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Articles 84181 - 84210 of 196902

Full-Text Articles in Engineering

Continuous Gas Processing Without Bubbles Using Thin Liquid Film Bioreactors Containing Biocomposite Biocatalysts, Michael C. Flickinger, Orlin D. Velev, Mark J. Schulte, Adam Wallace, Christopher Duran, Nilay Chakraborty, Michael Guarnieri, Kamelia Boodhoo Sep 2017

Continuous Gas Processing Without Bubbles Using Thin Liquid Film Bioreactors Containing Biocomposite Biocatalysts, Michael C. Flickinger, Orlin D. Velev, Mark J. Schulte, Adam Wallace, Christopher Duran, Nilay Chakraborty, Michael Guarnieri, Kamelia Boodhoo

Integrated Continuous Biomanufacturing III

Continuous microbial gas processing without bubbles is possible with thin liquid film, plug flow bioreactors. We have demonstrated that power input can be minimized by using a falling liquid film operating under laminar wavy flow conditions (Re <200) in contact with highly concentrated living, non-growing microbes stabilized in a porous biocomposite biocatalyst. This composite materials approach to continuous gas processing can dramatically increase mass transfer rates >100 fold compared to bubble aeration, decrease process volume, significantly decrease gas-liquid mass transfer energy input, decrease water use, and increase secreted product concentration. We have shown that this approach can also increase microbial specific activity for some organisms compared to microbes suspended in liquid media. Paper-based biocomposite biocatalysts provide a rough hydrophilic surface resulting in uniform ~300 μm thick falling liquid films. …


Novel Ir-X Thermal Protection Coatings Designed For Extreme Aerodynamic Heating Environment, Kaili Zhang, Yicong Ye, Li`An Zhu, Shuxin Bai Sep 2017

Novel Ir-X Thermal Protection Coatings Designed For Extreme Aerodynamic Heating Environment, Kaili Zhang, Yicong Ye, Li`An Zhu, Shuxin Bai

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

Due to the rapid evaporation of SiO2 protective layer, most Si-containing oxidation resistant coatings could not withstand a temperature above 1800℃, which is not enough for hypersonic voyage in upper atmosphere. With a higher melting point (2440℃) and lower oxygen permeability(10-20g·m-1·s-1), iridium is supposed to be a promising coating material for ultra-high temperature applications. However, Iridium has a low emissivity ε(0.017 for 2.5-25μm) and high recombination coefficient γ(0.64 at 1200℃) of atomic oxygen, resulting in a much higher thermal response compared with the ceramic materials under the same aerodynamic environment. To solve this …


Cost Modeling Of An Integrated, Continuous Downstream Mab Platform, Mark Schofield Sep 2017

Cost Modeling Of An Integrated, Continuous Downstream Mab Platform, Mark Schofield

Integrated Continuous Biomanufacturing III

Continuous manufacturing offers great potential for reducing costs in biopharmaceutical production through process intensification. However, adoption of new manufacturing methods and technologies is dependent on proof that the risk is worth the reward. Here Pall Life Science’s integrated, continuous downstream mAb platform is modeled in BioSolve Process. Supporting information is generated from a real, PD scale continuous platform. Perfusion and traditional fed batch cell culture processes are also modeled in both stainless steel and single-use forms. The cost associated with these three downstream strategies are compared across a range of bioreactor volumes, titers, and number of batches per year. This …


Conference Program, Jon Binner, Bill Lee Sep 2017

Conference Program, Jon Binner, Bill Lee

Ultra-High Temperature Ceramics: Materials for Extreme Environment Applications IV

No abstract provided.


Development Of A Scale Down Toolbox For Perfusion Process Development, Jean-Marc Bielser Sep 2017

Development Of A Scale Down Toolbox For Perfusion Process Development, Jean-Marc Bielser

Integrated Continuous Biomanufacturing III

Background and novelty Merck KGaA has a legacy of perfusion manufacturing processes with several commercial products that were developed in the 90s. These processes were developed for adherent cell systems. Since then, with the advances in media design and the monoclonal antibody driven portfolio, development efforts have been focusing on fed-batch with suspended cells. Recently and as many players in the biomanufacturing industry, Merck is working on the development of an integrated continuous process. To support this effort a process development platform for perfusion cell culture needs to be developed. Process development for fed-batch is clearly defined and scale down …


Novel Concepts For Efficient And Predictable Membrane Separation In Continuous Cell Retention And Downstream Processing, Ulrich Kulozik, Martin Hartinger, Maria Weinberger Sep 2017

Novel Concepts For Efficient And Predictable Membrane Separation In Continuous Cell Retention And Downstream Processing, Ulrich Kulozik, Martin Hartinger, Maria Weinberger

Integrated Continuous Biomanufacturing III

Membranes are applied in biotechnological operations for sterile filtration, cell retention during continuous oper-ation, and cell separation as the first step after fermentation. Membranes are also in use in various steps during purification and isolation of certain target components. In all applications the retained substances, mainly bio-genic material such as cells, protein or polysaccharides, form a deposited layer at the membrane surface. This layer acts as an often dominating secondary membrane, which affects the permeability of the whole system more than the membrane as such. Thus, predictability, efficiency and consistency of all affected processing steps are impaired, which might create …


Supervisory Control Of Integrated Continuous Downstream Processes, Bernt Nilsson, Anton Löfgren, Joaquin Gomis Fons, Niklas Andersson, Lotta Berghard Sep 2017

Supervisory Control Of Integrated Continuous Downstream Processes, Bernt Nilsson, Anton Löfgren, Joaquin Gomis Fons, Niklas Andersson, Lotta Berghard

Integrated Continuous Biomanufacturing III

Smart downstream processing can be performed with a sequence of integrated purification steps, which minimize the number of storage tanks and reduce hold-up time. The result is an integrated unit operation sequence that performs straight through processing of the target protein, with minimal time from expression to formulation. This downstream processing technique is well suited to be connected to a continuous upstream process based on perfusion. To develop these kinds of processes it is important to do studies in small-scale in a convenient way. This paper presents a methodology for supervisory control of integrated continuous downstream processes in lab-scale. A …


Process Analytical Technology (Pat) In Continuous Bioprocessing, Edita Botonjic-Sehic Sep 2017

Process Analytical Technology (Pat) In Continuous Bioprocessing, Edita Botonjic-Sehic

Integrated Continuous Biomanufacturing III

In recent years biotech companies have been emphasizing on the implementation and utilization of process analytical technology (PAT) in continuous bioprocessing. An overview of PAT concepts for biotech processes with emphasis on integrated continuous bioprocessing and production of monoclonal antibodies will be presented. Biotech processes consist of several unit operations, with each unit operation serving a defined purpose. For some of the product quality attributes, a certain level of redundancy in the process is expected. The need for appropriate control of each step and continuous evaluation of its performance is of great importance. The objective of commonly used unit operations …


The Gmo/Ge Debate, Joanna K. Sax Sep 2017

The Gmo/Ge Debate, Joanna K. Sax

Texas A&M Law Review

We live longer and healthier lives because advances in science create easier and better ways to sustain and survive. Society has an intricate relationship with biotechnology. Vaccines save lives. Fluoridated water decreases dental issues. Antibiotics treat bacterial infections. Nuclear power is a form of clean energy. With any emerging technology, the benefits do not exist in a vacuum, thus, negative consequences result as well. Our widespread uses of antibiotics are creating antibiotic-resistant strains of bacteria. Our research into nuclear energy also facilitated the creation of nuclear bombs. Perhaps it is human nature to use scientific advances for good and for …


Cyclic Compression Behavior Of Concrete-Filled Hybrid Large Rupture Strain Frp Tube, Monika Nain, Mohanad M. Abdulazeez, Mohamed Elgawady Sep 2017

Cyclic Compression Behavior Of Concrete-Filled Hybrid Large Rupture Strain Frp Tube, Monika Nain, Mohanad M. Abdulazeez, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper experimentally investigates the behavior of concrete-filled-fiber-reinforced polymer (FRP) cylinders under cyclic axial compression. The FRP used in this study were either large rupture strain FRP (LRS-FRP) or hybrid LRS-FRP and conventional glass FRP (GFRP). LRS-FRP are manufactured out of polyethylene naphthalate (PEN) and polyethylene terephthalate (PET) obtained from recycled plastics. Hence, they are much cheaper and environment-friendly than conventional GFRP or carbon FRP (CFRP). LRS-FRPs has high tensile rupture strain (usually greater than 5%) compared to 1-2% for GFRP and CFRP. This study presents the results of 4 specimens with different confinement ratios to investigate the behavior of …


Torsional Behavior Of Hollow-Core Frp-Concrete-Steel Bridge Columns, Sujith Anumolu, Omar I. Abdelkarim, Mohanad M. Abdulazeez, Ahmed Gheni, Mohamed Elgawady Sep 2017

Torsional Behavior Of Hollow-Core Frp-Concrete-Steel Bridge Columns, Sujith Anumolu, Omar I. Abdelkarim, Mohanad M. Abdulazeez, Ahmed Gheni, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper presents the behavior of hollow-core fiber reinforced polymer-concrete-steel (HC-FCS) column under pure torsion loading with constant axial load. The HCFCS consists of outer FRP tube and inner steel tube with concrete shell sandwiched between the two tubes. The FRP tube was stopped at the surface of the footing and provided confinement to the concrete shell from outer direction. The steel tube was embedded into the footing to a length of 1.8 times to the diameter of the steel tube. The longitudinal and transversal reinforcements of the column were provided by the steel tube only. A large-scale HC-FCS column …


Nonlinear Analysis Of Hollow-Core Composite Building Columns, Mohanad M. Abdulazeez, Mohamed Elgawady Sep 2017

Nonlinear Analysis Of Hollow-Core Composite Building Columns, Mohanad M. Abdulazeez, Mohamed Elgawady

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

This paper numerically investigates the behavior of hollow-core fiber-reinforced polymer-concrete-steel (HC-FCS) building columns under combined axial compression and flexural loadings. The HC-FCS column for buildings consists of an outer circular fiber-reinforced polymer (FRP) tube, an inner square steel tube, and a concrete wall between them. A three-dimensional numerical model has been developed using LS_DYNA software for modeling of large scale HC-FCS columns. The nonlinear FE models were designed and validated against experimental results gathered from HC-FCS columns tested under cyclic lateral loading. The FE results were in decent agreement with the experimental backbone curves. These models subsequently were used to …


Compensating For Cryogenic Propellant Boiloff For A Cargo Mission To Mars, Thomas M. Perrin, James Casler Sep 2017

Compensating For Cryogenic Propellant Boiloff For A Cargo Mission To Mars, Thomas M. Perrin, James Casler

Space Studies Faculty Publications

A previous work by the authors (Architecture Study for a Fuel Depot Supplied from Lunar Resources – AIAA 2016-5306) examined architectures for a fuel depot supplied from lunar ice deposits. The study recommended a fuel depot be located at Earth-Moon L1. The study used three design reference missions in the formulation of candidate architectures – among them a Mars Cargo Vehicle (MCV). Each vehicle used 60 layers of multi-layer insulation (MLI) to minimize the boiloff of cryogenic propellants. Boiloff was shown to not be a driver in architecture selection, but it was noted that reducing the number of layers of …


Characterization And Scaling Study Of Energy Pathways In Small Four-Stroke Internal Combustion Engines, Jason R. Blantin Sep 2017

Characterization And Scaling Study Of Energy Pathways In Small Four-Stroke Internal Combustion Engines, Jason R. Blantin

Theses and Dissertations

A study of the efficiency and energy losses of a selection of five small (40 - 200 cm3 displacement) single cylinder, four-stroke engines was accomplished. The study was performed as part of a larger effort to improve the range and endurance of small internal combustion engines (ICE) that power Group II Unmanned Aerial Vehicles (UAVs). Little is known about the performance, efficiency, and allocation of energy losses for four-stroke ICEs in this size range. The goal of the study was to characterize these parameters for use in future research efforts. Three research objectives were developed to guide the study …


Drones For Commercial Last-Mile Deliveries: A Discussion Of Logistical, Environmental, And Economic Trade-Offs, Miguel Figliozzi Sep 2017

Drones For Commercial Last-Mile Deliveries: A Discussion Of Logistical, Environmental, And Economic Trade-Offs, Miguel Figliozzi

Civil and Environmental Engineering Faculty Publications and Presentations

There are no studies that model the potential effectiveness of Unmanned Aerial Vehicles (UAVs) or drones to reduce CO2e lifecycle (including both utilization and vehicle phase) emissions when compared to conventional diesel vans, electric trucks, electric vans, and tricycles. This study presents a novel analysis of lifecycle UAV and ground commercial vehicles CO2e emissions.


Cyberinfrastructure For Advancing Hydrologic Knowledge Through Collaborative Integration Of Data Science, Modeling And Analysis, David Tarboton Sep 2017

Cyberinfrastructure For Advancing Hydrologic Knowledge Through Collaborative Integration Of Data Science, Modeling And Analysis, David Tarboton

Funded Research Records

No abstract provided.


When Big Data Gets Too Big Sep 2017

When Big Data Gets Too Big

SIGNED: The Magazine of The Hong Kong Design Institute

Computer modelling has long been used as a design tool, and big data is a massive resource on which to build these models. But when the datasets get too big for computers to handle, innovative design solutions are needed. And the urge to play has driven technology forward


Engineered Surfaces To Control Secondary Electron Yield For Multipactor Suppression, James M. Sattler Sep 2017

Engineered Surfaces To Control Secondary Electron Yield For Multipactor Suppression, James M. Sattler

Theses and Dissertations

A significant problem for satellites, vacuum electron devices, and particle accelerators is multipactor: an avalanche of electrons caused by recurring secondary electron emission (SEE) in a time-varying electric field. The consequences of multipactor range from temporary to permanent device failure. This research studied how surface topography can be engineered to minimize SEE and suppress multipactor. Two new semi-empirical models (one based on a 2D pore, the other based on a 3D pore) were developed to predict the secondary electron yield (SEY) of a porous surface based on pore aspect ratio and porosity. The models were validated with experimental SEY measurements …


Effect Of Fused Filament Fabrication Process Parameters On The Mechanical Properties Of Carbon Fiber Reinforced Polymers, Abdulrahman S. Alwabel Sep 2017

Effect Of Fused Filament Fabrication Process Parameters On The Mechanical Properties Of Carbon Fiber Reinforced Polymers, Abdulrahman S. Alwabel

Theses and Dissertations

Carbon fiber reinforced polymer manufactured using additive manufacturing process is relatively a new process. The ability to predict the mechanical properties of these parts with high confidence will spread the use of these high-strength materials in more applications. The purpose of this research was to determine the effect of the build time between successive layers, arrangement of fiber and nylon layers, fiber start location, and the use of support material on the mechanical properties CFRP produced by additive manufacturing process using the MarkForged (MarkOne) 3D printer. A design of experiment (DOE) we preformed to develop a mathematical model describing the …


Evaluating Process Improvement Courses Of Action Through Modeling And Simulation, Joseph R. Owens Sep 2017

Evaluating Process Improvement Courses Of Action Through Modeling And Simulation, Joseph R. Owens

Theses and Dissertations

Quantifying an expected improvement when considering moderate-complexity changes to a process is time consuming and has potential to overlook stochastic effects. By modeling a process as a Numerical Design Structure Matrix (NDSM), simulating the proposed changes, and evaluating performance, quantification can be rapidly accomplished to understand stochastic effects. This thesis explores a method to evaluate complex process changes within Six Sigma DMAIC process improvement to identify the most desirable outcome amongst several improvement options. A tool to perform the modeling and evaluation is developed. This process evaluation tool is verified for functionality, then is demonstrated against generic processes, a case …


Characterization Of Jet Fuel Combustion Emissions During A C-130 Aeromedical Evacuation Engines Running Onload, Michelle L. Page Sep 2017

Characterization Of Jet Fuel Combustion Emissions During A C-130 Aeromedical Evacuation Engines Running Onload, Michelle L. Page

Theses and Dissertations

The purpose of this research was to characterize jet fuel combustion emissions (JFCE) in an occupational setting. Prior research demonstrated that aircraft emit hazardous species, especially at engine start-up and ground idle. Complaints of eye, nose, and throat irritation from occupational exposures near aircraft exist. In this study JFCE were tested during an aeromedical evacuation engines running patient onload (ERO) on a C-130 Hercules at the 179th Airlift Wing, Mansfield-Lahm Air National Guard. Ultrafine particles, VOC, formaldehyde, carbon monoxide (CO), sulfuric acid, and metals were sampled simultaneously in approximate crew and patient breathing zones. Testing methods were portable condensation …


New Fractals For Computer Generated Art Created By Iteration Of Polynomial Functions Of A Complex Variable, Charles F. Babbs Sep 2017

New Fractals For Computer Generated Art Created By Iteration Of Polynomial Functions Of A Complex Variable, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

Novel fractal forms can be created by iteration of higher order polynomials of the complex variable, z, with both positive and negative exponents, followed by optional integer power transformation, k zz . Such functions lead to an expanded universe of fascinating fractal patterns that can be incorporated into computer generated art.


Generalized Fractals For Computer Generated Art: Preliminary Results, Charles F. Babbs Sep 2017

Generalized Fractals For Computer Generated Art: Preliminary Results, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

This paper explores new types of fractals created by iteration of the functions xn+1 = f1(xn, yn) and yn+1 = f2(xn, yn) in a general plane, rather than in the complex plane. Iteration of such functions generates orbits with novel fractal patterns. Especially interesting are N-th order polynomials, raised to a positive or negative integer power, p.

Such functions create novel fractal patterns, including budding, spiked, striped, dragon head, and bat-like forms. The present faculty working paper shows how to create a rich variety of complex and fascinating fractals using this generalized approach, which is accessible to students with high …


A Location-Aware Middleware Framework For Collaborative Visual Information Discovery And Retrieval, Andrew J.M. Compton Sep 2017

A Location-Aware Middleware Framework For Collaborative Visual Information Discovery And Retrieval, Andrew J.M. Compton

Theses and Dissertations

This work addresses the problem of scalable location-aware distributed indexing to enable the leveraging of collaborative effort for the construction and maintenance of world-scale visual maps and models which could support numerous activities including navigation, visual localization, persistent surveillance, structure from motion, and hazard or disaster detection. Current distributed approaches to mapping and modeling fail to incorporate global geospatial addressing and are limited in their functionality to customize search. Our solution is a peer-to-peer middleware framework based on XOR distance routing which employs a Hilbert Space curve addressing scheme in a novel distributed geographic index. This allows for a universal …


Dynamics Of Chemical Degradation In Water Using Photocatalytic Reactions In An Ultraviolet Light Emitting Diode Reactor, John E. Stubbs Sep 2017

Dynamics Of Chemical Degradation In Water Using Photocatalytic Reactions In An Ultraviolet Light Emitting Diode Reactor, John E. Stubbs

Theses and Dissertations

This work examined ultraviolet (UV) light emitting diodes (LED) and hydrogen peroxide in an advanced oxidation process in support of a USAF installation net zero water initiative. A UV LED reactor was used for degradation of soluble organic chemicals. There were linear relationships between input drive current, optical output power, and first order degradation rate constants. When drive current was varied, first order degradation rates depended on chemical identities and the drive current. When molar peroxide ratios were varied, kinetic profiles revealed peroxide-limited or radical-scavenged phenomena. Molar absorptivity helped explain the complexity of chemical removal profiles. Degradation kinetics were used …


Spatial Scale Gap Filling Using An Unmanned Aerial System: A Statistical Downscaling Method For Applications In Precision Agriculture, Leila Hassan-Esfahani, Ardeshir M. Ebtehaj, Alfonso F. Torres-Rua, Mac Mckee Sep 2017

Spatial Scale Gap Filling Using An Unmanned Aerial System: A Statistical Downscaling Method For Applications In Precision Agriculture, Leila Hassan-Esfahani, Ardeshir M. Ebtehaj, Alfonso F. Torres-Rua, Mac Mckee

Civil and Environmental Engineering Faculty Publications

Applications of satellite-borne observations in precision agriculture (PA) are often limited due to the coarse spatial resolution of satellite imagery. This paper uses high-resolution airborne observations to increase the spatial resolution of satellite data for related applications in PA. A new variational downscaling scheme is presented that uses coincident aerial imagery products from “AggieAir”, an unmanned aerial system, to increase the spatial resolution of Landsat satellite data. This approach is primarily tested for downscaling individual band Landsat images that can be used to derive normalized difference vegetation index (NDVI) and surface soil moisture (SSM). Quantitative and qualitative results demonstrate promising …


Open Source 3-D Printed Nutating Mixer, Dhwani K. Trivedi, Joshua M. Pearce Sep 2017

Open Source 3-D Printed Nutating Mixer, Dhwani K. Trivedi, Joshua M. Pearce

Department of Materials Science and Engineering Publications

As the open source development of additive manufacturing has led to low-cost desktop three-dimensional (3-D) printing, a number of scientists throughout the world have begun to share digital designs of free and open source scientific hardware. Open source scientific hardware enables custom experimentation, laboratory control, rapid upgrading, transparent maintenance, and lower costs in general. To aid in this trend, this study describes the development, design, assembly, and operation of a 3-D printable open source desktop nutating mixer, which provides a fixed 20° platform tilt angle for a gentle three-dimensional (gyrating) agitation of chemical or biological samples (e.g., DNA or blood …


Measured Performance Of A High-Efficiency Solar-Assisted Heat Pump Water Heater, Florida Solar Energy Center, Carlos Colon Sep 2017

Measured Performance Of A High-Efficiency Solar-Assisted Heat Pump Water Heater, Florida Solar Energy Center, Carlos Colon

FSEC Energy Research Center®

This paper describes a novel solar photovoltaic-assisted heat pump water heater (PV-HPWH). The system uses two 310 Wp PV modules, micro-inverters and innovative controls to produce and store daily hot water. The system likely costs half that of solar thermal systems, with greater reliability, no freeze protection and potentially superior performance in cloudy locations. Moreover, no net metering is needed for the PV, which with two modules makes for a simple installation.The HPWH controls have been modified through experimentation such that higher tank temperatures are achieved during the day when solar availability is high while avoiding triggering the compressor during …


Cross-Species Complementation Reveals Conserved Functions For Early Flowering 3 Between Monocots And Dicots, He Huang, Malia A. Gehan, Sarah E. Huss, Sohpie Alvarez, Cesar Lizarraga, Ellen L. Gruebbling, John Gierer, Michael J. Naldrett, Rebacca K. Bindbeutel, Bradley S. Evans, Todd C. Mockler, Dmitri A. Nusinow Sep 2017

Cross-Species Complementation Reveals Conserved Functions For Early Flowering 3 Between Monocots And Dicots, He Huang, Malia A. Gehan, Sarah E. Huss, Sohpie Alvarez, Cesar Lizarraga, Ellen L. Gruebbling, John Gierer, Michael J. Naldrett, Rebacca K. Bindbeutel, Bradley S. Evans, Todd C. Mockler, Dmitri A. Nusinow

Nebraska Center for Biotechnology: Faculty and Staff Publications

Plant responses to the environment are shaped by external stimuli and internal signaling pathways. In both the model plant Arabidopsis thaliana (Arabidopsis) and crop species, circadian clock factors are critical for growth, flowering, and circadian rhythms. Outside of Arabidopsis, however, little is known about the molecular function of clock gene products. Therefore, we sought to compare the function of Brachypodium distachyon (Brachypodium) and Setaria viridis (Setaria) orthologs of EARLY FLOWERING 3, a key clock gene in Arabidopsis. To identify both cycling genes and putative ELF3 functional orthologs in Setaria, a …


On Dual-Band Amplifications Using Dual Two-Tones: Clarifications And Discussion, Siyuan Yan, Xianzhen Yang, Xiao Li, Fu Lo Sep 2017

On Dual-Band Amplifications Using Dual Two-Tones: Clarifications And Discussion, Siyuan Yan, Xianzhen Yang, Xiao Li, Fu Lo

Electrical and Computer Engineering Faculty Publications and Presentations

A significant development of recent research in nonlinear distortion is the expansion of the conventional two-tone test for power amplifiers to the concurrent dual-band transmitters, by Amin et al. A general framework using dual two-tones is developed, which shows that the output signal is affected not only by intermodulation (IM) products but also by cross-modulation (CM) products. In this paper, we will make a number of clarifications to Amin et al.'s paper. The effects of IM and CM in passband will be discussed, IM represents a reduction for compressive devices, and CM reflects an interference caused by the signal from …