Silo construction

The construction of silos has been for many years one of the principal lines of investigation followed by the Agricultural Engineering Section of the Iowa Experiment Station. Its results were first published in Bulletin No. 100, which was distributed in July, 1908. This was revised and republished, owing to the unusual demand for it, in July, 1909. In addition to describing the more common types of silos then in use, this second bulletin presented a . design of a new type of silo with walls of hollow clay building blocks. In June, 1910, after the success of this silo had been carefully observed and the methods of construction developed, Bulletin No. 117 was prepared and distributed. This described in detail the construction of this type of silo and although it was published in a large edition it has been out of print for some time. This new Bulletin No. 140, covers briefly the field of both former bulletins as far as possible and adds a description of several other types of silos developed recently. The Agricultural Engineering Section does not favor or recommend any one type of silo above all others. Different types have different merits and the cost of materials varies widely, which clearly indicates that the selection of a silo depends upon individual conditions and circumstances

Concrete fence posts

Concrete fence posts, when properly made, give very satisfactory service, but success with them depends very much upon good design, good workmanship and good material. These facts are clearly shown in the investigation of concrete posts conducted over a long period of years by the Agricultural Engineering section of the Agricultural Experiment Station and reported in this bulletin. The essentials of design, the requisites in materials and the methods of making are also presented and the whole subject discussed from the standpoint of service, practicability and economy, including an estimate of the cost of the various types of posts, adjusted to the present prices of material and labor

Life, service and cost of service of farm machinery

1. The average life of farm machines on Iowa farms varies from 8 years for a spring-tooth harrow to 24 years for the farm wagon An average life for all machines is 15.2 years. 2. The life of individual machines varies much from the average. The average life of grain binders, for illustration, was found to be 16 years, but machines were found which lasted only 5 years; while others had a life of 33 years. 3. The average annual service of farm machines in days of use is very low, varying from 4 days for the seeder to 80 days for the wagon and gasoline engine. The average annual use of all farm machines is 16 days. 4. With few exceptions, the life of farm, machines is not directly influenced by the number of days used per year. 5. The annual cost of repairs varies from 1/2 of one percent of first cost for the roller, seeder and spring-tooth harrow, to 5 percent for one-row cultivators. 6. The average cost of service for one day varies from 8 cents for the one-row cultivator to $10.11 for ansilage cutter. 7. The most important factor in reducing the cost of each day’s service is a large number of days of use per year. 8. The total annual cost of a farm machine varies from 12 percent to 21 percent of the first cost. 9. While the housing of farm machinery is desirable, systematic repairing has more influence on the life of farm machines. 10. A well-equipped farm shop is a definite aid to systematic repair of farm machines

Infrasonic observations of large-scale HE events

The Los Alamos Infrasound Program has been operating since about mid-1982, making routine measurements of low frequency atmospheric acoustic propagation. Generally, the authors work between 0.1 Hz to 10 Hz; however, much of the work is concerned with the narrower range of 0.5 to 5.0 Hz. Two permanent stations, St. George, UT, and Los Alamos, NM, have been operational since 1983, collecting data 24 hours a day. For the purposes of this discussion, the authors concentrate on their measurements of large, high explosive (HE) events at ranges of 250 km to 5330 km. Because their equipment is well suited for mobile deployments, they can easily establish temporary observing sites for special events. The measurements are from the permanent sites, as well as from various temporary sites. A few observations that are typical of the full data set are given

The L-Block: A type of concrete block adapted to the economical construction of farm buildings

The L-Concrete Block, so named on account of its shape, is an outcome of a careful study and search by the Agricultural Engineering Section of the Iowa Agricultural Experiment Station for a durable and economical type of construction for the walls of farm buildings. With normal costs for the constituent materials, concrete in the plastic stage as it comes from the mixer or mixing board is an economical building material. The problem of economical construction with concrete, therefore, depends upon efficient utilization of the material and labor. The L-Block reduces the amount of material usually required and greatly reduces the cost of placing the concrete in the building. With ordinary concrete blocks, or the so-called unit construction, much labor is required in making, handling and placing the blocks in the wall, while with monolithic construction the cost of forms is often excessive, exceeding in some instances the cost of the concrete

Creamery organization and construction

Nearly two years ago the Iowa Agricultural Experiment station set out to answer a demand from scores of communities for accurate information on when, where, and how creamery associations might be organized with profit and how a satisfactory creamery should be bulit. Since that time, the station has assisted in the organization of different creamery companies and aided in the construction of eight different creamery buildings. The companies represent every type, from individual ownership to regularly incorporated associations and the buildings are of various types and sizes, ranging in cost from less than $2,000 to more than$6,000. Much valuable detailed information was secured which is now published so that it may be of service to other communities which face the question of organizing a creamery association and erecting a creamery building

Precision measurement of the branching ratio in the 6P3/2 decay of BaII with a single trapped ion

We present a measurement of the branching ratios from the 6P3/2 state of BaII into all dipoleallowed decay channels (6S1/2, 5D3/2 and 5D5/2). Measurements were performed on single 138Ba+ ions in a linear Paul trap with a frequency-doubled mode-locked Ti:Sapphire laser resonant with the 6S1/2->6P3/2 transition at 455 nm by detection of electron shelving into the dark 5D5/2 state. By driving a pi Rabi rotation with a single femtosecond pulse, a absolute measurement of the branching ratio to 5D5/2 state was performed. Combined with a measurement of the relative decay rates into 5D3/2 and 5D5/2 states performed with long trains of highly attenuated 455 nm pulses, it allowed the extraction of the absolute ratios of the other two decays. Relative strengths normalized to unity are found to be 0.756+/-0.046, 0.0290+/-0.0015 and 0.215+/-0.0064 for 6S1/2, 5D3/2 and 5D5/2 respectively. This approximately constitutes a threefold improvement over the best previous measurements and is a sufficient level of precision to compare to calculated values for dipole matrix elements.Comment: 6 pages, 5 figures, 1 tabl

Events, processes, and the time of a killing

The paper proposes a novel solution to the problem of the time of a killing (ToK), which persistently besets theories of act-individuation. The solution proposed claims to expose a crucial wrong-headed assumption in the debate, according to which ToK is essentially a problem of locating some event that corresponds to the killing. The alternative proposal put forward here turns on recognizing a separate category of dynamic occurents, viz. processes. The paper does not aim to mount a comprehensive defense of process ontology, relying instead on extant defenses. The primary aim is rather to put process ontology to work in diagnosing the current state of play over ToK, and indeed in solving it

Cation Exchange Capacity of the Clay Fraction of Loess in Southwestern Iowa

The cation exchange capacity of clay-size material extracted from soil with a low organic matter content is largely dependent on the kinds of clay minerals present. If the extracted clay is composed mostly of one kind of clay mineral, the exchange capacity will indicate what that mineral is. This paper reports on cation exchange capacity determinations made on the minus 2 micron clay-size range of selected samples of loess from the southwestern Iowa area