Results for “storing” — Page 3

DOE OSTI2020

Customizable Scale-Out Key-Value Stores

Enterprise KV stores are often not well suited for HPC applications, and thus cumbersome end-to-end KV design customization is required to meet the needs of modern HPC applications. To this end, in this article we present bespoKV, an adaptive, extensible, and scale-out KV store framework. bespoKV decouples the KV store design into the control plane for distributed management and the data plane for local data store. For the control plane, bespoKVprovides pre-built modules, called controlets, supporting common distributed functionalities (e.g., replication, consistency, and topology) and their various combinations. This decoupling allows bespoKV to take a user-provided single-server KV store, called a datalet, and transparently enables a scalable and fault-tolerant distributed KV store service. The resulting distributed stores are also adaptive to consistency or topology requirement changes and can be easily extended for new types of services. Such specializations enable innovative uses of KV stores in HPC applications, especially for emerging applications that utilize KV-friendly workloads. We evaluate bespoKV in a local testbed as well as in a public cloud settings. Experiments show that bespoKV-enabled distributed KV stores scale horizontally to a large number of nodes, and performs comparably and sometimes 1.2× to 2.6× better than the state-of-the-art systems.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2016

Response of a store with tunable natural frequencies in compressible cavity flow

Fluid–structure interactions that occur during aircraft internal store carriage were experimentally explored at Mach 0.58–1.47 using a generic, aerodynamic store installed in a rectangular cavity having a length-to-depth ratio of seven. The store vibrated in response to the cavity flow at its natural structural frequencies, and it exhibited a directionally dependent response to cavity resonance frequencies. Cavity tones excited the store in the streamwise and wall-normal directions consistently, whereas the spanwise response to cavity tones was much more limited. Increased surface area associated with tail fins raised vibration levels. The store had interchangeable components to vary its natural frequencies by about 10–300 Hz. By tuning natural frequencies, mode-matched cases were explored where a prominent cavity tone frequency matched a structural natural frequency of the store. Mode matching in the streamwise and wall-normal directions produced substantial increases in peak store vibrations, though the response of the store remained linear with dynamic pressure. Near mode-matched frequencies, changes in cavity tone frequencies of only 1% altered store peak vibrations by as much as a factor of two. In conclusion, mode matching in the spanwise direction did little to increase vibrations.

42 ENGINEERING↗

NASA NTRS1966

Summary of External-Store Drag

The drag problems associated with the addition of external stores to airplanes are reviewed. Current analytic techniques for estimating drag penalties associated with the addition of stores in both subsonic and supersonic flight are discussed. In subsonic flight, the drag penalty caused by the addition of external stores is shown to be a function of the type of store installation. In supersonic flight, the drag is shown to be a function of the type of store installation and also of the location of the store installation with respect to the rest of the airplane components. Special store arrangements and attention to the design of the store itself can reduce the drag penalty of the store installation.

Shrout, B. L.↗

DOE OSTI2024

Frozen Freedom: Unleashing Grocery Store Demand Flexibility: Preprint

Grocery stores consumed approximately 3% of total electricity used by commercial buildings in the U.S. in 2018 (EIA 2018), representing a unique end-use load profile characterized by the critical use of refrigerated display cases. Exploring demand response (DR) scenarios in grocery stores presents an opportunity to enhance the efficiency and sustainability of surrounding communities. In addition, recent studies demonstrate that implementing control algorithms considering demand flexibility strategies can lead to load and peak reductions in standalone refrigerated display cases. Because small business grocery stores operate on thin margins, the energy bill cost savings DR might provide could make a positive difference toward continued operations. Still, uncertainty remains about the extent of demand flexibility potential controls could provide when coupling refrigeration with whole building operation. To enhance economic viability and grid stability, it is essential to quantify the load flexibility capability of grocery stores. Advanced controls can optimize energy consumption by responding to load shedding, shifting, and DR events, as well as daily Time-of-Use (TOU) rates without compromising food safety. Using both quantitative data and interviews with community-based organizations, we developed a full-size store model and two small store models with controlled refrigerated cases, HVAC, and lighting systems based on actual grocery store properties. Through simulations, we have assessed load flexibility strategies with varied DR events. The results highlight potential for energy and peak reduction with advanced or basic controls. However, interviews and data indicate that more support is needed to make DR strategies consistently accessible to small grocery stores.

demand flexibility↗

DOE OSTI2018

Stored energy release in neutron irradiated silicon carbide

The purpose of this investigation is to experimentally quantify the stored energy release upon thermal annealing of previously irradiated high-purity silicon carbide (SiC.) Samples of highly-faulted polycrystalline CVD β-SiC and single crystal 6HSiC were irradiated in a mixed spectrum fission reactor near 60 °C in a fluence range from 5 × 10 23 to 2 × 10 26 n/m 2 (E > 0.1 MeV), or about 0.05–20 dpa, in order to quantify the stored energy release and correlate the release to the observed microscopic swelling, lattice dilation, and microstructure as observed through TEM. Within the fluence of this study the crystalline material was observed to swell to a remarkable extent, achieving 8.13% dilation, and then cross a threshold dose for amorphization at approximately 1 × 10 25 n/m 2 (E > 0.1 MeV) Once amorphized the material attains an as-amorphized swelling of 11.7% at this irradiation condition. Coincident with the extraordinary swelling obtained for the crystalline SiC, an equally impressive stored energy release of greater than 2500 J/g at the critical threshold for amorphization is inferred. As expected, following amorphization the stored energy in the structure diminishes, measured to be approximately 590 J/g. Generally, the findings of stored energy are consistent with existing theory, though the amount of stored energy given the large observed crystalline strain is remarkable. The overall conclusion of this work finds comparable stored energy in SiC to that of nuclear graphite, and similar to graphite, a stored energy release in excess of its specific heat in some irradiation conditions.

36 MATERIALS SCIENCE↗

DOE OSTI2018

BESPOKV: Application Tailored Scale-Out Key-Value Stores

Enterprise KV stores are not well suited for HPC applications, and entail customization and cumbersome end-to-end KV design to extract the HPC application needs. To this end, in this paper we present BESPOKV, an adaptive, extensible, and scale-out KV store framework. BESPOKV decouples the KV store design into the control plane for distributed management and the data plane for local data store. BESPOKV takes as input a single-server KV store, called a datalet, and transparently enables a scalable and fault-tolerant distributed KV store service. The resulting distributed stores are also adaptive to consistency or topology requirement changes and can be easily extended for new types of services. Experiments show that BESPOKV-enabled distributed KV stores scale horizontally to a large number of nodes, and performs comparably and sometimes better than the state-of-the-art systems.

Anwar, Ali↗

DOE OSTI2016

De-Inventory Plan for Transuranic Waste Stored at Area G

This report describes the strategy and detailed work plan developed by Los Alamos National Laboratory (LANL) to disposition transuranic (TRU) waste stored at its Area G radioactive waste storage site. The focus at this time is on disposition of 3,706 m 3 of TRU waste stored above grade by June 30, 2014, which is one of the commitments within the Framework Agreement: Realignment of Environmental Priorities between the Department of Energy (DOE) National Nuclear Security Administration (NNSA) and the State of New Mexico Environment Department (NMED), Reference 1. A detailed project management schedule has been developed to manage this work and better ensure that all required activities are aligned and integrated. The schedule was developed in conjunction with personnel from the NNSA Los Alamos Site Office (LASO), the DOE Carlsbad Field Office (CBFO), the Central Characterization Project (CCP), and Los Alamos National Security, LLC (LANS). A detailed project management schedule for the remainder of the above grade inventory and the below grade inventory will be developed and incorporated into the De-Inventory Plan by December 31, 2012. This schedule will also include all newly-generated TRU waste received at Area G in FYs 2012 and 2013, which must be removed by no later than December 31, 2014, under the Framework Agreement. The TRU waste stored above grade at Area G is considered to be one of the highest nuclear safety risks at LANL, and the Defense Nuclear Facility Safety Board has expressed concern for the radioactive material at risk (MAR) contained within the above grade TRU waste inventory and has formally requested that DOE reduce the MAR. A large wildfire called the Las Conchas Fire burned extensive areas west of LANL in late June and July 2011. Although there was minimal to no impact by the fire to LANL, the fire heightened public concern and news media attention on TRU waste storage at Area G. After the fire, New Mexico Governor Susana Martinez also requested that LANL accelerate disposition of TRU waste stored above grade at Area G. The 3,706 m 3 volume of TRU waste stored above grade consists of 4,495 containers that include all above grade non-cemented waste as well as above grade cemented waste that was ready for characterization on October 1, 2011. This volume includes all newly-generated TRU waste currently stored at Area G as of October 1, 2011. This volume does not include the Bolas Grandes spheres, mixed low level waste (MLLW) containers, empty containers, cemented waste that requires remediation, projected newly generated TRU waste from FY 2012 and later, or TRU waste stored below grade. The 3,706 m 3 volume represents about 86 per cent of the total volume of TRU waste stored above grade on October 1, 2011. The De-Inventory Plan supports the DOE Office of Environmental Management (EM) goal to disposition 90% of the Legacy TRU waste within the DOE complex by the end of 2015 as stated in its Roadmap for EM’s Journey to Excellence (Reference 2). The plan also addresses precursor actions for disposition of TRU waste that are necessary for compliance with the Compliance Order on Consent issued by the NMED in 2005 (Reference 3).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗

NASA NTRS1986

Transonic aeroelasticity of wings with tip stores

The presence of tip stores influences both aerodynamic and aeroelastic performances of wings. Such effects are more pronounced in the transonic regime. In this study, transonic aeroelasticity of wings with tip stores is studied for the first time by a theoretical method using the unsteady-small disturbance transonic aerodynamic equations coupled with modal structural equations of motion. The aerodynamic and structural equations of motion are simultaneously integrated by a time-accurate numerical scheme. To validate the tip store simulation, aeroelastic computations are made for a typical rectangular wing with a tip store and results are correlated with available wind tunnel data for the corresponding wing without a tip store at various flight conditions. Aeroelastic computations are also made for a typical fighter wing with a tip store. Present computations show that it is important to account for the aerodynamics of the tip store, particularly in the transonic regime where the tip store can make the wing aeroelastically unstable.

Guruswamy, G. P.↗

NASA NTRS1988

Efficient vibration mode analysis of aircraft with multiple external store configurations

A coupling method for efficient vibration mode analysis of aircraft with multiple external store configurations is presented. A set of low-frequency vibration modes, including rigid-body modes, represent the aircraft. Each external store is represented by its vibration modes with clamped boundary conditions, and by its rigid-body inertial properties. The aircraft modes are obtained from a finite-element model loaded by dummy rigid external stores with fictitious masses. The coupling procedure unloads the dummy stores and loads the actual stores instead. The analytical development is presented, the effects of the fictitious mass magnitudes are discussed, and a numerical example is given for a combat aircraft with external wing stores. Comparison with vibration modes obtained by a direct (full-size) eigensolution shows very accurate coupling results. Once the aircraft and stores data bases are constructed, the computer time for analyzing any external store configuration is two to three orders of magnitude less than that of a direct solution.

Karpel, M.↗

NASA NTRS1989

New test techniques to evaluate near field effects for supersonic store carriage and separation

Store separation and store carriage drag studies were conducted. A primary purpose is to develop new experimental methods to evaluate near field effects of store separation and levels of store carriage drag associated with a variety of carriage techniques for different store shapes and arrangements. Flow field measurements consisting of surface pressure distributions and vapor screen photographs are used to analyze the variations of the store separation characteristics with cavity geometry. Store carriage drag measurements representative of tangent, semi-submerged, and internal carriage installations are presented and discussed. Results are included from both fully metric models and models with only metric segments (metric pallets) and the relative merits of the two are discussed. Carriage drag measurements for store installations on an aircraft parent body are compared both with prediction methods and with installations on a generic parent body.

Sawyer, Wallace C.↗

DOE OSTI2016

Silent store detection and recording in memory storage

An aspect includes receiving a write request that includes a memory address and write data. Stored data is read from a memory location at the memory address. Based on determining that the memory location was not previously modified, the stored data is compared to the write data. Based on the stored data matching the write data, the write request is completed without writing the write data to the memory and a corresponding silent store bit, in a silent store bitmap is set. Based on the stored data not matching the write data, the write data is written to the memory location, the silent store bit is reset and a corresponding modified bit is set. At least one of an application and an operating system is provided access to the silent store bitmap.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2017

Silent store detection and recording in memory storage

An aspect includes receiving a write request that includes a memory address and write data. Stored data is read from a memory location at the memory address. Based on determining that the memory location was not previously modified, the stored data is compared to the write data. Based on the stored data matching the write data, the write request is completed without writing the write data to the memory and a corresponding silent store bit, in a silent store bitmap is set. Based on the stored data not matching the write data, the write data is written to the memory location, the silent store bit is reset and a corresponding modified bit is set. At least one of an application and an operating system is provided access to the silent store bitmap.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2017

Silent store detection and recording in memory storage

An aspect includes receiving a write request that includes a memory address and write data. Stored data is read from a memory location at the memory address. Based on determining that the memory location was not previously modified, the stored data is compared to the write data. Based on the stored data matching the write data, the write request is completed without writing the write data to the memory and a corresponding silent store bit, in a silent store bitmap is set. Based on the stored data not matching the write data, the write data is written to the memory location, the silent store bit is reset and a corresponding modified bit is set. At least one of an application and an operating system is provided access to the silent store bitmap.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2017

Silent store detection and recording in memory storage

An aspect includes receiving a write request that includes a memory address and write data. Stored data is read from a memory location at the memory address. Based on determining that the memory location was not previously modified, the stored data is compared to the write data. Based on the stored data matching the write data, the write request is completed without writing the write data to the memory and a corresponding silent store bit, in a silent store bitmap is set. Based on the stored data not matching the write data, the write data is written to the memory location, the silent store bit is reset and a corresponding modified bit is set. At least one of an application and an operating system is provided access to the silent store bitmap.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2017

Store operations to maintain cache coherence

In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2017

Store operations to maintain cache coherence

In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

97 MATHEMATICS AND COMPUTING↗

DOE OSTI2014

Ammonia reactions with the stored oxygen in a commercial lean NO x trap catalyst

Ammonia is an important intermediate of the NO x reduction in a NO x storage and reduction catalyst (aka lean NO x trap). NH 3 formed under rich conditions in the reduced front part of the catalyst is transported by convection downstream to the unregenerated (still oxidized) zone of the catalyst, where it further reacts with the stored oxygen and NO x . In this paper, the kinetics and selectivity of NH 3 reactions with the stored oxygen are studied in detail with a commercial Ba-based NO x storage catalyst containing platinum group metals (PGM), Ba and Ce oxides. Furthermore, steady-state NH 3 decomposition, NH 3 oxidation by O 2 and NO, and N 2 O decomposition are examined in light-off experiments. Periodic lean/rich cycling is measured first with O 2 and NH 3 , and then with NO x + O 2 and NH 3 to discriminate between the NH 3 reactions with the stored oxygen and the stored NO x . The reaction of NH 3 with the stored O 2 is highly selective towards N 2 , however a certain amount of NO x and N 2 O is also formed. The formed NO x by-product is efficiently adsorbed on the NO x storage sites such that the NO x is not detected at the reactor outlet except at high temperatures. The stored NO x reacts with NH 3 feed in the next rich phase, contributing to the N 2 O formation. Water inhibits the reactions of NH 3 with the stored oxygen. On the contrary, the presence of CO 2 increases the NH 3 consumption. Furthermore, CO 2 is able to provide additional oxygen for NH 3 oxidation, forming –CO in analogy to the reverse water gas shift reaction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

NASA NTRS1987

Flutter study of an advanced composite wing with external stores

A flutter test using a scaled model of an advanced composite wing for a Navy attack aircraft has been conducted in the NASA Langley Research Center Transonic Dynamics Tunnel. The model was a wall-mounted half-span wing with a semi-span of 6.63 ft. The wing had an aspect ratio of 5.31, taper ratio of 0.312, and quarter-chord sweep of 25 degrees. The model was supported in a manner that simulated the load path in the carry-through structure of the aircraft and the symmetric boundary condition at the fuselage centerline. The model was capable of carrying external stores from three pylon locations on the wing. Flutter tests were conducted for the wing with and without external stores. No flutter was encountered for the clean wing at test conditions which simulated the scaled airplane operating envelope. Flutter boundaries were obtained for several external store configurations. The flutter boundaries for the fuel tanks were nearly Mach number independent (occurring at constant dynamic pressure). To study the aerodynamic effect of the fuel tank stores, pencil stores (slender cylindrical rods) which had the same mass and pitch and yaw inertia as the fuel tanks were tested on the model. These pencil store configurations exhibited a transonic dip in the flutter dynamic pressure, indicating that the aerodynamic effect of the actual fuel tanks on flutter was significant. Several flutter analyses methods were used in an attempt to predict the flutter phenomenon exhibited during the wind-tunnel test. The analysis gave satisfactory predictions of flutter for the pencil store configurations, but unsatisfactory correlation for the actual fuel tank configurations.

Cole, Stanley R.↗