Know Your Phosphates!

If we are to keep up crop yields and quality, many of our soils must have phosphate fertilizer. If we can’t get enough superphosphate because of the war, then what about the other phosphate fertilizers? Can they “pinch hit’’ for superphosphate

Direct model reference adaptive control of a flexible robotic manipulator

Quick, precise control of a flexible manipulator in a space environment is essential for future Space Station repair and satellite servicing. Numerous control algorithms have proven successful in controlling rigid manipulators wih colocated sensors and actuators; however, few have been tested on a flexible manipulator with noncolocated sensors and actuators. In this thesis, a model reference adaptive control (MRAC) scheme based on command generator tracker theory is designed for a flexible manipulator. Quicker, more precise tracking results are expected over nonadaptive control laws for this MRAC approach. Equations of motion in modal coordinates are derived for a single-link, flexible manipulator with an actuator at the pinned-end and a sensor at the free end. An MRAC is designed with the objective of controlling the torquing actuator so that the tip position follows a trajectory that is prescribed by the reference model. An appealing feature of this direct MRAC law is that it allows the reference model to have fewer states than the plant itself. Direct adaptive control also adjusts the controller parameters directly with knowledge of only the plant output and input signals

Radiation-induced myeloid leukaemia in CBA/H mice: a non-immunogenic malignant disease in syngeneic mice.

In vivo growth characteristics of myeloid leukaemia induced by whole-body irradiation of CBA/H male mice were examined in the strain of origin by procedures expected to enhance or depress immunological responses. Syngeneic growth in vivo (survival time and frequency of takes) was not modified by attempted active immunization with radiation-inactivated cells or by sublethal whole-body irradiation of recipients before inoculation of small numbers of clonogenic cells. Since the growth stimuli involved in in vivo repair of severely damaged normal haemopoietic tissue also did not modify the growth of the radiation-induced leukaemia cells in syngeneic passage, their growth in vivo in the irradiated primary hosts can be regarded as autonomous by the stage at which leukaemia was diagnosed. Challenge inocula in the "immunization" experiments were 1-9 clonogenic cells from 4 different passaged lines and in the whole-body radiation experiments, 1-10(3) clonogenic cells derived from 11 different primary hosts and 4 different passaged lines

Going to Use Fertilizer?

For every ton of commercial fertilizer that Iowa farmers used 6 years ago, they are now using 9 tons—a nine times increase in 6 years. It’s likely that still more fertilizer will be used in the coming years

How Much Fertilizer for Corn?

Support prices for corn are high and certain. Many Iowa farmers could profitably push their corn yields up to 100 to 125 bushels per acre in favorable seasons. Here\u27s what heavy fertilizer applications can do

Fertilizers boost yields of small grains, grasses and legumes

Corn is king in Iowa. But corn should not be grown continuously. It should be rotated with small grains, clover or alfalfa. Such a rotation insures a good nitrogen level in the soil, cuts down on erosion, and helps keep the soil in good tilth. These factors in turn result in higher corn yields. Too often we neglect or omit our small grains and seedings because they don’t give us the high cash return of corn. One way to make them more profitable is to increase their yields. You can give the yields a real boost with fertilizers. There are two ways to use fertilizers on small grains and forages— the,right and the wrong. Among other things, the right way involves using the correct kind and amount of fertilizer, applying it effectively to the soil and at the best time. You must know how to do these things. They will determine the returns you will get from your fertilizer. To give you the best possible information on these points, the Iowa Agricultural Experiment Station has conducted several hundred experiments on the fields over the state during the past few years. It is the purpose of this bulletin to give you the information gathered from these experiments along with other pointers to help you in your fertilizer program

Carryover Fertilizer- How Much?

What happens to the fertilizer you apply? Usually, several things

Top-Dress Your Legume Meadow

Top-dressing phosphate or potash fertilizers isn\u27t a substitute for good fertilizer practices at seeding time, but in many cases it will pay dividends

Soil Survey of Iowa, Report No. 73—Crawford County Soils

Crawford County is located in western Iowa in the second tier of counties east of the Missouri River and in the middle tier between the north and south state boundaries. It lies entirely in the Missouri loess soil area and the soils of the county are, therefore, chiefly of loessial origin