Abstract: A hybrid transactional/analytical processing database includes an OLTP engine, OLAP engine, and shared storage including a mass storage device holding data of multiple tenants. The shared storage includes processing circuitry configured to implement a query executor configured to continuously monitor actual memory usage of the shared storage while the shared storage is responding to one or more queries from the OLTP engine or OLAP engine. Upon determining the actual memory usage of an operator evaluating the one or more of the queries from the OLTP engine or OLAP engine at the shared storage exceeds the preventative memory usage threshold but does not exceed the system memory usage threshold, the query executor is further configured to spill one or more fragments of query memory corresponding to the one or more queries to the mass storage device, without terminating the one or more queries.

Abstract: A method for determining an average oxidation state (AOS) of a redox flow battery system includes measuring a charge capacity for a low potential charging period starting from a discharged state of the redox flow battery system to a turning point of a charge voltage; and determining the AOS using the measured charge capacity and volumes of anolyte and catholyte of the redox flow battery system. Other methods can be used to determine the AOS for a redox flow battery system or use discharge voltage instead of charging voltage.

Abstract: A hybrid transactional/analytical processing database includes an OLTP engine, OLAP engine, and shared storage including a mass storage device holding data of multiple tenants. The shared storage includes processing circuitry configured to implement a query executor configured to continuously monitor actual memory usage of the shared storage while the shared storage is responding to one or more queries from the OLTP engine or OLAP engine. Upon determining the actual memory usage of an operator evaluating the one or more of the queries from the OLTP engine or OLAP engine at the shared storage exceeds the preventative memory usage threshold but does not exceed the system memory usage threshold, the query executor is further configured to spill one or more fragments of query memory corresponding to the one or more queries to the mass storage device, without terminating the one or more queries.

Abstract: The present disclosure describes storage techniques for hybrid transactional and analytical processing. Data captured by a first processing engine may be received. The first processing engine may be configured to perform online transactional processing). Multiple replicas of logical logs generated based on the data may be distributed to a Delta Store by applying a quorum protocol on the multiple replicas. Data in the Delta Store are stored in a row format and are visible to a query for online analytical processing performed by a second processing engine. Data may be flushed from the Delta Store to a Base Store based on one or more predetermined rules. Data in the Base Store are stored in a columnar format and may be accessible by the second processing engine.

Abstract: A method for determining an average oxidation state (AOS) of a redox flow battery system includes measuring a charge capacity for a low potential charging period starting from a discharged state of the redox flow battery system to a turning point of a charge voltage; and determining the AOS using the measured charge capacity and volumes of anolyte and catholyte of the redox flow battery system. Other methods can be used to determine the AOS for a redox flow battery system or use discharge voltage instead of charging voltage.

Abstract: A redox flow battery system includes an anolyte having a first ionic species in solution; a catholyte having a second ionic species in solution, where the redox flow battery system is configured to reduce the first ionic species in the anolyte and oxidize the second ionic species in the catholyte during charging; a first electrode in contact with the anolyte, where the first electrode includes channels for collection of particles of reduced metallic impurities in the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte. A method of reducing metallic impurities in an anolyte of a redox flow battery system includes reducing the metallic impurities in the anolyte; collecting particles of the reduced metallic impurities; and removing the collected particles using a cleaning solution.

Abstract: A method for determining an average oxidation state (AOS) of a redox flow battery system includes measuring a charge capacity for a low potential charging period starting from a discharged state of the redox flow battery system to a turning point of a charge voltage; and determining the AOS using the measured charge capacity and volumes of anolyte and catholyte of the redox flow battery system. Other methods can be used to determine the AOS for a redox flow battery system or use discharge voltage instead of charging voltage.

Abstract: The present disclosure describes storage techniques for hybrid transactional and analytical processing. Data captured by a first processing engine may be received. The first processing engine may be configured to perform online transactional processing). Multiple replicas of logical logs generated based on the data may be distributed to a Delta Store by applying a quorum protocol on the multiple replicas. Data in the Delta Store are stored in a row format and are visible to a query for online analytical processing performed by a second processing engine. Data may be flushed from the Delta Store to a Base Store based on one or more predetermined rules. Data in the Base Store are stored in a columnar format and may be accessible by the second processing engine.

Abstract: A redox flow battery system includes an anolyte having a first ionic species in solution; a catholyte having a second ionic species in solution, where the redox flow battery system is configured to reduce the first ionic species in the anolyte and oxidize the second ionic species in the catholyte during charging; a first electrode in contact with the anolyte, where the first electrode includes channels for collection of particles of reduced metallic impurities in the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte. A method of reducing metallic impurities in an anolyte of a redox flow battery system includes reducing the metallic impurities in the anolyte; collecting particles of the reduced metallic impurities; and removing the collected particles using a cleaning solution.

Abstract: A redox flow battery system includes an anolyte having a first ionic species in solution; a catholyte having a second ionic species in solution, where the redox flow battery system is configured to reduce the first ionic species in the anolyte and oxidize the second ionic species in the catholyte during charging; a first electrode in contact with the anolyte, where the first electrode includes channels for collection of particles of reduced metallic impurities in the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte. A method of reducing metallic impurities in an anolyte of a redox flow battery system includes reducing the metallic impurities in the anolyte; collecting particles of the reduced metallic impurities; and removing the collected particles using a cleaning solution.

Abstract: A redox flow battery system includes an anolyte having chromium ions in solution; a catholyte having iron ions in solution, where a molar ratio of chromium in the anolyte to iron in the catholyte is at least 1.25; a first electrode in contact with the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte.

Abstract: A method for determining a storage capacity or average oxidation state (AOS) of a redox flow battery system including an anolyte and a catholyte includes discharging a portion of the anolyte and catholyte of the redox flow battery system at a discharge rate that is within 10% of a preselected discharge rate; after discharging the redox flow battery system, determining an end OCV; and determining the storage capacity or AOS from the end OCV. Other methods can be used to determine the storage capacity or AOS using a measured OCV.

Abstract: A method for determining an average oxidation state (AOS) of a redox flow battery system includes measuring a charge capacity for a low potential charging period starting from a discharged state of the redox flow battery system to a turning point of a charge voltage; and determining the AOS using the measured charge capacity and volumes of anolyte and catholyte of the redox flow battery system. Other methods can be used to determine the AOS for a redox flow battery system or use discharge voltage instead of charging voltage.

Abstract: A system includes a redox flow battery system that includes an anolyte, a catholyte, a first half-cell having a first electrode in contact with the anolyte, a second half-cell having a second electrode in contact with the catholyte, and a first separator separating the first half-cell from the second half-cell. The system also includes a balance arrangement that includes a balance electrolyte having vanadium ions in solution, a third half-cell having a third electrode in contact with the anolyte or the catholyte, a fourth half-cell having a fourth electrode in contact with the balance electrolyte, and a reductant in the balance electrolyte or introducible to the balance electrolyte for reducing dioxovanadium ions.

Abstract: A redox flow battery system includes an anolyte having chromium ions in solution; a catholyte having iron ions in solution, where a molar ratio of chromium in the anolyte to iron in the catholyte is at least 1.25; a first electrode in contact with the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte.

Abstract: A method for determining a storage capacity or average oxidation state (AOS) of a redox flow battery system including an anolyte and a catholyte includes discharging a portion of the anolyte and catholyte of the redox flow battery system at a discharge rate that is within 10% of a preselected discharge rate; after discharging the redox flow battery system, determining an end OCV; and determining the storage capacity or AOS from the end OCV. Other methods can be used to determine the storage capacity or AOS using a measured OCV.

Abstract: A redox flow battery system includes an anolyte having a first ionic species in solution; a catholyte having a second ionic species in solution, where the redox flow battery system is configured to reduce the first ionic species in the anolyte and oxidize the second ionic species in the catholyte during charging; a first electrode in contact with the anolyte, where the first electrode includes channels for collection of particles of reduced metallic impurities in the anolyte; a second electrode in contact with the catholyte; and a separator separating the anolyte from the catholyte. A method of reducing metallic impurities in an anolyte of a redox flow battery system includes reducing the metallic impurities in the anolyte; collecting particles of the reduced metallic impurities; and removing the collected particles using a cleaning solution.

Abstract: A system includes a redox flow battery system that includes an anolyte, a catholyte, a first half-cell having a first electrode in contact with the anolyte, a second half-cell having a second electrode in contact with the catholyte, and a first separator separating the first half-cell from the second half-cell. The system also includes a balance arrangement that includes a balance electrolyte having vanadium ions in solution, a third half-cell having a third electrode in contact with the anolyte or the catholyte, a fourth half-cell having a fourth electrode in contact with the balance electrolyte, and a reductant in the balance electrolyte or introducible to the balance electrolyte for reducing dioxovanadium ions.

Abstract: A system includes a redox flow battery system that includes an anolyte having chromium ions in solution, a catholyte having iron ions in solution, a first half-cell having a first electrode in contact with the anolyte, a second half-cell having a second electrode in contact with the catholyte, and a first separator separating the first half-cell from the second half-cell. The system also includes a balance arrangement that includes a balance electrolyte having vanadium ions in solution, a third half-cell having a third electrode in contact with the anolyte or the catholyte, a fourth half-cell having a fourth electrode in contact with the balance electrolyte, and a reductant in the balance electrolyte or introducible to the balance electrolyte for reducing dioxovanadium ions.