Engineering Commons^™

Modelling Of Heat Transfer In An Air Solar Collector, Shakhnoza Abduvaxitovna Sultanova, Jasur Esirgapovich Safarov, A.A. Mambetsheripova

Technical science and innovation

This study is the prediction, depending on time and different geographical and climatic situations, of different operating parameters: solar radiation, ambient and outlet coolant temperature, heat exchange coefficients and losses. All these determine, in the absence of measurements, the efficiency of the system modelled with existing models with respect to these parameters. These models are usually compared with experimental results. Before modelling, it is necessary to investigate the different heat transfer and exchange regimes that exist between the different elements of this system in order to eventually have a system of equations governing this exchange. The modelling principle is to …

Mathematical Modeling Of Fruit Drying And System Analysis Of The Process (On The Example Of Persimmon), Gani Dadayev, Jasur Safarov, Shakhnoza Sultanova, Qobiljon Muxiddinov

Technical science and innovation

Vegetable raw materials, as an object of drying, are characterized by a large amount of water and a low content of dry substances. Vegetable raw materials have a capillary-porous structure. Food products contain both bound and free moisture at the same time. The removal of moisture from the material during drying depends on the total moisture content and the form of connection of moisture with the material. Adsorption and osmotic - bound moisture is retained at the interface of colloidal particles with the environment. Food products contain both bound and free moisture at the same time. The quantitative ratio between …

Improvement Of Convective Drying Equipment, A Ponasenko, Jasur Safarov, Shaxnoza Sultanova

Technical science and innovation

Drying of agricultural raw materials is an energy-consuming but integral process. Therefore, increasing the efficiency of drying and improving the quality indicators of dried material at minimum material and energy costs is relevant for producers of agricultural products. By present time numerous researches on improvement of constructions and processes of work of dryers providing satisfactory parameters of energy saving have been carried out. In some scientific materials it is shown that the use of generative gas and straw as fuel allows to reduce energy costs for the drying process in the fluidised bed dryer by 10-30%, the quality of seeds …

Concise Summary Of Existing Correlations With Thermophysical Properties Of Seawater With Applications: A Recent Review, Furqan Jamil, Hafiz Muhammad Ali, Mehdi Haji Khiadani

Research outputs 2022 to 2026

Physical and thermal specifications of seawater are used by researchers and engineers in different fields. Accordingly, a vast array of literature has been devoted to developing different correlation equations for calculating seawater characteristics. This review presents a concise investigation of various physical and thermal specifications of seawater including: density, boiling point and vapor pressure, osmotic coefficient and pressure, surface tension, thermal conductivity, viscosity, specific enthalpy, specific entropy, specific heat capacity, isothermal compressibility, isobaric expansivity and Gibbs energy. Further to this, apsects of temperature, salinity and pressure have a significant influence on these properties, and will also be considered here. The …

Systematic Literature Review Of Roof Systems On Energy Efficiency Of A Building To Support An Ideal Study Framework, Ayushi Raj Dua

All Theses

A sustainable building envelope is a crucial element to build energy efficient structures that contribute towards sustainable communities. The demand for sustainable building envelopes has grown in response to a growing emphasis on sustainable living. The roofing system is an important component of a sustainable building envelope because it influences the building's energy consumption and indoor comfort levels. The current study focuses on roofing systems and associated solar reflectance and albedo values to document the impact on energy efficiency via cooling/heating energy usage, dollar savings and temperature (ambient and surface) reductions due to the roofing systems. Additionally, the study focuses …

Assessing The Ability Of Arduino-Based Sensor Systems To Monitor Changes In Water Quality, Josiah Hacker

Honors College Theses

Access to safe water is vital to public health. While developed countries like the United States are recognized as having reliable and safe water, many small water utilities struggle with supplying consistent water quality. Technicians of these utilities will periodically test water samples from the influent and throughout the distribution system. However, this laborious and costly process does not capture sudden changes in influent water quality due to environmental conditions or pipes breaking in the distribution system. Here I show how an Arduino-based sensor can be used as a real-time, low-cost monitor of water quality parameters. Specifically, I developed a …

An Analysis Of The Effect Of Temperature On Asphalt Paving In South Dakota, S M Rahat Rashedi

Electronic Theses and Dissertations

Temperature is an important parameter to consider for asphalt paving since this work is generally susceptible to weather due to outdoor construction. The South Dakota Department of Transportation (SDDOT) developed working day weather charts in 1998 to address the expected adverse weather days. This thesis investigated the effect of temperature on adverse weather days for asphalt paving and compared them to the value reported in the 1998 SDDOT study. Moreover, the thesis also examined how closely the maximum temperature data from project sites' weekly progress reports (WPR) matched the data from the closest weather stations. When the maximum temperature (TMAX) …

Effect Of Hot Weather Concreting On The Mechanical And Durability Properties Of Concrete-A Review, Rawan Ramadan, Hassan Ghanem, Jamal Khatib, Adel Elkordi

BAU Journal - Science and Technology

Nowadays, hot weather is an essential motivator that leads concrete to lose its special characteristics. The high loss of moisture by evaporation and rapid hardening encourage the cracking potential and placement operations. The fresh mixed and hardened concrete tend to be damaged due to several conditions such as: high concrete temperature, High ambient temperature, low relative humidity, and high wind speed. These circumstances accelerate the rate of moisture loss and cement hydration. This article briefly reviews hot weather concreting problems precautions, and curing methods and also discusses the role of incorporation SCMs in reducing the temperature of concrete and enhancing …

Investigation Of Temperature, Solution Strength, And Applied Stress Effects On Cation Exchange Processes In Geosynthetic Clay Liners, Kurt Katzenberger

Master's Theses

A laboratory test program was conducted to investigate the effects of temperature, solution strength, and applied stress over increasing conditioning durations on cation exchange processes in sodium bentonite (Na-B) geosynthetic clay liners (GCLs). The test program was intended to determine if the variables of temperature, solution strength, and applied stress had beneficial or detrimental effects on the engineering behavior of Na-B GCLs in municipal solid waste (MSW) landfills and laboratory testing applications. Needlepunched-reinforced, double non-woven Na-B GCL specimens were conditioned in fluids of increasing ionic strength (DI water, 2 mM CaCl2, 50 mM CaCl2, and 200 mM CaCl2 representing control, …

Features Designing Special Clothing For The Hot Climate Of Uzbekistan, N Kh Mirtalipova, N A. Isaxujayeva

Technical science and innovation

This paper considers the issues of establishing the relationship between the properties of fabric, clothing design and the comfort of clothing; communication of the size of the human body, allowance for free fitting, modern design when developing the design of clothing; connection of the allowance for free fitting with a suitable air gap. A diagram is given that characterizes the dependence of the comfort of clothing on its design and properties of fabrics. A mathematical model of the processes of air exchange in the underwear space is considered, which will allow obtaining more complete information and establishing more stringent dependences …

Applications Of Stretching Technique And Time Window Effects On Ultrasonic Velocity Monitoring In Concrete, Bibo Zhong, Jinying Zhu

Department of Civil and Environmental Engineering: Faculty Publications

Coda wave interferometry (CWI) has been used to measure the relative wave-velocity change (dV/V) caused by small changes in materials. This study uses the stretching processing technique which has been used for CWI analysis to investigate velocity changes of direct longitudinal (P) wave, direct shear (S) wave, and coda wave in concrete by choosing different time windows of ultrasonic signals. It is found that the obtained wave-velocity change depends on the time window position, because the relative contribution of P wave and S wave is different in each signal window. This paper presents three experimental scenarios of velocity …

Classifying Mixing Regimes In Ponds And Shallow Lakes, Meredith A. Holgerson, David C. Richardson, Joseph Roith, Lauren E. Bortolotti, Kerri Finlay, Daniel J. Hornbach, Kshitij Gurung, Andrew Ness, Mikkel R. Andersen, Sheel Bansal, Jacques C. Finlay, Jacob A. Cianci-Gaskill, Shannon Hahn, Benjamin D. Janke, Cory Mcdonald, Jorrit P. Mesman, Rebecca L. North, Cassandra O. Roberts, Jon N. Sweetman, Jackie R. Webb

Michigan Tech Publications

Lakes are classified by thermal mixing regimes, with shallow waterbodies historically categorized as continuously mixing systems. Yet, recent studies demonstrate extended summertime stratification in ponds, underscoring the need to reassess thermal classifications for shallow waterbodies. In this study, we examined the summertime thermal dynamics of 34 ponds and shallow lakes across temperate North America and Europe to categorize and identify the drivers of different mixing regimes. We identified three mixing regimes: rarely (n = 18), intermittently (n = 10), and often (n = 6) mixed, where waterbodies mixed an average of 2%, 26%, and 75% of the study period, respectively. …

Copulas For Hydroclimatic Analysis: A Practice-Oriented Overview, Faranak Tootoonchi, Mojtaba Sadegh, Jan Olaf Haerter, Olle Räty, Thomas Grabs, Claudia Teutschbein

Civil Engineering Faculty Publications and Presentations

A warming climate is associated with increasing hydroclimatic extremes, which are often interconnected through complex processes, prompting their concurrence and/or succession, and causing compound extreme events. It is critical to analyze the risks of compound events, given their disproportionately high adverse impacts. To account for the variability in two or more hydroclimatic variables (e.g., temperature and precipitation) and their dependence, a rising number of publications focuses on multivariate analysis, among which the notion of copula-based probability distribution has attracted tremendous interest. Copula is a mathematical function that expresses the joint cumulative probability distribution of multiple variables. Our focus is to …

Precipitation And Temperature Extremes And Association With Large-Scale Climate Indices: An Observational Evidence Over India, S Rehana, Pranathi Yeleswarapu, Ghouse Basha, Francisco Munoz-Arriola

Biological Systems Engineering: Papers and Publications

Climate change exposes more frequent natural hazards and physical vulnerabilities to the built and natural environments. Extreme precipitation and temperature events will have a significant impact on both the natural environment and human society. However, it is unclear whether precipitation and temperature extremes increase physical vulnerabilities across scales and their links with large-scale climate indices. This study investigates the relationship between precipitation and temperature extremes, as recommended by the Expert Team on Climate Change Detection and Indices (ETCCDI), and large scale climatological phenomenon indices (Indian Summer Monsoon Index (ISMI), Arctic Oscillation (AO), and North Atlantic Oscillation (NAO)), using India as …

Applications Of Stretching Technique And Time Window Effects On Ultrasonic Velocity Monitoring In Concrete, Bibo Zhong, Jinying Zhu

Department of Civil and Environmental Engineering: Faculty Publications

Coda wave interferometry (CWI) has been used to measure the relative wave-velocity change (dV/V) caused by small changes in materials. This study uses the stretching processing technique which has been used for CWI analysis to investigate velocity changes of direct longitudinal (P) wave, direct shear (S) wave, and coda wave in concrete by choosing different time windows of ultrasonic signals. It is found that the obtained wave-velocity change depends on the time window position, because the relative contribution of P wave and S wave is different in each signal window. This paper presents three experimental scenarios of velocity …

Strain And Temperature Measurement From Distributed Fiber Optic Sensors In Performance-Based Fire Engineering, Yanping Zhu

Doctoral Dissertations

"Strain and temperature measurement of steel and concrete structures under fires is critical to the understanding of structural performance yet historically challenging due to a significant gap in measurement science. This Ph.D. study characterizes in six parts low-cost distributed fiber optic sensors and applies them to strain, and temperature measurements based on Rayleigh and Brillouin light scattering. The first part aims to quantify the Rayleigh scattering based measurement accuracy of distributed fiber optic sensors under a heating-holding load protocol and characterize the effect of polymer coating on the sensors as the polymer softens and melts at elevated temperatures. The second …

Temperature Effect On The Mechanical Properties Of Steel Fiber Reinforced Ultra-High-Performance Concrete, Jenny Bernadette Gomes

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The contemporary innovation in concrete technology is ultra-high-performance concrete (UHPC). In this work, mechanical properties of UHPC are studied at ambient terrestrial temperature conditions. Specimens are prepared under laboratory environments maintaining the temperature of -25°C, -5°C, 15°C, 35°C, and 55°C. A freeze thaw chamber is utilized to condition the specimens at specified temperatures. Compressive strength, flexural strength, toughness, and modulus of elasticity are determined under varying temperature and steel fiber volume content. The results indicate that both temperature and steel fibers have effect on the mechanical properties of UHPC. The flexural and compressive strength show an opposite trend of strength …

Synthesis And Polymerization Processes Of 1-Chlorine-3- Piperidine -2-Propylmethacrylate Monomer, N U. Pulatova, O S. Maksumova, Izabela Barszczewska Rybarek

Technical science and innovation

An amino alcohol was synthesized on the basis of piperidine and epichlorohydrin. The esterification reaction of methacrylic acids with the obtained amino alcohol was studied. In order to identify optimal synthesis conditions, the influence of temperature, reaction duration and ratio of reactive reagents was investigated. The processes of obtaining unsaturated esters by esterification reactions with 1-chlorine-3-piperidine-2-propanol and acrylic-, methacrylic acids have been studied. The effect of monomer concentration on the rate of polymerization reaction and the yield of polymer formation was studied . The radical polymerization of a new monomer with a piperidine cycle in the presence of a nitrogen-containing …

Multiscale Investigation Of Thixotropy In Soft Clays, Jing Peng

Doctoral Dissertations

Fine-grained clay particles of <2 >µm in size are ubiquitous in soils and sedimentary rocks. Due to their platy shape, high aspect ratio, and surface charges, clay particles play a dominant role in controlling the mechanical properties of those fine-grained geomaterials such as soft clays and shales. In physics and engineering, some materials show that the strength and stiffness increases with time even if the boundary conditions remain unchanged (e.g., no change in pressure, temperature, or composition), and such a phenomenon is called thixotropy. It is generally agreed that the principle of thixotropy of wet clays is complex. For a closed, …

Concrete Maturity Method Applied To Rapid-Setting Calcium-Sulfoaluminate (Csa) Concretes For Pavement Repair Under Different Ambient Temperatures, Ryan Nicholas Langford

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

With more and more people using roadways the need for fast and efficient repair work is becoming increasingly important. Lane closures impede traffic flow and result in congestion. To further limit the amount of time lane closures are needed for repair work, calcium sulfoaluminate (CSA) cement concrete has become an increasing popular construction material for its ability to reach adequate strength requirements within four hours. Because of this accelerated repair time, advanced testing methods are needed to verify that the replaced concrete does indeed meet or exceed the minimum compressive strength requirements.

The maturity method is one test used to …

Cellulose Biodegradability And Its Impact On Enhanced Biological Phosphorus Removal, Moustafa Ibrahim Elbahrawi

Electronic Thesis and Dissertation Repository

Cellulose from toilet paper contributes approximately one third of the influent organic suspended solids (TSS) to wastewater treatment plants and is a key target for resources recovery. Cellulose recovery is beneficial as it reduces the required energy for treatment and biosolids treatment cost. Hence, understanding the hydrolysis of cellulose in wastewater which is mainly affected by temperature and the solids retention time (SRT), is a major key to determine the optimum location for its recovery. In order to assess the impact of temperature and SRT on cellulose degradation, this study investigated the biological aerobic degradation of cellulose in four laboratory-scale …

Effect Of Temperature On Early‐Age Properties Of Self‐Consolidating Concrete Equivalent Mortar, Nima Farzadnia, Jing Pan, Kamal Khayat, Eric Wirquin

Civil, Architectural and Environmental Engineering Faculty Research & Creative Works

In this study, the effect of ambient temperature during casting on fresh properties, hydration kinetics, and early‐age compressive strength of self-consolidating concrete (SCC) was evaluated. Concrete equivalent mortars (CEMs) with water‐to‐binder ratios of 0.41 and 0.45 were cast based on SCC mixture designs for building and infrastructure construction and precast applications. The CEMs were prepared at temperatures ranging from 8 to 36°C. Superplasticizer (SP) and air‐entraining agent (AEA) demand were evaluated for the CEM mixtures made with different supplementary cementing material (SCM) and limestone filler types. Test results showed that the ambient temperature can significantly affect the SP and AEA …

Study On Creep Characteristics Of Claystone Under Thermo-Hydro- Mechanical Coupling, Wei-Zhong Chen, Fan-Fan Li, Jiang Lei, Hong-Dan Yu, Yong-Shang Ma

Rock and Soil Mechanics

As an alternative medium for the underground disposal of radioactive waste, claystone will be in the complex conditions of thermo-hydro-mechanical coupling for a long time. In order to study the long-term stability of surrounding rocks, a series of heating-cooling drainage creep tests on claystone was carried out under different confining pressures and deviatoric stresses, and the following conclusions were drawn. The rise of temperature will increase the creep rate of claystone, and extend the time of decay creep stage. But during the cooling process, the samples mainly experience shrinkage deformation without obvious creep deformation being observed. The decrease of confining …

Field Assessment Of Interreplicate Variability From Eight Electromagnetic Soil Moisture Sensors, Tsz Him Lo, Daran Rudnick, Jasreman Singh, Hope Njuki Nakabuye, Abia Katimbo, Derek M. Heeren, Yufeng Ge

Biological Systems Engineering: Papers and Publications

Interreplicate variability—the spread in output values among units of the same sensor subjected to essentially the same condition—can be a major source of uncertainty in sensor data. To investigate the interreplicate variability among eight electromagnetic soil moisture sensors through a field study, eight units of TDR315, CS616, CS655, HydraProbe2, EC5, 5TE, and Teros12 were installed at a depth of 0.30 m within 3 m of each other, whereas three units of AquaSpy Vector Probe were installed within 3 m of each other. The magnitude of interreplicate variability in volumetric water content (θ_v) was generally similar between a static …

Establishment Of A Numerical Model For Sulfate Attacked Concrete Considering Multi-Factors, Shanshan Qin, Dujian Zou, Jun Jiang, Tiejun Liu

International Conference on Durability of Concrete Structures

Sulfate attack is one of the major durability problems of concrete structures, which is manifested by expansive cracks and deterioration of cement paste. In this study, a numerical model is proposed to predict the process of ionic diffusion into concrete under external sulfate attack. The chemical reaction and diffusion processes are considered in this model. Furthermore, the influence of calcium leaching, chemical activity of multi-ions, temperature and changes in porosity are also taken into account. The initial porosity and tortuosity are assumed to be homogeneous in concrete, and the chemical potential gradient is regarded as the driving force for ions …

Effects Of Temperature And Curing Duration On The Stability Of Slag Cements In Combined Chloride-Sulphate Environments, Joseph Onah Ukpata, P. A. M. Basheer, Leon Black

International Conference on Durability of Concrete Structures

This experimental study investigates the effects of temperature and curing duration on the stability of slag blended cement systems exposed at 20 °C and 38 °C to combined sodium chloride (30 g/L) – sodium sulphate (3 g/L) solutions. Two slags, designated as slag 1 and 2, having CaO/SiO₂ ratios of 1.05 and 0.94, were respectively blended with Portland cement CEM I 52.5R at 30 wt.% replacement level. Mortar prisms and cubes with w/b ratio of 0.5 and binder/aggregate ratio of 1:3 were then prepared for length and mass changes. The samples were cured in lime water for either 7 …

Analysis Of Characteristics Of Parabolic And Parabolocylindrical Hubs, Comparison Of Data Obtained On Them, J.R. Kodirov, S.Sh. Khakimova, Sh.M. Mirzaev

Journal of Tashkent Institute of Railway Engineers

Solar energy technologies can be quickly deployed and have the potential for a global transfer of technology and innovation. In order to manufacture parabolic and parabolic cylindrical concentrators, an analytical review of these two types of solar devices was carried out and, after their creation, experiments were conducted on them in the season of maximum solar radiation. The article also presents data and their comparison for planning subsequent actions of research activities.

Multi-Resolution Spatio-Temporal Change Analyses Of Hydro-Climatological Variables In Association With Large-Scale Oceanic-Atmospheric Climate Signals, Kazi Ali Tamaddun

UNLV Theses, Dissertations, Professional Papers, and Capstones

The primary objective of the work presented in this dissertation was to evaluate the change patterns, i.e., a gradual change known as the trend, and an abrupt change known as the shift, of multiple hydro-climatological variables, namely, streamflow, snow water equivalent (SWE), temperature, precipitation, and potential evapotranspiration (PET), in association with the large-scale oceanic-atmospheric climate signals. Moreover, both observed datasets and modeled simulations were used to evaluate such change patterns to assess the efficacy of the modeled datasets in emulating the observed trends and shifts under the influence of uncertainties and inconsistencies. A secondary objective of this study was to …

Using A Balloon-Launched Unmanned Glider To Validate Real-Time Wrf Modeling, Travis J. Schuyler, S. M. Iman Gohari, Gary Pundsack, Donald Berchoff, Marcelo I. Guzman

Chemistry Faculty Publications

The use of small unmanned aerial systems (sUAS) for meteorological measurements has expanded significantly in recent years. SUAS are efficient platforms for collecting data with high resolution in both space and time, providing opportunities for enhanced atmospheric sampling. Furthermore, advances in mesoscale weather research and forecasting (WRF) modeling and graphical processing unit (GPU) computing have enabled high resolution weather modeling. In this manuscript, a balloon-launched unmanned glider, complete with a suite of sensors to measure atmospheric temperature, pressure, and relative humidity, is deployed for validation of real-time weather models. This work demonstrates the usefulness of sUAS for validating and improving …

Future Changes Of Hydroclimatic Extremes In Western North America Using A Large Ensemble: The Role Of Internal Variability, Mohammad Hasan Mahmoudi

Electronic Thesis and Dissertation Repository

Increases in the intensity and frequency of extreme events in Western North America (WNA) can cause significant socioeconomic problems and threaten existing infrastructure. In this study we analyze the impacts of climate change on hydroclimatic extremes and assess the role of internal variability over WNA, which collectively drain an area of about 1 million km². We used gridded observations and downscaled precipitation, maximum and minimum temperature from seven General Circulation Models (GCMs) that participated in the Coupled Model Intercomparison Project Phase 5 (CMIP5) and a large ensemble of CanESM2 model simulations (CanESM2-LE; 50 members) for this analysis. Spatial …