The Deborah number (De) is defined as follows:
De = relaxation time of the material / time scale of the process or experiment
When De<<1, the material may be described as being “liquid-like” in its response, and when
De>>1, the material may be described as “solid-like”. At intermediate values, the material may
be described as being viscoelastic, having a dual liquid (visco-) and solid (elastic) behavior.
(a) From this definition explain why at room temperature water and window glass are not
viscoelastic while a compound like silly putty is.
(b) How does the phenomenon of the glass transition temperature relate to viscoelasticity?
(c) Please give an example of a viscoelastic phenomenon that may occur during melt processing
of a polymer.
How are scientists trying to reduce impacts of black carbon?
Many people have done a reasonably good job conserving water, primarily by turning off their landscape irrigation and allowing their yards to dry up; others have not.
1. Your neighbor wants to conserve water, but does not want to stop watering altogether. They do want to try and keep their landscape green and healthy. What advice / suggestions would you offer your neighbor?
2. 2017 Update: With all of the rain we had the winter of 2017, and the snow pack at almost 180% of normal, do you think that the drought is over and we can go back to our normal water usage, or do you believe that this will be temporary, and we should continue to practice water efficiency and water conservation?
3. 2020 Update: How might the winter of 2019/2020 change your answer for question #2 above?
Around 650 million years ago, the Earth was covered from pole to pole with glaciers during a period referred to as Snowball Earth. Identify and describe a set of 3 realistic global scale feedback mechanisms that address the following:
a. A feedback mechanism that allowed the Earth to descend into a global glaciation
b. A feedback mechanism that kept the Earth in a permanent glaciation for millions of years
c. A feedback mechanism that allowed the Earth to escape from the glacial period to the warm period that followed.
how are Americans responding to mass media news coverage of COVID-19 and the Coronavirus pandemic?
Reasons for understanding petroleum as being of biogenic origin.
Please explain the "BIG FIVE" greatest mass extinctions and the results.
Then answer the questions: "Are mass extinctions a thing of the past? Why or Why Not?"
A sample contains 80% of radioactive Carbon 13C. Calculate the age of the sample if you knew that the half time of Carbon isotope is 5730 year. Radioactive decay follows first-order reaction kinetics.
Absolute or 100% ethanol is produced from a mixture of 95% ethanol and 5% water using the Keyes distillation process. A third component, benzene, is added to lower the volatility of the alcohol. Under these conditions, the overhead product is a constat-boiling mixture of 18.5% ethanol, 7.4% water and 74.1% benzene. Use the following data to calculate the volume of benzene that should be fed to the still in order to produce 250 litres of absolute ethanol: density of 100% ethanol = .785g/cm3 and density of benzene = .872 g/cm^3
1. What are some lethal ranges for pH and what effect do they have on aquatic organisms?
2. Describe how the Hudson River salinity compares to other major rivers in the U.S. (use the ppt unit of measurement and the chart in your lab to help answer this question)
3. What are some factors that can contribute to the turbidity of water?
4. After a heavy rainfall, would you expect phosphate levels in the Hudson River to increase or decrease relative to after a period of dry weather? Why?
5. Explain the process of eutrophication, and how elevated phosphate levels can lead to low dissolved oxygen.
6. Why is it important to test two different sites for a river or a body of water?
7. Besides the dissolved oxygen, temperature, salinity, pH, and turbidity, what else could you investigate to see how healthy a river is.
Anaerobic fermentation is carried in a bioreactor where glucose
(C6H12O6) is digested to form the
products ethanol (C2H5OH) and propenoic acid (C2H3CO2H). The product stream is analyzed and
found to contain 96.5 mole % water, 1.34 mole % C2H5OH, 0.79 mole % C2H3CO2H, 1.12 mole
% CO2 and 0.25 mole % C6H12O6. Given the specific gravity of ethanol is 0.789.
a. Calculate the mass fraction of each compound and the average molecular weight of the
product stream mixture.
b. Determine the total mass and molar flow rates of the product stream if the production rate
of ethanol is 160 L/day
1. From now until 2050, the human population is expected to grow bigger, more slowly, older, and more urban. Of these four factors, which do you think will have the biggest effect on the climate or environment?
2. In the U.S., more and more people are living alone in their own homes and buying their own cars instead of living with family or carpooling. How can materialism and capitalism impact climate or environment?
3. The author proposes three lines of action to reduce both poverty and global greenhouse gas emissions: universal secondary education, voluntary contraception, and maternal health services, and smarter urban design and construction. Of these three, which do you think will have the greatest impact and why? Alternatively, suggest a different line of action and explain why you chose that.
4. Demographic factors (household size, city size, population density), institutional and economic factors (availability of public transport at reasonable cost/convenience), and a host of behavioral factors (propensity to walk, bike, carpool, or drive solo to work) can influence a person’s carbon footprint. Think about your personal carbon footprint. What do you think is your number one contributing factor to CO2emissions? What is one way that you think you could reasonably reduce your carbon footprint?
Adaptations for digesting foods high in fiber, protein, and structural carbohydrates include _____.
a- gut fermentation
b- opposable thumbs
c- teeth designed for shredding
d- gut fermentation and teeth designed for shredding
e- all of the adaptations listed here
The Racing Extinction Documentary discusses the 6th Extinction. What is mass extinction? How many have occurred in the past? What is the 6th Extinction and how does it compare to previous extinctions? What are you doing to drive the 6th Extinction? What could you do to stop it?
An orifice meter is used to measure flow rate of liquid in pipe shows a pressure difference of ' x ' m of water column when the flow rate is Q If flow rate is doubled then what is delta P?