Design And Evaluation Of A Home- Scale Arsenic Removal System

The problem of arsenic contamination affects millions of people worldwide. A home-scale arsenic removal system could provide families in Nepal access to clean drinking water. It would also reduce the risk of adverse health issues that are associated with ingesting arsenic contaminated water. Our experiments show that using electrocoagulation is an effective method of removing arsenic from water. We were able to get the level of arsenic below 10 ppb in 60 minutes of treatment using various system configurations. We identified several parameters that affect the treatment process, the most important being the charge loading, or the amount of charge that passes through the solution during treatment. The more current supplied, the faster the treatment, but too much current is inefficient. We identified an effective range for charge loading to be between 150 and 180 C/L. For a home-scale arsenic removal system to be used in Nepal, we recommend using a 6V rechargeable battery supplying 170 C/L of charge to a 3.5 gallon bucket (13L) and a electrochemical cell which consists of five 4 x4 steel plates. Water treated in the first stage then moves to a sand filter containing 10 inches of fine sand and a simple underdrain nozzle. The water will then be stored in a large container. With the battery constraint reduced or removed, the system can be upgraded to a larger treatment system or even an automated semi-continuous flow system. The design of this removal system is manufacturable, but is dependent upon the identification of a local manufacturer to maintain low cost. A manufacturer can be identified after field testing to observe the system\u27s performance in the intended environment is completed

Phase correction in holographically produced gratings

Several technques for producing holographic optical elements that are free from the inherent phase errors of their substrate irregularities are given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22260/1/0000697.pd

Modal and Polarization Qubits in Ti:LiNbO3_3 Photonic Circuits for a Universal Quantum Logic Gate

Lithium niobate photonic circuits have the salutary property of permitting the generation, transmission, and processing of photons to be accommodated on a single chip. Compact photonic circuits such as these, with multiple components integrated on a single chip, are crucial for efficiently implementing quantum information processing schemes. We present a set of basic transformations that are useful for manipulating modal qubits in Ti:LiNbO$_3$ photonic quantum circuits. These include the mode analyzer, a device that separates the even and odd components of a state into two separate spatial paths; the mode rotator, which rotates the state by an angle in mode space; and modal Pauli spin operators that effect related operations. We also describe the design of a deterministic, two-qubit, single-photon, CNOT gate, a key element in certain sets of universal quantum logic gates. It is implemented as a Ti:LiNbO$_3$ photonic quantum circuit in which the polarization and mode number of a single photon serve as the control and target qubits, respectively. It is shown that the effects of dispersion in the CNOT circuit can be mitigated by augmenting it with an additional path. The performance of all of these components are confirmed by numerical simulations. The implementation of these transformations relies on selective and controllable power coupling among single- and two-mode waveguides, as well as the polarization sensitivity of the Pockels coefficients in LiNbO$_3$

Index modulation and spatial harmonic generation in dichromated gelatin films

A model for volume hologram formation in thick dichromated gelatin films is given. Using the model and a few basic film measurements, we can quantify the index modulation vs. exposure curve. The effects of saturation and dynamic absorption increase during exposure are considered in the generation of spatial harmonics. The effects of exposure with non-unity beam-ratio and multiple incoherent exposures are predicted and experimentally verified. The thick transmission grating diffraction efficiencies resulting from first-and higher-order index modulations are calculated and compared to experiments. The methods and conclusions are applicable to other phase materials.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47028/1/339_2004_Article_BF00929527.pd

An infrared integrated optic astronomical beam combiner for stellar interferometry at 3-4 microns

Integrated-optic, astronomical, two-beam and three-beam, interferometric combiners have been designed and fabricated for operation in the L band (3 - 4 microns) for the first time. The devices have been realized in titanium-indiffused, x-cut lithium niobate substrates, and on-chip electro-optic fringe scanning has been demonstrated. White light fringes were produced in the laboratory using the two-beam combiner integrated with an on-chip Y-splitter.Comment: This paper was published in Optics Express and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/oe. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under la

Thick grating analysis of interferometrically produced waveguides

The thin grating decomposition method of thick grating analysis is used to analyze guiding effects in thick phase gratings having sinusoidal refractive index modulation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/22042/1/0000460.pd

The American Institute for Manufacturing Integrated Photonics: advancing the ecosystem

The American Institute for Manufacturing Integrated Photonics (AIM Photonics) is focused on developing an end-to-end integrated photonics ecosystem in the U.S., including domestic foundry access, integrated design tools, automated packaging, assembly and test, and workforce development. This paper describes how the institute has been structured to achieve these goals, with an emphasis on advancing the integrated photonics ecosystem. Additionally, it briefly highlights several of the technological development targets that have been identified to provide enabling advances in the manufacture and application of integrated photonics

Analysis of optical propagation in thick holographic gratings

A method of analyzing optical propagation in thick holographic gratings by decomposition of the thick material into thin gratings is discussed. The method is readily applicable to study propagation in multiple gratings of arbitrary spatial frequency and orientation recorded in the same thick emulsion. Applied to the double grating case, the method predicts strong cross-coupling between the two gratings for proper relative slope of the gratings. Results are given.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47036/1/339_2004_Article_BF00900516.pd