Leakage dynamics of fault zones: experimental and analytical study with application to CO2 storage

Fault zones have the potential to act as leakage pathways through low permeability structural seals in geological reservoirs. Faults may facilitate migration of groundwater contaminants and stored anthropogenic carbon dioxide (CO $_2$ ), where the waste fluids would otherwise remain securely trapped. We present an analytical model that describes the dynamics of leakage through a fault zone cutting multiple aquifers and seals. Current analytical models for a buoyant plume in a semi-infinite porous media are combined with models for a leaking gravity current and a new model motivated by experimental observation, to account for increased pressure gradients within the fault due to an increase in Darcy velocity directly above the fault. In contrast to previous analytical fault models, we verify our results using a series of analogous porous medium tank experiments, with good matching of observed leakage rates and fluid distribution. We demonstrate the utility of the model for the assessment of CO $_2$ storage security, by application to a naturally occurring CO $_2$ reservoir, showing the dependence of the leakage rates and fluid distribution on the fault/aquifer permeability contrast. The framework developed within this study can be used for quick assessment of fluid leakage through fault zones, given a set of input parameters relating to properties of the fault, aquifer and fluids, and can be incorporated into basin-scale models to improve computational efficiency. The results show the utility of using analytical methods and reduced-order modelling in complex geological systems, as well as the value of laboratory porous medium experiments to verify results.

Construction of Digital Culture Copyright Protection System Based on Blockchain Technology

Digital cultural copyright protection is an important means of digital cultural works protection. The existing digital cultural copyright protection has some problems in data storage security, rights confirmation efficiency, traceability means and copyright transaction. As an emerging technology in the Internet era, Blockchain can mobilize the enthusiasm of the whole network nodes and improve the security and reliability of digital culture copyright protection. By analyzing the applicability of Blockchain technology in digital culture copyright protection, a digital culture copyright protection system based on Blockchain technology is constructed.

Cryptography: A Quantitative Analysis of the Effectiveness of Various Password Storage Techniques

Recently, there has been a rise in impactful data breaches releasing billions of people’s online accounts and financial data into the public domain. The result is an increased importance of effective cybersecurity measures, especially regarding the storage of user passwords. Strong password storage security means that an actor cannot use the passwords in vectors such as credential-stuffing attacks despite having access to breached data. It will also limit user exposure to threats such as unauthorized account charges or account takeovers. This research evaluates the effectiveness of different password storage techniques. The storage techniques to be tested are: BCRYPT Hashing, SHA-256 Hashing, SHA-256 with Salt, and SHA-256 with MD5 Chaining. Following the National Institute of Standards and Technology (NIST) guidelines on password strength, both a weak and robust password will be passed through the stated techniques. Reversal of each of the results will be attempted using Rainbow Tables and dictionary attacks. The study results show that pairing a strong password that has not been exposed in a data breach with the BCRYPT hashing algorithm results in the most robust password security. However, SHA-256 hashing with a salt results in a very similar level of security while maintaining better performance. While plain SHA-256 hashing or chaining multiple hashing algorithms together is theoretically as secure, in practice, they are easily susceptible to simple attacks and thus should not be used in a production environment. Requiring strong password which have not been exposed in previous data breaches was also found to greatly increase security.

A Study on Cloud Storage Security Method Using Data Classification

Cloud computing is a new model for providing diverse services of software and hardware. This paradigm refers to a model for enabling on-demand network access to a shared pool of configurable computing resources, that can be rapidly provisioned and released with minimal service provider interaction .It helps the organizations and individuals deploy IT resources at a reduced total cost. However, the new approaches introduced by the clouds, related to computation outsourcing, distributed resources and multi-tenancy concept, increase the security and privacy concerns and challenges. It allows users to store their data remotely and then access to them at any time from any place .Cloud storage services are used to store data in ways that are considered cost saving and easy to use. In cloud storage, data are stored on remote servers that are not physically known by the consumer. Thus, users fear from uploading their private and confidential files to cloud storage due to security concerns. The usual solution to secure data is data encryption, which makes cloud users more satisfied when using cloud storage to store their data. Motivated by the above facts; we have proposed a solution to undertake the problem of cloud storage security. In cloud storage, there are public data that do not need any security measures, and there are sensitive data that need applying security mechanisms to keep them safe. In that context, data classification appears as the solution to this problem. The classification of data into classes, with different security requirements for each class is the best way to avoid under security and over security situation. The existing cloud storage systems use the same Journal of University of Shanghai for Science and Technology ISSN: 1007-6735 Volume 23, Issue 9, September – 2021 Page-1105 key size to encrypt all data without taking into consideration its confidentiality level. Treating the low and high confidential data with the same way and at the same security level will add unnecessary overhead and increase the processing time. In our proposal, we have combined the K-NN (K Nearest Neighbors) machine learning method and the goal programming decision-making method, to provide an efficient method for data classification. This method allows data classification according to the data owner security needs. Then, we introduce the user data to the suitable security mechanisms for each class. The use of our solution in cloud storage systems makes the data security process more flexible, besides; it increases the cloud storage system performance and decreases the needed resources, which are used to store the data.

Penilaian Standar Mutu Pada Aplikasi Parkir Universitas Muhammadiyah Gresik Dengan ISO 9241-11 Dan Fishbone Analisis

The parking application service at the University of Muhammadiyah Gresik is an update from the previous system. Of course, this application requires a system that is practical, efficient, and also has good data storage security. One of the references that can be used that these things have been fulfilled in this application is an analysis using ISO 9241-11. The purpose of this study was to analyze the application of UMG parking for the feasibility of ISO 9241-11. Analytical research methods used include determining clauses, checklists, Likert scales, maturity levels, and fishbone diagrams. Clause, checklist use for getting assessment based on the park system, then from that result will be used to get the qualification of this system with liket scale in each clause of this standard, and assessment of all clause with likert scale , the result of level quality assurance of this system will be found. Next the using fishbone diagram can analyze to get the root cause of clause dan quality assurance in ISO 9241-11. Because that , with this study we can know the qualification and the root cause of park system. And the analysis using that tool, this system still not suitable to use ISO 9241-11. The parent of root cause is in efficiency clause in organitation like less costing and planning.

The impact of heterogeneous mixed siliciclastic-carbonate systems on CO2 geological storage

Three different outcrops are selected in this study, each representing a shallow marine system with varying heterogeneity provided by siliciclastic-carbonate mixing that may form a small or large stratigraphic trap. The impact of these styles of mixed facies on CO2 storage is relatively poorly known. This study demonstrates the significance of these systems for safe CO2 geological storage, as stratigraphic traps are likely to be a significant feature of many future storage sites. The three 3D models are based on the: 1. Grayburg Formation (US), which displays spatial permeability linked to variations in the mixture of siliciclastic-carbonate sediments; 2. Lorca Basin outcrop (Spain), which demonstrates the interfingering of clastic and carbonate facies; and 3. Bridport Sand Formation outcrop (UK), an example of a layered reservoir, which has thin carbonate-cemented horizons.This study demonstrates that facies interplay and associated sediment heterogeneity have a varying effect on fluid flow, storage capacity and security. In the Grayburg Formation, storage security and capacity are not controlled by heterogeneity alone but influenced mainly by the permeability of each facies (i.e., permeability contrast), the degree of heterogeneity, and the relative permeability characteristic of the system. In the case of the Lorca Basin, heterogeneity through interfingering of the carbonate and clastic facies improved the storage security regardless of their permeability. For the Bridport Sand Formation, the existence of extended sheets of cemented carbonate contributed to storage security but not storage capacity, which depends on the continuity of the sheets. These mixed systems specially minimise the large buoyancy force that act on the top seal and reduce the reliance of the storage security on the overlying caprock. They also increase the contact area between injected CO2 and brine, thereby promoting the CO2 dissolution processes. Overall, mixed systems contribute to the safe storage of CO2.Thematic collection: This article is part of the Geoscience for CO2 storage collection available at: https://www.lyellcollection.org/cc/geoscience-for-co2-storage