Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Other Mechanical Engineering (10)
- Computer-Aided Engineering and Design (8)
- Manufacturing (8)
- Materials Science and Engineering (8)
- Acoustics, Dynamics, and Controls (7)
-
- Electro-Mechanical Systems (7)
- Heat Transfer, Combustion (7)
- Applied Mechanics (6)
- Biomedical Engineering and Bioengineering (5)
- Chemical Engineering (5)
- Electrical and Computer Engineering (5)
- Polymer and Organic Materials (5)
- Aerospace Engineering (4)
- Biomechanical Engineering (4)
- Energy Systems (4)
- Other Engineering (4)
- Physical Sciences and Mathematics (4)
- Computer Engineering (3)
- Controls and Control Theory (3)
- Electrical and Electronics (3)
- Nanoscience and Nanotechnology (3)
- Petroleum Engineering (3)
- Robotics (3)
- Aerodynamics and Fluid Mechanics (2)
- Artificial Intelligence and Robotics (2)
- Biomedical Devices and Instrumentation (2)
- Civil and Environmental Engineering (2)
- Computational Engineering (2)
- Keyword
-
- Film cooling (6)
- Heat transfer (6)
- Combustion (5)
- MEMS (5)
- Combustor (4)
-
- Fatigue (4)
- ANSYS (3)
- Alumina (3)
- Composite (3)
- FEA (3)
- Gas turbine (3)
- Heat Transfer (3)
- Impact (3)
- LIGA (3)
- Magnetic field (3)
- Meletis (3)
- Mems (3)
- Microchannel (3)
- Microchannels (3)
- Microfabrication (3)
- Microfluidics (3)
- Programming (3)
- SU-8 (3)
- Self-healing (3)
- Syntactic foam (3)
- Tribology (3)
- Water transport (3)
- Adhesion (2)
- Axis-switching (2)
- Blade cooling (2)
Articles 211 - 240 of 255
Full-Text Articles in Mechanical Engineering
Ultra Deep Su-8 Manufacturing And Characterization For Mems Applications, Charles Joseph Becnel
Ultra Deep Su-8 Manufacturing And Characterization For Mems Applications, Charles Joseph Becnel
LSU Master's Theses
The Micro Systems Engineering Team (mSET) at Louisiana State University (LSU) utilizes microfabrication for a number of heat and mass transfer devices. These include cross flow heat exchangers, mechanical seals with integrated micro heat exchangers, catalytic converters, and micro reactors. In all of these applications, micro honeycomb arrays provide increased surface area per unit volume which significantly enhances heat and mass transfer. In the past, it was only possible to fabricate SU-8 structures approximately 1.5 mm tall. Furthermore, qualitatively, it is much more difficult to fabricate close packed feature arrays than sparse arrays. For many of the previously mentioned applications, …
Design Of A Microfabricated Device For Ligase Detection Reaction (Ldr), Dwhyte Omar Barrett
Design Of A Microfabricated Device For Ligase Detection Reaction (Ldr), Dwhyte Omar Barrett
LSU Master's Theses
The Ligase Detection Reaction (LDR) is a mutation detection technique used to identify point mutations in deoxyribonucleic acid (DNA). Developed by Francis Barany and associates at Cornell University it is used to find specific low abundant point mutations that may lead to colorectal cancer in the early stages of disease development. The research objective was to design and manufacture a microscale Ligase Detection Reaction (LDR) device in polycarbonate. The LDR module will be incorporated with other microdevices such as: Continuous Flow Polymerase Chain Reaction (CFRCR) and Capillary Electrophoresis (CE) in modular lab-on-a-chip technology. In making the microdevice, the duration of …
Towards Automation Of Forensic Facial Reconstruction, Hemant Narendra Khatod
Towards Automation Of Forensic Facial Reconstruction, Hemant Narendra Khatod
LSU Master's Theses
Forensic facial reconstruction is a blend of art and science thus computerizing the process leads to numerous solutions. However, complete automation remains a challenge. This research concentrates on automating the first phase of forensic facial reconstruction which is automatic landmark detection by model fitting and extraction of feature points. Detection of landmarks is a challenging task since the skull orientation in a 3D scanned data cloud is generally arbitrary and unknown. To address the issue, well defined skull and mandible models with known geometric structure, features and orientation are (1) aligned and (2) fit to the scanned data. After model …
Optimal Rate Of Freezing Biological Systems, Sreedhar Thirumala
Optimal Rate Of Freezing Biological Systems, Sreedhar Thirumala
LSU Master's Theses
This thesis addresses optimization techniques for cryopreservation of biological systems. A part of the thesis (Chapter 2) reports a simplified procedure to predict the optimal rate of freezing biological systems once the cell level parameters are known a priori. The key cell level parameters investigated were, reference permeability of the membrane to water (Lpg), apparent activation energy (ELp), inactive cell volume (Vb), diameter (D), and the ratio of the available surface area for water transport to the initial volume of intracellular water (SA/WV). The simplified procedure was developed by performing a thorough analysis of the water transport model over a …
Design, Fabrication And Thermomechanical Testing Of A Vertical Bimorph Sensor In The Wafer Plane, Madhulika Sathe
Design, Fabrication And Thermomechanical Testing Of A Vertical Bimorph Sensor In The Wafer Plane, Madhulika Sathe
LSU Master's Theses
A bimetallic recurve device was designed, fabricated and tested as a temperature sensor. The device is to be used for sensing temperatures up to 300 C inside oil wells for downhole condition monitoring. Continuous downhole measurements at high temperatures and pressures are required to monitor conditions downhole instruments are exposed to during use. Currently mercury thermometers and resistive temperature detectors (RTD) are used for downhole temperature measurements. Microsensors have potential application downhole, due to their small size and inherent robustness. The principle of a bimetallic beam was used to measure temperature. A bimetallic beam deflects with changes in temperature due …
Study Of Characteristics Of Plasma Nitriding And Oxidation Of Superalloy In738lc, Mary Shanti Pampana
Study Of Characteristics Of Plasma Nitriding And Oxidation Of Superalloy In738lc, Mary Shanti Pampana
LSU Master's Theses
IN738LC is a nickel base superalloy, widely used in various applications in turbine engines at high temperatures. Its oxidation and nitriding characteristics were focused in this study. Oxidation kinetics of IN738LC in dry air was studied at selected temperatures, specially chosen depending on the chemical dynamics of the alloy at such high temperatures during annealing. Isothermal oxidation in dry air was carried out at 1000°C, 1090°C, 1140°C and 1190°C. XRD results indicated an interesting onset of preferred orientation in the ã’ depleted layer in all the samples. The XPS and XRD analyses revealed the main oxide phases present in the …
Innovative Cooling Configurations For Low Emission Gas Turbine Combustors, Ryan Thomas Hebert
Innovative Cooling Configurations For Low Emission Gas Turbine Combustors, Ryan Thomas Hebert
LSU Master's Theses
Presently, effective cooling of modern low NOx combustor liners is achieved through combinations of innovative impingement configurations and other heat transfer enhancement methods. An inherent characteristic of conventional impingement configurations is the occurrence of downstream heat transfer degradation due to increased crossflow effects. In the present study, two different impingement configurations are studied. Both impingement configurations examined in this study aim to increase heat transfer effectiveness by reducing the detrimental effects of spent air crossflow. In Part I, a combination technique wherein impingement is combined with ribs placed in between impingement rows is studied. Three configurations with increased rib placements …
Tissue Interactions With Lasers And Liquid Nitrogen: A Novel Cryopreservation Method, Deepak Kandra
Tissue Interactions With Lasers And Liquid Nitrogen: A Novel Cryopreservation Method, Deepak Kandra
LSU Master's Theses
The importance of the imposed cooling rate in cryopreserving native cells and tissues has been long recognized in the field of cryobiology. When biological tissues are subjected to cooling rates in excess of thousands of degree C per minute, the characteristic structural and physical manifestations of the ice formed are such that the traditional damage due to ice formation at lower cooling rates are suppressed. Hence, achieving high cooling rates in tissues and cells of biologically relevant sizes (mm’s and cm’s) has been a long standing research problem. In the present study, we present a novel technique to achieve high …
Heat/Mass Transfer In Smooth And Ribbed Rectangular Serpentine Passages Of Different Aspect Ratio's And Orientation, Peeyush Agarwal
Heat/Mass Transfer In Smooth And Ribbed Rectangular Serpentine Passages Of Different Aspect Ratio's And Orientation, Peeyush Agarwal
LSU Master's Theses
An experimental study of heat/mass transfer in rectangular smooth and ribbed serpentine passages with and without rotation in two different aspect ratios (1:4 and 4:1) channel is performed for two different orientations of the test section (90-degree and 45-degree). The Reynolds number is varied in the range of 5,000 to 40,000 and rotation numbers in the range of 0-0.12. Such passages are encountered close to the mid-chord sections or towards the trailing edge of the turbine blade. Two different configurations of the Normal ribs (e/Dh=0.3125, P/e=8 and e/Dh=0.156, P/e=11.2) are placed on the leading and the …
Synthesis, Characterization And Tribological Behavior Of Nitrogen-Doped Chromium-Diamond-Like Carbon Nanocomposite Thin Films, Sunil Kumar Pal
Synthesis, Characterization And Tribological Behavior Of Nitrogen-Doped Chromium-Diamond-Like Carbon Nanocomposite Thin Films, Sunil Kumar Pal
LSU Master's Theses
Diamond-like carbon (DLC) films have been extensively studied for more than two decades due to their highly attractive properties. These films exhibit unique mechanical, chemical and electronic properties and thus, possess great potential for applications in tribology. However, two drawbacks in the DLC films are high level of internal stress developed during growth preventing deposition of thick films and low thermal stability. Synthesis of Me-DLC (Cr-DLC and N-doped Cr-DLC) presents a way to overcome these drawbacks. In the present study, DLC, Cr-DLC and N-doped Cr-DLC films were deposited on Si substrate using a hybrid Plasma assisted CVD/PVD process. Film characterization …
Fabrication And Assembly Of An Array Of Micro Fuel Injector Nozzles For A Trapped-Vortex Combustor, Tracy Ettel Morris
Fabrication And Assembly Of An Array Of Micro Fuel Injector Nozzles For A Trapped-Vortex Combustor, Tracy Ettel Morris
LSU Master's Theses
An array of four fuel injector nozzles, each with micrometer-scale swirlers and a microhole, is created on a single coupon. The nozzles are intended to atomize fuel to blend with swirling air before ejecting into a trapped-vortex combustion chamber. A first-generation metal prototype is fabricated in order to form the micro features, supply the fuel and gas to the nozzles, and guide the mixture to the combustion chamber. Microfabrication methods and precision machining are used to create a multiple plate laminate assembly. The central plate contains the four microholes, which atomize the fuel, and facilitate the swirler structures needed to …
Towards Automated Capture Of 3d Foot Geometry For Custom Orthoses, Rajeev Madazhy
Towards Automated Capture Of 3d Foot Geometry For Custom Orthoses, Rajeev Madazhy
LSU Master's Theses
This thesis presents a novel method of capturing 3D foot geometry from images for custom shoe insole manufacture. Orthopedic footwear plays an important role as a treatment and prevention of foot conditions associated with diabetes. Through the use of customized shoe insoles, a podiatrist can provide a means to better distribute the pressure around the foot, and can also correct the biomechanics of the foot. Different foot scanners are used to obtain the geometric plantar surface of foot, but are expensive and more generic in nature. The focus of this thesis is to build 3D foot structure from a pair …
Numerical And Experimental Investigation Of Transport Processes In Biological Systems, Yimeng He
Numerical And Experimental Investigation Of Transport Processes In Biological Systems, Yimeng He
LSU Master's Theses
This thesis focuses on optimization techniques for transport process during the cryopreservation of biological systems. In the first part of this thesis, a well established shape independent Differential Scanning Calorimeter (DSC) technique was used to measure the dehydration response during freezing of Pacific oyster sperm cells. Volumetric shrinkage during freezing of diploid and tetraploid pacific oyster sperm cell suspensions was obtained at cooling rates of 5 and 20 ˚C/min in the presence of extracellular ice and CPAs. By fitting a model of water transport to the experimentally obtained volumetric shrinkage data the best fit membrane permeability parameters (Lpg and …
A Novel Mechanical Seal Design With Superior Thermal Characteristics, Anoop Kumar Somanchi
A Novel Mechanical Seal Design With Superior Thermal Characteristics, Anoop Kumar Somanchi
LSU Master's Theses
A mechanical face seal is an important component of variety of pumps used in chemical, petrochemical and process industry. The primary function of a mechanical seal is to prevent leakage of the process fluid from the pump housing and shaft to the environment. The factors that affect the performance of a mechanical seal to leak are friction, wear and its thermal characteristics. Improving upon the thermal characteristics of a mating ring in a mechanical seal would enhance its performance. Implanting a heat exchanger in the mating ring hold great promise for improving the performance of mechanical seals from the viewpoint …
An Experimental Investigation Of Whirl Instability Including Effects Of Lubricant Temperature In Plain Circular Journal Bearings, Darryl, Jr. Chauvin
An Experimental Investigation Of Whirl Instability Including Effects Of Lubricant Temperature In Plain Circular Journal Bearings, Darryl, Jr. Chauvin
LSU Master's Theses
The purpose of this thesis is to experimentally investigate the effect of lubricant temperature on the presence of whirl instability in journal bearings. The first set of conditions that are studied is an extremely low eccentricity rotor and the occurrence of oil whirl at the start-up of the experiment. Lubricant temperature, bearing temperature, frequency and amplitude of vibration, and rotational speed are monitored and analyzed in relation to presence of whirl instability. Additionally, another rotor with a slightly higher eccentricity is tested with respect to the presence of such instability. Particularly with this rotor, the system is brought just below …
Structure And Mechanical Properties Of Ti-Si-N Coatings, Xiaodong Zhang
Structure And Mechanical Properties Of Ti-Si-N Coatings, Xiaodong Zhang
LSU Master's Theses
In order to better define conditions under which ~{!0~}super-strengthening~{!1~} occurs in the Ti-Si-N system, we performed detailed experimental studies on how the structure and mechanical properties of Ti-Si-N coatings are influenced by the deposition temperature. Different series of Ti-Si-N specimens were prepared in an inductively coupled plasma (ICP)-assisted reactive sputtering system at both low and high temperatures. Coating compositions were measured by Rutherford backscattering spectrometry (RBS) technique, surface roughness was examined on an atomic force microscope (AFM), coating thicknesses were obtained by performing cross-sectional scanning electron microscopy (SEM), and their structure examined with transmission electron microscopy (TEM). Vibrational frequency results …
A Disjoining Pressure For Small Contact Angles And Its Applications, Qingfang Wu
A Disjoining Pressure For Small Contact Angles And Its Applications, Qingfang Wu
LSU Master's Theses
A thin liquid film experiences additional intermolecular forces when the film thickness h is less than roughly 100 nm. The effect of these intermolecular forces at the continuum level is captured by the disjoining pressure . Since dominates at small film thicknesses, it determines the stability and wettability of thin films. To leading order, a thin film can be treated as uniform and . This form, however, cannot be applied to films with non-zero contact angles. A recent ad-hoc derivation to include the slope leads to a that allows a contact line to move without slip. This work derives a …
Thermohydrodynamic Analysis Of Compressible Gas Flow In Compliant Foil Bearings, Zhengchun Peng
Thermohydrodynamic Analysis Of Compressible Gas Flow In Compliant Foil Bearings, Zhengchun Peng
LSU Master's Theses
This thesis deals with the development of mathematical models and numerical schemes for simulating the hydrodynamic pressure and temperature rise of compliant foil bearings lubricated by a thin gas film in between its compliant bearing surface and the rotating shaft. The model accounts for the compressibility of gas, the compliance of the bearing surface, and the interaction between the pressure field and temperature field of the gas film in the bearing system. Numerical solutions obtained over a fairly large range of operating speeds show excellent agreement with existing experimental data from both load performance test and bearing temperature measurement. A …
Precipitate Growth Features In The Duplex Size Gamma Prime Distribution In The Superalloy In738lc, Indranil Roy
Precipitate Growth Features In The Duplex Size Gamma Prime Distribution In The Superalloy In738lc, Indranil Roy
LSU Master's Theses
IN738LC is a modern, nickel base superalloy utilized at high temperatures in aggressive environments. Durability of this superalloy is dependent on the retention of strengthening by Gamma Prime precipitates. The precipitate growth features in the duplex size (fine and coarse) precipitate distribution was studied by heating the alloy for various times in vacuum at selected temperatures in the range 800 °C to 1100 °C. Increasing the holding times from 1 hour to 100 hours shows joining of the fine particles to form bigger particles, leading to distinct raft patterns. Two different Gamma Prime precipitate growth processes had been observed: merging …
Axis-Switching In Square Coaxial Jets, Victor Piffaut
Axis-Switching In Square Coaxial Jets, Victor Piffaut
LSU Master's Theses
Airflow from single and coaxial contoured nozzles with a square cross section is studied using constant temperature anemometry. The inner to outer jet velocity ratio is 1.5. The Reynolds number of the outer jet based on the hydraulic diameter of the outer nozzle exit is 15,300. Results are compared to previous data obtained with circular nozzles under the same conditions. Properties of the jets and their shear layers such as turbulence shear layer thicknesses and growth rates were derived from the velocity record. The mixing between the jets and with the external flow was found to be enhanced by passive …
Effect Of Jet Hole Arrays Arrangement On Impingement Heat Transfer, Lujia Gao
Effect Of Jet Hole Arrays Arrangement On Impingement Heat Transfer, Lujia Gao
LSU Master's Theses
A comprehensive investigation on impingement heat transfer of different jet array arrangements is presented. Experiments on the inline jet arrays and the linearly stretched arrays are performed using transient liquid crystal technique. Three experimented basic inline jet arrays are configurations 4X4, 8X4 and 8X8. Two experimented cases for the linearly stretched arrays are the uniform diameter case and the varying diameter case. For the inline jet arrays, three jet heights Z/D=1, 3 and 5 and three Reynolds numbers Re=5000, 10000 and 15000 are investigated. For linearly stretched arrays, the same three jet heights and Re=2000, 6000 and 10000 are investigated. …
Evaluation Of Mechanical Fitness For Service Of High Temperature Hydrogen Attacked Steels, Brent Matthew Saba
Evaluation Of Mechanical Fitness For Service Of High Temperature Hydrogen Attacked Steels, Brent Matthew Saba
LSU Master's Theses
A novel approach is introduced in evaluating one of industry’s most complex corrosion phenomena, high temperature hydrogen attack (HTHA). Limited efforts have been made by industry to address this degradation mechanism and even less data are available to properly utilize their evaluation techniques. The predominant fracture mechanics based analysis of HTHA relies on Charpy V-Notch (CVN) impact test data. In the face of limited CVN test data, accurate results are shaky at best. The HTHA evaluation set forth in this paper combines the analysis tools of plastic collapse and both static and dynamic fracture mechanics. The first condition addresses plastic …
Effect Of Unsteady Wake, Free Stream Turbulence, Tip Geometry On Blade Tip Flow And Heat Transfer, Vikrant Saxena
Effect Of Unsteady Wake, Free Stream Turbulence, Tip Geometry On Blade Tip Flow And Heat Transfer, Vikrant Saxena
LSU Master's Theses
A comprehensive investigation of the effect of various tip sealing geometries is presented on the blade tip leakage flow and associated heat transfer. The linear cascade is made of four blades scaled up HPT turbine in a low speed wind tunnel facility with the two corner blades acting as guides. The tip section of a HPT first stage rotor blade is used to fabricate the 2-D blade. The wind tunnel accommodates an 116 degree turn in the flow through the blade cascade. The mainstream Reynolds number based on the axial chord length at cascade exit is 4.83e5. The center blade …
Predictions For Multi-Scale Shock Heating Of A Granular Energetic Material, Venugopal Jogi
Predictions For Multi-Scale Shock Heating Of A Granular Energetic Material, Venugopal Jogi
LSU Master's Theses
This thesis addresses the multi scale heating of a granular energetic solid due to shock loading. To this end, an existing mathematical model that has been used to predict low pressure bulk and localized heating of the granular high-explosive HMX ([CH2NNO2]4) is extended to account for compressibility and melting of the pure phase solid. Dense granular HMX has a heterogeneous structure composed of randomly packed small grains (average size ~ 100 µm) having a free-pour density that is approximately 65% of the pure phase solid density. The shock loading response of this material is …
Film Cooling From Cylindrical Holes In Transverse Slots, Mohammed Altorairi
Film Cooling From Cylindrical Holes In Transverse Slots, Mohammed Altorairi
LSU Master's Theses
In this study, heat transfer coefficient and film effectiveness distributions are investigated for a film cooling hole configuration that has inclined holes discharging into a tangential slot before interactions with the mainstream. The cylindrical holes are inclined 35° along the mainstream direction. The effect of coolant-to-mainstream blowing ratio is examined for M=0.5 and M=1.0. Different slot width to hole ratios and also the effect of hole exit condition (square edge and triangular edge) is considered. The mainstream velocity and free-stream turbulence intensity in the low speed wind tunnel are 9 m/s and 7% respectively and the mainstream Reynolds number based …
Numerical Solution Of Ocular Fluid Dynamics, Satish Kumar
Numerical Solution Of Ocular Fluid Dynamics, Satish Kumar
LSU Master's Theses
Numerical calculations of the aqueous humor dynamics in the anterior chamber of both the rabbit and the human eye are presented to delineate the basic flow and transport mechanisms. The calculations are based on a geometrical model of the eye, which represents the Trabecular mesh (TM) as a multi-layered porous zone of specified pore sizes and void fraction. Buoyancy is observed to be the dominant driving mechanism for the convective motion in both orientations (horizontal and vertical) of the eye. Reducing the TM pore size does not appear to have a significant influence on the intra-ocular pressure (IOP) until the …
Micro Molding Of 3 D Ceramic Parts, Dinakar Palaparti
Micro Molding Of 3 D Ceramic Parts, Dinakar Palaparti
LSU Master's Theses
The objective of this research was to manufacture and evaluate three-dimensional (3D) ceramic parts with microstructures, characterize the ceramic injection molding process used for it along with fabrication and evaluation of various mold insert formats, electroplated patterns and X-ray masks used in the process. The patterns were electroplated in nickel on two formats of mold insert substrates. The first format was a modified 1” diameter stainless/tool steel plug suitable for test structures and for complete penetration by melt during injection. The molding was done by CoorsTekâ (Golden CO) as they possessed the required wherewithal and the mold base. The second …
Minimization Of Power Losses In Active Magnetic Bearing Control, Nader Motee
Minimization Of Power Losses In Active Magnetic Bearing Control, Nader Motee
LSU Master's Theses
A solution to the problem of AMB control with reduced electrical power losses will be presented in this thesis. The proposed control solution will be founded on the integrator backstepping technique, which decouples the rotor stabilization problem from the bias flux design problem. It further allows for the easy redesign of the control law to compensate for uncertainties in the AMB system. A class of nonlinear controllers will be developed that reduces the AMB power losses in comparison to standard fixed-bias controllers, while containing no control singularity. Control laws will be presented for the standard AMB operating mode where both …
The Rapid Template Fabrication Process For Producing A Liga Heat Exchanger Bonded To A Mechanical Seal, Jason Patrick Tuma
The Rapid Template Fabrication Process For Producing A Liga Heat Exchanger Bonded To A Mechanical Seal, Jason Patrick Tuma
LSU Master's Theses
Mechanical seals are widely used in the chemical processing, aerospace, and automotive, industries. When a mechanical seal fails, considerable cost is typically involved in replacing the seal. Most seal failures are a result of high temperatures generated by frictional heating. Effectively removing the heat generated would significantly increase the mechanical seal’s work life and lead to significant monetary savings. One method of removing the heat generated is bonding an effective LIGA micro heat exchanger to the mechanical seal and forcing coolant through the heat exchanger. Previous work on this subject revealed promising results, especially for micro heat exchangers with microstructures …
Design, Development, And Analysis Of A Twin-Fluid Fire Suppression Atomizer And Characterization Of Electrostatically Charged Droplet Sprays, Chad Everett Moore
Design, Development, And Analysis Of A Twin-Fluid Fire Suppression Atomizer And Characterization Of Electrostatically Charged Droplet Sprays, Chad Everett Moore
LSU Master's Theses
A twin-fluid water mist fire suppression atomizer is designed, developed, and analyzed. Of primary interest is the development of a twin-fluid atomizer that produces a large droplet diameter and velocity distribution and also produces a mist with sufficient cone angle to be effective in fire suppression applications. Spray characterization experiments are conducted utilizing Phase Doppler Particle Analysis (PDPA). The effect of atomizer nozzle geometry on internal two-phase flow and resulting spray pattern is investigated. National Fire Protection Association (NFPA) Standard 750 characterization experiments are conducted to verify that the sprays produced by the developed atomizer are classified as a water …