I-PLUS Presentations

Terahertz applications for detection of explosives

Jian Chen — Thu, 01 Apr 2010 11:51:18 PDT

In this project, we first used THz time domain spectroscopy (THz-TDS) to investigate explosives and establish a spectra database of these materials in the THz frequency range. The future THz imaging system will apply innovative pattern recognition and classification methods to distinguish explosives from non-explosive objects via these THz spectra.

Tunnel detection using cross borehole radar

Clay Kurison — Thu, 01 Apr 2010 11:51:18 PDT

Shallow tunnels present both military and homeland security threats. Smugglers with intentions of avoiding border security have turned tunnels into transit routes for trafficking weapons, people, drugs and other illegal materials. Shallow tunnels are also used by prisoners to escape prisons. While drug and human trafficking have long been border concerns, the threat of international terrorism has transformed the effort to detect tunnels into a national security priority. Imminent threats include assailants entering military fortifications by burrowing under buildings, detonation of high grade explosives from foundations of high security facilities, and high level prisoners escaping detention centers through tunnels. Real-time...

Suicide bomber detection using millimeter-wave radar

Richard Sullivan — Thu, 01 Apr 2010 11:51:17 PDT

Amidst the manifold threats currently afflicting public welfare, that of body-worn explosives is significant if not altogether paramount. Commonly referred to as ""suicide bombers,"" the bearers of body-worn, improvised explosive devices (IEDs) enter crowded public areas in order to detonate the IDE, inflicting lethal damage to themselves and surrounding individuals. Constructed of non-standard parts and veiled under layers of clothing, these body-worn IEDs go frequently undetected. The aim of this research is to examine the feasibility of using millimeter-wave (MMW) radar to detect body-worn IEDs at distances up to 50 meters. In order to achieve a beamwidth capable of illuminating...

Reflector antenna discrete distortion determination : an iterative-field-matrix solution

José Ángel Martinez-Lorenzo — Thu, 01 Apr 2010 11:51:16 PDT

The idealized shapes of satellite reflector antennas are often distorted once they are placed in orbit. The performance of such antennas can be improved by identifying the locations and amount of their surface distortions and then by correcting them using active surface distortion or array feeding. This work presents a method to determine the required discrete surface distortions to correct errors. The algorithm starts by discretizing the entire reflector surface into triangular patches, then by finding a linear relationship between the local distortion and the difference of the distorted and undistorted farfields patterns. A linear system of equations with the...

Simulating GPR for diagnosis of civil infrastructure

Laura Carey — Thu, 01 Apr 2010 11:51:16 PDT

At the present, a large proportion of our nation's bridges and roadways are falling into disrepair. About 27.5% of U.S. bridges are structurally deficient or functionally obsolete (ASCE, 2001, 2003). Nondestructive testing methods, such as GPR, are becoming more and more important in diagnosing the condition of such concrete structures. GPR is a high-resolution electromagnetic technique used to investigate the immediate subsurface of the earth, building materials, roads, and bridges. This poster shows my work in GPR modeling during a summer undergraduate experience through CenSSIS. A specialized MATLAB toolbox designed by Kim Belli created all data presented here. The use...

Photo-thermal coherent confocal microscope

Sean Sullivan — Thu, 01 Apr 2010 11:51:15 PDT

Confocal microscopy has been shown to be useful in imaging skin slightly below the junction of the dermis and epidermis. However, the depth of imaging is a significant limitation. We present a novel concept designed both to improve the depth of penetration and to increase the information content of images obtained with a reflectance confocal microscope. Using an approach similar to optoacoustics, we plan to explore the use of laser heating to generate tissue expansion, which will be measured by the microscope. The microscope will incorporate a pulsed heating laser along the same optical path as the imaging laser in...

Mitochondrial distribution in mouse oocytes and embryonic stem cells

Judith A. Newmark — Thu, 01 Apr 2010 11:51:14 PDT

Mitochondria are the organelles that generate the energy for the cell. They are also critical regulators of apoptosis (programmed cell death). The activity and localization of mitochondria influence whether a cell lives or dies. We are using imaging techniques in order to gain insight into how mitochondria influence cellular health in two biological systems: mouse oocytes and embryonic stem cells. Post-ovulatory oocytes undergo apoptosis if they are not fertilized. We have characterized the pattern of mitochondrial distribution in mouse oocytes in relation to post-ovulatory age, and discovered that the mitochondria do not simply clump as an oocyte ages, but they...

Imaging to study signal transduction of Qa-2 protein on T cells

Carmit Goldstein — Thu, 01 Apr 2010 11:51:13 PDT

One of the major challenges of biological research is to understand how proteins located on the cell surface transmit signals to the inside of the cell. Using the mouse as a model system our laboratory has studied one such protein, Qa-2 protein, which controls the rate of cell division of preimplantation embryos. Qa-2 is attached to the outer layer of the cell membrane by a glycosylphosphatidylinositol (GPI) linkage, which does not traverse the cell membrane. Thus, cell surface Qa-2 protein cannot initiate a signal on its own, but requires a partner molecule(s). In order to search for the partner molecule(s)...

Imaging HIFU lesions using ultrasound

Andy Draudt — Thu, 01 Apr 2010 11:51:12 PDT

High intensity focused ultrasound (HIFU) is a non-invasive method by which ultrasound can be used to thermally ablate tissue. One important application is the treatment of tumours. However, real-time imaging of the heating of tissue and lesion formation is a major barrier for HIFU. Our research involves employing a multi-modal approach, based on ultrasound imaging system, by which temperature distribution and the presence of a lesion can be determined. Methods we plan to use include classical backscatter, ultrasound tomography, acousto-optic imaging and elastography. By combining acoustical, optical and mechanical properties of the lesion we anticipate developing a robust approach to...

Forward time domain GPR modeling of bridge decks for detecting deterioration

Kimberly Belli — Thu, 01 Apr 2010 11:51:11 PDT

Ground penetrating radar (GPR) for nondestructive testing is a relatively young technology, especially with application to civil infrastructure such as bridges and roadways. Conventional methods of processing and analyzing GPR data for civil infrastructure are often qualitative, using relative reflection amplitude from subsurface boundaries or reinforcing steel (rebars) as an indicator of health. This poster brings well understood electrical engineering analysis tools to the application of nondestructive testing of bridges using GPR. Using iterative forward modeling to improve upon conventional permittivity and depth calculations, a computational model geometry is computed for the assumed bridge deck with no anomalies present. A...

FDTD simulation of a confocal microscope using a theta line scan

Blair Simon — Thu, 01 Apr 2010 11:51:10 PDT

We describe a 2-D computational model of the optical propagation in human skin from a confocal reflectance theta microscope. As an effect of decreasing the size of the microscope so that it is more clinically useful, the usual point source and detector with a raster scan is changed to a line source with a 1-D array detector. Because there is only one dimension of scanning, the microscope is confocal in one direction, but not in the other, however, this results in additional localized decreases in signal. We hypothesize that these result from the interaction of the bi-static imaging configuration with...

Computational modeling and analysis of radar scattering by metallic body-worn explosive devices covered with wrinkled clothing

Amanda J. Angell — Thu, 01 Apr 2010 11:51:09 PDT

In this study, we address the problem of detecting bodyworn improvised explosive devices (IEDs) from a safe distance using radar. We have used a finite difference frequency domain (FDFD) model to simulate the radar signature of a typical scenario for body-worn IEDs, and have analyzed wrinkled clothing as a possible source of clutter. Our analysis shows distinct characteristics of the IED backscattered farfield signal, with no significant clutter added when the metallic IED is covered by wrinkled clothing.

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Compact dual wedge point scanning confocal reflectance microscope

William C. Warger II — Thu, 01 Apr 2010 11:51:08 PDT

Confocal reflectance microscopy has been shown to provide optical sectioning and resolution sufficient to provide useful information about skin to a depth below the epidermis. However, existing instruments are large and expensive, because of the need for fast twodimensional scanning in the pupil, and the associated relay optics. A more compact scanning system could lead to an affordable hand-held instrument for in vivo imaging. Several approaches are being considered with different advantages and disadvantages. Here we report one approach that incorporates a dual-wedge scanner within a point-scanning configuration. The dual-wedge scanner is implemented by replacing the two scanning mirrors and...

BomDetec - wide area surveillance and suicide bomber detection

John Beaty — Thu, 01 Apr 2010 11:51:07 PDT

Amidst the manifold threats currently afflicting society, that of body-worn explosives is significant if not altogether paramount. Veiled under layers of clothing by individual suicide bombers, these explosives are often constructed of non-standard parts, making detection at a safe distance difficult. It behooves us to develop a detection system capable of locating such explosives at distances sufficient to prevent suicide bombers from approaching densely populated or strategically important areas. Funded by the Department of Homeland Security, the intent of this project is to synthesize four technologies--intelligent video, radar, X-ray, and terahertz--into one surveillance system for suicide bomber detection. Ideally, bombers...

A method for analyzing electrical impedance spectroscopy data from breast cancer patients

B. S. Kim — Thu, 01 Apr 2010 11:51:06 PDT

Electrical Impedance Tomography (EIT) is an imaging modality that estimates and reconstructs the electrical properties in a body from voltage and current measurements made at electrodes on its surface. Research on freshly-excised breast tissues and in an in vitro impedance cell has shown found that breast tumors have different conductivity and permittivity from normal or non-malignant anomalies. Therefore, the contrast in the electric properties between normal and malignant tissues may provide a basis for breast cancer detection using EIT. In this presentation, we describe a procedure for collecting electrical impedance spectroscopy data simultaneously and in register with Tomosynthesis data from...

A compensated radiolucent electrode array for combined EIT and mammography

Tzu-Jen Kao — Thu, 01 Apr 2010 11:51:04 PDT

The long-term goal of this project is to develop Electrical Impedance Tomography (EIT) to improve the diagnosis of breast cancer. Electrical Impedance Imaging is the technology for making images of the electrical properties of the interior of a body from measurements of voltage and current made at electrodes applied to the body's surface. When these measurements are made across a wide spectrum of frequencies, the term "impedance spectroscopy" is used. EIT offers promise as a diagnostic adjuvant in breast cancer, since several investigators have reported clear distinctions between carcinoma, benign lesions and normal tissues in freshly-obtained mastectomy tissue samples. We...