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2020

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Articles 7231 - 7260 of 10642

Full-Text Articles in Engineering

Power Efficiency Enhancement And Linearization Techniques For Power Amplifiers In Wireless Communications, Haider Al-Kanan Mar 2020

Power Efficiency Enhancement And Linearization Techniques For Power Amplifiers In Wireless Communications, Haider Al-Kanan

Dissertations and Theses

Wireless communication systems require Power Amplifiers (PAs) for signal transmissions. The trade-off between power efficiency and nonlinear distortion in PAs degrades the communication performance. Thus, power efficiency and nonlinearity are two main concerns of operating PAs in communication systems. Nonlinear behavioral models are typically used to quantify and mitigate the distortion effects of PAs on communication systems. This dissertation presents an estimation approach for modeling and linearizing the PA Amplitude-to-Amplitude (AM/AM) nonlinearity using the design specifications of PAs, such as gain, the third-order intercept point, and 1dB compression point. Furthermore, an enhanced approach for modeling solid-state power amplifiers is developed …


Effect Of Channelized And Unchannelized Lateral Outflow On Three-Dimensional Flow Structure And Sediment Transport Mechanisms In A River Delta, Mohammad Kifayath Chowdhury Mar 2020

Effect Of Channelized And Unchannelized Lateral Outflow On Three-Dimensional Flow Structure And Sediment Transport Mechanisms In A River Delta, Mohammad Kifayath Chowdhury

LSU Master's Theses

Spatial and temporal patterns in three-dimensional flow structure have been linked to channel morphology and processes in many environments, including river meander bends, confluences-diffluences, and bedrock canyons. However, there is not yet an understanding of how channelized and gradual, distributed lateral outflows that are often prevalent in deltaic distributary systems influence three-dimensional flow structure and sediment transport mechanisms. This thesis presents an analysis of 3D flow structure data collected from Wax Lake Delta, a naturally developing river-dominated delta in the northern Gulf of Mexico. Three hydrographic surveys were conducted using boat-mounted acoustic Doppler current profiler (ADCP) at two sites: an …


W-Gun: Whale Optimization For Energy And Delay-Centric Green Underwater Networks, Rajkumar Singh Rathore, Houbing Song, Suman Sangwan, Sukriti Mazumdar, Omprakash Kaiwartya, Kabita Adhikari, Rupak Kharel Mar 2020

W-Gun: Whale Optimization For Energy And Delay-Centric Green Underwater Networks, Rajkumar Singh Rathore, Houbing Song, Suman Sangwan, Sukriti Mazumdar, Omprakash Kaiwartya, Kabita Adhikari, Rupak Kharel

Publications

Underwater sensor networks (UWSNs) have witnessed significant R&D attention in both academia and industry due to their growing application domains, such as border security, freight via sea or river, natural petroleum production and the fishing industry. Considering the deep underwater-oriented access constraints, energy-centric communication for the lifetime maximization of tiny sensor nodes in UWSNs is one of the key research themes in this domain. Existing literature on green UWSNs are majorly adapted from the existing techniques in traditional wireless sensor network relying on geolocation and the quality of service-centric underwater relay node selection, without paying much attention to the dynamic …


Contextual Adjustment Of The Ite Trip Generation Rates Using Wi-Fi And Bluetooth Technologies, Saba Doulabi Mar 2020

Contextual Adjustment Of The Ite Trip Generation Rates Using Wi-Fi And Bluetooth Technologies, Saba Doulabi

LSU Master's Theses

The ITE Trip Generation Handbook has been in common use for about half a century to estimate vehicle trips generated by more than 172 land use categories as a function of establishment size (floor area) only. However, observed trip rates display a huge error range across different sites. Although contextual adjustment factors can ameliorate the error in the ITE trip generation estimates considerably, local site-specific trip generation rates should be collected for this purpose. Due to the huge time and monetary costs of data collection, adjusting the ITE trip generation rate is ignored by many jurisdictions. The primary contribution of …


Explaining Weapon System Sustainment's Impact To Aircraft Availability, Michael D. Ingram Mar 2020

Explaining Weapon System Sustainment's Impact To Aircraft Availability, Michael D. Ingram

Theses and Dissertations

This research focused on understanding the phenomena behind the cost growth of Weapon System Sustainment (WSS) and the simultaneous degradation in USAF aircraft system availability. The primary modelling technique used was Ordinary Least Squares (OLS) while incorporating temporal effect. Other studies have looked at cost factors related to the Flying Hour Program, flying conditions and age. This study found empirical relationships between each of the four WSS business processes and the lead time in months it takes to realize improvements in system aircraft availability.


Characterization Of A Sagnac Loop Mirror-Based Hybrid Passive Variable Optical Coupler/Attenuator, Simeon Bikorimana, Muhammad A. Ummy, Abdullah Hossain, Richard Lin, Roger Dorsinville Mar 2020

Characterization Of A Sagnac Loop Mirror-Based Hybrid Passive Variable Optical Coupler/Attenuator, Simeon Bikorimana, Muhammad A. Ummy, Abdullah Hossain, Richard Lin, Roger Dorsinville

Publications and Research

The implementation and performance of a unidirectional all-single mode fiber hybrid passive variable optical coupler/attenuator based on a Sagnac loop mirror with a continuous variable coupling ratio using off-the-shelf optical sub-components are discussed. Parameters of two output ports of the unidirectional hybrid passive variable optical coupler/attenuator, such as maximum coupling ratio, insertion loss, excess loss, and wavelength-dependent return loss over the C-band at room temperature are reported. The reflectivity of the Sagnac loop mirror continuously varies from 0.1% to 99.9% by adjusting retarders of a polarization controller. The 3-dB coupling ratio (i.e., 50:50) between the two output ports of the …


A Bibliometric Analysis Of Soil Pollution Due To Microplastics, Sangita Dike, Sayali Apte Mar 2020

A Bibliometric Analysis Of Soil Pollution Due To Microplastics, Sangita Dike, Sayali Apte

Library Philosophy and Practice (e-journal)

Microplastic pollution is a global problem because of its ecological and socioeconomic impacts on the environment. The large size plastic waste, under the action of ultraviolet radiation, pressure, and wind or wave action, breaks down into particles smaller than 5 mm referred to as microplastic. This huge amount of microplastic enters the ecosystem eventually leading to soil pollution. It has been established that microplastics enter the food chain when animals eat or ingest contaminated food materials.and have an adverse effect on human health The present paper investigates, past researches in the area of microplastic pollution of soil, by a detailed …


The Effects Of Cultural Factors On Safety In Aviation Focusing On Asian And Western Cultures, Jiyeon Song Mar 2020

The Effects Of Cultural Factors On Safety In Aviation Focusing On Asian And Western Cultures, Jiyeon Song

National Training Aircraft Symposium (NTAS)

Several aviation accidents from the past, such as the Asiana Flight 214 crash at San Francisco International Airport in 2015, have highlighted possible effects of Korean hierarchy culture on the safety of flight. Previous research conducted primarily with the use of surveys revealed that Asian pilots are less likely to report an unsafe condition out of fear that it will damage their relationships with coworkers and superiors. Western pilots see reporting as dealing with the problem and not a person, thus they feel more open to it. This study looked at student pilots’ ability to recognize and deny an unsafe …


Measuring Fatigue And Sleepiness In Collegiate Aviation Pilots, Julius Keller Ph.D., Flavio A. C. Mendonca Ph.D., Erik Levin, Aaron Teo Mar 2020

Measuring Fatigue And Sleepiness In Collegiate Aviation Pilots, Julius Keller Ph.D., Flavio A. C. Mendonca Ph.D., Erik Levin, Aaron Teo

National Training Aircraft Symposium (NTAS)

The National Transportation Safety Board has communicated the need to reduce fatigue related accidents through the top ten most wanted list. Additionally, the International Civil Aviation Organization and Federal Aviation Administration have continuously promoted fatigue risk management. Most fatigue related research as well as safety standards in aviation involve air carrier and military operations. However, there has been a recent revival of fatigue related research in collegiate aviation. A recent study found that 85% of collegiate aviation pilots (n = 141) reported fatigue negatively impacted their flight training activities. Results of a qualitative study indicated poor knowledge and behaviors by …


Drones Are Everywhere!, Andreas Wesemann Ph.D. Mar 2020

Drones Are Everywhere!, Andreas Wesemann Ph.D.

National Training Aircraft Symposium (NTAS)

Drones are everywhere! Using technology to enhance learning in collegiate and secondary school education.

Unmanned Aerial Systems are invading our campus at Utah State University, and we see drones flying everywhere. Using hands-on activities, including design, building and actually flying, students are becoming FAA certified Remote Pilot as part of a new minor at USU. This workshop will discover how this program was created, how the use of active learning labs compliment student programs in all disciplines from journalism to business, and landscape architecture to natural resources. Using examples from the first two years of course offerings, participants will discover …


Student Learning And Retention Using A Flight Training Device: A Case Study, Adeel Khalid Mar 2020

Student Learning And Retention Using A Flight Training Device: A Case Study, Adeel Khalid

National Training Aircraft Symposium (NTAS)

Student learning and retention as a function of the mode of teaching is analyzed in this study. Different groups of students receive information about aircraft flight operations either via lecture, through directed study, a combination of the two or through a pre-recorded flight demonstration video. Their level of learning is assessed by evaluating how well they fly an aircraft and perform a predefined mission using a flight simulator. Scores of different groups are compared qualitatively and quantitatively and students are surveyed after the flight. It is hypothesized that students that learn through watching a demonstration video and have the ability …


Permanent Vibrodiagnosis Of The Pump Unit, F.A. Bekchanov Mar 2020

Permanent Vibrodiagnosis Of The Pump Unit, F.A. Bekchanov

Irrigation and Melioration

Currently, increasing the efficiency of operation of pumping stations is associated with the development of energy-saving and resource-saving technologies. Diagnostics is one of the modern and perfect ways to determine the main malfunctions that occur in pumping units. The main goal of diagnosing the technical condition of pumping units is to preliminarily identify the occurring malfunctions in it and ensure durability, reliability, reliability and operational efficiency. The article presents the effect of vibration on pumping units and analysis of methods of vibration diagnostics, information is given on the possibility and advantages of devices for continuous vibration diagnostics.


Energy Saving Issues In Pumping Units, A.I. Anarbaev, D.B. Kodirov, R.A. Zakhidov, B. Usmanov Mar 2020

Energy Saving Issues In Pumping Units, A.I. Anarbaev, D.B. Kodirov, R.A. Zakhidov, B. Usmanov

Irrigation and Melioration

The article presents the issues of energy saving, which are becoming increasingly relevant due to the constant increase in tariffs and the introduction of the demands on energy efficiency and energy conversation. To save energy at pumping units, the characteristics of controlling the electric drive of pumping stations with frequency-controlled control are considered. For adequate adjustment by the technological process of water movement and power supply, corresponding analytical dependencies are obtained. An analysis of the physical expressions of water pumping processes allowed us to determine energy-saving modes of operation and technologies for improving the efficiency of equipment.


Importance Of Creating A System Of Land And Cadastral Data For Subjects Of Agriculture, К. Rakhmonov, M.O. Abdurakhimova Mar 2020

Importance Of Creating A System Of Land And Cadastral Data For Subjects Of Agriculture, К. Rakhmonov, M.O. Abdurakhimova

Irrigation and Melioration

A separate model and model were developed for compiling cadastral maps used by the authors for agricultural organizations. The model is intended for enterprises operating in the Tashkent region. The article is based on the scientific and methodological order and the system of destruction of irrigated lands. Based on the experience of leading foreign countries in this area, the possibilities of introducing modern electronic computers in Uzbekistan are presented. The procedure for converting data into a specific algorithm is recommended for the formation of a system of land cadastral data in agricultural entities. It is necessary to create an information …


Apple Orchard Drip Irrigation Conditions Of The Tashkent Region Of Uzbekistan, Sardor Gulyamov, Bakir Serikbaev, Anvar Sherov Mar 2020

Apple Orchard Drip Irrigation Conditions Of The Tashkent Region Of Uzbekistan, Sardor Gulyamov, Bakir Serikbaev, Anvar Sherov

Irrigation and Melioration

The article presents the results of many years of theoretical experimental field research on drip irrigation of the apple orchard of the Golden variety in the conditions of the Tashkent region. Based on the analysis of climatic, soil, hydrogeological, geological, hydrological and economic conditions of the experimental plot, as well as biological features of the garden, the values of total water consumption, water consumption deficit, irrigation, irrigation rate and the number of irrigation by the bioclimatic method are determined.


Calculation Of The Placement Of Vertical Drainage Wells Near An Open Water Source In The Conditions Of Waterlogging Of Built-Up Areas, B.K. Saliev Mar 2020

Calculation Of The Placement Of Vertical Drainage Wells Near An Open Water Source In The Conditions Of Waterlogging Of Built-Up Areas, B.K. Saliev

Irrigation and Melioration

The article discusses the methodology for calculating the intercepting drainage well that reveals the upper layer of the multilayer horizon, and presents analytical dependencies based on the hydrodynamic theory and formulas for approximate calculation of the location of the axial line of the blocking drainage between the source of flooding and the protected built-up area from flooding. In particular, mathematical methods have been improved to solve the forecast problems of flooding in conditions of different pressure, based on the relationship between the depressions and the incoming flow of pressure water into the drainage well. The presence of underground pressure water …


Multisector Water Consumption Database: Surkhandarya Region Of The Republic Of Uzbekistan, М. Ikramova, С. Batishev, О. Ikramov, H. Kabilov, D. Nazaraliev, А. Khodjiev, I. Akhmedkhodjaeva Mar 2020

Multisector Water Consumption Database: Surkhandarya Region Of The Republic Of Uzbekistan, М. Ikramova, С. Batishev, О. Ikramov, H. Kabilov, D. Nazaraliev, А. Khodjiev, I. Akhmedkhodjaeva

Irrigation and Melioration

The available water resources in the country are used by the different sectors of economy as industry, agriculture, energy, communal service and etc. In this case the water distribution within the river basin requires perfect information service and data exchange facilities. In the paper the developed unified multi-sector on-line database is presented aimed to monitor the water distribution among sectors of economy, database structure, and data exchange tools. The software works at operative mood, allows evaluating the combined water use efficiency by water users.


Field Research Methods And Some Results For Distribution Of Suspended Sediment In Flow Constrained By Transverse Dams, M.R. Bakiev, K.T. Yakubov, O.M. Matkarimov, Z.B. Dovlatov Mar 2020

Field Research Methods And Some Results For Distribution Of Suspended Sediment In Flow Constrained By Transverse Dams, M.R. Bakiev, K.T. Yakubov, O.M. Matkarimov, Z.B. Dovlatov

Irrigation and Melioration

The article presents methods for determining the main parameters of flow of medium hydraulic size sediment, turbidity, sampling methods in field and the instruments used for sampling, methods of processing the samples in laboratory. Methods for setting sections and gage points and conducting field and laboratory research have been developed for flow deformed by blank and through flow transverse dams, water surface longitudinal and transverse slope takes place in the flow constrained by transverse dams, changes in suspended sediment distribution occur inversely. Location of sections for sampling is determined in the article: in the headrace –beyond dam influence zone, maximal …


Hydromechanical Parameters Of River Sediment, A.M. Arifjanov, D.Sh. Allayorov Mar 2020

Hydromechanical Parameters Of River Sediment, A.M. Arifjanov, D.Sh. Allayorov

Irrigation and Melioration

The main problem today in irrigation canals is the danger of siltation, in this process it is important to correctly assess the factors affecting the throughput (hydromechanical parameters of sediment) and using their justification of the hydraulic elements of the flow. The article presents the results of theoretical studies of the main hydromechanical parameters (hydraulic fineness) of river sediments, in hydraulic structures, in particular in irrigation canals, which currently increasingly affect adversely moving water. It has been established that the hydraulic size entering the right bank irrigation sump of the Kokand hydropower complex varies in the range of 189-429 mm/s, …


Design Dimensions Of Flow In Compressed Flow Beyond Combined Dikes, O. Kodirov, О. Хаlimbetov Mar 2020

Design Dimensions Of Flow In Compressed Flow Beyond Combined Dikes, O. Kodirov, О. Хаlimbetov

Irrigation and Melioration

The experimental research has shown that the kinematic pattern of flow deformed by combined structures (core part is blank and made of local materials, and the head part is made of piles), and it is more complicated than usual, although the qualitative flow schemes have much in common. The flow has the zones of backup, compression and spreading. Compression zone is discussed in the article, and the largest transverse and longitudinal drops in elevation and velocity are observed in this zone, therefore theoretically it is very difficult to set the main design dimensions of flow in this zone. Therefore, the …


Certain Particularities Of Hydrotechical Concrete Water Permeabity, F.R. Yunusova, T.D. Muslimov Mar 2020

Certain Particularities Of Hydrotechical Concrete Water Permeabity, F.R. Yunusova, T.D. Muslimov

Irrigation and Melioration

The article discusses the issues of hydrotechnical concrete water permeability based on the requirements set to them, methods for determining concrete water permeability, characteristics of porosity and capillaries formed in concrete, as well as possibilities to decrease hydrotechnical concrete water permeability with the use of chemical admixtures and colmatation.


Determination Of Water Discharge Of A Jet Device Taking Into Account Mutflow Flow, Q.T. Rakhimov, D.A. Abduraimova Mar 2020

Determination Of Water Discharge Of A Jet Device Taking Into Account Mutflow Flow, Q.T. Rakhimov, D.A. Abduraimova

Irrigation and Melioration

In many sectors of the water economy, one can observe the movement of a sediment stream in pressured systems. The pressure losses in the liquid and sediment joint stream are different than the movement of a single-phase flow according to their pressure loss. In this case, some difficulties arise in determining the coefficients that affect the flow rate and the average flow rate. In the article given theoretical and experimental foundations for determining the hydraulic flow parameters in during the movement of a sediment and liquid flow. Theoretical studies are based on the laws of energy conservation, and laboratory studies …


Minimizing Control Circuits Using Logic Elements, R.T. Gaziyeva, A.M. Nigmatov, E.O. Ozodov Mar 2020

Minimizing Control Circuits Using Logic Elements, R.T. Gaziyeva, A.M. Nigmatov, E.O. Ozodov

Irrigation and Melioration

In this article considered information about contact and non-contact automation. In most cases, contact automation is used in many pumping stations. These phenomena are a power surge or voltage drop. And also the use of contact automation occupies a large place and inconvenience in operation. Non- contactless automation solves these problems. Pumping stations are usually designed with the calculation of their operation without permanent duty personnel. At large stations, a small staff is provided, which primarily carries out control functions. Set the automatic operation of pumping units. Often, automatic selection of switched-on units is carried out, reserve is withdrawn, station …


Importance Of Creating A System Of Land And Cadastral Data For Subjects Of Agriculture, К. Rakhmonov Mar 2020

Importance Of Creating A System Of Land And Cadastral Data For Subjects Of Agriculture, К. Rakhmonov

Irrigation and Melioration

The generation of electronic data using the land plot scheme while maintaining the land cadastre provides significant convenience for users. Based on this concept, the author explains the conditions, factors and elements of the formation of the contours of land within the land, which plays an important role in the land cadastral work. In particular, the elements of the contour of the earth, that is, the conditions and composition of the border, the area and the order of formation of numbers, are reflected in a separate figure. It is known that the composition of agricultural land plays an important role …


Method Of Determining The Parameters Of The Working Bodies Of The Centrifugal Fan Installed To The Sprayer, D. Dzhuraev, M.S. Halilov, I.Zh. Toirov, A.E. Urishev Mar 2020

Method Of Determining The Parameters Of The Working Bodies Of The Centrifugal Fan Installed To The Sprayer, D. Dzhuraev, M.S. Halilov, I.Zh. Toirov, A.E. Urishev

Irrigation and Melioration

The article presents the data of scientists who conducted theoretical and experimental research on centrifugal fans, they refined the calculations, improved technical characteristics and aerodynamic designs of centrifugal fans. Aerodynamic and technological schemes of centrifugal fans installed to the sprayer have been developed. The theoretical and experimental studies conducted by scientists are described: Nevelson MI, Cherkassky VM, Kalinushkin MP, Ivanov O. P., Turbin B. G., on the basis of which the authors developed a method for calculating the main parameters of the working bodies centrifugal fan. Based on the developed calculation methodology, the main parameters of the working bodies of …


Experience Of Creation The Combined Power Complexes On The Basis Of Renewable Energy Sources, R.A. Zakhidov, A.I. Anarbaev, D.B. Kodirov, F.H. Mukhtarov Mar 2020

Experience Of Creation The Combined Power Complexes On The Basis Of Renewable Energy Sources, R.A. Zakhidov, A.I. Anarbaev, D.B. Kodirov, F.H. Mukhtarov

Irrigation and Melioration

At the article the combined energy complexes based on renewable energy sources implemented in various countries is analyzed. The regime issues of the most efficient use of maximum generation of electrical energy from solar, wind, biogas sources at reserved diesel station are given. Designs of generator modules based on a kinetic energy buffer storage device for preserving the quality of electricity from renewable energy sources with frequent changes in electrical loads of consumers are considered.


Analysis Of Results Of Researches Of Electrotechnological Treatment Of The Cotton Trouble Up To The First Crop Collection, A. Muhammadiev, A.I. Pardaev Mar 2020

Analysis Of Results Of Researches Of Electrotechnological Treatment Of The Cotton Trouble Up To The First Crop Collection, A. Muhammadiev, A.I. Pardaev

Irrigation and Melioration

This article discusses the electrophysical characteristics of plants, more precisely the disclosure of the mechanism of electrical action on the plant through the study of the specific electrical resistance, as well as the task of developing the technological parameters of the electro-technological processing of crops. Knowledge of current value is given, passing through the minted and the rest of the cotton, determination of the negative impact of electrotechnological stamping of cotton on growth and development, yield, by electrotechnological method, including studies of the minted part of cotton, the death of the leaves, the seeds of the pests, the absence of …


Importance Of Creating A System Of Land And Cadastral Data For Subjects Of Agriculture, К. Rakhmonov Mar 2020

Importance Of Creating A System Of Land And Cadastral Data For Subjects Of Agriculture, К. Rakhmonov

Irrigation and Melioration

The generation of electronic data using the land plot scheme while maintaining the land cadastre provides significant convenience for users. Based on this concept, the author explains the conditions, factors and elements of the formation of the contours of land within the land, which plays an important role in the land cadastral work. In particular, the elements of the contour of the earth, that is, the conditions and composition of the border, the area and the order of formation of numbers, are reflected in a separate figure. It is known that the composition of agricultural land plays an important role …


Obtaining A Highly Effictive Antikorrosion And Depressant Additives Based On Local Raw Materiales, Abdumalik Nabievich Rizaev, Maksimovich Khakimov Abror, Shavkat Nabievich Rizaev Mar 2020

Obtaining A Highly Effictive Antikorrosion And Depressant Additives Based On Local Raw Materiales, Abdumalik Nabievich Rizaev, Maksimovich Khakimov Abror, Shavkat Nabievich Rizaev

Journal of Tashkent Institute of Railway Engineers

Possibility of the syntheses new lubricant materials are shown in work to lubricant on base local swam to resources. Possibility of the practical application polymeric additive are shown


The Engineering Decisions For Mitigation Of Damages In Landslide Hazardous Regions Of Uzbekistan, M.Х. Miralimov, Sh.U. Normurodov Mar 2020

The Engineering Decisions For Mitigation Of Damages In Landslide Hazardous Regions Of Uzbekistan, M.Х. Miralimov, Sh.U. Normurodov

Journal of Tashkent Institute of Railway Engineers

The article provides information on ongoing measures to protect the population, territory and infrastructure from the hazards associated with landslides and the elimination of their consequences. The whole complex of measures aimed to the decision the engineering tasks of anti-landslide protection are turned into the recognition and assessment of threats, stabilization and retention of the landslide massif.