A solution calorimeter was constructed with a temperature range of one degree in the region of 25°C. The precision of the calorimeter was about 0.3%. The heats of reaction of the following silver ethylenediamine complexes were measured: Ag(en)⁺, Ag₂(en)₂⁺⁺, Ag(en)₂⁺, and AgHen⁺⁺. With the formation constants determined by Schwarzenbach (6), the respective entropies were calculated. Enthalpy and entropy data for the Ag(en)⁺, Ag₂(en)₂⁺⁺, and Ag(en) ₂⁺ complexes are reasonable. The data for the AgHen⁺⁺ complex seems anomalous. / Master of Science

Production of casting in sand molds is the basic original method employed by the foundry industry. Other methods are the results of the technological advances, but none has resulted in the extreme flexibility of the sand casting process. The control of the sand properties is important in order to produce casting of good quality. This paper presents a limited analysis of the properties of the green molding sand and the fluidity of Aluminum•Silicon alloys in the green sand molds. The fluidity is the casting property of an alloy or metal, in a qualitative measure to completely fill the mold before it solidifies and is normally expressed as inches of flow in a small channel. The properties of the green molding sand with change in the composition of sand viz., clay and moisture contents. The standard AFS procedure is suggested in testing the physical properties of the green molding sand. In fluidity test a standard method of molding, melting and pouring is suggested to control certain variables. The statistical analysis of results indicates that there is no appreciable difference in the fluidity values 1. For different metal composition (Aluminum 12% silicon and Aluminum 6% silicon) 2. In green sand molds of vary composition of clay and moisture (clay 5%, 7% and 10%, moisture 5% and 7%) / Master of Science

Preliminary experiments in Virginia by Wallace and Turner (1961) on face fly control indicated that there was some promise using low-level feeding of a chemical such as ronnel in a mineral salt mixture as a larvicide. In cooperation with the Moorman Manufacturing Company and Mr. H. C. Stuart of Elk Garden, Virginia, a large scale experiment was initiated in the spring of 1962 . Approximately 1600 head of cattle in 23 pastures were utilized in this experiment. All of the pastures received a mineral salt mixture containing 5.5 percent ronnel with the exception of two pastures on the perimeter of the treated area that received no ronnel and were used as checks. Adult and larval counts were made on 7 of the 23 treated pastures and both of the untreated pastures. Results indicated that: (1) In spite of good larval control adult fly counts remained high, especially in treated pastures near untreated areas. Apparently the face fly has a natural tendency for dispersion, and, therefore, area control by low-level feeding of salt containing a larvicide is difficult. (2) When the consumption of ronnel remained above 5.5 mg per kg of animal body weight per day, larval control was above 95 percent. (3) During hot, dry periods animals reduced their salt consumption and this resulted in decreased larval control. (4) When salt boxes were placed in areas where cattle were seldom seen to frequent, salt consumption was lowered, as was larval control. / Master of Science

This thesis consists of an experimental study of the velocity distribution in tranquil, stable tumbling and rapid flow regimes in a steep rectangular channel with artificial roughness elements. Four shapes of roughness elements, rectangular, parallelogram, triangular, and semi-circular, were used. Effects on velocity distribution due to variations in discharge, flume slope and roughness geometry were studied for each shape of roughness element. The applicability of logarithmic law was examined and the inflection points in tranquil and rapid flow regime were studied. Also the velocity coefficients in tumbling regime were studied. The findings were confirmed through the analysis of data taken from project 405 of the Civil Engineering Department. A review of literature on this subject and a bibliography are included. / Master of Science

The primary objectives this investigation are: 1. To present a discussion of known submerged arc welding variables and their general affect on weld bead appearance 2. To design an experiment to investigate the affect on weld joint strength and hardness distribution across the weldment by using (1) Four different welding currents (450, 500, 550, and 650 amps). (2) Three different steels (M 1020, SAE 1045 and SAE 1095) and (3) Two different electrodes (Hobart type C-10 and C-20) as variables in the experiment. 3. To establish the welding technique and procedure to control welding variables. 4. To collect unavailable data about the submerged arc process by experimentation and statistically interpret this data. After the preliminary investigation, the author statistically designed the testing procedure for the randomized test specimens for hardness of weld zone and hear-affected zone and applied statistical technique to determine significant effects on weld quality due to the variables. The conclusions are given in chapter I. / Master of Science

This investigation is a study of the effect of adult influence of the directed and non-directed paintings of preschool children, the relationship of the mental age and the chronological age to the acceptance of suggestions, and the relationship of the mental age and the chronological age to the ability to represent form, Factors considered were the length of enrollment and age of the subjects. The subjects were sixteen preschool children, eight of whom were enrolled in the School of Home Economics Nursery School of the Virginia Polytechnic Institute, Blacksburg, Virginia, and eight enrolled in the Radford College Nursery School, Radford, Virginia. Mental age was determined by the Stanford Binet Intelligence Test Form IM. Each subject was given a directed and a non-directed experience using a toy fur kitten and a directed and a non-directed experience using a dog story. Comments of the subjects were recorded in both sessions. The results of the collected data showed that as the chronological age and mental age increases, the ability to represent form becomes greater. Spontaneous verbal expression was greater in the non-directed experiences than in the directed experiences. The paintings were judged to determine which were directed and non-directed. Scoring by the judges shows that verbal interference is discernible in preschool children’s paintings. / Master of Science

The high school has an important responsibility of aiding individuals in making their choices, plans and adjustments, in undertaking self-direction, and in meeting social, mental, physical, and spiritual problems. Accepting this responsibility has added a new dimension to the high school program known as guidance. Purpose of the Study. The main purpose of this study was to construct a guidance program to meet the needs of the student body of Dan River High School. Other purposes were to: 1. Develop an organized system for administering a guidance program. 2. Develop a means of collecting and compiling data about each pupil. 3. Develop a system for providing educational and occupational information for each student. 4. Develop a system of providing counseling services for each student. 5. Develop a system of providing placement services for each student. 6. Develop a system for the evaluation of the high school guidance program. Scope of the Study. Data were secured from 530 Dan River High School students in grades eight through twelve, a study of the present guidance program of Dan River High School was made, and principles and practices of guidance validated through research were compiled. Procedures Used in Making the Study. Information having implications for guidance was secured with the use of a questionnaire from each student. The present guidance program was studied, a review of literature was made, and this iInformation was used in constructing a guidance program for Dan Fiver High School. Summary of the Proposed Guidance Program. A guidance program operates effectively when it is carefully planned and well organized. This requires the cooperation of each member of the school staff working under the leadership of a capable guidance director. As the staff plans and organizes the program together and understands and appreciates the different phases of the program, staff assignments and responsibilities need to be made very clear and definite. An effective guidance program is dependent upon how well the guidance services function. These services require the understanding and assistance of each staff member. / Master of Science

This thesis is concerned with the buckling problem of a cantilever thin plate with its tree end subjected to uniform shear. The same problem waa originally solved by Prandtl in 1899, based on the equilibrium condition of a deep beam. The author baa used the energy method based on the thin plate theory to attack the problem. After the displacement is assumed, the potential energy can be formulated. From the condition that the potential energy assume a minimum value in an equilibrium configuration, results a system of n linear homogeneous algebraic equations ot n parameters which are introduced in the assumed displacement. For a non-trivial solution, the determinant of the coefficients must vanish. This gives a characteristic equation from which the buckling load is determined. The author has obtained a curve for maximum stress at buckling state, which shows that the result 1a better than that obtained by Prandtl in certain cases. The energy method has been generalized to a three dimensional problem to consider the displacement in all directions. / Master of Science

Owing to the continued increase in kilowatt capacity of new power stations being built today, proper sizing and selection of mechanical equipment has a vital effect on dollar savings, both for operation and maintenance costs as well as the initial cost of unit installation. In today's steam-electric plants, the power consumption of the motor-driven boiler feed pumps has been rising along with the increase of operating pressures and capacities. Power savings thus becomes a more significant factor than ever in selection of boiler feed pumping arrangement. Therefore, use of a more economical and justifiable boiler feed pumping arrangement with constant speed drive or variable speed drive through hydraulic couplings would vastly improve power plant economy and operation. This study compares the costs and operating characteristics of two constant-speed boiler feed pumps operating in parallel, against those of one constant-speed pump operating in parallel with one variable speed pump which is driven through hydraulic coupling (all pumps are of half-size capacity, motor-driven). This cost comparison shows that the former pumping arrangement is more economical than the latter at the unit base load. / Master of Science

Results indicate that the durability of the concrete mixes using poor aggregates can be improved to a considerable extent by moist-curing. / Master of Science