Engineering Commons^™

Fertigation Chemicals, Charles M. Burt

BioResource and Agricultural Engineering

When deciding what chemicals to inject, there are numerous considerations to be made. This paper addresses some of the more common factors which should be considered, but which are often overlooked. Because nitrogen fertilizer is injected more widely than any other nutrient, special attention is given to it

A Model For General Periodic Excitation With Random Disturbance And Its Application, Y. K. Zhou, Z. K. Hou, M. F. Dimentberg, Mohammad N. Noori

Office of the Dean (CENG) Scholarship

Many vibration problems involve a general periodic excitation such as those of a triangular or rectangular waveform. In practice, the periodic excitation may become disordered due to uncertainties. This paper presents a stochastic model for general periodic excitations with random disturbances which is constructed by introducing random amplitude and phase disturbances to individual terms in the Fourier series of the corresponding deterministic periodic function. Mean square convergence of the random Fourier series are discussed. Monte Carlo simulation of disordered sawtooth, triangular, and quadratic wave forms are illustrated. An application of the excitation is demonstrated by vibration analysis of a single-degree-of-freedom …

Development Of A Mechatronics Design Studio, Sema E. Alptekin

Industrial and Manufacturing Engineering

Mechatronics is a combination of mechanics, electronics and information technology intended to raise the intelligence level and flexibility of products and devices. There is a need to develop programs and laboratories in Mechatronics to create an understanding of how new technologies influence the traditional methods of designing products and manufacturing systems. A model "Mechatronics Design Studio" has recently been developed to support the Mechatronics and Manufacturing Automation courses offered at Cal Poly's Industrial and Manufacturing Engineering Department. Laboratory experiments have been developed and several student projects have been completed. In this paper, an overview of the design studio and select …

Design Techniques And Paradigms Toward Design Of Low-Voltage Cmos Analog Circuits, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

Techniques for the design of robust low-voltage CMOS analog circuits are given. It is shown that both Vt-independence and proper alignment between the input and output swings are crucial for effective design of low-voltage circuits.

Determination Of Drag From Three-Dimensional Viscous And Inviscid Flowfield Computations, David L. Hunt, Russell M. Cummings, M. B. Giles

Aerospace Engineering

A momentum balance approach is used to extract the drag from flowfield computations for wings and wing/bodies in subsonic/transonic flight. The drag is decomposed into vorticity, entropy, and enthalpy components which can be related to the established engineering concepts of induced drag, wave and profile drag, and engine power and efficiency. This decomposition of the drag is useful in formulating techniques for accurately evaluating drag using computational fluid dynamics calculations or experimental data. A formulation for reducing the size of the region of the crossflow plane required for calculating the drag is developed using cut-off parameters for viscosity and entropy. …

Environmental Engineering Design, Harold M. Cota, Samuel A. Vigil

Civil and Environmental Engineering

This paper outlines the capstone environmental engineering design course that has been used effectively at California Polytechnic State University. Senior level students work in teams on a multi-media industrial problem. The experience involves literature review, problem formulation, proposal writing, time management, technical and economic analysis and an oral and written presentation of the results. Feedback from alumni and employers has been positive.

Energy Based Approach To Earthquake Response Of Asymmetric Systems, Rakesh K. Goel

Civil and Environmental Engineering

No abstract provided.

Evaluation Of Code Period Formula For Concrete Mrf Buildings, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

The empirical formula specified in US building codes for fundamental vibration period of concrete moment resisting frame buildings is evaluated using periods of buildings measured from their strong motion records. The presented results show that the current code formula may lead to fundamental periods that are much shorter than the measured periods. In order to obtain better correlation between measured and computed periods, regression analysis technique has been used. The results indicate that the value of C, in the current code formula should be increased from its present value of 0.030 to 0.035.

A Differential Active Load And Its Applications In Cmos Analog Circuit Designs, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

In this paper we describe a CMOS differential active load and show how it can be used to create various useful structures. Tunable current gain stages and current squaring circuits are discussed. Their connection to a differential pairbased transconductor results in broad-range tunable transconductor structures suitable for adaptive continuous-time filtering applications and a four-quadrant voltage multiplier.

Permeability Study Of Cracked Concrete, Kejin Wang, Daniel C. Jansen, Surendra P. Shah, Alan F. Karr

Civil and Environmental Engineering

Cracks in concrete generally interconnect flow paths and increase concrete permeability. The increase in concrete permeability due to the progression of cracks allows more water or aggressive chemical ions to penetrate into the concrete, facilitating deterioration. The present work studies the relationship between crack characteristics and concrete permeability. In this study, feedback controlled splitting tests are introduced to generate crack width-controlled concrete specimens. Sequential crack patterns with different crack widths are viewed under a microscope. The permeability of cracked concrete is evaluated by water permeability tests. The preliminary results indicate that crack openings generally accelerate water flow rate in concrete. …

Ultrasonic Method For Evaluation Of Annular Seals For Wells And Instrument Holes, Nazli Yesiller, Tuncer B. Edil, Craig H. Benson

Civil and Environmental Engineering

An ultrasonic testing method employing the pulse-echo inspection technique was developed to assess the integrity of annular seals surrounding casings (i.e., instrument tubes or well casings). This nondestructive testing method permits testing a seal from inside a casing without disturbing the casing, seal, or formation. Seals constructed with cement-based and bentonite-based sealants surrounding various types and sizes of casings can be evaluated using the method. An evaluation is conducted by sending and receiving ultrasonic waves using a single piezoelectric transducer and commercially available hardware (a pulser receiver and a waveform analyzer). A probe was designed and constructed for downhole testing. …

Evaluation Of Bridge Abutment Capacity And Stiffness During Earthquakes, Rakesh K. Goel, Anil K. Chopra

Civil and Environmental Engineering

The “actual” capacity and stiffness values of the abutment‐soil systems at the US 101/Painter Street Overpass, determined from its earthquake motions, are used to investigate how abutment stiffness varies during earthquakes and to evaluate current modeling procedures. It is found that the “actual” abutment stiffness may be significantly different during different phases of the shaking and decreases significantly as the abutment deformation increases. The CALTRANS modeling procedure leads to a good estimate of the transverse abutment stiffness and capacity. However, this procedure may overestimate the normal abutment stiffness and capacity by a factor of over two, indicating that the assumed …

Bipolar/Cmos (Weak Inversion) Rail-To-Rail Constant-G M Input Stage, Vladimir I. Prodanov, Michael M. Green

Electrical Engineering

A rail-to-rail constant-g_m input stage suitable for bipolar or weak inversion CMOS implementation is presented. To achwe rail-to rail operation, two complementary differential pairs driven in parallel are used. To guarantee constant net transconductance each differential pair is augmented with a suitable biasing circuit. The biasing circuits are implemented without current mirrors, which results in low sensitivity to process variations and potentially higher bandwidth.

Residual Strength Of Equine Bone Is Not Reduced By Intense Fatigue Loading: Implications For Stress Fracture, R. B. Martin, V. A. Gibson, S. M. Stover, J. C. Gibeling, L. V. Griffin

Biomedical Engineering

Fatigue or stress fractures are an important clinical problem in humans as well as racehorses. An important question in this context is, when a bone experiences. fa!igue damage ~uring e~treme use, how much is it weakened compared to its original state? Since there are very ltmtted data on thts quesuon and stress fractures are common in racehorses, we sought to determine the effect of fatigue loading on the monotonic l:trength of equine cortical bone. Beams were machined from the dorsal, medial and lateral cortices of the third metacarpal bones of six thoroughbred racehorses. Beams from left and right bones were …

Effect Of Length On Compressive Strain Softening Of Concrete, Daniel C. Jansen, Surendra P. Shah

Civil and Environmental Engineering

The concept of localization during the postpeak of compressive strain softening is presented. To explore localization in compression, a feedback-control method using a linear combination of displacement and force that partially subtracts the elastic response of the specimen to give a stable feedback signal is used. Results are presented from two test series (45 and 90 MPa) that use this method to test cylinders with length-to-diameter ratios ranging from 2.0 to 5.5. It is shown that compression failure is in fact a localized phenomenon. The compressive fracture energy is divided into energy dissipated in the prepeak and the postpeak portions …

Assessment Of Cased-Borehole Seals Using An Ultrasonic Method, Nazli Yesiller, Craig H. Benson, Tuncer B. Edil, James Klima

Civil and Environmental Engineering

Tests were conducted in Wisconsin from 1994 through 1996 in several boreholes using an ultrasonic method that was developed at the University of Wisconsin-Madison to assess the integrity of annular seals. Initially, three model boreholes simulating monitoring wells were installed to evaluate the effectiveness of the ultrasonic method. Different types of seals were placed around the casings and defects were purposely introduced in the seals to test the ultrasonic method. The ultrasonic method was effective for detecting the presence of different types of seals and defects and also the changes in the condition of seals with time. Then tests were …

Characteristic Of A Broadband Ti:Linbo3, Optical Modulator With Buried Electrodes And Etched Grooves In The Buffer Layer, Jinyang Hu, Boyu Wu, Xiaomin Jin

Electrical Engineering

Traveling wave Ti:LiNbO₃ Mach-Zehnder optical modulators with buried electrodes and etched grooves in the SiO₂ buffer layer are analyzed by the finite element method. The tradeoff between the bandwidth BW and the half-wave voltage Vπ is discussed. The value of BW/V_π is used to weight the total performance of the modulator. Taking a thick buffer layer and etching deep grooves in the buffer layer are demonstrated as two effective methods to improve the performance of the modulator. A 3-dB optical bandwidth of 18 GHz with half-wave voltage 5V at a wavelength of 1.55 pm could be obtained …

Simulating The Distribution Of Axon Size In Nerves, Robert B. Szlavik, Hubert De Bruin

Biomedical Engineering

The electrical excitation threshold of a nerve axon is dependent upon the physical properties of the axon membrane as well as the axon diameter. Histological studies have confirmed that peripheral afferent muscle nerves have a characteristic distribution of axon diameters. We approximate a probability density function for this distribution that consists of the summation of several Gaussian functions. A transformation technique is then applied for the random generation of the nerve axon diameters from uniformly distributed random numbers. For the example presented, the resultant distribution of peripheral afferent muscle nerve axon diameters conforms approximately to the characteristic distribution that has …

Capacity And Stiffness Of Bridge Abutments During Earthquakes, Rakesh K. Goel

Civil and Environmental Engineering

No abstract provided.

The Threshold Value Of A Quality Index For Formation Of Cellular Manufacturing Systems, Hamid Seifoddini, Manocher Djassemi

Industrial Technology and Packaging

The superiority of cellular manufacturing to job shop manufacturing has been questioned by a number of simulation studies. The initial structure of the machine-part matrix seems to play an important role in the failure of cellular manufacturing systems in these studies. In this paper a grouping measure called 'quality index - QI' will be used to evaluate the relationship between the quality of a machine-part matrix and the performance of the corresponding cellular manufacturing system. A simulation study will be conducted to demonstrate how the procedure can be used to determine the threshold value for QI beyond which the cellular …

Modern Water Control And Management Practices In Irrigation: Methodoloy And Criteria For Evaluating The Impact On Performance, Charles M. Burt

BioResource and Agricultural Engineering

No abstract provided.

Development Of Outcome Assessments At Wpi, William W. Durgin, Lance Schachterle

Office of the Provost Scholarship

The WPl PLAN, adopted by the WPl faculty in 1970, strongly anticipates current thinking about student outcomes assessments by structuring degree requirements that mandate that students demonstrate their ability to perform professional functions embodied in ABET Criteria 2000, especially Criteria 3 and 4. The WPI faculty has also practiced both student and self evaluations of these outcomes through respectively grades and peer review (both departmental and campus-wide) of student performance.

Preparing The Leaders For Mechatronics Education, Sema E. Alptekin

Industrial and Manufacturing Engineering

Mechatronics is the synergetic combination of precision mechanical engineering, electronic control and systems thinking in the design of products and processes. There is a need to develop interdisciplinary programs in Mechatronics that better prepare our graduates to design, build, and operate the products and systems of today and tomorrow. To address this need, National Science Foundation funded a project entitled "Preparing the Leaders for Mechatronics Education" undertaken by Cal Poly in 1995 - 1996. In this paper, the activities that took place during this two-year program is outlined. Several courses and course modules have already been developed and implemented by …

Random Response To Periodic Excitation With Correlated Disturbances, Zhikun Hou, Yunshen Zhou, Mikhail F. Dimentberg, Mohammad N. Noori

Office of the Dean (CENG) Scholarship

The paper addresses non-Gaussian stationary response of linear single-degree-of-freedom (SnOF) systems subject to a periodic excitation with correlated random amplitude and phase disturbances that are modeled as correlated Gaussian white noise processes. Correlation between amplitude and phase modulation is specified by the cross-correlation coefficient. Numerical results for the second and fourth moment responses are presented. The probability density function of the response is calculated based on the cumulant-neglect closure method. Non-Gaussian nature of the response is discussed in terms of the excess factor. The results show that the moment responses generally increase with larger random amplitude disturbance and may decrease …

Row Crop Drip Irrigation On Peppers Study, Charles M. Burt, Stuart Styles

BioResource and Agricultural Engineering

High Rise Farms, located just north of Morgan Hill installed a new buried row crop drip irrigation system in 1993. The amount of the CEC loan was $42,700.

The installation of the drip irrigation system on the Peppers did provide significant improvements in the amount of water use, energy required and yield increases especially in the first year of operation (1993) and the third year of operation (1995). The second year of the project (1994) did not have yield increases. The primary lessons learned from this project included:

• The yield differential between drip and the furrow irrigation methods was attributed …

Row Crop Drip Irrigation On Bell Peppers Study, Charles M. Burt, Stuart Styles

BioResource and Agricultural Engineering

Underwood Ranches, located near Oxnard, installed a buried drip system on 50 acres of peppers in 1993. The amount of the CEC loan was $50,000.

The buried drip system provided sufficient advantages in water management, energy savings, and yield increases to convince the farm to expand its drip acreage to 140 acres in June 1995, and 320 acres in Sept. 1996. The farmer was an ideal cooperator.

The primary lessons learned on this project were:

• A grower needs approximately two years of experience and technical assistance in order to feel comfortable with a buried drip system. Even after that time, …

Distributed Activation Energy Model Of Heterogeneous Coal Ignition, John C. Chen

Mechanical Engineering

We present a model that simulates the conventional tube-furnace experiment used for ignition studies. The Distributed Activation Energy Model of Ignition accounts for particle-to-particle variations in reactivity by having a single preexponential factor and a Gaussian distribution of activation energies among the particles. The results show that the model captures the key experimental observations, namely, the linear increase in ignition frequency with increasing gas temperature and the variation of the slope of the ignition frequency with oxygen concentration. The article also shows that adjustments to the model parameters permit a good fit with experimental data.

Pulsed Transient Tissue Conductivity Measurement, Robert B. Szlavik, Hubert De Bruin

Biomedical Engineering

The authors present an alternative technique for obtaining tissue conductivity as a function of frequency. Pulsed transient tissue impedance measurement differs significantly from other commonly used swept frequency techniques in that the conductivity of a tissue sample can be obtained from a voltage transient response to a current pulse. By obtaining the conductivity across a band of frequencies from a transient measurement, the necessity for direct conductivity measurements at each frequency point is eliminated. Calibration and verification of the technique was carried out by measuring the impedance magnitude and phase of simple RC circuit combinations. The authors present conductivity measurements …

Spice Compatible Equivalent Circuit Models Of Skeletal Muscle Tissue, Robert B. Szlavik, Hubert De Bruin

Biomedical Engineering

The authors present equivalent circuit models of skeletal muscle tissue for the directions parallel and transverse to the fiber. The parallel model is based on a distributed parameter equivalent circuit approach where the tissue between the electrodes is divided into small segments, each of which is represented by an equivalent circuit. Parameters for the equivalent circuits me calculated from the electrical characteristics of the tissue components and their physical arrangement. The authors compare the conductivity frequency response of the equivalent circuit modelling approach to other models presented in the literature. The advantage to the authors' equivalent circuit approach is that …

Sensitivity Analysis In Cellular Manufacturing System In The Case Of Product Mix Variation, Hamid Seifoddini, Manocher Djassemi

Industrial Technology and Packaging

In this paper, performance measures such as mean flow time and work-in-process inventories will be used to determine the changes in the performance of a cellular manufacturing system due to product mix variations.