Engineering Commons^™

Seismic Control Of Asymmetric Structures, Rakesh K. Goel

Civil and Environmental Engineering

No abstract provided.

Simulations Of Passive Matrix Polymer Image Sensors, David Braun, G. Yu

Electrical Engineering

Two-dimensional passive photodiode matrices are hardly useful for image sensing due to the crosstalk between pixels. This crosstalk makes it difficult to recover information from individual pixels. A switching unit attached to each sensing unit has been the common solution in image sensors (such as in CMOS sensors and in TFT-PiN a-Si photosensors). A novel organic photodiode with voltage-switchable photosensitivity was developed recently. Passive photodiode matrices made with such organic photodiodes can be used for image sensing applications. This circuit simulation study demonstrates an effective scheme to extract images from passive photodiode matrices, concluding that individual photodiode parameters determine the …

Three Reasons To Broaden Your Fertigation Knowledge, Charles M. Burt

BioResource and Agricultural Engineering

No abstract provided.

Capacity-Demand-Diagram Methods For Estimating Seismic Deformation Of Inelastic Structures: Sdf Systems, Anil K. Chopra, Rakesh K. Goel

Civil and Environmental Engineering

The ATC-40 and FEMA-274 documents contain simplified nonlinear analysis procedures to determine the displacement demand imposed on a building expected to deform inelastically. The Nonlinear Static Procedure in these documents, based on the capacity spectrum method, involves several approximations: The lateral force distribution for pushover analysis and conversion of these results to the capacity diagram are based only on the fundamental vibration mode of the elastic system. The earthquake-induced deformation of an inelastic SDF system is estimated by an iterative method requiring analysis of a sequence of equivalent linear systems, thus avoiding the dynamic analysis of the inelastic SDF system. …

Capacity-Demand-Diagram Methods For Estimating Seismic Deformation Of Inelastic Structures: Sdf Systems, Anil K. Chopra, Rakesh K. Goel

Civil and Environmental Engineering

The ATC-40 and FEMA-274 documents contain simplified nonlinear analysis procedures to determine the displacement demand imposed on a building expected to deform inelastically. The Nonlinear Static Procedure in these documents, based on the capacity spectrum method, involves several approximations: The lateral force distribution for pushover analysis and conversion of these results to the capacity diagram are based only on the fundamental vibration mode of the elastic system. The earthquake-induced deformation of an inelastic SDF system is estimated by an iterative method requiring analysis of a sequence of equivalent linear systems, thus avoiding the dynamic analysis of the inelastic SDF system. …

Hand Held Data Recorder (Hhdr), Charles M. Burt, Stuart Styles

BioResource and Agricultural Engineering

A HHDR is used to collect data from the field and to download that data to a database to generate reports for meters in the districts. The data can be collected intermittently or on a daily basis since these are not route based data collectors. The data is collected by means of a hand held portable unit that scans a bar code identification label that is permanently affixed to the meter. Data is then entered by means of a keypad or a scan sheet and the operator goes to the next meter. At the end of the day the unit …

Irrigation Water Balance Fundamentals, Charles M. Burt

BioResource and Agricultural Engineering

Water balances are essential for making wise decisions regarding water conservation and water management. The paper defines the essential ingredients of water balances, and distinguishes between farm and district-level balances. An example of a hypothetical district-level balance is provided. The importance of listing confidence intervals is highlighted. Classic errors in water balance determination are noted

Water Balance-Related Performance Indicators For International Projects, Charles M. Burt, Stuart W. Styles

BioResource and Agricultural Engineering

A unique study to examine the impacts of irrigation project modernization was funded by the Research Committee of the World Bank and managed by the International Program for Technology Research in Irrigation and Drainage (IPTRID). The project examined 16 irrigation projects in 10 developing countries, 15 of which have been partially modernized in some aspects of hardware and/or management. Besides developing specific recommendations for donor agencies interested in irrigation project modernization, this project also accomplished the following: 1. A Rapid Appraisal Process (RAP) was developed to quickly (within a week) evaluate an irrigation project to assess what type of modernization …

Subsurface Flows Water Balance Components For Irrigation Districts In The San Joaquin Valley, Stuart W. Styles, Charles M. Burt

BioResource and Agricultural Engineering

Cal Poly ITRC has conducted several water balances for regions or districts within the San Joaquin Valley. In each case, the greatest unknown component for the water balance is subsurface flows (ITRC, 1994). Water balance calculations can be confusing, especially in districts where there is groundwater pumping. This paper will discuss ITRC efforts to determine both lateral and vertical components of subsurface flow, the accuracy of the estimates, and the impact upon the accuracy of the final estimates of irrigation district or regional irrigation efficiencies.

Closure To "Irrigation Performance Measures: Efficiency And Uniformity", Albert J. Clemmens, Charles M. Burt, Kenneth H. Solomon, Terry A. Howell, Theodor S. Strelkoff

BioResource and Agricultural Engineering

No abstract provided.

Fabrication Of Visible Light Emitting Diodes Soluble Semiconducting Polymers, Alan J. Heeger, David Braun

Electrical Engineering

Visible light LEDs are produced having a layer of conjugated polymer which is cast directly from solution or formed as a gel-processed admixture with a carrier polymer. The LEDs can be formed so as to emit polarized light.

Some Traffic Features At Freeway Bottlenecks, Michael J. Cassidy, Robert L. Bertini

Civil and Environmental Engineering

Observations from two freeway bottlenecks in and near Toronto, Canada indicate that the average rate vehicles discharge from a queue can be 10% lower than the flow measured prior to the queue's formation. Absent any influences from downstream, the queue discharge flows exhibited nearly stationary patterns that alternated between higher and lower rates. These alternating flow patterns were especially evident at one of the two sites, although the feature occurred at both sites during periods that immediately followed the onset of upstream queuing; i.e. a queue's formation was always accompanied by a relatively low discharge rate followed later by a …

Long-Term Memory Motion-Compensated Prediction, Thomas Wiegand, Xiaozheng Zhang, Bernd Girod

Electrical Engineering

Long-term memory motion-compensated prediction extends the spatial displacement vector utilized in block-based hybrid video coding by a variable time delay permitting the use of more frames than the previously decoded one for motion compensated prediction. The long-term memory covers several seconds of decoded frames at the encoder and decoder. The use of multiple frames for motion compensation in most cases provides significantly improved prediction gain. The variable time delay has to be transmitted as side information requiring an additional bit rate which may be prohibitive when the size of the long-term memory becomes too large. Therefore, we control the bit …

Room Temperature Fatique Response Of Γ-Tial To Impact Damage, Trevor S. Harding, J. Wayne Jones, P. S. Steif, T. M. Pollock

Materials Engineering

Gamma based titanium aluminides have received considerable attention recently as candidate materials in gas turbine applications, particularly low pressure turbine blades (1–3). Their low density and high specific stiffness, result in potentially significant weight savings in structures such as gas turbine engines if substituted for current materials. Two γ-TiAl microstructures are predominately identified in the literature: a lamellar microstructure consisting of alternating plates of γ and α₂, and a duplex microstructure consisting of equiaxed γ grains and lamellar colonies (3,4). Lamellar alloys generally exhibit better fracture toughness and fatigue crack growth resistance (5–7). Duplex alloys, on the other …

Worn Tool Forces Based On Ploughing Stresses, Daniel Waldorf, Shiv G. Kapoor, Richard E. Devor

Industrial and Manufacturing Engineering

Recent work in modeling of the ploughing mechanism in basic metal machining may provide a means of estimating the additional forces to be expected when cutting with a worn tool. The results predict the rubbing stresses due to the finite radius of an unworn tool edge. Since an unworn tool can be thought of as a worn tool with a wear land width VB = 0, these stresses can make up part of a strategy for predicting the additional forces incurred by a worn tool. This paper develops a wear model by proposing a technique for utilizing the stresses predicted …

Managing District Data Needs – Narrowing In On A Moving Target, Charles M. Burt

BioResource and Agricultural Engineering

San Luis Water District, Panoche Water District, Delano-Earlimart Irrigation District (DEID), Westside Water District, Glide-Kanawha Water District (GKWD), and Central California Irrigation District (CCID) are blazing data management trails in the Mid-Pacific Region of the USBR. Ditchriders in these districts use or are beginning to use hand held data recorders (HHDR) to gather field information. The data management needs of these districts differ and as a result, the approach for each district differs. Further, each district is tackling portions of its data management needs in a stepwise fashion. The success of each step and the successes of other district approaches …

Evaluation Of Subsurface Drip Irrigation On Peppers, Stuart W. Styles, Charles M. Burt

BioResource and Agricultural Engineering

This paper is a summary of two farms that utilized the California Energy Commission's low-interest loan program to facilitate their entry into drip irrigation. One farm is located near Oxnard, California, USA and the other is located near Gilroy, California, USA. Both of these growers farm about 162 hectares (400 acres) in their overall operations and used the loans to purchase subsurface drip irrigation systems for Peppers. Over $4 million in low-interest loans have been made available to California growers from the California Energy Commission (CEC) since 1986. The CEC initiated the loan program for growers to help implement energy …

Location Effects Of Passive Damping Material In Cross-Ply Laminates On Natural Frequency And Mode Shape, E. I. Elghandour, F. A. Kolkailah

Aerospace Engineering

This study presents an experimental investigation of the free vibration of cantilevered composite laminated plates with embedded passive damping material at different stages. A total of five composite laminated plates are considered. The lay-up sequences for the five composite laminated plates with and without two embedded layers of passive damping material are [90°/0°/90°/0°]_s, [90°/0°/90°/0°/d]_s, [90°/0°/90°/d/0°]_s, [90°/0°/d/90°/0°]_s, and [90°/d/0°/90°/0°]_s. The passive damping material employed is a 3M material, SJ-2015 ISD 112, with peak damping properties in the ambient temperature range of 32°F to 140°F. The composite material used is a carbon …

Irrigation Sagacity: A Measure Of Prudent Water Use, Kenneth H. Solomon, Charles M. Burt

BioResource and Agricultural Engineering

Within the western United States, water rights are granted for reasonable and beneficial water use, and a measure of irrigation performance that embodies this standard is needed. A new performance parameter, irrigation sagacity (IS), is recommended for this purpose. The term `sagacity' comes from `sagacious', meaning wise or prudent. IS is more closely tied to the water rights granted, and to the potential for water conservation and reallocation than is the traditional irrigation efficiency, which considers only beneficial uses. Sagacious uses are either beneficial, or non-beneficial but reasonable. Reasonable uses are those that, while not directly benefiting agronomic production within …

Production Of Biogenic Mn Oxides By Leptothrix Discophora Ss-1 In A Chemically Defined Growth Medium And Evaluation Of Their Pb Adsorption Characteristics, Yarrow M. Nelson, Leonard W. Lion, William C. Ghiorse, Michael L. Shuler

Civil and Environmental Engineering

Biogenic Mn oxides were produced by the bacterium Leptothrix discophora SS-1 (= ATCC 3182) in a chemically defined mineral salts medium, and the Pb binding and specific surface area of these oxides were characterized. Growth of SS-1 in the defined medium with pyruvate as a carbon and energy source required the addition of vitamin B₁₂. Complete oxidation of Mn(II) within 60 h required the addition of ≥0.1 μM FeSO₄. Pb adsorption isotherms were determined for the biogenic Mn oxides (and associated cells with their extracellular polymer) and compared to the Pb adsorption isotherms of cells and …

Problems Of Irrigation In Developing Countries, Phillip Z. Kirpich, Dorota Z. Haman, Stuart W. Styles

BioResource and Agricultural Engineering

This paper describes the crucial importance of irrigated agriculture to developing countries and to the world as a whole. This is followed by a summary of key problems that restrict and diminish the benefits of irrigated agriculture. Solution of these problems will above all require a holistic approach and will require changes in the institutions involved. These institutions include those of the developing countries, of the developed countries that provide aid, and of the international financing and technical-assistance agencies. Engineers in the developed countries have had, and will continue to have, a leading role but will need some redirection. ASCE …

District Application Of Hand Held Data Recorder Technology, Stuart Styles, Charles M. Burt

BioResource and Agricultural Engineering

A hand held data recorder (HHDR) enables a district to collect field data in a quick and virtually error-free manner. These units can be used to scan bar code location/equipment identifiers or the operator can manually key in this information followed by the current data. Some HHDRs can be programmed with error checking routines that prompt the operator when an entry is inconsistent with regards to the previous reading from that location. Each entry includes a time and date stamp. When the operator has collected all of the data for the day or for a route, the data is downloaded …

Simple, Portable Water Level Monitoring Package, Charles M. Burt, Stuart Styles

BioResource and Agricultural Engineering

Electronic water level sensing equipment is becoming increasingly important for the implementation of water conservation programs in irrigation districts. A need has risen for information on costs, advantages/disadvantages, required support equipment, and required maintenance for the various options. For this reason, the Water Conservation Office of the Mid-Pacific Region of the USBR contracted with the Cal Poly ITRC to conduct a study on water level sensors and dataloggers and to produce a report.

One application covered in the water level sensor and datalogger report is the need to have a simple, portable water level monitoring package. This paper supplements the …

A Compensated Acoustic Actuator For Systems With Strong Dynamic Pressure Coupling, Charles Birdsong, Clark J. Radcliffe

Mechanical Engineering

This study improves the performance of a previously developed acoustic actuator in the presence of an acoustic duct system with strong pressure coupling. The speaker dynamics and the acoustic duct dynamics are first modeled separately. The two systems are then coupled, and the resulting system is modeled. A velocity sensor is developed and used in feedback compensation. The resulting speaker system has minimal magnitude and phase variation over a 20–200 Hz bandwidth. These conclusions are verified through experimental results.

Optimal Stimulus Electrode Dipole Orientation, Robert B. Szlavik, Hubert De Bruin

Biomedical Engineering

The elicited M-Wave that results from the surface stimulation of the median nerve is highly dependent upon the geometric orientation of the stimulus electrode dipole. This phenomenon could make standardization of M-Wave measurements between tests performed on a single subject problematic. We present an experimental paradigm that illustrates this variability in terms of an estimate of the slope of the M-Wave peak potential versus stimulus current amplitude and the minimum stimulus current required to consistently elicit a minimal response. The design of an automated instrument for selecting the optimal stimulus electrode dipole orientation based on the electrode orientation experiment is …

The Effects Of Testing Methods On The Flexural Fatigue Life Of Human Cortical Bone, L. V. Griffin, J. C. Gibeling, R. B. Martin, V. A. Gibson, S. M. Stover

Biomedical Engineering

A flexural model of four-point bending fatigue that has been experimentally validated for human cortical bone under load control was used to determine how load and displacement control testing affects the fatigue behavior of human cortical bone in three-point and symmetric four-point bending. Under load control, it was predicted that three-point bending produced no significant differences in fatigue life when compared to four-point bending. However, three-point bending produced less stiffness loss with increasing cycles than four-point bending. In four-point bending, displacement control was predicted to produce about one and a half orders of magnitude greater fatigue life when compared to …

Fertigation Basics, Charles M. Burt

BioResource and Agricultural Engineering

Fertigation is widely practiced with drip irrigation, yet remains very unsophisticated. Major areas which need improvement are (i) making certain the irrigation system applies water with a high DU (uniformity), (ii) using proper injection pumps and protection hardware, (iii) recognizing that chemicals can interact with each other and with water to form precipitates which will clog emitters, (iv) understanding of nutrient ratios in plants and soil, (v) recognizing that nitrogen fertilization requires attention to the type of nitrogen, and (vi) developing programs for spoon-feeding chemicals. This paper covers the first 4 topics, plus discusses some specific fertilizers.

Model For Trace Metal Exposure In Filter-Feeding Flamingos At Alkaline Rift Valley Lake, Kenya, Yarrow M. Nelson, Ramesh J. Thampy, Gideon K. Motelin, Jackson A. Raini, Cynthia J. Disante, Leonard W. Lion

Civil and Environmental Engineering

Abstract—Toxic trace metals have been implicated as a potential cause of recent flamingo kills at Lake Nakuru, Kenya. Chromium (Cr), copper (Cu), lead (Pb), and zinc (Zn) have accumulated in the lake sediments as a result of unregulated discharges and because this alkaline lake has no natural outlet. Lesser flamingos (Phoeniconaias minor) at Lake Nakuru feed predominantly on the cyanobacterium Spirulina platensis, and because of their filter-feeding mechanism, they are susceptible to exposure to particle-bound metals. Trace metal adsorption isotherms to lake sediments and S. platensis were obtained under simulated lake conditions, and a mathematical model was …

Screen Printing Process Design Of Experiments For Fine Line Printing Of Thick Film Ceramic Substrates, Jianbiao Pan, Gregory L. Tonkay, Alejandro Quintero

Industrial and Manufacturing Engineering

Screen printing has been the dominant method of thick film deposition because of its low cost. Many experiments in industry have been done and many models of the printing process have been developed since the 1960’s. With a growing need for denser packaging and a drive for higher pin count, screen printing has been refined to yield high resolution prints. However, fine line printing is still considered by industry to be difficult. In order to yield high resolution prints with high first pass yields and manufacturing throughput, the printing process must be controlled stringently.

This paper focuses on investigating the …

A Slip-Line Field For Ploughing During Orthogonal Cutting, Daniel J. Waldorf, Richard E. Devor, Shiv. G. Kapoor

Industrial and Manufacturing Engineering

Under normal machining conditions, the cutting forces are primarily due to the bulk shearing of the workpiece material in a narrow zone called the shear zone. However, under finishing conditions, when the uncut chip thickness is of the order of the cutting edge radius, a ploughing component of the forces becomes significant as compared to the shear forces. Predicting forces under these conditions requires an estimate of ploughing. A slip-line field is developed to model the ploughing components of the cutting force. The field is based on other slip-line fields developed for a rigid wedge sliding on a half-space and …