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Articles 5431 - 5460 of 6342

Full-Text Articles in Engineering

Energy Fact Sheet: Heat Pumps For Residential Heating And Cooling: Some Questions And Answers, Larry W. Turner Apr 1979

Energy Fact Sheet: Heat Pumps For Residential Heating And Cooling: Some Questions And Answers, Larry W. Turner

Agricultural Engineering Energy Series

WHAT IS A HEAT PUMP?

A heat pump is an electrically-powered refrigeration cycle device which is capable of providing both heating and cooling to a residence. In the summer, it operates like an air conditioner by "moving" heat from inside the house to the outside. In the winter, the refrigerant flow is reversed, "moving" heat into the house by further chilling the already cold outside air and transferring the heat gained in the process to the inside.


An Evaluation Of Permissive Left-Turn Phasing, Kenneth R. Agent Apr 1979

An Evaluation Of Permissive Left-Turn Phasing, Kenneth R. Agent

Kentucky Transportation Center Research Report

In this study, exclusive left-turn phasing was replaced with permissive left-turn phasing at four trial intersections. Delay and accident studies were done before and after the trial installations. Also, a questionnaire was issued to determine public opinion concerning the signals.

The use of permissive-turn phasing resulted in a 50-percent reduction in left-turn delay and a 24-percent reduction in total delay compared to exclusive phasing. The permissive left-turn phasing did result in an increase in left-turn accidents. Other accident types, such as rear-end accidents, did not change. The number of left-turn accidents decreased as drivers became more familiar with the signals. …


The Effectiveness Of Regulatory School Flashers In Reducing Vehicle Speeds, Charles V. Zegeer, Robert C. Deen Apr 1979

The Effectiveness Of Regulatory School Flashers In Reducing Vehicle Speeds, Charles V. Zegeer, Robert C. Deen

Kentucky Transportation Center Research Report

Pedestrian safety for school-age children has been a growing problem in recent years. Children between the ages of five and nine represent less than 10 percent of Kentucky's population but over 16 percent of all pedestrian fatalities. A study was conducted to evaluate the effectiveness of regulatory school flashers used in school zones to reduce vehicle speeds and alert motorists of pedestrian activity and to determine measures which promote safety in school zones.

Speed studies were conducted during flashing and non-flashing periods at 48 school zones where regulatory school flashers were used. The locations involved a variety of speed limits …


Fatigue Damage Of Flexible Pavements Under Heavy Loads, James H. Havens, Herbert F. Southgate, Robert C. Deen Apr 1979

Fatigue Damage Of Flexible Pavements Under Heavy Loads, James H. Havens, Herbert F. Southgate, Robert C. Deen

Kentucky Transportation Center Research Report

A modified Chevron N-Layer computer program has the capability of calculating the "work" done by the total load on a given load group. Earlier analyses of AASHO Road Test sections and test vehicles had permitted the development of damage factor relationships. This paper presents seven, namely two-tire and four-tire single axles, tandems, triaxles, and four-axle, five-axle, and six-axle groups. The two-tire axle (front or steering axle) has the most severe damage relationship. The 80-kN (18-kip) four-tire single axle was used as the reference axle and was assigned a damage factor of 1.0 for a specific amount of "work". Other axle …


Interstate Safety Improvement Program, Jerry G. Pigman, Kenneth R. Agent, Charles V. Zegeer Mar 1979

Interstate Safety Improvement Program, Jerry G. Pigman, Kenneth R. Agent, Charles V. Zegeer

Kentucky Transportation Center Research Report

A previous report dealt with development of procedures for preparation of an Interstate Safety Improvement Program. The purpose of this report was to prepare prioritized rankings of recommended improvements which could be implemented for the Interstate Safety Improvement Program. Together, these two reports include logical and comprehensive procedures for the selection, scheduling, construction, and evaluation of highway safety improvement projects.

Considerable detail is presented which documents analysis procedures used to determine sites, sections, and elements of the roadway in need of improvement. The average number of accidents per interchange, bridge, 1.0-mile (1.6-km) section, and 0.3-mile (0.48-km) spots were summarized for …


Use Of Economic Analyses And Dynamic Programming In The Selection Of Projects For Resurfacing, Charles V. Zegeer, Kenneth R. Agent, Rolands L. Rizenbergs Feb 1979

Use Of Economic Analyses And Dynamic Programming In The Selection Of Projects For Resurfacing, Charles V. Zegeer, Kenneth R. Agent, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

The objective of this study was to develop a dynamic programming procedure using economic analyses to assist in optimizing expenditures in the pavement resurfacing program in Kentucky. Benefit relationships were determined from expected accident reduction, improved comfort, time savings, fuel savings, and maintenance savings. The only cost input to the program was the resurfacing cost of each project.

Dynamic programming was adapted to the selection of projects for resurfacing. Over $8.4 million of additional user benefits would have been realized in 1976 if dynamic programming had been used in selecting projects. The benefit-cost ratio of sections selected for resurfacing was …


Ground Driven Power Tillage Device, Daniel E. Hammett, Edward M. Smith Jan 1979

Ground Driven Power Tillage Device, Daniel E. Hammett, Edward M. Smith

Biosystems and Agricultural Engineering Faculty Patents

A power tillage device is provided having a passive rolling coulter as the prime mover for a power tillage blade which is carried in the lead of the coulter on a transfer case mounted as a radius arm on the counter shaft. The tillage blade rotates in the opposite direction from the coulter and is designed for optimum efficiency for shearing and lifting soil from a furrow.


The Influence Of Harvest Rate And Drying Time On Grain Drying And Storage Facility Selection, Thomas C. Bridges, Otto J. Loewer Jr., Douglas G. Overhults Jan 1979

The Influence Of Harvest Rate And Drying Time On Grain Drying And Storage Facility Selection, Thomas C. Bridges, Otto J. Loewer Jr., Douglas G. Overhults

Biosystems and Agricultural Engineering Faculty Publications

No abstract provided.


Determination Of Strategy For Harvesting Burley Tobacco, Yasuhiko Miyake, Larry G. Wells, George A. Duncan, Jimmie Rankin Jan 1979

Determination Of Strategy For Harvesting Burley Tobacco, Yasuhiko Miyake, Larry G. Wells, George A. Duncan, Jimmie Rankin

Biosystems and Agricultural Engineering Faculty Publications

The decision-making process associated with the scheduling of burley tobacco harvesting operations was formulated as a multi-stage decision process, and solved using a procedure called dynamic programming. The solution of a stochastic dynamic programming model provides a set of optimal decision rules, that is, a strategy. When certain user-specified parameters are provided, the decision model provides information concerning the optimal date to start harvesting, the optimal number of hours to harvest on each day, the optimal date to introduce hired labor, and the optimal number of workers which should be hired.

The solution of the dynamic programming model makes it …


Energy Fact Sheet: Design Considerations For Below-Grade Housing, University Of Kentucky College Of Agriculture Cooperative Extension Service Jan 1979

Energy Fact Sheet: Design Considerations For Below-Grade Housing, University Of Kentucky College Of Agriculture Cooperative Extension Service

Agricultural Engineering Energy Series

Below-grade living is not new; prehistoric man instinctively sought out subterranean shelters for protection against his enemies and extreme environmental conditions. Historically, the designs of below-grade enclosures were determined by such factors as availability of building materials, climatic elements, defensive needs, ceremonial beliefs, and cultural concerns. Contemporary use of underground house components includes basements, cellars, and other similar spaces. In most cases, however, individuals occupying below-grade quarters have either had access to an above-grade structure or have considered such quarters as temporary. The notorious basement that is wet, cold, and without adequate lighting has given an undesirable image to below-grade …


Solar Energy For Heating Farm Structures In Kentucky, Richard S. Hiatt, Blaine F. Parker Jan 1979

Solar Energy For Heating Farm Structures In Kentucky, Richard S. Hiatt, Blaine F. Parker

Agricultural Engineering Extension Updates

This report is intended to summarize the important decisions which must be made by farmers in Kentucky, who are considering the utilization of solar energy for heating farm buildings or drying grain.


A Computer Model For Evaluating Corn Harvesting, Handling, Drying And Storage Systems, Thomas C. Bridges, Otto J. Loewer Jr., John N. Walker, Douglas G. Overhults Jan 1979

A Computer Model For Evaluating Corn Harvesting, Handling, Drying And Storage Systems, Thomas C. Bridges, Otto J. Loewer Jr., John N. Walker, Douglas G. Overhults

Biosystems and Agricultural Engineering Faculty Publications

No abstract provided.


Energy Fact Sheet: Residential Solar Heating, Blaine F. Parker, Larry W. Turner Dec 1978

Energy Fact Sheet: Residential Solar Heating, Blaine F. Parker, Larry W. Turner

Agricultural Engineering Energy Series

Heating a residence and the domestic water supply with solar energy is technically feasible in Kentucky. However, it is not feasible to provide 100 percent of the heat requirements. Some backup system is needed for continuous heat during cloudy weather and the cold part of winter. Both passive and active solar heating systems are technically feasible.


Acoustic Emission Monitoring Of Weldments, Theodore Hopwood Ii, James H. Havens Dec 1978

Acoustic Emission Monitoring Of Weldments, Theodore Hopwood Ii, James H. Havens

Kentucky Transportation Center Research Report

Weld tests were performed on low-carbon and high-strength, low-alloy steel weldments. The weldments were monitored with an acoustic emission detector during both the 'in-process' and the 'in-cooling' phases of the welding operation. Artificial defects were induced in several of the welds to promote cracking. Some high-strength weldments were designed to produce welds subject to high restraint.

Nondestructive and destructive evaluation of the completed weldments revealed that high acoustic emission activity 'in-cooling' could be correlated with embedded defects and cold-cracking. Copious emission activity was also detected from unflawed weldments. Acoustic emissions were detected in high-strength steel weldments for periods up to …


Low-Void Concrete Mixtures, Assaf S. Rahal, James H. Havens Dec 1978

Low-Void Concrete Mixtures, Assaf S. Rahal, James H. Havens

Kentucky Transportation Center Research Report

The purpose of this study was to modify concrete mix-design formulas to supplant all water over and above that needed for hydration with a non-evaporable liquid material and(or) a super-water-reducer or plasticizer -- thus producing a low-void concrete. A water-cement ratio of 0.244 - 0.30 was presumed minimal for hydration of the cement. Several polymeric materials, asphalts, oils, and superplasticizers were used. Success was achieved with two latexes, one epoxy, and several superplasticizers. The use of these materials in concrete resulted in improved strength, reduction of air voids and permeability, and enhancement of resistance to corrosive chloride salts.


Large Cylindrical Bale Transporter, Larry G. Wells Nov 1978

Large Cylindrical Bale Transporter, Larry G. Wells

Biosystems and Agricultural Engineering Faculty Patents

The present application is directed to a transporter for transporting large cylindrical bales which includes a mast assembly adapted to be directly attached to a standard three-point hitch of a tractor. The transporter unit includes a two-wheel type trailer and a bale engaging assembly which is rotatably mounted upon the axle of the wheel assembly so that a load positioned on the bale engaging means may be rotated upwardly to support the load directly on the wheels of the transporter. By pivotally attaching the transporter to the mast assembly, the present invention may readily support the entire transporter above the …


Priority Programming For Highway Reconstruction, Charles V. Zegeer, Rolands L. Rizenbergs Nov 1978

Priority Programming For Highway Reconstruction, Charles V. Zegeer, Rolands L. Rizenbergs

Kentucky Transportation Center Research Report

An adequacy-rating procedure was developed for use in priority programming for highway reconstruction. The procedure makes use of 15 roadway and traffic elements to rate highway sections in urban and rural areas based on 100 points. Condition elements (35 points) include a subjective rating of highway foundation, pavement surface, drainage, and maintenance economy. Safety elements (35 points) are stopping sight distance, highway alignment, skid resistance, accident experience, and traffic control devices. Service elements (30 points) include shoulder width, passing opportunity, rideability, surface width, volume/capacity ratio, and average speed.

Some of the advantages of the new procedure include computerized analysis of …


Energy In Agriculture: Grassland Renovation--Conserves Oil And Energy And Increases Returns From Grass Fields, Edward M. Smith, Larry W. Turner Nov 1978

Energy In Agriculture: Grassland Renovation--Conserves Oil And Energy And Increases Returns From Grass Fields, Edward M. Smith, Larry W. Turner

Agricultural Engineering Energy Series

Fifty-four percent (1.2 billion acres) of land area in the 48 continental United States consists of grasslands, shrublands and open forests. For the most part, there is no alternative use of these land resources in production of food for man other than by way of ruminant animals. Sixty-nine percent (835 million acres) of these land resources is being utilized by grazing animals and forms the basis for a livestock industry which represents 43% of all agricultural receipts in the United States.


Energy In The Home: Energy Usage In Agricultural Production, John N. Walker Nov 1978

Energy In The Home: Energy Usage In Agricultural Production, John N. Walker

Agricultural Engineering Energy Series

Agriculture, even in its most primitive state, includes activities related to the collection and storage of solar energy in a form that can be used to sustain life. Energy must be expended in terms of human labor, animal labor, and fossil energy used for products and machinery utilized by agriculture. Because fossil energy is in short supply, many people are concerned, and rightfully so, about the effect that restricted energy availability will have upon agriculture production.


Seatbelt Usage In Kentucky [Nov. 1978], Kenneth R. Agent, Michael Barclay, Robert C. Deen Nov 1978

Seatbelt Usage In Kentucky [Nov. 1978], Kenneth R. Agent, Michael Barclay, Robert C. Deen

Kentucky Transportation Center Research Report

In this report, the effectiveness and usage of seatbelts in Kentucky and factors affecting usage are examined and identified. Data were obtained from three sources: field observations, accident reports, and a questionnaire.

Kentucky drivers and passengers were found to have lower seatbelt usage rates (slightly under 10 percent) than drivers and passengers in other states. The accident data showed that the chances of being killed or severely injured is greatly reduced by wearing a seatbelt. Seatbelts reduced the chance of being killed by a factor of six and the chance of being severely injured by a factor of two. Several …


Design System For Asphaltic Concrete Overlays, Herbert F. Southgate, Gary W. Sharpe, Robert C. Deen Nov 1978

Design System For Asphaltic Concrete Overlays, Herbert F. Southgate, Gary W. Sharpe, Robert C. Deen

Kentucky Transportation Center Research Report

A method of designing asphaltic concrete overlays has been developed from (1) Kentucky's theoretical design curves, (2) an estimate of future traffic and the associated fatigue (five procedures are presented according to types of information available), (3) strength of subgrade on subject project (laboratory CBR tests or results of dynamic in-place tests such as the Road Rater), and (4) present condition of the existing pavement (from dynamic in-place tests, roughness measurements, or present serviceability index). Deterioration has been expressed as reduced or effective thicknesses of new-quality materials producing the same measured dynamic deflections. The total thickness required for the future …


Analysis Of Weekday, Weekend, And Holiday Accident Frequencies, Jerry G. Pigman, Rolands L. Rizenbergs, Donald R. Herd Nov 1978

Analysis Of Weekday, Weekend, And Holiday Accident Frequencies, Jerry G. Pigman, Rolands L. Rizenbergs, Donald R. Herd

Kentucky Transportation Center Research Report

On rural roads, the largest number of accidents have occurred on Saturdays, Fridays, and Sundays, respectively. Tuesdays generally had the lowest number of accidents. The highest accident rates for two-lane roads were on Sundays and Saturdays, and the rates for expressways (interstates and toll roads) were the highest on Sundays. Accident rates on weekends were substantially higher than on weekdays. Rates of fatal and all accidents were lower during holiday periods than during weekends not involving holidays. Holiday periods had fewer accidents per day than weekends but had more accidents per day than weekdays. Traffic during holidays, however, was significantly …


Statewide Survey Of Skid Resistances Of Pavements [Nov. 1978], Rolands L. Rizenbergs, James L. Burchett Nov 1978

Statewide Survey Of Skid Resistances Of Pavements [Nov. 1978], Rolands L. Rizenbergs, James L. Burchett

Kentucky Transportation Center Research Report

In 1969, a research-type, skid-test trailer was acquired, U.S. routes were surveyed in 1970 and 1971, and the interstate and toll-road systems were surveyed in 1971. The data were used for research purposes and have been reported. The interstate and toll-road systems were surveyed again for research purposes in 1974. Since October 1974, surveys have been performed under highway safety project grants (interaccounted to 108, subsection OSKID). Primary and principal secondary roads, involving 4,613 miles (7,427 km), were surveyed in 1975. A second skid tester, a survey-type, was acquired in April 1976; and survey-testing of major, rural collector roads continued …


Pavement Evaluation Using Dynamic Deflections, Gary W. Sharpe, Herbert F. Southgate, Robert C. Deen Nov 1978

Pavement Evaluation Using Dynamic Deflections, Gary W. Sharpe, Herbert F. Southgate, Robert C. Deen

Kentucky Transportation Center Research Report

Dynamic test deflections have been duplicated by elastic theory using the Chevron N-layered computer program. Dynamic surface deflections obtained using the Road Rater have been used in conjunction with elastic theory to analyze pavement behavior. A procedure has been developed to use field measured Road Rater deflections to estimate the elastic moduli of the foundation material and to determine the equivalent thicknesses of new material which approximate the behavior of the structure. The estimated moduli and (or) equivalent thicknesses may be used as inputs to design overlay thicknesses. An analysis of the deflections of the first three sensors of the …


Energy In Agriculture: Dryeration Performance Evaluation, Otto J. Loewer, Thomas C. Bridges, G. M. White, Robert L. Fehr, Larry W. Turner Oct 1978

Energy In Agriculture: Dryeration Performance Evaluation, Otto J. Loewer, Thomas C. Bridges, G. M. White, Robert L. Fehr, Larry W. Turner

Agricultural Engineering Energy Series

When grain is dried using continuous flow or portable batch dryers it must be cooled before it is placed in storage. The cooling process removes the sensible heat that was used to bring the grain temperature up to the drying air temperature, and hopefully reduces the grain temperature to a point where mold growth is no longer a problem. Unfortunately, rapid cooling of grain results in increased grain damage in terms of stress cracks, and is an energy-inefficient process in that the heat stored in the grain is not used for any useful purpose.


Energy In Agriculture: Performance Evaluation For Natural Air And Low-Temperature Drying Systems, Otto J. Loewer, Thomas C. Bridges, G. M. White, Robert L. Fehr, Larry W. Turner Oct 1978

Energy In Agriculture: Performance Evaluation For Natural Air And Low-Temperature Drying Systems, Otto J. Loewer, Thomas C. Bridges, G. M. White, Robert L. Fehr, Larry W. Turner

Agricultural Engineering Energy Series

Natural air and low-temperature drying systems are generally not recommended for Kentucky because of their slow drying rates. In such systems the grain near the top of the drying bin may remain undried for an extended period of time, possibly leading to grain spoilage and/or the production of aflatoxin.


Energy In The Home: Grain Drying Performance Evaluation, Otto J. Loewer, Thomas C. Bridges, G. M. White, Robert L. Fehr Oct 1978

Energy In The Home: Grain Drying Performance Evaluation, Otto J. Loewer, Thomas C. Bridges, G. M. White, Robert L. Fehr

Agricultural Engineering Energy Series

When grain is harvested in Kentucky at moisture contents exceeding 13 to 14 percent, it must be dried to insure long-term safe storage. The drier the stored grain, the longer it will retain its quality.


Warrants For Left-Turn Signal Phasing, Kenneth R. Agent, Robert C. Deen Oct 1978

Warrants For Left-Turn Signal Phasing, Kenneth R. Agent, Robert C. Deen

Kentucky Transportation Center Research Report

Warrants for the installation of left-turn phasing were developed. A review of literature was conducted along with a survey of the policies of other states. Field data of delays and conflicts were taken before and after installation of exclusive left-turn signalization. Left-turn delay studies were conducted at intersections with varying volume conditions. Analysis of the effect on accidents of adding a left-turn phase was made. The relationship between left-turn accidents and conflicts was investigated. Other types of analyses concerning gap acceptance, capacity, and benefit-cost ratios were also performed.

It was found that exclusive left-turn phasing significantly reduced left-turn accidents and …


A Rational Thickness Design System For Asphaltic Concrete Overlays, Herbert F. Southgate, Gary W. Sharpe, Robert C. Deen Oct 1978

A Rational Thickness Design System For Asphaltic Concrete Overlays, Herbert F. Southgate, Gary W. Sharpe, Robert C. Deen

Kentucky Transportation Center Research Report

A method of designing asphaltic concrete overlays has been developed making use of (1) Kentucky's proposed design curves, (2) an estimate of future traffic and the associated fatigue (five procedures are presented according to types of information available), (3) strength of subgrade on subject project (laboratory CBR tests or results of dynamic in-place tests such as the Road Rater), and (4) present condition of the existing pavement (from dynamic in-place tests, roughness measurements, or present serviceability index). Deterioration was expressed as reduced thicknesses of new-quality materials producing the same measured dynamic deflections. The total thickness for the predicted traffic minus …


Simulation Of Travel Patterns For Small Urban Areas, Jerry G. Pigman, Robert C. Deen Oct 1978

Simulation Of Travel Patterns For Small Urban Areas, Jerry G. Pigman, Robert C. Deen

Kentucky Transportation Center Research Report

The objective of this study was to develop models which would simulate internal-external trips and external-external (through) trips. Regression analysis and cross-classification of data were tested in an attempt to predict the number of internal-external trips and the percentage of through trips. Regression analysis was used in the development of a through-trip distribution model. Grouping data for analysis created some problems; however, trial-and-error evaluation enabled selection of variables which produced reasonable results. Variables found to be most significant in the development of internal-external models were population and employment. For through-trip models, variables used were population, functional classification, AADT at the …