Fresh Water Studies Commons^™

Cost Advantages Of Far East/Europe Trunk Route Deployment With Port Selection In East Asia, Tai Hui-Huang, Chang Chin-Wei

Journal of Marine Science and Technology–Taiwan

To cater to the gradually increasing sizes of ships, several traditional container ports in East Asia built deep-water wharves to attract shipping carriers to berth, a decision that is considered highly reasonable because it allows for shipping carriers to gain a cost advantage. For traditional Far East/Europe (F/E) trunk routes, shipping carriers must deploy vessels that are large enough at hub ports to maintain low transshipment costs. However, for a port to attract shipping carriers, it should be able to first meet the cargo demand of these carriers. The port would also need to improve the loading ratio to enjoy …

Influence Of Vacuum Condition On Rapid Chloride Migration (Rcm) Test For Chloride Penetration Resistance Of Concrete, Chih-Yen Lin, Chun-Fu Chang, Chung-Chia Yang

Journal of Marine Science and Technology–Taiwan

NT Build 492 regulates that the pressure be set at 7.5–37.5 torr and be maintained for 3 h for vacuum processing. This large range of acceptable vacuum pressure is awkward for research, and 3 h of pump-down time may be excessive. In this study, vacuum conditions were divided into vacuum pressure and pump-down time groups: various vacuum pressures and pump-down times were used to preprocess specimens to explore the effect of vacuum conditions on the RCM test. The salt ponding test was also conducted to identify the optimal vacuum conditions. It is shown that the relationship between vacuum pressure and …

Exhaust Noise Elimination Using Silencers Fortified With Perforated Tubes, Extended Tubes, Penetrable Resin Inlet And Orifice Plate, Min-Chie Chiu, Ho-Chih Cheng

Journal of Marine Science and Technology–Taiwan

Pneumatic equipment in marine diesel engine and associated piping system often emit extremely high level of noises when releasing pressure. Concerning the crew’s hearing health, discovering an efficient noise silencing device becomes essential. A silencer fortified with extended tubes, perforated tubes, orifice plate, and penetrable resin inlet is presented in order to competently dampen the blown-up noises. A simplified objective function by means of FEM, Artificial Neural Networks (ANNs), and a Genetic Algorithm (GA) is established to enable the numerical calculation when using a finite element method. Three silencer designs, silencer A (with element A, a penetrable resin inlet), B …

Deep Learning–Based, Oceantdlx Sea Ice Detection Model For Sar Image, Liu Lin, Li Wanwu, Li Hang, Sun Yi

Journal of Marine Science and Technology–Taiwan

This study constructs four deep-learning OceanTDLx series models and uses a WinR-AdaGrad gradient descent algorithm to train and optimize the constructed models. Through an analysis of the loss, accuracy, and time consumption of the four models (i.e., OceanTDL2, OceanTDL3, OceanTDL5 and OceanTDL8), we reveal that the models’ performance does not improve when the number of layers is increased and that OceanTDL5 provides the optimal performance. OceanTDL5 is compared with OceanTDA9 (a model that we previously constructed), and the curves for training loss_batch and training accuracy_batch indicate that OceanTDL5 is more suitable than OceanTDA9 for detecting distributed targets, particularly semi-melted sea …

Application Of Unmanned Aerial Vehicle–Based Infrared Images In Determining Characteristics Of Sea Surface Temperature Distribution, Hsing-Yu Wang, Hui-Ming Fang, Yun-Chih Chiang

Journal of Marine Science and Technology–Taiwan

This study investigated the temperature field of a body of water by using rotary-wing unmanned aerial vehicles (DJI Mavic 2 Enterprise Dual) comprising visible light and infrared cameras to determine sea temperature distribution. With a flight height of 150 m, image overlap of 80%, and image resolution of 4.75 cm/pixel, the proposed method was more effective than the conventional portable conductivity–temperature–depth device in rapidly measuring sea surface temperature and determining sea temperature distribution. The discharged heated water of the Hoping Power Plant traveled 100–330 m from the wastewater outfall and then gradually diffused in the range of 100–490 m before …

Projected Long-Term Climate Trends Reveal The Critical Role Of Vapor Pressure Deficit For Soybean Yields In The Us Midwest, Wenguang Sun, David Fleisher, Dennis Timlin, Chittaranjan Ray, Zhuangji Wang, Sahila Beegum, Vangimalla Reddy

Nebraska Water Center: Faculty Publications

Extreme climate events including heat waves and droughts are projected to become more frequent under future climate change conditions. However, the mechanisms between soybean yields and climate factors, specifically involving variable rainfall and high heat episodes, are still unclear, particularly with respect to spatial trends in the United States (US) Midwest. A recently modified version of the model GLYCIM was used to evaluate rainfed soybean production across 12 states at a 10 km spatial resolution for three time periods (2011–2020, 2051–2060, 2091–2099) under Representative Concentration Pathway (RCP) scenarios 4.5 and 8.5. Results showed that except for the northernmost Midwest counties, …

Simulation Of Monthly Mean And Monthly Base Flow Of Streamflow Using Random Forests For The Mississippi River Alluvial Plain, 1901 To 2018, Benjamin J. Dietsch, William H. Asquith, Brian K. Breaker, Stephen M. Westenbroek, Wade H. Kress

United States Geological Survey: Water Reports and Publications

Improved simulations of streamflow and base flow for selected sites within and adjacent to the Mississippi River Alluvial Plain area are important for modeling groundwater flow because surface-water flows have a substantial effect on groundwater levels. One method for simulating streamflow and base flow, random forest (RF) models, was developed from the data at gaged sites and, in turn, was used to make monthly mean streamflow and base-flow predictions at 162 ungaged sites in the study area. Daily streamflow observations and computed base flow from 247 streamgages were used as the basis for the development of these RF models. RF …

Importance Of Snowmelt On Soil Nitrate Leaching To Groundwater – A Model Study, Sahila Beegum, Arindam Malakar, Chittaranjan Ray, Daniel D. Snow

Nebraska Water Center: Faculty Publications

The movement of nitrate to surface water bodies during snow accumulation and melting has been extensively studied, but there are only limited studies on the influence of snow processes on nitrate leaching to groundwater. The present study investigated the impact of snow processes on nitrate leaching to groundwater based on a simulation modeling approach using HYDRUS-1D. HYDRUS-1D model has a temperature threshold-based snow model in addition to water, solute, and heat simulation components. The snow component in HYDRUS-1D was previously not applied to snow simulation studies since the method does not consider a detailed physical and process-based representation of snow …

Constituent Loads And Trends In The Upper White River Basin: A Nonpoint Source Management Program Priority Watersheds, Erin M. Grantz, Brian E. Haggard

Arkansas Water Resources Center Technical Reports

The Arkansas Department of Agriculture – Natural Resources Division (ANRD) has identified the Upper White River Basin (UWRB; HUC 11010001) a hydrologic unit code (HUC) 8 watersheds, located in Northwest Arkansas, for prioritization by the Nonpoint Source (NPS) Management Program. UWRB includes Beaver Lake in its borders, the drinking water source for 1 in 6 Arkansans. Nonpoint source pollution concerns in these watersheds are excess nutrients from agriculture and sediment from changes in land use/land cover (LULC).

Local, state, and national groups, including the NPS Source Management Program, have invested in education, best management practices, and streambank restoration in the …

Constituent Loads And Trends In The Upper Illinois River Watershed: A Nonpoint Source Management Program Priority Watershed, Erin M. Grantz, Brian E. Haggard

Arkansas Water Resources Center Technical Reports

The Arkansas Department of Agriculture - Natural Resources Division (ANRD) has identified the Upper Illinois River Watershed (UIRW; 11110103), a hydrologic unit code (HUC) 8 watershed, located in Northwest Arkansas for prioritization by the Nonpoint Source (NPS) Management Program. URIW encompasses the Illinois River from its headwaters to the state line with Oklahoma and has been the subject of interstate disputes over water quality for decades. Nonpoint source pollution concerns in UIRW are excess nutrients from agriculture and sediment from changes in land use/land cover (LULC).

Local, state, and national groups, including the NPS Source Management Program, have invested in …

Time Domain Reflectometry Waveform Interpretation With Convolutional Neural Networks, Zhuangji Wang, Shan Hua, Dennis Timlin, Yuki Kojima, Songtao Lu, Wenguang Sun, David Fleisher, Robert Horton, Vangimalla R. Reddy, Katherine Tully

Nebraska Water Center: Faculty Publications

Interpreting time domain reflectometry (TDR) waveforms obtained in soils with non-uniform water content is an open question. We design a new TDR waveform interpretation model based on convolutional neural networks (CNNs) that can reveal the spatial variations of soil relative permittivity and water content along a TDR sensor. The proposed model, namely TDR-CNN, is constructed with three modules. First, the geometrical features of the TDR waveforms are extracted with a simplified version of VGG16 network. Second, the reflection positions in a TDR waveform are traced using a 1D version of the region proposal network. Finally, the soil relative permittivity values …

Home Tap Water In Nonmetropolitan Nebraska, Rebecca J. Vogt

Cornhusker Economics

Water is an important resource in Nebraska. Most of the drinking water in the state (85%) comes from groundwater sources. Public water sources are required to test their water to ensure it is safe. However, private wells are not subject to any safety or quality standards. Given that, what are the main sources of home tap water for rural Nebraskans? Do they test or treat their water? The 2022 Nebraska Rural Poll examined these questions.

Flood-Inundation Maps For An 8-Mile Reach Of Papillion Creek Near Offutt Air Force Base, Nebraska, 2022, Kellan R. Strauch, Christopher M. Hobza

United States Geological Survey: Water Reports and Publications

Digital flood-inundation maps for an 8-mile reach of Papillion Creek near Offutt Air Force Base, Nebraska, were created by the U.S. Geological Survey (USGS) in cooperation with the U.S. Air Force, Offutt Air Force Base. The flood-inundation maps, which can be accessed through the USGS Flood Inundation Mapping Program website at https://www.usgs.gov/mission-areas/water-resources/science/flood-inundation-mapping-fim-program, depict estimates of the areal extent and depth of flooding corresponding to selected water levels (stages) at the USGS streamgages Papillion Creek at Fort Crook, Nebr. (station 06610795), and Papillion Creek at Harlan Lewis Road near La Platte, Nebr. (station 06610798). Near-real-time stages at these streamgages may …

Selected Anthropogenic Contaminants In Groundwater, Papio-Missouri River Natural Resources District, Eastern Nebraska, 1992–2020, Brent M. Hall, Cory L. Kavan, Amanda Flynn, Mikaela L. Cherry

United States Geological Survey: Water Reports and Publications

A study in cooperation with the Papio-Missouri River Natural Resources District was completed in 2019 to determine the concentration of contaminants of emerging concern (CEC) in groundwater in the Papio-Missouri River Natural Resources District, eastern Nebraska. Each well was sampled twice (in June and October or November) in 2019, totaling 34 samples. Samples were analyzed for 132 CECs, which include pharmaceutical, steroid hormone, and other organic chemicals. Seven of the 132 CEC analytes were detected in samples collected during this study. The most commonly detected CEC in this study was the antibiotic sulfamethoxazole. Other CECs detected in this study were …

An Integrated Hydrologic Model To Support The Central Platte Natural Resources District Groundwater Management Plan, Central Nebraska, Jonathan (Jp) Traylor, Moussa Guira, Steven M. Petersen

United States Geological Survey: Water Reports and Publications

The groundwater and surface-water supply of the Central Platte Natural Resources District supports a large agricultural economy from the High Plains aquifer and Platte River, respectively. This study provided the Central Platte Natural Resources District with an advanced numerical modeling tool to assist with the update of their Groundwater Management Plan.

An integrated hydrologic model, called the Central Platte Integrated Hydrologic Model, was constructed using the MODFLOW-One-Water Hydrologic Model code with the Newton solver. This code integrates climate, landscape, surface water, and groundwater-flow processes in a fully coupled approach. Model framework included 163 rows; 327 columns; 2,640 feet cell sides; …

Droughtscape, Winter 2023, National Drought Mitigation Center

DroughtScape: Quarterly Newsletter of the National Drought Mitigation Center (2007–2023)

DroughtScape, Winter 2023

A Methodology For Statistical Mean Wave Climate Regime Characterisation In Oceanic Islands: The Case Of The Southern Coast Of Tenerife, Emilio Megías, Manuel García-Román

Journal of Marine Science and Technology–Taiwan

Oceanic islands of volcanic origin tend to have peculiar characteristics, such as: exposure to many wave directions; grouping in archipelagos; steep coastal slopes; and small coastal shelves. All these features require certain considerations in wave climate studies. These types of studies, when wave spectra are not available and have to be performed with parametric data, can be unreliable without an adequate systematic treatment. In this work we propose a methodology consisting of pre-classification according to the peak period and subsequent separation into different sectors according to the geographical fetch. The island of Tenerife is the case study, and in particular …

Context-Dependent Data-Envelopment-Analysis-Based Efficiency Evaluation Of Coastal Ports In China Based On Social Network Analysis, Yu Yu, Dai-Peng Ma, Guo-Ya Gan

Journal of Marine Science and Technology–Taiwan

An emerging trend in performance evaluation is combining social network analysis methods with data envelopment analysis (DEA) models and using network centrality methods to distinguish DEA results. One study employed an input-oriented variable-returns-to-scale DEA model to address referent decision-making units and the corresponding lambda values to construct a network. This study referenced the literature and improved on the use of DEA weight sets to construct a network. We employed a context-dependent DEA model to delineate multiple effective frontier planes, aggregate the reference set relationships on each frontier plane to construct a network relationship matrix, and assess the influences of the …

Research On Improving The Salary Structure Of Port State Control Officers In Taiwan, Te-Yi Chang, Wen-Chih Ho, Chung-Ping Liu, Yung-Wei Chen

Journal of Marine Science and Technology–Taiwan

The implementation of port state control (PSC) has been challenging in Taiwan due to the lack of port state control officers (PSCOs), and foreign ships berthing at ports in Taiwan that cannot be effectively inspected. PSCOs of Taiwan are subordinate to the public service system and restrained by the number of personnel by the Executive Yuan. Compared with similar professions, their salaries are significantly different from those of the industry, making recruiting and retaining PSCOs a difficult task. Accordingly, this study improved the salary structure of PSCOs by conducting field interviews with existing PSCOs in Taiwan and applying the Fuzzy-AHP …

Numerical Analysis Of Silencer With A Coiled Tube And Straight Perforated Tube Using Fem, Min-Chie Chiu, Ho-Chih Cheng

Journal of Marine Science and Technology–Taiwan

Marine diesel engine is essential on a ship, but emits extremely loud noise harmful to human hearing. Therefore, it is mandatory to use silencers to reduce the venting noise of the marine diesel engine. An advanced silencer with a new acoustical element of a curved tube, along with perforated holes, is presented to suppress the noise wave. To predict the silencer's acoustical performance for high-order waves, a finite element model was built using COMSOL. The influence of the silencer's noise reduction ability was investigated by exploring sensitivity using acoustical simulations on COMSOL, regarding the silencer's geometric factors. The results proved …