Frequency‐Dependent Moment Tensors of Induced Microearthquakes

Analysis of 984 induced microearthquakes from The Geysers geothermal reservoir in California reveals that the retrieved moment tensors depend on the frequency band of the inverted waveforms. The observed dependence is more significant for the percentages of the double‐couple, compensated linear vector dipole, and isotropic (ISO) components than for the focal mechanisms. The average root‐mean‐square of the moment tensors obtained in different frequency bands is correlated with spectra of ambient noise. The percentages of double‐couple and ISO components tend to decrease and increase with the upper cutoff frequency (fu), respectively. This suggests that shear rupture radiates energy preferentially in a lower frequency band and tensile rupture in a higher frequency band. Events displaying a strong increase of the ISO with fu are confined within the same depth interval as the injection points. This might be related to the strong thermoelastic effects in the vicinity of injection points that promote opening of small cracks adjacent to the main fractures

An Experimental Comparison of the Feeding Value of Soy Bean with Alfalfa Hay for Feeding Dairy Cows

The tendency during the last few years has been to use more and more of the legumes for feeding dairy cows. Just a few years ago (1)”Dairymen near the Yakima Valley, Washington state, fed their cows nothing but alfalfa hay during the winter. The cows received 40 to 50 pounds of alfalfa per cow per day and produced from 6,000 to 7, 000 pounds of milk per year. A Guernsey cow gave 20 pounds of milk per day, four and one-half months after calving and have received no feed but alfalfa hay for two months previous to that time. The Todd herd of Holsteins, said by many to be the best producing herd in the state of Washington, is fed on corn silage and 25-30 pounds of alfalfa hay per cow per day. Mr. Price, formerly dairy specialist for Washington State Agricultural College, and who is familiar with dairy conditions, said that cows had produced as high as 10, 000 pounds of milk in a year on alfalfa hay alone.” Although alfalfa is used more widely than any other of the legumes as dry roughage for feeding dairy cows, soy bean hay is rapidly coming to the front in the southeastern and central states. This increase in the use of soy bean hay seems to be natural and healthy condition, for legume hays are our cheapest sources of protein for winter feeding. Furthermore, soy bean hay is better adapted to those sections of the country where it is more difficult to grow the maximum yields of alfalfa hay. The average percentage composition of American feedings stuffs, table (2) shows soy bean hay to be 1.1 percent higher protein, 3.3 percent lower in crude fiber, 2.2 percent higher in nitrogen- free extract, and 0.5 percent higher in fat than alfalfa. The table for digestible nutrients shows soy bean hay to have 1.1 pounds more crude digestible protein, 0.2 of a pound more carbohydrates, 0.3 of a pound more fat and 2 pounds more total digestible nutrients per hundred pounds than does alfalfa hay. It is probable therefore, that soy bean hay may proves to be a desirable and profitable legume hay for feeding dairy cows. With this probability in mind, the experience discussed in this thesis was planned. Carried out, and the data tabulated for use in determining the feeding value of soy bean hay as a legume roughage for dairy cows

Photo sensor array technology development

The development of an improved capability photo sensor array imager for use in a Viking '75 type facsimile camera is presented. This imager consists of silicon photodiodes and lead sulfide detectors to cover a spectral range from 0.4 to 2.7 microns. An optical design specifying filter configurations and convergence angles is described. Three electronics design approaches: AC-chopped light, DC-dual detector, and DC-single detector, are investigated. Experimental and calculated results are compared whenever possible using breadboard testing and tolerance analysis techniques. Results show that any design used must be forgiving of the relative instability of lead sulfide detectors. A final design using lead sulfide detectors and associated electronics is implemented by fabrication of a hybrid prototype device. Test results of this device show a good agreement with calculated values

The Economic Costs and Benefits of Dental Education: An Empirical Analysis

The rising costs associated with obtaining a dental education have caused some to question the financial benefit of pursuing a dental degree. There is a concern that recent graduates may have difficulty finding professional opportunities that provide the income necessary to service their accumulated educational debt. The aim of this study was to evaluate the trends in educational costs to aid in making an accurate appraisal of the financial benefit of a dental education. Adjusted into constant dollar terms, data from a variety of sources were collected for economic variables such as tuition, fees, student indebtedness, and dentists’ earnings. These variables were then analyzed to determine the true costs and benefits of obtaining a dental education. The results showed that, over the course of the last decade, educational costs increased faster than the real net income of practicing dentists, which led to a decline in the return on investment in dental education. However, regardless of an applicant’s choice of public or private dental school, there continues to be a positive economic return on students’ commitment of both financial resources and time to receive a dental education

Study of SEM induced current and voltage contrast modes to assess semiconductor reliability

The purpose of the scanning electron microscopy study was to review the failure history of existing integrated circuit technologies to identify predominant failure mechanisms, and to evaluate the feasibility of their detection using SEM application techniques. The study investigated the effects of E-beam irradiation damage and contamination deposition rates; developed the necessary methods for applying the techniques to the detection of latent defects and weaknesses in integrated circuits; and made recommendations for applying the techniques

Dynamic Mechanical Behavior of Black Cherry (Prunus Serotina EHRH.)

The dynamic mechanical properties of black cherry (Prunus serotina Ehrh.) have been investigated as a function of temperature at audio frequencies. Relaxation processes are evident near 200, 360, and 510 K. The process near 200 K was investigated as a function of initial moisture content (based on mass measurements prior to testing). At moisture contents greater than about 20%, the damping peak is centered near 185 K. This relaxation shifts with moisture content, and at moisture contents below 6%, the peak is centered near 225 K. The relaxation in the 360 K region is also associated with initial moisture content. For oven-dry black cherry specimens, the dynamic mechanical properties in the 360 K region are nearly temperature-independent. The relaxation near 510 K is believed to be associated with thermal degradation of wood constituents that are known to degrade in that temperature region

Some Physical Properties of Birch Carbonized in A Nitrogen Atmosphere

The dynamic mechanical properties, mass loss, and shrinkage data of birch carbonized in a nitrogen atmosphere to different temperatures from 473 to 973 K have been investigated. The dynamic elastic modulus data decreased as the heat treatment temperatures approached 673 K. Major mass loss and shrinkage accompanied the decrease in the modulus data. Treatments at higher temperatures (> 673 K) produced substantially less additional mass loss and shrinkage but produced increased rigidity in the char. The internal friction behavior of the char was complex