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Articles 2401 - 2430 of 6118

Full-Text Articles in Engineering

Investigation Of The Effectiveness Of An Integrated Flooded-Bed Dust Scrubber On A Longwall Shearer Through Laboratory Testing And Cfd Simulation, Sampurna N. Arya Jan 2018

Investigation Of The Effectiveness Of An Integrated Flooded-Bed Dust Scrubber On A Longwall Shearer Through Laboratory Testing And Cfd Simulation, Sampurna N. Arya

Theses and Dissertations--Mining Engineering

Dust generation at an underground coal mine working face continues to be a health and safety issue. Prolonged exposure to high concentrations of airborne respirable dust can cause a debilitating and often fatal respiratory disease called Black Lung. In addition, the deposition of float dust in mine return airways poses a serious safety hazard if not sufficiently diluted with inert rock dust. A localized methane explosion can transition into a self-propagating dust explosion. Since dust is a byproduct of various mining activities, such as cutting and loading, crushing, and transportation, the dust-related issues cannot be totally eliminated. However, the adverse …


Pressure-Driven Stabilization Of Capacitive Deionization, Landon S. Caudill Jan 2018

Pressure-Driven Stabilization Of Capacitive Deionization, Landon S. Caudill

Theses and Dissertations--Mechanical and Aerospace Engineering

The effects of system pressure on the performance stability of flow-through capacitive deionization (CDI) cells was investigated. Initial data showed that the highly porous carbon electrodes possessed air/oxygen in the micropores, and the increased system pressure boosts the gases solubility in saline solution and carries them out of the cell in the effluent. Upon applying a potential difference to the electrodes, capacitive-based ion adsorption occurs in competition with faradaic reactions that consume oxygen. Through the addition of backpressure, the rate of degradation decreases, allowing the cell to maintain its salt adsorption capacity (SAC) longer. The removal of oxygen from the …


Evaluating Hydrologic Fluxes Through Stormwater Treatment Systems: Implication To Freshwater Springs In A Karst Environment, Nyle Rice Jan 2018

Evaluating Hydrologic Fluxes Through Stormwater Treatment Systems: Implication To Freshwater Springs In A Karst Environment, Nyle Rice

Electronic Theses and Dissertations

In recent years, concentrations of nutrients such as nitrogen and phosphorus have increased in surface and groundwater resources, due in part to non-point source pollution associated with stormwater runoff. The elevated nutrient concentrations found in stormwater runoff have prompted the design of best management practices (BMP's) to mitigate the problem. The overall objective within this thesis is to analyze the performance of innovative surface BMPs and investigate connections between the BMPs and groundwater flows to freshwater springs within a karst environment. The performance of two stormwater BMPs, blanket filters and vertical reactors containing Bio-sorption Activated Media (BAM), are assessed in …


Use Of Accelerated Calcite Precipitation Method To Investigate Calcium Carbonate Precipitation From Recycled Concrete For Drainage System Applications, Toni Curate Jan 2018

Use Of Accelerated Calcite Precipitation Method To Investigate Calcium Carbonate Precipitation From Recycled Concrete For Drainage System Applications, Toni Curate

Electronic Theses and Dissertations

Recycled concrete aggregate (RCA) is a sustainable construction material that is a viable option for use in drainage systems by replacing virgin aggregate. Replacing virgin aggregate with RCA is beneficial from both economic and environmental perspectives. However, the use of RCA as pipe backfill materials may cause a long-term performance issue such as potential clogging due to fines accumulation and calcite precipitation on filter fabric. Previous studies investigated the long-term performance of RCA regarding flow rate. Therefore, this study investigated calcite precipitation potential of RCA. The Accelerated Calcite Precipitation (ACP) procedure was devised and used to estimate "life-time" calcite precipitation …


Mechanisms Controlling Copper Transport In Natural Soils, Julie A. Luisi Jan 2018

Mechanisms Controlling Copper Transport In Natural Soils, Julie A. Luisi

Civil and Environmental Engineering Master's Project Reports

Biosolids are used as amendments to agricultural soils and can be a source of trace metals. It is unknown if these land-applied trace metals travel through the soil column to the water table. This study aims to determine the transport behavior of copper in natural soils, including 'aged' soils, commercial agricultural soils that have had multiple years of biosolids applications. Using acid digests and Darcy column apparatus it was determined that factors such as pH, soil composition, especially organic matter content, and the presence of other trace metals influence copper’s complex transport behavior in these soils. Natural soil appears to …


Evaluation, Improvement, And Application Of Models Of Environmental Fate And Transport Of Atmosphere-Surface Exchangeable Pollutants (Aseps), Tanvir Khan Jan 2018

Evaluation, Improvement, And Application Of Models Of Environmental Fate And Transport Of Atmosphere-Surface Exchangeable Pollutants (Aseps), Tanvir Khan

Dissertations, Master's Theses and Master's Reports

Certain toxic, semivolatile chemicals, also known as atmosphere-surface exchangeable pollutants (ASEPs) are emitted into the environment from anthropogenic activities and natural sources. This dissertation focused on the (i) evaluation and improvement of dry particle deposition and atmosphere-surface exchange parameterizations of ASEPs for use in chemical transport models (CTMs), and (ii) application of a dynamic multimedia model to examine recovery of Lake Superior from historical inputs of polychlorinated biphenyl (PCB) compounds (a class of ASEPs) contamination.

Current knowledge has been inadequate to propose quantitative measures of the relative performance of available dry particle deposition parameterizations. In Chapter 1 of this dissertation, …


Modeling Canopy Effect In The Great Lakes Cladophora Model, Ankita Bakshi Jan 2018

Modeling Canopy Effect In The Great Lakes Cladophora Model, Ankita Bakshi

Dissertations, Master's Theses and Master's Reports

Cladophora glomerata is a filamentous green alga native to the Great Lakes. However, its nuisance growth in phosphorus rich waters negatively affects the lakes’ aesthetic and water quality. The Great Lakes Cladophora Model (GLCM) v1, developed in 1982, was the first mechanistic model to simulate Cladophora growth basing phosphorus availability and environmental conditions followed by Cladophora Growth Model and GLCM v2. In this study, the light and temperature mediation factors for Cladophora net growth are revised as a necessary step prior to the development of a self-shading algorithm. The concept of a fixed-value, maximum achievable biomass (carrying capacity) employed in …


Predicting The Organic Compound Degradation In Aqueous-Phase Ultraviolet (Uv) And Uv-Based Advanced Oxidation Processes, Erica Coscarelli Jan 2018

Predicting The Organic Compound Degradation In Aqueous-Phase Ultraviolet (Uv) And Uv-Based Advanced Oxidation Processes, Erica Coscarelli

Dissertations, Master's Theses and Master's Reports

Clean safe drinking water is vital for society. With increasing water scarcity and the increased numbers of chemicals identified in waterways, it is important for us to fully understand how to destroy contaminants of concern and prevent potentially hazardous byproducts that may be produced from the degradation processes. Little is known about how nitrogen containing organics behave and degrade in current water treatment systems and therefore their role in water reuse. N-nitrosodimethylamine (NDMA), is carcinogenic and is being formed during conventional chlorination of drinking water. Ultraviolet (UV) photooxidation has been shown to degrade NDMA, but the degradation pathways and their …


Transient Simulations Of Freshwater Lens Depletion In Response To A Range Of Sea Level Rise Rates And Climate Gradients, Qiuyuan Nan Jan 2018

Transient Simulations Of Freshwater Lens Depletion In Response To A Range Of Sea Level Rise Rates And Climate Gradients, Qiuyuan Nan

Dissertations, Master's Theses and Master's Reports

The freshwater lens in the island can become the only freshwater resources in some regions. Numerical simulations are used to determine freshwater lens volume and average concentration is in response to the range of sea-level rise rates and climate gradients. The sea-level rise rates (0.56 mm/yr, 6.22 mm/yr, and 11.78 mm/yr) are selected for projected and the climate gradient is computed from the islands in the Bahamian archipelago (Inagua, San Salvador, and Grand Bahamas) in the north, central and south. Based on the simulation results, all cases presented the upward trend of the average salinity but have the oscillation in …


Optimizing Chlorine Disinfection By Chlorine Injection Location And Pipe Diameter Selection In A Water Distribution System, Margaret Neff Jan 2018

Optimizing Chlorine Disinfection By Chlorine Injection Location And Pipe Diameter Selection In A Water Distribution System, Margaret Neff

Dissertations, Master's Theses and Master's Reports

Due to a variety of factors chlorination is common water disinfectant for community-scale distribution systems. The town of Suyo, Peru was already equipped with a gravity fed water system and drip chlorinator which achieved 4-log inactivation of viruses throughout the town, however, it was not providing 3-log inactivation of giardia cysts at all points of the system.

This project used an EPANET model to determine and compare the potential benefits of changes which could be made to the pre-existing water system in Suyo.

The model was used to compare current operating conditions of the Suyo system, 1.5 mg/L chlorine addition …


Polychlorinated Biphenyls (Pcbs): A Legacy Of Contamination In Michigan's Rivers, Emily Shaw Jan 2018

Polychlorinated Biphenyls (Pcbs): A Legacy Of Contamination In Michigan's Rivers, Emily Shaw

Dissertations, Master's Theses and Master's Reports

Polychlorinated biphenyls (PCBs) are ubiquitous contaminants worldwide and are the most frequent contaminant at US and bi-national Great Lakes areas of concern (AOCs). This study evaluated existing evidence to answer the questions: how does total PCB contamination compare between fish species, are there spatial patterns in PCB contamination in fish species, and have our remediation efforts been effective? Using multi-variate statistics (e.g. analysis of variance (ANOVA), principal component analysis (PCA), and multiple linear regression (MLR)), this research evaluated Michigan Department of Environmental Quality (MDEQ) fish contaminant monitoring data to attempt to answer the questions above.

PCB concentrations between the species …


Molecular Biogeochemistry Of A Poor Fen, Zhimin Song Jan 2018

Molecular Biogeochemistry Of A Poor Fen, Zhimin Song

Dissertations, Master's Theses and Master's Reports

Variations in climate may rapidly change the carbon balance of peatlands and increase greenhouse gas emissions through accelerated decomposition of peat and dissolved organic matter (DOM). In this study, porewater samples were collected monthly from May to October in 2017 to study the effects of plant functional groups (PFGs) on DOM, dissolved inorganic and organic nitrogen through the season in a poor fen with replicate plots dominated by different PFGs in Nestoria, Michigan, USA (46.34˚N 88.16˚W). The composition of the peat porewater showed strong statistical significance with plot type and season.The observed PFG and season impact on the composition of …


Wildfire Emissions In The Context Of Global Change And The Implications For Mercury Pollution, Aditya Kumar Jan 2018

Wildfire Emissions In The Context Of Global Change And The Implications For Mercury Pollution, Aditya Kumar

Dissertations, Master's Theses and Master's Reports

Wildfires are episodic disturbances that exert a significant influence on the Earth system. They emit substantial amounts of atmospheric pollutants, which can impact atmospheric chemistry/composition and the Earth’s climate at the global and regional scales. This work presents a collection of studies aimed at better estimating wildfire emissions of atmospheric pollutants, quantifying their impacts on remote ecosystems and determining the implications of 2000s-2050s global environmental change (land use/land cover, climate) for wildfire emissions following the Intergovernmental Panel on Climate Change (IPCC) A1B socioeconomic scenario.

A global fire emissions model is developed to compile global wildfire emission inventories for major atmospheric …


Two Pumps, One Volcano: An Epanet Feasbility Study Of Connecting Two Groundwater Pumps In Rural Coastal Communities In West Ambae, Vanuatu, Helen Amiri Jan 2018

Two Pumps, One Volcano: An Epanet Feasbility Study Of Connecting Two Groundwater Pumps In Rural Coastal Communities In West Ambae, Vanuatu, Helen Amiri

Dissertations, Master's Theses and Master's Reports

In situations where groundwater supply shows vulnerability, improving water distribution network resiliency can be desirable. To do so, one water source can be linked with another to provide a redundant source.

On the South Pacific island of Ambae, the water demands of its residents routinely exceeded supply. Residents had traditionally used rainwater collection as their sole water supply source. In 2017, groundwater drilling operations created an alternative water supply at two community institutions, Ndui Ndui Health Center and Londua Junior Secondary School. One borehole went dry during pump testing; the feasibility of linking these two boreholes is investigated herein.

EPANET …


The Transport Of Non-Spherical Particles In A Simulated Ocean Environment, Hannah Reed Jan 2018

The Transport Of Non-Spherical Particles In A Simulated Ocean Environment, Hannah Reed

REU Final Reports

Plastic particles contaminating the world’s oceans and accumulating in oceanic gyres has become a ubiquitous problem and the solution involving how to clean up the debris efficiently has still not been found. One particular issue is understanding where the greatest densities of debris may be. It is known that floating trash will tend to accumulate in large circular systems of ocean water called gyres, however these areas span thousands of miles of ocean. The present study aims to understand the transport of anisotropic particles in conditions similar to an oceanic environment using experimental methods in an effort to better predict …


Day Laborers & Extreme Heat: Recommendations For Reducing Heat Stress, Sandra Mena Jan 2018

Day Laborers & Extreme Heat: Recommendations For Reducing Heat Stress, Sandra Mena

REU Final Reports

The Intergovernmental Panel on Climate Change (IPCC) has various Global Climate Models (GCM). One of them, models three greenhouse gases. The increasing amount of greenhouse gases are just a fraction of factors that fuel global climate change. According to the IPCC 2014, climate related extremes such as heatwaves are likely to occur more regularly and are likely to increase in duration. Since 1979, there has been over 9000 deaths that occurred from heat-related incidents in the United States (U.S. Environmental Protection Agency, 2016). Which brings attention to population groups who are exposed to hot temperatures on a frequent basis due …


Water Quality Factor Prediction Using Supervised Machine Learning, Kathleen Joslyn Jan 2018

Water Quality Factor Prediction Using Supervised Machine Learning, Kathleen Joslyn

REU Final Reports

The objective of this research is to explore prediction accuracy of water quality factors, with techniques and algorithms in machine learning consisting of a variation of support vector machines - Support Vector Regression (SVR) and the gradient boosting algorithm Extreme Gradient Boosting (XGBoost). Both the XGBoost and SVR algorithms were used to predict nine different factors with success rates ranging from 79% to 99%. Parameters of these algorithms were also explored to test the prediction accuracy levels of individual water quality factors. These parameters included normalizing the data, filling missing data points, and training and testing on a large set …


Effects Of Land Development And Season On Heavy Metal Concentrations In Urban Streams, Helen Daigle Jan 2018

Effects Of Land Development And Season On Heavy Metal Concentrations In Urban Streams, Helen Daigle

REU Final Reports

Although it is generally understood that urban development can impact the quality of urban streams, there are many factors that affect the concentrations of pollutants being transferred from the built environment to a given output. This study examines the impact of land use surrounding urban streams, specifically, the degree of development and presence or absence of green infrastructure (GI) in these areas on heavy metal (HM) concentrations in Portland, Oregon. After collecting 1021 water quality samples from 2010-2018, we examined the difference in concentrations of HM pollutants across different combinations of land use and season. Increased levels of calcium, magnesium, …


Cellulose And Sulfate Degradation In A Biochemical Reactor During Treatment Of Mine Drainage, Sweta Ojha Jan 2018

Cellulose And Sulfate Degradation In A Biochemical Reactor During Treatment Of Mine Drainage, Sweta Ojha

Masters Theses

"Seventy-two biochemical reactors were set up, and operated using a mixture of chip-bark, horse manure, and gravel as the biochemical treatment substrate. The simulated mine water containing sulfate (1000 mg/l) was pumped into each reactor at a flow rate of 0.5 ml/minute (approximate), giving an empty bed contact time of 8 days. The main idea is that the microorganisms present in horse manure would convert the cellulose in chip-bark into volatile fatty acids. The produced volatile fatty acid would enhance the metabolism of sulfate-reducing bacteria (SRB) initially present in horse manure, which would degrade (and eventually remove) the sulfate from …


Numerical Modeling Of Capillary-Driven Flow In Open Microchannels: An Implication Of Optimized Wicking Fabric Design, Mehrad Gholizadeh Ansari Jan 2018

Numerical Modeling Of Capillary-Driven Flow In Open Microchannels: An Implication Of Optimized Wicking Fabric Design, Mehrad Gholizadeh Ansari

Masters Theses

"The use of microfluidics to transfer fluids without applying any exterior energy source is a promising technology in different fields of science and engineering due to their compactness, simplicity and cost-effective design. In geotechnical engineering, to increase the soil's strength, hydrophilic wicking fibers as type of microfluidics have been employed to transport and drain water out of soil spontaneously by taking advantage of natural capillary force without using any pumps or other auxiliary devices. The objective of this study is to understand the scientific mechanisms of the capability for wicking fiber to drain both gravity and capillary water out of …


A Model To Predict Concentrations And Uncertainty For Mercury Species In Lakes, Ashley Hendricks Jan 2018

A Model To Predict Concentrations And Uncertainty For Mercury Species In Lakes, Ashley Hendricks

Dissertations, Master's Theses and Master's Reports

To increase understanding of mercury cycling, a seasonal mass balance model was developed to predict mercury concentrations in lakes and fish. Results indicate that seasonality in mercury cycling is significant and is important for a northern latitude lake. Models, when validated, have the potential to be used as an alternative to measurements; models are relatively inexpensive and are not as time intensive. Previously published mercury models have neglected to perform a thorough validation. Model validation allows for regulators to be able to make more informed, confident decisions when using models in water quality management. It is critical to quantify uncertainty; …


Factors Contributing To Elevated Concentrations Of Mercury And Pcbs In Fish In The Inland Lakes Of Michigan's Upper Peninsula And Lake Superior, Mugdha Priyadarshini Jan 2018

Factors Contributing To Elevated Concentrations Of Mercury And Pcbs In Fish In The Inland Lakes Of Michigan's Upper Peninsula And Lake Superior, Mugdha Priyadarshini

Dissertations, Master's Theses and Master's Reports

Mercury (Hg) pollution adversely affects ecosystems and human health. Mercury in the form of methylmercury (MeHg) bioaccumulates in aquatic ecosystems, thereby affecting fish, fish-eating wildlife and humans. The goal of this research was to clarify the effects of environmental factors on MeHg concentrations in fish in the inland lakes of the Upper Peninsula of Michigan. Of the 74 lakes for which data were available, 56 had fish mercury concentrations above the water quality guideline. Multivariate statistical analyses indicated different factors affect fish Hg concentrations in large and small lakes.

Polychlorinated biphenyl (PCB) compounds are a class of persistent, bioaccumulative and …


A Comparative Study Characterizing Traffic Related Air Pollutant Concentrations At Near-Road Communities In El Paso, Texas, Adan Rangel Jan 2018

A Comparative Study Characterizing Traffic Related Air Pollutant Concentrations At Near-Road Communities In El Paso, Texas, Adan Rangel

Open Access Theses & Dissertations

Numerous scientific studies have demonstrated the influence of traffic related air pollution at near-road communities and the associated health risks for these populations. This study uses on-site air quality monitors to characterize air pollutants at near-road schools in El Paso, TX to understand children's exposure to traffic-related air pollutants. Ambient air monitoring stations were installed at Coldwell Elementary, Bliss Elementary, and a residential house located in close proximity to major inter-state roadways. In this study, air quality data for PM2.5, PM10, NO2, and O3 was collected over a period of nine weeks in Fall 2018. The spatial and temporal variability …


Experimental Study Of Hydraulic Conductivity Of A Soil-Bentonite Cutoff Wall, Landon Crawford Barlow Jan 2018

Experimental Study Of Hydraulic Conductivity Of A Soil-Bentonite Cutoff Wall, Landon Crawford Barlow

Master’s Theses

Soil-bentonite (SB) cutoff walls are commonly employed in the US to control groundwater flow and subsurface contaminant migration. In these applications, both the short-term (as built) integrity of the barrier and the potential for degradation in the integrity of the barrier over time are of critical importance. Although many laboratory studies have been conducted to investigate the performance of SB cutoff walls as hydraulic barriers and the various factors affecting this performance, field investigations are scarce. With support from the National Science Foundation, a 200 m long, 7 m deep, and 0.9 m wide SB cutoff wall has been designed, …


Multi-State Multi-Objective Reliability Analysis Of Renewable Energy Systems, Luis Ramirez Jan 2018

Multi-State Multi-Objective Reliability Analysis Of Renewable Energy Systems, Luis Ramirez

Open Access Theses & Dissertations

This work presents a new multi-objective evolutionary algorithm (MOEA), capable of obtaining a system's reliability while considering other objectives that concurrently need to be optimized. The algorithm is applied in two different case studies. One of the problems considers a multi-state, multi-objective renewable energy system which tries to find a configuration between solar panels and wind turbines that maximizes the system's reliability of achieving specific energy demand, while also minimizes the purchasing cost of the system. The second case study analyzes a flexible manufacturing system that contains different machines that can perform different functions. The primary objective is to obtain …


Evaluation Of Orthophosphate Based Corrosion Inhibitors In Treated Water For El Paso Region, Francisco Solis Jr Jan 2018

Evaluation Of Orthophosphate Based Corrosion Inhibitors In Treated Water For El Paso Region, Francisco Solis Jr

Open Access Theses & Dissertations

Corrosion is an electrochemical phenomenon that involves the deterioration of a metal by the reaction of itself with its surrounding environment. One of the greatest issues for water utilities around the country is to keep the water quality safe. Corrosion can affect the quality of the water that we use on a daily basis by adding a bad taste, increasing the concentration of heavy metals, and allowing outside contaminants to enter the distribution system. The use of phosphate based corrosion inhibitors was tested in two different metals: iron and copper. The phosphate in the inhibitors react with the calcium in …


Evaluation Of Commercial Pervaporation Membranes For Desalination Of Saline And Brackish Waters, Andres F. Sanchez Jan 2018

Evaluation Of Commercial Pervaporation Membranes For Desalination Of Saline And Brackish Waters, Andres F. Sanchez

Open Access Theses & Dissertations

Pervaporation is a solution separation method that occurs by vapor transport through a selective membrane. As the need to provide drinking water to the growing population increases, pervaporation has potential merit as an alternative desalination technology, especially for water with very high salinity.

To our knowledge, there are no commercially available pervaporation membranes made specifically for desalination applications. Thus, the membranes PERVAP 4100 and PERVAP 4101 manufactured by DeltaMemAG were tested to evaluate their performance in desalination. Because the driving force in pervaporation is the difference in vapor pressure between the feed side and the permeate side of the membrane, …


An Assessment Of Trihalomethanes And Haloacetic Acids On The Cancer Exposure Risk Of Ohio Drinking Water Systems, Stephen Sykes Jan 2018

An Assessment Of Trihalomethanes And Haloacetic Acids On The Cancer Exposure Risk Of Ohio Drinking Water Systems, Stephen Sykes

Williams Honors College, Honors Research Projects

The cancer exposure risk from drinking chlorine-based disinfection by-products (DBPs) such as trihalomethanes (THMs) and haloacetic acids (HAAs) has been established as a major concern to public health as 98% of the United States drinking water systems in operation use chlorinated systems to disinfect the water they provide [2]. Using data collected from the Ohio Environmental Protection Agency from January 2014 to September 2017 in the cites of Cleveland, Columbus, Cincinnati, Canton, and Akron this study attempts to look at the risk of cancer caused by the DBPs. To show the relative risk of several different systems in operation from …


Viability Of Graywater Reuse In Lesotho’S Lowland Agricultural District, Ryan Wagner Jan 2018

Viability Of Graywater Reuse In Lesotho’S Lowland Agricultural District, Ryan Wagner

Dissertations, Master's Theses and Master's Reports

Water security has become a large issue with populations rising and weather patterns changing to drier and hotter conditions in southern Africa. Lesotho, a mountainous country landlocked by South Africa, is responsible for a large amount of the rainfall in southern Africa. As such, Lesotho provides water to South Africa in exchange for national economic growth. Lesotho, however, is also prone to droughts and with water reserves being sold to South Africa, water security has become a national issue. This study looked at Lesotho’s current water use habits and found that graywater reuse could lead to much more available water. …


Detection Of Multi-Tomato Leaf Diseases (Late Blight, Target And Bacterial Spots) In Different Stages By Using A Spectral-Based Sensor, Jinzhu Lu, Reza Ehsani, Yeyin Shi, Ana Isabel De Castro, Shuang Wang Jan 2018

Detection Of Multi-Tomato Leaf Diseases (Late Blight, Target And Bacterial Spots) In Different Stages By Using A Spectral-Based Sensor, Jinzhu Lu, Reza Ehsani, Yeyin Shi, Ana Isabel De Castro, Shuang Wang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Several diseases have threatened tomato production in Florida, resulting in large losses, especially in fresh markets. In this study, a high-resolution portable spectral sensor was used to investigate the feasibility of detecting multi-diseased tomato leaves in different stages, including early or asymptomatic stages. One healthy leaf and three diseased tomato leaves (late blight, target and bacterial spots) were defined into four stages (healthy, asymptomatic, early stage and late stage) and collected from a field. Fifty-seven spectral vegetation indices (SVIs) were calculated in accordance with methods published in previous studies and established in this study. Principal component analysis was …