Field Case Research Articles

Assessment of Informal Settlement in Central Kandahar: A Case Study of Area Within Four Historic Gateways

Afghanistan's post-war recovery, commencing in 2001 following the cessation of hostilities, precipitated rapid urbanization, notably witnessed by a substantial proliferation of informal settlements, primarily concentrated in Kandahar Province. This phenomenon, exacerbated by significant rural-to-urban migration and population expansion, has emphasized the imperative for exhaustive research aimed at comprehensively understanding its definitions, associated types and potential impacts of informal settlement. The proliferation of informal settlements in Kandahar's historic gateways presents a complex challenge necessitating meticulous and nuanced analysis. The research endeavors to undertake a comprehensive exploration of the definitional constructs of informal settlements, encompassing diverse typologies and their ramifications on urban settings. Central to this endeavor are key objectives aimed at scrutinizing squatter settlements, discerning their typologies, including Spontaneous Sheltering, Homeless Encampments, Nomadic Tents, Refugee Camps, Carts and Wagons, Squatter Settlements, Slums, Self-Help Housing, Shantytowns, Informal Subdivisions and Tenement Housing. Furthermore, the research aims to assess the effects associated with informal supplementary settlements, which encompass a broad spectrum of socioeconomic and environmental ramifications, such as Overcrowding, Poor Living Conditions, High Levels of Poverty, Limited Basic Services, Social Marginalization, Health Risks, Inadequate Sanitation Facilities and Vulnerability. Employing a mixed-methods approach integrating field observations, surveys, Case Studies and literature review, the research seeks to comprehensively understand the complexities of informal settlement dynamics, thus providing insights for informed policy formulation and interventions in urban planning.

PELAKSANAAN PROGRAM PENDAFTARAN TANAH SISTEMATIS LENGKAP (PTSL) DI KANTOR BPN KAB. PROBOLINGGO

Abstract
 
 The land registration program through complete systematic land registration (PTSL) which targets land registration throughout Indonesia is expected to be completed in 2025. This is the first land registration activity to be carried out simultaneously. How is it implemented and what obstacles are faced by BPN Kab. Probolinggo in implementing the PTSL program. Apart from that, this research also aims to identify steps that can be taken to overcome these obstacles and increase the efficiency of PTSL implementation. This research uses an empirical juridical approach. Data was obtained through field case studies, literature and policy analysis relevant to the PTSL Program. This research found that PTSL has an important role in providing legal certainty and protection of land rights in Indonesia. However, obstacles faced include limited human resources, geographic challenges, and administrative complexity. To overcome this, it is necessary to increase recruitment and training of human resources, use of information technology, collaboration between related parties, and a holistic, technology-based approach. By overcoming these obstacles, PTSL can be implemented more efficiently and provide greater benefits in providing legal certainty and protection of land rights in Indonesia.
 
 Keywords: Land Registration, PTSL Program, Land Certificate

A data-driven strategy for pre-fracturing design of pump rate in deep shale gas fracturing

The deep shale formation (>3500 m) reserves rich oil and gas resources but is difficult to exploit due to the high risk and low efficiency of hydraulic fracturing, for instance, the high level of wellhead pressures (∼100 MPa) and difficulties in proppant injection. The sand screen-out occurs frequently in deep shale fracturing, during which the pump schedule is usually designed referring to neighbor wells or relying on human experiences. A scientific criterion for optimizing the pump schedule at field-practical scales is urgent for deep shale fracturing compared with the previous empirical estimation. Therefore, the pump rate for proppant injection (PRPI) is defined as a new strategy for the pre-fracturing design. A data-driven workflow is established to process the field data to fit the PRPI, which integrates numerical models (for feature extractions), machine learning algorithms (for feature optimization) and the STATA software. Field data of sand screen-out cases are collected from deep shale gas fracturing wells. The sand-fluid ratio (the volume ratio of injected proppant and fluids) is optimized as the moderating variable for fitting the PRPI based on the Pearson correlation coefficient and the variable importance measure (VIM, Random Forest algorithm). The pre-designed pump rate is fitted in STATA software under different levels of sand-fluid ratio, based on which a positive linear correlation (between pump rate and sand-fluid ratio) and an exponential correlation (between screen-out probability and sand-fluid ratio) are obtained. A field case of deep shale gas fracturing is also presented to verify and explain the usage of PRPI, in which the optimized pump rate is around 15.7 m3/min. This new strategy provides a scientific and quantitative criterion for the pre-fracturing design of pump schedules compared with empirical estimations based on individual experience, which may be significant for improving proppant injection and securing real-time operations of deep shale fracturing.

Metastability for the degenerate Potts Model with positive external magnetic field under Glauber dynamics

We consider the ferromagnetic q-state Potts model on a finite grid graph with non-zero external field and periodic boundary conditions. The system evolves according to Glauber-type dynamics described by the Metropolis algorithm, and we focus on the low temperature asymptotic regime. We analyze the case of positive external magnetic field associated to one spin value. In this energy landscape there is one stable configuration and q−1 metastable states. We study the asymptotic behavior of the first hitting time from any metastable state to the stable configuration as β→∞ in probability, in expectation, and in distribution. We also identify the exponent of the mixing time and find an upper and a lower bound for the spectral gap. Finally, we identify all the minimal gates and the tube of typical trajectories for the transition from any metastable state to the unique stable configuration by giving a geometric characterization.

Mechanisms of Waterflood Inefficiency: Analysis of Geological, Petrophysical and Reservoir History, a Field Case Study of FWU (East Section)

The petroleum reservoir represents a complex heterogeneous system that requires thorough characterization prior to the implementation of any incremental recovery technique. One of the most commonly utilized and successful secondary recovery techniques is waterflooding. However, a lack of sufficient investigation into the inherent behavior and characteristics of the reservoir formation in situ can result in failure or suboptimal performance of waterflood operations. Therefore, a comprehensive understanding of the geological history, static and dynamic reservoir characteristics, and petrophysical data is essential for analyzing the mechanisms and causes of waterflood inefficiency and failure. In this study, waterflood inefficiency was observed in the Morrow B reservoir located in the Farnsworth Unit, situated in the northwestern shelf of the Anadarko Basin, Texas. To assess the potential mechanisms behind the inefficiency of waterflooding in the east half, geological, petrophysical, and reservoir engineering data, along with historical information, were integrated, reviewed, and analyzed. The integration and analysis of these datasets revealed that several factors contributed to the waterflood inefficiency. Firstly, the presence of abundant dispersed authigenic clays within the reservoir, worsened by low reservoir quality and high heterogeneity, led to unfavorable conditions for waterflood operations. The use of freshwater for flooding exacerbated the adverse effects of sensitive and migratory clays, further hampering the effectiveness of the waterflood. In addition to these factors, several reservoir engineering issues played a significant role in the inefficiency of waterflooding. These issues included inadequate perforation strategies due to the absence of detailed hydraulic flow units (HFUs) and rock typing, random placement of injectors, and uncontrolled injected fresh water. These external controlling parameters further contributed to the overall inefficiencies observed during waterflood operations in the east half of the reservoir. A detailed understanding of the mechanistic factors of inefficient waterflood operation will provide adequate insights into the development of the improved recovery technique for the field.

Prestack sparse envelope seismic inversion method adopting the L0−L2-norm regularization

The high drilling costs limit the possibility of obtaining reliable low-frequency constrained models in marine environments or areas with sparse well-log data, making it difficult to constrain lateral continuity and deep data. To enhance stability and accuracy in prestack seismic inversion in these areas, an elastic parameter estimation approach using sparse envelope inversion with [Formula: see text]-norm regularization is proposed. The method combines signal sparse representation and modulation theories to derive a new formula for sparse envelope extraction at lower frequencies. By applying [Formula: see text]-norm regularization to the sparse envelope, we obtain parameter inversion results with smoothed trends, augmenting low-wavenumber information for improved model constraints. In addition, taking the envelope inversion results obtained by the [Formula: see text] norm as the model constraint, the sparsest inversion results with obvious block-like characteristics are obtained by regularizing the inversion equation with the [Formula: see text] norm. Notably, the new method effectively suppresses wavelet side lobes, resulting in stable and accurate inversions without the need for initial low-frequency models. A synthetic example is used to illustrate the feasibility and stability of proposed approach and further demonstrate its practicality in reservoir parameter estimation through a field case study of gas exploration.

Generalized Analytical Well-Test Solutions for Vertically Fractured Wells in Commingled Reservoirs

Abstract Layered zones with vertical fracture are often found in analyzing well-test data of deep/ultra-deep reservoirs and tight reservoirs. Analyzing and modeling the well-test data in a computation-accurate and easy-program manner have been a challenge for these problems due to the lack of suitable solutions. This work thus presents the generalized analytical well-test solutions for vertically fractured wells in infinite and bounded commingled reservoirs with computation accuracy and functional simplicity. These solutions are derived based on the early-time approximate solution of the infinite/finite-conductivity fracture model, Laplace and Fourier cosine transformation, pressure superposition principle, and Duhamel principle. Subsequently, model validation is carried out by comparing the pressure and derivative results with those of commercial saphir software. The results show that the average absolute percent deviation between the presented analytical solutions and saphir for three kinds of outer boundaries is ∼2% for pressure results and ∼4% for pressure derivative results. Finally, a field case in Xinjiang oilfield is interpreted, indicating that the proposed analytical well-test solutions are feasible to interpret the parameters of commingled reservoirs.

Generalized Pohst inequality and small regulators

Current methods for the classification of number fields with small regulator depend mainly on an upper bound for the discriminant, which can be improved by looking for the best possible upper bound of a specific polynomial function over a hypercube. In this paper, we provide new and effective upper bounds for the case of fields with one complex embedding and degree between five and nine: this is done by adapting the strategy we have adopted to study the totally real case, but for this new setting several new computational issues had to be overcome. As a consequence, we detect the four number fields of signature ( r 1 , r 2 ) = ( 6 , 1 ) (r_1,r_2)=(6,1) with smallest regulator; we also expand current lists of number fields with small regulator in signatures ( 3 , 1 ) (3,1) , ( 4 , 1 ) (4,1) and ( 5 , 1 ) (5,1) .

Indigofera cryptantha-induced pigmenturia in cattle in South Africa

Two field cases of reddish-black pigmenturia occurred where cattle grazed on an established Cenchrus ciliaris (blue buffalo grass) pasture in South Africa. The pasture was noticeably invaded by Indigofera cryptantha, which was heavily grazed. Apart from the discolored urine, no other clinical abnormalities were detected. Urinalysis revealed hemoglobinuria, proteinuria and an alkaline pH. When the animals were immediately removed from the infested pasture, they made an uneventful recovery. However, a bull died when one of the herds could not be removed from the I. cryptantha-infested pasture. Macroscopically, the kidneys were dark red in color and the urinary bladder contained the dark pigmented urine. Microscopically, the renal tubules contained eosinophilic, granular pigment casts in the lumen. In addition, many renal tubular epithelial cells were attenuated with granular cytoplasm and were detached from the basement membranes. Chemical analysis was performed on dried, milled plant material and two urine samples collected during the field investigations. Qualitative UPLC-UV-qTOF/MS analysis revealed the presence of indican (indoxyl-β-glucoside) in the stems, leaves and pods of I. cryptantha and indoxyl sulfate was identified, and confirmed with an analytical standard, in the urine samples. It is proposed that following ingestion of I. cryptantha, indican will be hydrolysed in the liver to indoxyl and conjugated with sulfate. Indoxyl sulfate will then be excreted in relatively high concentrations in the urine. In the alkaline urine, two indoxyl molecules might dimerize to form leucoindigo with subsequent oxidation to indigo, thus, contributing to the dark pigmentation of the urine. It is also possible that indoxyl sulfate contributed to the renal failure and death of the bull. Although I. suffruticosa-induced hemoglobinuria has been described in Brazil, this is the first report of I. cryptantha-induced pigmenturia in cattle in South Africa.

Comparison of multi-coil and multi-frequency frequency domain electromagnetic induction instruments

IntroductionCharacterization of the shallow subsurface in mountain catchments is important for understanding hydrological processes and soil formation. The depth to the soil/bedrock interface (e.g., the upper ~5 m) is of particular interest. Frequency domain electromagnetic induction (FDEM) methods are well suited for high productivity characterization for this target as they have short acquisition times and do not require direct coupling with the ground. Although traditionally used for revealing lateral electrical conductivity (EC) patterns, e.g., to produce maps of salinity or water content, FDEM inversion is increasingly used to produce depth-specific models of EC. These quantitative models can be used to inform several depth-specific properties relevant to hydrological modeling (e.g. depths to interfaces and soil water content).Material and methodsThere are a number of commercial FDEM instruments available; this work compares a multi-coil device (i.e., a single-frequency device with multiple receiver coils) and a multi-frequency device (i.e., a single receiver device with multiple frequencies) using the open-source software EMagPy. Firstly, the performance of both devices is assessed using synthetic modeling. Secondly, the analysis is applied to field data from an alpine catchment.ResultsBoth instruments retrieved a similar EC model in the synthetic and field cases. However, the multi-frequency instrument displayed shallower sensitivity patterns when operated above electrically conductive grounds (i.e., 150 mS/m) and therefore had a lower depth of investigation. From synthetic modeling, it also appears that the model convergence for the multi-frequency instrument is more sensitive to noise than the multi-coil instrument.ConclusionDespite these limitations, the multi-frequency instrument is smaller and more portable; consequently, it is easier to deploy in mountainous catchments.

Promotion of CO2 fracturing for CCUS—the technical gap between theory and practice

CO2, used as an environmentally friendly fracturing fluid, has encountered a bottleneck in development in recent years. Despite great efforts in research work, limited progress has been made in field applications. In this study, an extensive literature review of research work and field cases was performed to summarize the technical issues and challenges of CO2 fracturing. The key issues of CO2 fracturing were analyzed to reveal the gap between fundamental research and field operations. The effects of CO2 properties on fracture creation and proppant transport were synthetically analyzed to extract new common research orientations, with the aim of improving the efficiency of CO2 injection. The hydraulic parameters of CO2 fracturing were compared with those of water-based fracturing fluids, which revealed a theory-practice gap. By studying the developing trends and successful experiences of conventional fluids, new strategies for CO2 fracturing were proposed. We identified that the major theory-practice gap in CO2 fracturing exists in pump rate and operation scale. Consequently, the friction reducer, effects of flow loss (due to leak-off) and distribution (within fracture networks), and shear viscosity of thickened CO2 are key factors in improving both fracture propagation and proppant transport. By increasing the scale of injected CO2, the CO2 fracturing technique can be enhanced, making it an essential option for carbon capture, utilization, and storage (CCUS) to reduce carbon emissions and mitigate climate change.

A new automatic geo-electric self-potential imaging technique for diverse sustainable development scenarios

This study introduces a rapid and efficient inversion algorithm designed for the interpretation of self-potential responses originating from mineralized and ore sources and hydrothermal activity, specifically addressing spherical, vertical, and horizontal cylindrical structures. The algorithm leverages local wavenumber and correlation imaging techniques to enhance accuracy in modeling. The correlation factor (Cf value) is crucial in this approach, calculated as the correlation between the local wavenumber of the measured self-potential field and that of the computed field. The algorithm identifies the maximum correlation Cf value (CF-max) as indicative of the optimal true model parameters. To validate the proposed algorithm, it was applied to three theoretical examples—one with contamination from regional background and another with multiple sources with and without different types of noises (random Gaussian and white Gaussian noises). Additionally, the approach was tested on three distinct real field cases related to mining, ore investigation and hydrothermal activity in India, Germany and USA. Through a comprehensive analysis of results from theoretical and real-world scenarios, including comparisons with different available data and literature information, the study concludes that the method is effective, applicable to multiple sources, accurate, and does not necessitate prior knowledge of the source shape. This algorithm presents a promising advancement in the field of self-potential interpretation for mineral exploration and geothermal exploration.

The challenge to understand the zoo of particle transport regimes during resonant wave-particle interactions for given survey-mode wave spectra

Quasilinear theories have been shown to well describe a range of transport phenomena in magnetospheric, space, astrophysical and laboratory plasma “weak turbulence” scenarios. It is well known that the resonant diffusion quasilinear theory for the case of a uniform background field may formally describe particle dynamics when the electromagnetic wave amplitude and growth rates are sufficiently “small”, and the bandwidth is sufficiently “large”. However, it is important to note that for a given wave spectrum that would be expected to give rise to quasilinear transport, the quasilinear theory may indeed apply for given range of resonant pitch-angles and energies, but may not apply for some smaller, or larger, values of resonant pitch-angle and energy. That is to say that the applicability of the quasilinear theory can be pitch-angle dependent, even in the case of a uniform background magnetic field. If indeed the quasilinear theory does apply, the motion of particles with different pitch-angles are still characterised by different timescales. Using a high-performance test-particle code, we present a detailed analysis of the applicability of quasilinear theory to a range of different wave spectra that would otherwise “appear quasilinear” if presented by e.g., satellite survey-mode data. We present these analyses as a function of wave amplitude, wave coherence and resonant particle velocities (energies and pitch-angles), and contextualise the results using theory of resonant overlap and small amplitude criteria. In doing so, we identify and classify five different transport regimes that are a function of particle pitch-angle. The results in our paper demonstrate that there can be a significant variety of particle responses (as a function of pitch-angle) for very similar looking survey-mode electromagnetic wave products, even if they appear to satisfy all appropriate quasilinear criteria. In recent years there have been a sequence of very interesting and important results in this domain, and we argue in favour of continuing efforts on: (i) the development of new transport theories to understand the importance of these, and other, diverse electron responses; (ii) which are informed by statistical analyses of the relationship between burst- and survey-mode spacecraft data.

THE IMPACT OF DIGITAL TRANSFORMATION ON EMPLOYEE ATTENDANCE MANAGEMENT IN UNIVERSITY

This research aims to comprehend how technological changes and the role of transformational leadership affect employee discipline and operational efficiency in the context of university. The research methodology employs a qualitative approach with a focus on field research and case studies in several units within universities. Data were collected through direct observations and interviews with professors, administrative staff, and other employees involved in digital transformation. The findings indicate that the implementation of GPS-based digital solutions significantly impacts employee attendance management, enhances operational efficiency, and raises ethical challenges related to privacy. Transformational leadership proves to be a key factor in creating an environment that supports discipline and innovation. The conclusions drawn from this study provide a holistic overview of how digital transformation and transformational leadership can synergistically shape a new paradigm in employee attendance management in higher education.

A Generalized Method for Dynamic Fracture Characterization Using Two-Phase Rate Transient Analysis of Flowback and Production Data

Summary This study presents a comprehensive method for characterizing reservoir properties and hydraulic fracture (HF) closure dynamics using the rate transient analysis of flowback and production data. The proposed method includes straightline analysis (SLA), type-curve analysis (TCA), and model history matching (MHM), which are developed for scenarios of two-phase flow in fracture, stimulated reservoir volume (SRV), and nonstimulated reservoir volume (NSRV) domains. HF closure dynamics are characterized by two key parameters, which are pressure-dependent permeability and porosity controlled by fracture permeability modulus and compressibility. The above techniques are combined into a generalized workflow to estimate iteratively the five parameters (including four optional parameters and one fixed parameter) by reconciling data in different domains of time (single-phase water flow, two-phase flow, and hydrocarbon-dominated flow), analysis methods (SLA, TCA, and MHM), and phases (water and hydrocarbon phase). We used flowback and production data from a shale gas well in the US and a shale oil well in China to verify the practicability of the method. The analysis results of the field cases confirm the good performance of the newly developed comprehensive method and verify the accuracy in estimating the static fracture properties [initial fracture pore volume (PV) and permeability] and the HF dynamic parameters using the proposed generalized workflow. The accurate prediction of the decreasing fracture permeability and porosity, fracture permeability modulus, and compressibility demonstrates the applicability of the comprehensive method in quantifying HF dynamics. The field application results suggest a reduction of the fracture PV by 15% and 20%, and a reduction of the fracture permeability by 80% and 90% for shale gas and shale oil wells, respectively.

Determination of the overconsolidation ratio and undrained shear strength of cohesive soils by CPTu measurement

Estimations of the undrained shear strength (Su) and overconsolition ratio (OCR) of cohesive soil are essential for the evaluation of geology investigation. In comparison to time-consuming laboratory tests, the field piezocone penetration test (CPTu) can rapidly evaluate these parameters. However, existing studies have mainly relied on empirical correlations to estimate the undrained shear strength Su and OCR from CPTu measurements. These correlations are mainly empirical, involving fixed coefficients multiplied by CPTu measurement. Based on the coupled Eulerian-Lagrangian method, this study employed large deformation finite element modeling to summarize and extend the relationships between CPTu measurement and the estimation of undrained shear strength Su and OCR in cohesive soils. These relationships allow for predictions based on CPTu measurements without the requirement for laboratory calibration or referencing to field benchmarks. The accuracy and applicability of the proposed prediction formulas are validated through field case studies for comparative analysis.

Connectivity of floodplain influences riverine carbon outgassing and dissolved carbon transport

Rivers not only function as a conduit for the delivery of terrestrial constituents to oceans, but they also serve as an essential medium for biogeochemical processing of the constituents. While extensive research has been conducted on carbon transport in many rivers, little is known about carbon transformation in engineered rivers reconnected with their floodplain network. Being the largest distributary of the levee-confined Mississippi River (MR), the Atchafalaya River (AR) carries 25 % of the MR water, flowing through North America's largest freshwater swamp basin and emptying into the Gulf of Mexico. Previous studies reported that this 200-km long, 5–30-km wide river basin can remove a substantial amount of riverine nutrients and organic carbon. This study aimed to test the hypothesis that the AR emits significantly higher CO2 into the atmosphere as it flows through its extensive floodplain network than the levee-confined MR does. From January 2019 to December 2021, we conducted biweekly – monthly in-situ measurements in the lower AR at Morgan City and in the lower Mississippi River at Baton Rouge. Field measurements included partial pressure of dissolved CO2 (pCO2), water temperature, chlorophyll a, colored dissolved organic matter, dissolved oxygen, pH, and turbidity. During each field sampling, water samples were collected and analyzed for concentrations of dissolved organic and inorganic carbon (DOC and DIC). Mass transport of DOC and DIC and outgassing of CO2 were quantified for the two rivers. We found that pCO2 levels were significantly higher in the AR (mean: 3563 μatm; min-max: 1130–8650 μatm) than those in the MR (1931 μatm, 836–3501 μatm), resulting in a doubled CO2 outgassing rate in the AR (486 mmol m2 d−1) than in the MR (241 mmol m2 d−1). The AR had higher DOC (8.5 mg L−1) but lower chlorophyll a (153.9 AFU) when compared with the MR (7.5 mg L−1 and 164.0 AFU). Water temperature was constantly higher in the AR than in the MR, especially during the wintertime. Since the Mississippi-Atchafalaya River system is among the world's largest and most engineered river systems, our assessment offers a field case study to inform on the potential implications of reconnecting rivers with their floodplains networks.

Investigating the impact of the future carbon market on the profitability of carbon capture, utilization, and storage (CCUS) projects; the case of oil fields in southern Iraq

Carbon capture utilization and storage for enhanced oil recovery (CCUS-EOR) is considered a promising solution to meet future global energy needs while significantly reducing carbon dioxide emissions. However, the future growth of CCUS-EOR is uncertain due to the global economic recession and low oil prices. This research analyzes the impact of uncertain oil and carbon market prices on the economic value of a CCUS-EOR project which contributes to appropriate investment and future policy decisions. To explore the potential trade-offs between available carbon dioxide (CO2) quantities for trading or injection for enhanced oil recovery, the market's trading mechanism is analyzed by predicting future oil and carbon prices. The forecasted market prices are then used in an optimization model to estimate the optimal cumulative cash flow from implementing a proposed CCUS-EOR project to capture CO2 from the Hartha power plant located in the southern Basra Province of Iraq, considering three different oil fields of Rumaila, Nassriya, and Noor. The results revealed that the profitability of the proposed CCUS-EOR project is affected by both oil and carbon market prices, and a higher carbon price is needed to compensate for the financial setbacks, resulting from reduced oil prices. The research also features the strategic decision-making of oil fields across different sizes in response to various price scenarios. The medium-sized fields consistently prioritize carbon injection for enhanced oil recovery (EOR) over market trading. In contrast, small and giant fields adapt their approach based on the prevailing market price dynamics.

Representation and interpretation about underwater sound speed gradient field in the GNSS-A observation

SUMMARY The Global Navigation Satellite System—Acoustic ranging combination technique (GNSS-A) is a seafloor geodetic observation technique that achieves an accuracy of centimetres by combining high-rate GNSS data with acoustic ranging. The technique determines the seafloor position by acoustic ranging between the sea surface and multiple seafloor stations, using GNSS data from the sea surface station. Here, the gradient state of the underwater sound speed structure (SSS) is a significant source of error. The open-source software GARPOS can reduce the effect from underwater gradient structures by retrieving the underwater disturbance as a parameter projected onto the sea surface and seafloor. To evaluate the effects of underwater disturbances, a quantitative comparison of the model parameters is necessary. In this study, we developed a representation method to evaluate features of the ocean field. Here, the expression method was described in the order of a formulation and an interpretation in the case of a 2-D cross-section and extension to the case of an actual 3-D field. This method makes it possible to evaluate SSS states in the GNSS-A observations. As an example, we showed the correlation between the anomaly of the expressed ocean state and the anomaly of the seafloor station position, showing that this expression method is an effective index for correcting bias errors. Additionally, we used the data from sites located in the Kuroshio area, a strong current near Japan, to show that the ocean state can be quantitatively interpreted using this expression method.

Resonances of Supernova Neutrinos in Twisting Magnetic Fields.

We investigate the effect of resonant spin conversion of the neutrinos induced by the geometrical phase in a twisting magnetic field. We find that the geometrical phase originating from the rotation of the transverse magnetic field along the neutrino trajectory can trigger a resonant spin conversion of Dirac neutrinos inside the supernova, even if there were no such transitions in the fixed-direction field case. We have shown that, even though resonant spin conversion is too weak to affect solar neutrinos, it could have a remarkable consequence on supernova neutronization bursts where very intense magnetic fields are quite likely. We demonstrate how the flavor composition at Earth can be used as a probe to establish the presence of non-negligible magnetic moments, potentially down to 10^{-15}μ_{B} in upcoming neutrino experiments like the Deep Underground Neutrino Experiment and the Hyper-Kamiokande. Possible implications are analyzed.