Open Access. Powered by Scholars. Published by Universities.®

Digital Commons Network

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 145

Full-Text Articles in Entire DC Network

Constraint Optimal Selection Techniques (Costs) For A Class Of Linear Programming Problems, Tai-Kuan Sung Dec 2021

Constraint Optimal Selection Techniques (Costs) For A Class Of Linear Programming Problems, Tai-Kuan Sung

Industrial, Manufacturing, and Systems Engineering Dissertations

This dissertation describes two classes of Constraint Optimal Selection Techniques (COSTs). An algorithm of each type is developed for solving nonnegative linear programming problems. In addition, geometric interpretations of these new algorithms are given, computational results for some large-scale problems are provided, and directions for future research are discussed.


Reuse Of Recycled Plastic For Plastic Road Design, Tahsina Islam Dec 2021

Reuse Of Recycled Plastic For Plastic Road Design, Tahsina Islam

Civil Engineering Dissertations

The ever-increasing volume of traffic and the volatility of daily and seasonal temperatures that are being experienced globally make it essential that the quality and durability of roads are improved. Modifiers can improve the engineering properties of the asphalt mix in these situations. Perhaps plastics are the most promising of all types of modifiers. Since the disposal of plastic waste is a major concern for the environment, recycling of these waste materials is highly desired. The recycling and reuse of plastic waste is a prime example of sustainable waste management. It reduces the buildup of waste in landfills, thereby reducing …


Evaluation Of Geotechnical Parameters Of Soil Using Electrical Resistivity Imaging, Md Asif Akhtar Dec 2021

Evaluation Of Geotechnical Parameters Of Soil Using Electrical Resistivity Imaging, Md Asif Akhtar

Civil Engineering Dissertations

Electric resistivity imaging (ERI) is an effective non-destructive and rapid measuring way of obtaining continuous soil subsurface resistivity profiles. An ERI technique can be used to identify moisture variations and soil heterogeneities in an area. Thus, ERI is becoming a popular tool in geotechnical (FHWA, 2015)engineering; however, it only provides qualitative information at the current time. Using qualitative images, it is challenging to extract quantitative geotechnical information, such as the type of soil, moisture content, degree of saturation, and atterberg limit, of the subsurface. Several studies have described the electrical resistance of soil as a function of pore fluid conductivity …


Improving Probabilistic Quantitative Precipitation Forecasting Using Machine Learning And Statistical Postprocessing Methods, Mohammadvaghef Ghazvinian Dec 2021

Improving Probabilistic Quantitative Precipitation Forecasting Using Machine Learning And Statistical Postprocessing Methods, Mohammadvaghef Ghazvinian

Civil Engineering Dissertations

The objective of this research is to address the limitations inherent in conventional statistical postprocessing schemes to generate probabilistic quantitative precipitation forecasts (PQPFs) and improve postprocessed PQPFs quality through introducing new robust statistical models and machine learning frameworks. This dissertation comprises three main elements. First, a new, two-part scheme for creating PQPFs from single-valued quantitative precipitation forecasts is introduced. This scheme, herein referred to as the Mixed-type Non-Homogenous Regression (MNHR), combines the use of logistic regression for estimating rainfall intermittency, and non-homogeneous regression for estimation of additional parameters of the conditional distribution. The performance of MNHR is evaluated relative to …


Identification Of Resilience Dimensions And Development Of A Decision-Making System To Measure The Resilience Level Of Highway Networks, Thahomina Jahan Nipa Dec 2021

Identification Of Resilience Dimensions And Development Of A Decision-Making System To Measure The Resilience Level Of Highway Networks, Thahomina Jahan Nipa

Civil Engineering Dissertations

Local as well as national economy and safety depend on the network characteristics of the transportation infrastructures. Destruction of transportation infrastructures causes the direct cost of the reconstruction as well as indirect cost due to loss of mobility. In addition, emergency response and recovery cannot be rendered if access to the affected community is hampered due to a damaged transportation network. Hence, researchers as well national and international organizations are focusing more on a resilience-based approach instead of a traditional recovery-based approach for the transportation infrastructures recently. As a result, there exist a high number of research articles that developed …


A Numerical Study Of Water Entry Problems Based On Overset Meshes, Yanni Chang Dec 2021

A Numerical Study Of Water Entry Problems Based On Overset Meshes, Yanni Chang

Mechanical and Aerospace Engineering Dissertations

A series of numerical experiments carried out on the water entry of circular cylinders are presented in this study. A cylinder was entering into the water with a prescribed inclined angle and velocity. The interface between water and air is tracked by the Piecewise Linear Interface Calculation (PLIC) schemes in conjunction with the Volume of Fluid (VOF) method. PLIC schemes have been extensively employed in the VOF method for interface capturing in numerical simulations of multiphase flows. Dynamic overset meshes, which have been widely used for problems with relative motions and complex geometric shapes, are applied to handle the moving …


Autonomous Guidance Of Unmanned Combat Air Vehicles In Basic Fighter Maneuvering, Jeffery G. Dean Dec 2021

Autonomous Guidance Of Unmanned Combat Air Vehicles In Basic Fighter Maneuvering, Jeffery G. Dean

Mechanical and Aerospace Engineering Dissertations

Basic fighter maneuvering, or BFM, is the dynamic engagement of two or more aircraft in close-range air combat. The relatively recent introduction of advanced unmanned combat air vehicles (UCAVs) has opened the possibility for automated systems to be players in this arena of air-to-air combat, which has thus far been limited to manned aircraft. In order to design an unmanned system that could fight and win a BFM engagement, the system must include an advanced system for guidance. This dissertation leverages techniques from gain scheduling and incorporates adjustable aimpoint guidance, in order to address the capability for UCAVs to execute …


Internal Pressure Response Of A Human Head Surrogate Model Subject To Variable Impact Loading With Finite Element Analysis, Aaron Ronald Jackson Dec 2021

Internal Pressure Response Of A Human Head Surrogate Model Subject To Variable Impact Loading With Finite Element Analysis, Aaron Ronald Jackson

Mechanical and Aerospace Engineering Theses

Traumatic brain injury (TBI) from blunt impacts to the head is a major cause of brain disease and dysfunction for thousands of people every year. Each year in the United States approximately 1 million TBI cases occur causing as many as 56,000 deaths and leaving nearly 90,000 individuals with long-term disabilities. Damage resulting from a TBI occurs on a multiscale level including the macroscopic, tissue, and neuron length scale. This research focuses on correlating the macroscopic blunt impact conditions to the internal pressure developed in the coup and countercoup for water and gelatin-filled head models. Two separate 3D printed models …


Multi-Parametric And Multi-Objective Optimization Of Heatsinks For Forced And Natural Convection Based Single-Phase Immersion Cooling Of Server, Tushar Rohidas Wagh Dec 2021

Multi-Parametric And Multi-Objective Optimization Of Heatsinks For Forced And Natural Convection Based Single-Phase Immersion Cooling Of Server, Tushar Rohidas Wagh

Mechanical and Aerospace Engineering Theses

An increase in utility of internet-based services, cloud computing and greater performance demands due to rising AI and ML applications have led to a steep growth in GPU and CPU thermal design power. Efficient thermal management of these processors has become a bottleneck in performance enhancement and corresponding power densification of these components. Furthermore, increased pressure on data center owners to reduce power demands and move towards green computing has exacerbated the data center cooling challenges. Single-phase immersion cooling allows data center owners to not only dissipate the increasing heat fluxes efficiently but can also potentially improve equipment reliability as …


Theoretical Prediction Of Mechanical Behavior Of Regular And Chiral Honeycombs Based On Loading Of Single Cell., Sai Krishna K. Pinnamaneni Dec 2021

Theoretical Prediction Of Mechanical Behavior Of Regular And Chiral Honeycombs Based On Loading Of Single Cell., Sai Krishna K. Pinnamaneni

Mechanical and Aerospace Engineering Dissertations

Cellular solids are both naturally occurring and man-made materials depending on the characteristic length or Stochastic manner, these materials exhibit a low-relative density usually 30% than the constituent solid material. Low-density cellular solids have been demonstrating superior mechanical properties in various applications from marine to aerospace and lightweight sandwich structures, which has intrigued in development of novel structured materials. Cellular solids offer great design flexibility ashowows how for the targeted geometric for the application-based industry. These materials are used in sandwich structures and come in the shape of hexagonal. An additional aspect of determining the properties and behavior is by …


Synthesis And Characterization Of Graphene-Reinforced Polymer Filaments For Additive Manufacturing, Sean Menezes Dec 2021

Synthesis And Characterization Of Graphene-Reinforced Polymer Filaments For Additive Manufacturing, Sean Menezes

Mechanical and Aerospace Engineering Theses

Fused Deposition Modeling (FDM) is a popular 3D printing process which uses a spool of thermoplastic polymer filament that is melted by the movable extruder printer head onto the bed to generate the required shape. The most used polymer filaments in FDM are Acrylonitrile Butadiene Styrene (ABS) and Poly Lactic Acid (PLA). However, these conventional polymer filaments have lower mechanical strength and are more susceptible to cracking as the cooler parts of the printed part shrink so much that they cause cracks to develop, leading to warping. The current investigation focuses on the synthesis of graphene, synthesis of polymer filaments …


Characterization And Enhancement Of Fatigue And Fracture Properties In Thermoplastic Fff Parts Using In-Situ Annealing, Manjarik Mrinal Dec 2021

Characterization And Enhancement Of Fatigue And Fracture Properties In Thermoplastic Fff Parts Using In-Situ Annealing, Manjarik Mrinal

Mechanical and Aerospace Engineering Dissertations

Fused filament fabrication (FFF) show high anisotropy and reduced mechanical properties as compared to conventional manufacturing techniques. This happens due to the poor interlaminar bonding between the layers, as a result of premature halt of bond healing process. Previous research works show multiple approaches to improve the bond quality to enhance the mechanical properties of FFF parts, however these are complex and expensive techniques. In this work a novel print head assembly is presented to offer a simple and effective solution by applying a thermal field to the part as it is being printed to preheat the previously deposited layer, …


Reverse Engineering To Create High Quality Polymer Parts Using Additive Manufacturing, Gurtej Singh Tarsem Singh Channa Dec 2021

Reverse Engineering To Create High Quality Polymer Parts Using Additive Manufacturing, Gurtej Singh Tarsem Singh Channa

Mechanical and Aerospace Engineering Theses

Reverse engineering is a process of recreating parts for which the tools no longer exist, reducing the cost of an original part by manufacturing it in-house or redesigning and improving the original part's function. This research demonstrates two methods to reverse engineer a part using Polyworks software, having it printed using an SLS printer and checking the accuracy of the printed part to the original scan. The part is first scanned using a Faro-Arm laser scanner to obtain the point cloud data. The two methods used to recreate and extract the STEP file are: • Exporting NURBS. • Exporting Features …


Development Of The Vehicle Configuration Compendium: A Comprehensive Data-Information-Knowledge System To Aid In High-Speed Vehicle Design, Stenila Simon Dec 2021

Development Of The Vehicle Configuration Compendium: A Comprehensive Data-Information-Knowledge System To Aid In High-Speed Vehicle Design, Stenila Simon

Mechanical and Aerospace Engineering Theses

The conceptual design phase is the most crucial phase in hypersonic vehicle design. Choices made during this phase will have significant impact on the success of the overall project and the feasibility of the end-product. Therefore, it is of utmost importance for the design decision-maker to be adequately informed of past-to-present projects throughout the aerospace community and lessons learned from them. This avoids wasting valuable time and resources for reinventing the wheel. There currently exists no one-stop solution in the aerospace industry to address the issue of lost data, information and knowledge in the field of high-speed vehicle design. The …


Relating Linear And Rotational Accelerations With Internal Pressures Developed Inside Human Head Surrogate Models, Arthur Thomas Koster Dec 2021

Relating Linear And Rotational Accelerations With Internal Pressures Developed Inside Human Head Surrogate Models, Arthur Thomas Koster

Mechanical and Aerospace Engineering Theses

Traumatic Brain Injury (TBI) is a chronic disease process that is difficult to both detect and treat. TBI can result from blast, kinetic, sonic, and electromagnet energy sources. This research focuses on correlating the bulk acceleration of a human-like head model to the localized internal pressure developed in the coup and contrecoup regions due to variable impact loading. Damage resulting in a TBI occurs on a multiscale level from the macroscale down to the damage of each individual neuron. Obtaining a relationship between bulk acceleration and localized internal pressure will allow for further correlation to the damage done on these …


Investigation Of Heat Transfer Performance Of Double Pipe Counter-Flow Heat Pipe Using Three Fluids Water, Dowtherm, And Water-Based Nanofluid, Alaa Abed Harchan Al Hasseun Dec 2021

Investigation Of Heat Transfer Performance Of Double Pipe Counter-Flow Heat Pipe Using Three Fluids Water, Dowtherm, And Water-Based Nanofluid, Alaa Abed Harchan Al Hasseun

Mechanical and Aerospace Engineering Theses

Heat pipes are two-phase devices, capable of converting a significant amount of energy with low losses. They have been used in several applications such as systems thermal control and cooling. The purpose of the present work is to investigate the thermal performance of a double pipe counterflow against the fluid type. The pipe is divided into three zones including evaporator, adiabatic, and condenser zones. All thermal boundary conditions are defined in terms of heating or cooling temperatures in which the operating temperatures are defined between 303 K to 470 K. using Ansys Fluent, the pipe is analyzed in two-and three-dimensional …


Prediction Of Solder Joint Fatigue Life Of Photonic Package Using ?-? Materials, Ojas Tyagi Dec 2021

Prediction Of Solder Joint Fatigue Life Of Photonic Package Using ?-? Materials, Ojas Tyagi

Mechanical and Aerospace Engineering Theses

Fatigue life prediction has become very important factor in reliability of any electronic components to withstand extreme thermal stresses in industrial standard. Hence, photonic packages are widely used in telecommunication and computer applications. The primary focus of this study is to determine the thermal cycles to crack initiation of solder bump used in laser array waferboard for telecommunication applications. This includes GaAs Laser chip on waferboard and Si substrate with pure Indium solder balls in between. Indium has proved higher fatigue life in various experimental studies in the field of reliability and lead-free material. Therefore, a solder ball was designed …


Analysis Of Blood Pressure Waveform For Detection And Diagnosis Of Cardiovascular Anomalies, Atul Shrotriya Dec 2021

Analysis Of Blood Pressure Waveform For Detection And Diagnosis Of Cardiovascular Anomalies, Atul Shrotriya

Mechanical and Aerospace Engineering Theses

Cardiovascular diseases are the leading cause of mortalities worldwide as well as in the United States. Early diagnosis and prediction of these diseases is critical to mitigate the risks to the patient. A common method to assess a person’s heart health is through the use of cuff type oscillometric devices placed on the arm of the patient. As the mean pressure in the cuff is increased the blood flow in the brachial artery becomes blocked. When the cuff pressure is reduced the blood starts flowing again; during this cycle, pressure fluctuations in the cuff are measured using a pressure transducer. …


Determination Of Guidance Laws For Uav Systems In Communication Networks Using Collision Cone Theory, Utsav Mudgal Dec 2021

Determination Of Guidance Laws For Uav Systems In Communication Networks Using Collision Cone Theory, Utsav Mudgal

Mechanical and Aerospace Engineering Theses

Unmanned Aerial Vehicles (UAVs), also commonly known as drones, are used in various applications, including military applications such as surveillance and intelligence-gathering as well as civilian applications such as search and rescue. The use of UAVs to form communication networks is a topic of active research interest. This thesis aims to investigate the development of guidance laws for multiple UAVs to form such communication networks. Toward this end, this thesis employs tools from collision cone theory and incorporates them with parameters used to describe a communication network. Different types of networks are evaluated for use of the guidance laws. Simulation …


Guidance Laws For N-Mobile Agents To Grip A Moving Target, Pranay Gadiya Dec 2021

Guidance Laws For N-Mobile Agents To Grip A Moving Target, Pranay Gadiya

Mechanical and Aerospace Engineering Theses

In this thesis, we consider the problem of n mobile agents carrying a gripper, with the objective of gripping a moving circular target. The target may move with constant velocity, or even maneuver. We develop guidance laws by which the agents can first cage the target and subsequently grip it. These guidance laws are developed based on a collision cone framework, using which the mobile agents cooperatively steer their velocity vectors in an appropriate fashion to meet their objective. It is assumed that each of the mobile agents are equipped with a lidar sensor, using which they obtain the range …


Accelerated Performance Degradation Of Single-Phase Cold Plates For Direct-To-Chip Liquid Cooled Data Centers, Lochan Sai Reddy Chinthaparthy Dec 2021

Accelerated Performance Degradation Of Single-Phase Cold Plates For Direct-To-Chip Liquid Cooled Data Centers, Lochan Sai Reddy Chinthaparthy

Mechanical and Aerospace Engineering Theses

Expanding demands for cloud-based computing and storage, the Internet of Things, and AI-based applications have escalated thermal loads in high-density data centers which necessitated the utilization of more efficient cooling technologies. Direct-to-chip liquid cooling using cold plates has proven to be one of the most efficient methods to dissipate the high heat fluxes of modern high-power CPUs and GPUs. While the published literature has well-documented research on the thermal aspects of direct liquid cooling, a detailed account of reliability degradation is missing. The present investigation provides an in-depth analysis of the reliability degradation of copper cold plates used in high-power …


Buckling Load Optimization Of Variable Stiffness Composite Plate Using Fem And Semi-Analytical Method, Jeegar Vallabhbhai Patel Dec 2021

Buckling Load Optimization Of Variable Stiffness Composite Plate Using Fem And Semi-Analytical Method, Jeegar Vallabhbhai Patel

Mechanical and Aerospace Engineering Theses

The advent of new composite manufacturing techniques like Automated Fiber Placement (AFP) offers greater flexibility in structural designs by allowing curvilinear fiber paths. Hence, it is now possible to change laminate stiffness locally, thereby enabling Variable Stiffness (VS) composite structures. Such structures demonstrate superior buckling performance over traditional constant stiffness structures. However, obtaining the optimum fiber paths to improve buckling performance remains an open area of research due to the complexity of determining such fiber paths. This research investigated two approaches for optimizing fiber paths; First, a Finite Element Method (FEM) approach that utilizes linear shape functions to interpolate local …


A Modular Platform For Intrusive Diagnostics And Tps Testing In The Onr-Uta Arc-Jet Facility, Blake Anthony Hamilton Dec 2021

A Modular Platform For Intrusive Diagnostics And Tps Testing In The Onr-Uta Arc-Jet Facility, Blake Anthony Hamilton

Mechanical and Aerospace Engineering Theses

This work presents an approach to the design, and successful experimental implementation, of a modular platform for intrusive diagnostics and TPS testing in the ONR-UTA Arc-Heated Wind Tunnel "Leste" Facility. The harsh conditions typical of arc-jet facilities (hypersonic, high-enthalpy, chemically-reacting, continuous flows) present a challenge to the design of insertion platforms. In this work a detailed analysis of the aerothermal loads is used to aid in the design process. Specific design points for this modular platform and its ancillary instrumentation have been identified. Based on this design approach, a modular platform for intrusive diagnostics and TPS testing has been developed. …


Role Of Binder Compositions And Carbonate Polymorphs On The Performance Of Carbonation Activated Cementitious Composites, Mohammad Rakibul Islam Khan Dec 2021

Role Of Binder Compositions And Carbonate Polymorphs On The Performance Of Carbonation Activated Cementitious Composites, Mohammad Rakibul Islam Khan

Civil Engineering Dissertations

The most energy-intensive manufacturing industry in the US is the Ordinary Portland Cement (OPC) industry. This industry is responsible for 5-8% of global CO2 emissions caused by humans. The calcination of limestone to produce high lime calcium silicate and high manufacturing temperature (1450°C) are responsible for this significant amount of CO2 emissions. This CO2 footprint of the cement-based composites can be decreased by utilizing cementitious materials with low-lime calcium silicate. Low-lime calcium silicates are typically semi-hydraulic or non-hydraulic. As a result, it is necessary to activate those materials in order to increase their reactivity. Alkali activators, carbonation curing (CO2 curing), …


Evaluation Of Surface Asphalt Mixes Containing Recycled Asphalt Materials In North-East Texas Using Accelerated Pavement Testing, Ana Maria Coca Dec 2021

Evaluation Of Surface Asphalt Mixes Containing Recycled Asphalt Materials In North-East Texas Using Accelerated Pavement Testing, Ana Maria Coca

Civil Engineering Dissertations

Reclaimed asphalt pavement (RAP) and Reclaimed Asphalt Shingles (RAS) has proved to be an effective alternative to virgin materials in HMA production. Despite that recycling asphalt creates a cycle that optimizes the use of natural resources and sustains the pavement industry, State transportation departments have limited the maximum amount of RAP used in surface layers because of the variability concerns and lack of guidance provided. Even though at the moment, the United Stated recycles more RAP than Europe does in terms of percentage of the total RAP extracted from old pavements, it still lags Japan and other countries. A special …


Designing And Advancing Contrast Agents For Ultrasound-Switchable Fluorescence Imaging, Yang Liu Dec 2021

Designing And Advancing Contrast Agents For Ultrasound-Switchable Fluorescence Imaging, Yang Liu

Bioengineering Dissertations

Fluorescence imaging is a remarkable tool for molecular targeting and multicolor imaging, but it suffers from poor resolution in centimeters-deep tissues. The recently developed ultrasound-switchable fluorescence (USF) imaging has overcome this challenge and achieved in vivo imaging with the help of the indocyanine green (ICG)-encapsulated poly(N-isopropylacrylamide) (ICG-PNIPAM) contrast agent. As USF imaging advances, there is a great demand to expand the contrast agent bank so that applications can be achieved using different types of contrast agents. Also, there is a need to improve the current ICG-PNIPAM nanogel. This study focused on improving the ICG-PNIPAM nanogel, formulating a novel contrast agent, …


Rainfall-Induced Slope Failure – An Early Warning System, Md Aminul Islam Dec 2021

Rainfall-Induced Slope Failure – An Early Warning System, Md Aminul Islam

Civil Engineering Dissertations

Globally, slope failures cause substantial death tolls and economic loss. Embankments constructed on high plasticity clay are vulnerable to cyclic swelling and shrinkage when subjected to climate. Thus, over time, soil softens and reduces effective shear strength, and shrinkage cracks on slopes can act as pathways for rainfall infiltration, which increases pore water pressure and lowers the shear strength below critical levels, resulting in slope failure. This study aims to develop early warning criteria for rainfall-induced slope failure. Study areas were Tarrant, Dallas, Johnson, and Ellis, where soil types and a humid subtropical climate result in frequent slope failures. The …


Effects Of Aging On Mouse Rotator Cuff Tendon Biomechanics, Chinmay Sagar Patwardhan Dec 2021

Effects Of Aging On Mouse Rotator Cuff Tendon Biomechanics, Chinmay Sagar Patwardhan

Bioengineering Theses

Rotator cuff tendon injuries and tear are caused by overuse, falling, or other accidents, and are often associated with old age. The severe injuries and tear can be debilitating and require nonsurgical treatment for partial tear and arthroscopic surgery for complete tear. The frequent location of injuries and tear are at the enthesis region, the interface where the tendon tissue gradually hardens and merges into the bone. Although aging has been identified as an important factor for rotator cuff tendon injuries and tear, how the mechanical properties of the bone-tendon complex evolve along with age is still a knowledge gap. …


Decision Tool For Prioritizing Bridge Repair Or Replacement, Nyoka Amy Florius Dec 2021

Decision Tool For Prioritizing Bridge Repair Or Replacement, Nyoka Amy Florius

Civil Engineering Dissertations

Bridges are typically damaged/deteriorated due to various factors that require close evaluation to make informed decisions about repair/replacement. There are several aspects of study to evaluate bridges for repair/replacement, such as age, structural adequacy, and frequent usage. Further, bridges which are in poor condition must be identified to mitigate their damage/deterioration and as a result, maintain a safe environment for users. Therefore, to assess the need for funding, state Departments of Transportation are required to evaluate bridges by considering several factors, while prioritizing safety. In Texas, the Highway Bridge Program is responsible for funding bridges which are listed for repair/replacement. …


Optimization Of Concrete Pavement Design To Truck Platoon Loading, Mohsen Talebsafa Dec 2021

Optimization Of Concrete Pavement Design To Truck Platoon Loading, Mohsen Talebsafa

Civil Engineering Dissertations

Transportation is the major contributor toward economic growth and development. In the United States, more than 90% of commodities are transported through the roadway system. Due to the high demand for transportation of goods, there is a high demand in the road freight industry for innovative solutions, and new technologies to improve the sustainability and efficiency of transportation. Truck platooning is one of the most recent technologies with great potential to make road freight safer, cleaner, and more efficient. This technology uses connectivity technologies and automated driving systems to interconnect two or more trucks in a convoy. These automation technologies …