual piloted missions to Mars and other planets. (2) It may be too soon to start planning your Martian vacation, however: there are good reasons to doubt that humans will be able to undertake long-distance space flights.

(3) For example, the body begins to lose muscle mass and bone density in low-gravity environments because the pressure of Earth’s atmosphere is removed. (4) Astronauts struggle to walk after returning from a six-month space mission; the effects of a three-year flight and a stay on Mars would be far greater. (5) Similarly, humans have a natural cycle of wakefulness and sleep attuned to daytime and nighttime on Earth. (6) Anyone who has experienced jet lag can attest to the mental and physical effects of disrupting this cycle, but we can only imagine the consequences of disrupting it for years on end.

(7) It remains to be seen whether these problems can be diminished enough for long space voyages, and it is true that monitoring, exercise, and technological fixes like sunlight-simulating LED lights have shown promise. (8) Other issues may be more troublesome. (9) Space missions are stressful, requiring long hours of repetitive activity performed in small, cramped spaces. (10) The stress lowers immune response even as outer space conditions cause microbes in astronauts’ bodies to mutate, potentially resulting in dangerous diseases. (11) Cosmic rays pose another health concern: a 2018 study from Georgetown University Medical Center found that prolonged exposure to cosmic radiation could lead to stomach and colon cancers. (12) Unless scientists can develop effective means of fighting these health risks, long-distance space travel may be too dangerous.

(13) With NASA’s attention directed to the problems of long space missions, it is certainly possible that other nations will invest in similar research. (14) But it is also possible that further research will turn up new problems that have not even been identified yet.

The writer wants to add a concluding sentence that brings the argument to a unified end by summing up the main claim of the passage and returning to a theme from the first paragraph. Which of the following choices, if added after sentence 14, best accomplishes this goal?

A.It is thus likely that for many years to come, the only way for humans to have an experience exploring distant planets will be by opening a book or going to the movies rather than hopping on a rocket.

B.Ultimately, these problems are likely to be overcome, because the efforts of NASA are now being supplemented by those of private spaceflight companies.

C.It is nonetheless important to remain optimistic about reaching Mars—the first step to achieving a goal is to envision a successful outcome.

D.Some argue that NASA’s space shuttle program took attention away from more ambitious goals and that preparing to go to Mars is a better direction for the agency.

E.Sending robots rather than humans eliminates many of the dangers and difficulties, but there is something uniquely inspiring about humans traveling into space.

A tank, containing O2 and H2, has a volume of 4.00 L and at total pressure is 24.44 atm. Calculate the mass of oxygen of which mole fraction is 0.4 in the tank at 25.0 °C .

chemical process industrial

Spent nuclear fuel and many areas where nuclear reactor materials have been accidentally released to the environment mainly contain quantities of two radioactive isotopes, strontium 90 (⁹⁰Sr) and cesium 137 (¹³⁷Cs). A nuclear underground waste storage tank contains 100 curies of each of these two isotopes. Plot the activity of each as they decay over the next 500 years. How much of each will remain after 300 years? Use half-lives from this web site: http://atom.kaeri.re.kr:81/ton/index.html

The emissivity coefficient of an oxidized iron surface is 0.612 and the same value can be accepted for the absorption coefficient of radiation received from the environment. Calculate the heat lost per square meter of the surface that is at 80 ° C, located vertically in a 20 ° C environment.

A flat furnace wall is constructed of a 4.5 in (114 mm) layer of Silo-cel brick, with a thermal conductivity of 0.08 Btu/ft·h·˚F (0.138 W/m·˚C), backed by a 9-in. (229-mm) layer of common brick, of conductivity 0.8 Btu/ft·h·˚F(1.38 W/m.˚C). The temperature of the inner face of the wall is 1400˚F (760˚C), and that of the outer face is 170˚F(76.6˚C).

(a) What is the heat loss through the wall?

(b) What is the temperature of the interface between the refractory brick and the common brick?

(c) Supposing that the contact between the two brick layers is poor and that a “contact resistance” of 0.50˚F·ft2.h/Btu (0.088˚Cm2/W) is present, what would be the heat loss?

An evaporator-crystallizer process is used to obtain solid potassium sulfate. The fresh feed to the evaporator contains 19.60% K₂SO₄ and is mixed with the recycled mother liquor stream before entering the evaporator. The crystal product of the crystallizer is still wet as it contains 10.00 kg solid K₂SO₄ per kg adhering mother liquor solution. The filtered mother liquor contains 40.00% K₂SO₄ and is recycled to join the fresh feed. Of all the water entering the evaporator, 45.00% is evaporated. The evaporator has a maximum capacity of 175.0 kg/s water evaporated. If the system is kept running at maximum capacity, determine the following:

1. Flow rates of feed, crystal product, recycle, and mixed feed
2. Composition of mixed feed in % by mass
3. If we want to have a higher quality crystal product (meaning, K₂SO₄ crystals with a lesser water content), what unit do you suggest we add to the process? Where do we add the unit?
4. How much water needs to be removed from the crystal product to obtain pure K₂SO₄ crystals?

Using The Degree of Advancement Variable

Methane and oxygen react in the presence of a catalyst to give formaldehyde. In a parallel reaction, methane is oxidized to carbon dioxide and water:

CH4 + O2 = HCHO + H2O

CH4 + O2 = CO2 + H2O

The reactor feed contains equimolar amounts of methane and oxygen. Assume as a base a feed of 100 mol / s.

The methane conversion fraction is 0.90 and the formaldehyde yield fraction is 0.855. Use the reaction advance degree method to determine the molar composition of the reactor outlet stream and the selectivity of formaldehyde production relative to carbon dioxide production.

1200 cm³/sec of water at 420 K is pumped in a 40 mm internal diameter pipe

through a length of 150 m in a horizontal direction and up through a vertical length of 10 m . In the pipe there is a control valve which may be taken as equivalent to 200 pipe diameters and other pipe fittings equivalent to 60 pipe diameter. Also in the line there is a heat exchanger across which there is a loss in head of 1.5 of water. What power must be delivered to the pump if the unit is 60% efficient?

PS: roughness factor not given

A chemical company propose to build a formaldehyde production plant using catalytic oxidation of methanol method. As a group of engineers in the company, you are assigned to write a material balance proposal for the plant. The material balance proposal should consider the following steps; a) Introduce background and reactions involve in the production of formaldehyde through catalytic oxidation of methanol method. Hence, identify the required raw materials for the process. b) Propose a process flow diagram, which consider mixer, reactor and separator as the main equipment. Unreacted reactants should be recycled, however 20% of the unreacted methanol should be send to the product stream of the separator as product stabilizer. 2 c) State basis of calculation and solve the material balance when overall conversion of methanol is within (80-90) %. Ratio on the amount of feed reactants should be fixed accordingly before entering the reactor. d) Present the material balance summary (from part c) in a form of table. The summary should consist of the mole and mass flowrates and compositions of each stream. Material balance of the process should be validated as a conclusion to prove the proposed design. e) You propose to further purify the produced formaldehyde from separator (part c) through reducing the amount of water content by 50%. The purification process should be performed in a condenser and consider only the water that condense. Determine composition of the gas and liquid outlet streams of the condenser. The produced formaldehyde gas mixture from separator enters the condenser at temperature of 120oC and should be cooled at constant pressure in the range of (500-600) mm Hg. In the condenser, vapour is in equilibrium with liquid, and the vapour is ideal. Use the pre-determined composition of water in gas outlet stream to determine the Tdp and set the outlet temperature of the gas mixture. The outlet temperature should not be set below the Tdp of methanol and formaldehyde of the mixture. Justify and prove your choice. f) The produced formaldehyde from condenser (part e) is then pump to a 300 L storage tank. The gas temperature should be set within (20-30)oC. Identify the suitable pressure to be set for the storage when the gas mixture is considered as i) an ideal gas and ii) non-ideal gas. Evaluate and discuss on the determined pressure.