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Weekly demand for an item averaged 100 units over the past year. Actual demand for the next eight weeks is shown in what follows: a. Plot the data on graph paper. b. Letting = 0.25, calculate the... If the standard deviation is calculated from weekly demand data at 100 units, what is the equivalent sigma for a 3-week lead time? If the safety stock for an item is 200 units and the lead time is 3 weeks, what should the safety stock become if the lead time is extended to 6 weeks? The safety stock on an SKU is set at 500 units. The supplier says it has to increase the lead time from 4 to 5 weeks. What should be the new safety stock? Visualize a slope in the landscape near where you live. Discuss how specific soil properties (such as colors. horizon thickness. types of horizons present. etc..) would likely change along the... Use the key given in Figure 3.11 to determine the soil order of a soil with the following characteristics: a spodic horizon at 30 cm depth, permafrost at 80 cm depth. Explain your choice of soil... Give four reasons why compacting a soil is likely to reduce the amount of water available to growing plants. In this book and elsewhere, the terms soil organic matter are used to mean almost the same thing. How are these terms related, conceptually and quantitatively? Why is the term organic carbon... How much limestone with a CaCO 3 equivalent of 90% would you need to apply to eliminate exchangeable aluminum in an Ultisol with CEC = 8 cmolc/kg and an aluminum saturation of 60%? In what ways are soils involved in the greenhouse effect that is warming up the Earth? What are some common soil-management practices that could be changed to reduce the negative effects and increase... During a year's time, some 250 kg nitrogen and only 30 g molybdenum have been taken up by the trees growing on a hectare of land. Would you therefore conclude that the nitrogen was mor essential for... Soybeans growing on a recently limed soil show evidence of a deficiency of a nutrient. thought by some to be molybdenum. Do you agree with this diagnosis? If not. what is your explanation? A park manager wants to fertilize an area of turfgrass with nitrogen and phosphorus at the rates of 60 kg/ha of N and 20 kg/ha of P. He has stocks of two types of fertilizers: urea (45-0-0) and... Certain soil properties generally make land susceptible to erosion by wind or erosion by water. List four properties that characterize soils highly susceptible to wind erosion. Indicate which two of... Discuss the types of reactions pesticides undergo in soils, and indicate what we can do to encourage or prevent such reactions. Even though large quantities of the so-called heavy metals are applied to soils each year, relatively small quantities find their way into human food. Why? Soil organic matter and some silicate clays chemically sorb some organic pollutants and protect them from microbial attack and leaching from the soil. What are the implications (positive and... What are two approaches to phytoremediation. and for what kinds of pollutants are they useful? Explain. suppose a nickel-contaminated soil 15 cm deep contained 800 mg/kg Ni, Vegetation was planted to remove the nickel by phytoremediation. The above-ground plant parts average 1% Ni on a dry-weight bas... If the opening inventory is 400 units, demand is 900 units, and production is 700 units, what will be the ending inventory ? A company wants to develop a level production plan. The beginning inventory is zero. Demand for the next four periods is given in what follows. a. What production rate per period will give a zero... If the opening backlog is 450 units, forecast demand is 700 units, and production is 800 units, what will be the ending backlog? A company wants to develop a level production plan for a family of products. The opening inventory is 100 units, and an increase to 130 units is expected by the end of the plan. The demand for each... In problem 2.2, how much will be produced in each of the three months? In Problem 2.2 A company wants to produce 480 units over the next three months at a uniform rate. The months have 19, 20, and 21... Worldwide Can-Openers, Inc., makes a family of two hand-operated can openers. The production plan is based on months. There are 4 weeks in this month. Opening inventory is 2000 dozen, and it is... Given the following product tree, determine the low-level codes for all the components. A D B Item A B D Low-Level Code In 1 week, a work center produces 75 standard hours of work. The hours scheduled are 80, and 72 hours are actually worked. Calculate the utilization and efficiency of the work center. A work center consisting of 3 machines operates 40 hours a week. In a 4-week period, it actually worked 355 hours and produced 475 standard hours of work. Calculate the utilization and efficiency of... How many standard hours are needed to run an order of 200 pieces if the setup time is 1.3 hours and the run time 0.3 hours per piece? How many actual hours are needed at the work center if the... Complete the following load report and suggest possible courses of action. Week Total 18 19 20 21 Released Load 160 155 100 70 485 Planned Load 70 80 150 Total Load Rated Capacity 150 150 150 150 600... A work center has the following open and planned orders for week 4. Calculate the total standard time required (load). Setup Time (hours) Order Run Time Total Time Quantity (hours/piece) (hours)... An order for 50 of a product is processed on work centers A and B. The setup time on A is 45 minutes, and run time is 5 minutes per piece. The setup time on B is 30 minutes, and the run time is 4... Back schedule the following shop order. All times are given in days. Move time between operations is 1 day, and wait time is 1 day. Due date is day 200. Assume orders start at the beginning of a day... A company decides to establish an EOQ for an item. The annual demand is 400,000 units, each costing $9, ordering costs are $35 per order, and inventory carrying costs are 22%. Calculate the... A company manufactures five sizes of screwdrivers. Ordering costs and carrying costs are not known, but it is known that they are the same for each size. At present, each size is produced four times... A company stocks an SKU with a weekly demand of 225 units and a lead time of 3 weeks. Management will tolerate one stockout per year. If sigma for the lead time is 175 and the order quantity is 800... The safety stock on an SKU is set at 220 units. The supplier says it can reduce the lead time from 8 to 6 weeks. What should be the new safety stock? A firm orders a number of items from a regional warehouse every 2 weeks. Delivery takes 1 week. Average demand is 200 units per week, and safety stock is held at 2 weeks supply. a. Calculate the... A company wishes to store the following SKUs so there is 100% accessibility. The items are stored on pallets that can be stacked three high. a. How many pallet positions are needed? b. What is the... A company wants to store the following seven SKUs so there is 100% accessibility. Items are stored on pallets that are stored four high. a. How many pallet positions are needed? b. What is the cube... a. Which of the following items are within tolerance? b. What is the percent accuracy by item? Part Shelf Inventory Within Tolerance? Number Count Record Difference % Difference Tolerance 635 A 650... One of Socolow and Pacalas wedges (see introduction) involves reducing the number of miles driven by each car by 50% (they predict 2 billion cars worldwide by 2056). Considering what you know about... Describe the five primary manufacturing strategies. How does each affect delivery lead time? Describe how the objectives of marketing, production, and finance are in conflict over customer service, disruption to production, and inventories. Given the following product tree, explode, offset, and determine the gross and net requirements. The quantities required are shown in parentheses. The master production schedule calls for the... Given the following average demand for each month, calculate the seasonal indices for each month. Your answer, if done correctly, should have all the seasonal indices add up to the number of periods... Describe the environmental contributions of two of the following: George Perkins Marsh, Theodore Roosevelt, Gifford Pinchot, John Muir, Aldo Leopold, Wallace Stegner, Rachel Carson, and Paul Ehrlich. Explain why economic well-being, environment, and ethics all contribute to sustainable development. The system encompassing Earths global mean surface temperature can be diagrammed as follows: Explain each part of this system. Sohr radiation absorbed by surface Outgoing long-wave (infrared) heat... How do greenhouse gases affect global climate conditions? The graph reflects the monitoring of dissolved oxygen concentrations at six stations along a river. The stations are located 20 m apart, with A the farthest upstream and F the farthest downstream.... Describe three serious problems associated with megacities in the developing world. Explain how certain tax and zoning laws increase the conversion of prime farmland to urban and suburban development. As a society, is our reliance on soils likely to increase or decrease in the decades ahead? Explain. What is loess, and what are some of its properties as a parent material? Assuming a level area of granite rock was the parent material in both cases, describe in general terms how you would expect two soil profiles to differ, one in a warm, semiarid grassland and the... Of the five soil-forming factors discussed in Chapter 2 (parent material, climate. Organisms. topography, and time). choose two that have had the dominant influence on developing soil properties... If you were investigating a site for a proposed housing development, how could you use soil colors to help predict where problems might be encountered? For two soils subjected to "no," "moderate," or -severe' compaction, Figure shows the volume fraction (cm 3 cm -3 ) of pores in three size classes. The symbol indicates the volume fraction of water.... Suppose you measured the following data for a soil: Estimate the total available water-holding capacity (AWHC) of this soil in centimeters of water. em at different water tensions, kg water/kg dry... In a humid region characterized by expansive soils, a homeowner experienced burst water pipes, doors that no longer closed properly, and large vertical cracks in the brick walls. The house had had no... What would you, as a home gardener, consider to be the three best and three worst things that you could do with regard to managing the soil structure in your home garden? Discuss the positive and negative impacts of tillage on soil structure. What is another physical consideration that you would have to take into account in deciding whether or not to change from a... What are the textural classes of two soils, the first with 15% clay and 45% silt, and the second with 80% sand and 10% clay? You are considering the purchase of some farm land in a region with variable soil textures. The soils on one farm are mostly sandy loams and loamy sands. while those on a second farm are mostly day... If you could somehow extract the soil solution from the upper 16 cm of 1 ha of moist acid soil (pH = 5), how many kg of pure CaCO 3 would be needed to neutralize the soil solution (bring its pH to... Explain why there is environmental concern about the adsorption by soil colloids of such normally beneficial substances as antibiotic drugs and natural insecticides. An accident at a nuclear power plant has contaminated soil with strontium -90 (Sr2+). a dangerous radionuclide. Health officials order forages growing in the area to be cut baled. and destroyed.... What is meant by buffering? Why is it so important in soils, and what are the mechanisms by which it occurs? Explain the importance of Kd and Koc in assessing the potential pollution of drainage water. Which of these expressions is likely to be most consistently characteristic of the organic compounds in... If you wanted to find a soil high in kaolinite, where would you go? The same for (1) Smectite and (2) Vermiculite? There are two basic processes by which silicate clays are formed by weathering of primary minerals. Which of these would likely be responsible for the formation of (1) fine-grained mica, and (2)... Which of the following would you expect to be most and least sticky and plastic when wet: (1) a soil with significant sodium saturation in a semiarid area. (2) a soil high in exchangeable calcium in... Which of the silicate clay minerals would be most and least desired if one were interested in (1) A good foundation for a building, (2) A high cation exchange capacity, (3) An adequate source of... Contrast the difference in crystalline structure among kaolinite, smectites, fine-grained micas, vermiculites and chlorites. How do you account for the difference in surface area associated with a grain of kaolinite clay compared to that of montmorillonite, a smectite? Describe the soil colloidal complex, indicate its various components. and explain how it tends to serve a tank" for plant nutrients. If you were in the field trying to delineate the so-called drier end of a wetland area, what are three soil properties and three other indicators that you might look for? What are the two principal gases involved with soil aeration, and how do their relative amounts change as one samples deeper into a soil profile? What does conservation tillage conserve? How does it do it? Weed control should reduce water losses by what process? What is the role of evaporation from the soil (E) in determining water-use efficiency, and how does it affect ET? List three practices that can be used to control losses by E. Define potential evapotranspiration and explain its significance to water management. State the basic principle that governs how water moves through the SPAC. Give two examples, one at the soil-root interface and one at the leaf-atmosphere interface. Describe and give an example of the indirect effects of plants on the hydrologic balance through their effects on the soil. Draw a simple diagram of the hydrologic cycle using a separate arrow to represent these processes: evaporation, transpiration, infiltration, interception, percolation, surface runoff, and soil... Descibe how the addition of certain types of organic materials to soil can cause a nitrate depression period. What are the ramifications of this phenomenon for plant growth? If you wanted to apply an organic material that would make a long-lasting munch on the soil surface, you would choose an organic material with what chemical and physical characteristics? What are the main food web roles played by nematodes, and how can we visually (with a microscope) distinguish among nematodes that play these roles? Explain and compare the effects of tillage and manure application on the abundance diversity of soil organisms. What are the four main types of metabolism carried out by soil organisms relative to their sources of energy and carbon? Calculate the leaching requirement to prevent the buildup of salts in the upper 45 cm of a soil if the ECdw of the drainage water is 6 dS/m and the ECiw, of the irrigation water is 1.2 dS/m. What physical and chemical treatments would you suggest to bring the soil described in question 5 back to its original state of productivity? Compare the availability of the following essential elements in alkaline soils with that in acid soils: (1) iron, (2) nitrogen. (3) molybdenum. And (4) phosphorus. Explain why compost is more environmentally sustainable than peat for use in potting media and as an amendment for golf course greens. Chemical fertilizers and manures with high N contents are commonly added to agricultural soils. Yet these soils are often lower in total N than are nearby soils under natural forest or grassland... Why are S deficiencies in agricultural crops more widespread today than 20 years ago? In some tropical regions, agroforestry systems that involve mixed cropping of trees and food crops are used. What advantages in nitrogen management do such systems have over monocropping systems that... Assume you add a soluble phosphate fertilizer to an Oxisol and to an Aridisol. In each case, within a few months most of the phosphorus has been changed to Insoluble forms. Indicate what these forms... Which is likely to have the higher buffeting capacity for phosphorus and potassium, a sandy loam or a clay? Explain.
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