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At least 631 records · Page 35
All sourcesNASA NTRSDOE OSTI
NASA NTRS1995

Electronic manufacturing and packaging in Japan

This report summarizes the status of electronic manufacturing and packaging technology in Japan in comparison to that in the United States, and its impact on competition in electronic manufacturing in general. In addition to electronic manufacturing technologies, the report covers technology and manufacturing infrastructure, electronics manufacturing and assembly, quality assurance and reliability in the Japanese electronics industry, and successful product realization strategies. The panel found that Japan leads the United States in almost every electronics packaging technology. Japan clearly has achieved a strategic advantage in electronics production and process technologies. Panel members believe that Japanese competitors could be leading U.S. firms by as much as a decade in some electronics process technologies. Japan has established this marked competitive advantage in electronics as a consequence of developing low-cost, high-volume consumer products. Japan's infrastructure, and the remarkable cohesiveness of vision and purpose in government and industry, are key factors in the success of Japan's electronics industry. Although Japan will continue to dominate consumer electronics in the foreseeable future, opportunities exist for the United States and other industrial countries to capture an increasingly large part of the market. The JTEC panel has identified no insurmountable barriers that would prevent the United States from regaining a significant share of the consumer electronics market; in fact, there is ample evidence that the United States needs to aggressively pursue high-volume, low-cost electronic assembly, because it is a critical path leading to high-performance electronic systems.

Kelly, Michael J.↗
NASA NTRS2021

Effect of High Temperature Storage on AC Characteristics of Polymer Tantalum Capacitors

Replacement of MnO2 with conductive polymers as cathode materials in chip tantalum capacitors allows for a substantial reduction of the equivalent series resistance (ESR), improvement of frequency characteristics, and elimination of the possibility of ignition during failures. One of the drawbacks of chip polymer tantalum capacitors (CPTCs) is a relatively poor long-term stability at high temperatures. In this work, variations of capacitance, dissipation factor, and ESR in different types of capacitors including automotive grade parts from three manufacturers have been monitored during storage at temperatures from 100 ºC to 175 ºC for up to 18,000 hours. Results show that ESR is the most and capacitance the least sensitive to degradation parameter. Times to parametric failures have been simulated using a Weibull-Arrhenius model that allowed for assessments of activation energies of the degradation and prediction of times to failure at the use temperature. Degradation of CPTCs was explained by thermo-oxidative processes in conductive polymers that result in exponential increasing of the resistivity with time of ageing. This process starts after a certain incubation period that depends on packaging materials and design and corresponds to the time that is necessary to form delamination between the encapsulating molding compound and lead frame. The effectiveness of the existing qualification procedures to assure stable operation of CPTCs is discussed.

Alexander A Teverovsky↗
NASA NTRSDate not supplied

Effect of High Temperature Storage on AC Characteristics of Polymer Tantalum Capacitors

Replacement of MnO2 with conductive polymers as cathode materials in chip tantalum capacitors allows for a substantial reduction of the equivalent series resistance (ESR), improvement of frequency characteristics, and elimination of the possibility of ignition during failures. One of the drawbacks of chip polymer tantalum capacitors (CPTCs) is a relatively poor long-term stability at high temperatures. In this work, variations of capacitance, dissipation factor, and ESR in different types of capacitors including automotive grade parts from three manufacturers have been monitored during storage at temperatures from 100 ºC to 175 ºC for up to 18,000 hours. Results show that ESR is the most and capacitance the least sensitive to degradation parameter. Times to parametric failures have been simulated using a Weibull-Arrhenius model that allowed for assessments of activation energies of the degradation and prediction of times to failure at the use temperature. Degradation of CPTCs was explained by thermo-oxidative processes in conductive polymers that result in exponential increasing of the resistivity with time of ageing. This process starts after a certain incubation period that depends on packaging materials and design and corresponds to the time that is necessary to form delamination between the encapsulating molding compound and lead frame. The effectiveness of the existing qualification procedures to assure stable operation of CPTCs is discussed.

Aging↗
NASA NTRSDate not supplied

Effect of High Temperature Storage on AC Characteristics of Polymer Tantalum Capacitors

Replacement of MnO2 with conductive polymers as cathode materials in chip tantalum capacitors allows for a substantial reduction of the equivalent series resistance (ESR), improvement of frequency characteristics, and elimination of the possibility of ignition during failures. One of the drawbacks of chip polymer tantalum capacitors (CPTCs) is a relatively poor long-term stability at high temperatures. In this work, variations of capacitance, dissipation factor, and ESR in different types of capacitors including automotive grade parts from three manufacturers have been monitored during storage at temperatures from 100 ºC to 175 ºC for up to 18,000 hours. Results show that ESR is the most and capacitance the least sensitive to degradation parameter. Times to parametric failures have been simulated using a Weibull-Arrhenius model that allowed for assessments of activation energies of the degradation and prediction of times to failure at the use temperature. Degradation of CPTCs was explained by thermo-oxidative processes in conductive polymers that result in exponential increasing of the resistivity with time of ageing. This process starts after a certain incubation period that depends on packaging materials and design and corresponds to the time that is necessary to form delamination between the encapsulating molding compound and lead frame. The effectiveness of the existing qualification procedures to assure stable operation of CPTCs is discussed.

Aging↗
NASA NTRS2021

Effect of High Temperature Storage on AC Characteristics of Polymer Tantalum Capacitors

Replacement of MnO2 with conductive polymers as cathode materials in chip tantalum capacitors allows for a substantial reduction of the equivalent series resistance (ESR), improvement of frequency characteristics, and elimination of the possibility of ignition during failures. One of the drawbacks of chip polymer tantalum capacitors (CPTCs) is a relatively poor long-term stability at high temperatures. In this work, variations of capacitance, dissipation factor, and ESR in different types of capacitors including automotive grade parts from three manufacturers have been monitored during storage at temperatures from 100 ºC to 175 ºC for up to 18,000 hours. Results show that ESR is the most and capacitance the least sensitive parameter to degradation. Times to parametric failures have been simulated using a Weibull-Arrhenius model that allowed for assessments of activation energies of the degradation and prediction of times to failure at the use temperature. Degradation of CPTCs was explained by thermo-oxidative processes in conductive polymers that result in exponential increase of the resistivity with time of aging. This process starts after a certain incubation period that depends on packaging materials and design and corresponds to the time that is necessary to form delamination between the encapsulating molding compound and lead frame. The effectiveness of the existing qualification procedures to assure stable operation of CPTCs is discussed.

high temperature storage (HTS)↗
NASA NTRS2021

Effect of Preconditioning on Post-Soldering Failures in Tantalum Capacitors

Soldering have a strong effect on performance and reliability of most surface mount technology components, including tantalum capacitors. High quality tantalum capacitors are likely the only type of components where soldering simulation is the first step during screening. Nevertheless, post-soldering failures of tantalum capacitors do happen and require additional analysis. Popcorning is a well-known effect in plastic encapsulated microcircuits (PEM) and it occurs also in chip tantalum capacitors. The sensitivity of parts to the presence of moisture during soldering is characterized by the moisture sensitivity level (MSL); however, contrary to PEMs, there is no standard procedure for establishing MSL for tantalum capacitors, and standard J-STD-020 is applicable partially only. In this work, the effect of absorbed moisture on soldering related degradation and failures in tantalum capacitors have been studied using 22 types of polymer and 11 types of MnO2 cathodes tantalum capacitors including single and multianode parts. The amount of moisture released during soldering has been estimated by measurements of mass and capacitance variations. Results show that moisture uptake in similar parts is approximately two times greater in polymer than in MnO2 capacitors. Cracking of the case and degradation of parameters can occur in both types of parts, but MnO2 capacitors are much more susceptible to catastrophic short circuit failures and their ignition is possible during the first power-on cycle. This type of failure in MnO2 capacitors is lot-related, can occur even at derated voltages and relatively low levels of moisture sorption corresponding to room conditions. Baking before soldering is an effective measure to prevent failures even in lots susceptible to popcorning damage. Recommendations for testing to establish MSL and for baking to reduce the probability of failures are suggested.

tantalum polymer capacitors↗
NASA NTRS1979

Characteristics of the advanced supersonic technology AST-105-1 configured for transpacific range with Pratt and Whitney aircraft variable stream control engines

Credence to systems weights and assurance that the noise study AST concept can be balanced were studied. Current titanium structural technology is assumed. A duct-burning turbofan variable stream control engine (VSCE), with noise reduction potential through use of a coannular nozzle was used. With 273 passengers, range of the AST-105-1 for a cruise Mach number of 2.62 is essentially transpacific. Lift-to-drag ratio is slightly higher than for previous AST configurations. It is trimmable over a center-of-gravity range of 4.7m (15.5 ft). Inherent high positive effective dihedral, typical of arrow-wing configurations in high-lift approach, would limit AST-105-1 to operating in crosswinds of 11.6 m/sec (22.4 kt), or less, with 75 percent of available lateral control. Normal power takeoff with cutback results in noise in excess of Federal Aviation Regulation Part 36 but less than for conventional procedure takeoff. Results of advanced (noncertificated) programmed throttle takeoff and approach procedures, not yet optimized, indicate that such can be an important additional method noise reduction.

Baber, H. T., Jr.↗
NASA NTRS2024

Assessment of Some IASMS-relevant Data Sources for Aviation Safety

An In-time Aviation Safety Management System (IASMS) [1,2] is a set of services, functions, and capabilities (SFCs) necessary for monitoring known hazards and emergent risks, assessing safety data for anomalies, precursors, and trends, mitigating hazards that reach safety thresholds, and assuring efficacy of controls in mitigating hazards. An IASMS will continually monitor the NAS to collect data on the status of aircraft, air traffic management systems, weather, and airports. Within the NASA Aeronautics Research Mission Directorate (ARMD) System-Wide Safety (SWS) project’s technical challenge called In-time Aviation Safety Management Systems (IASMS) for Commercial Aviation Operations, which we often refer to as Technical Challenge 6 (TC-6), we have performed an assessment of several aviation data sources we have found that are relevant to assessing the safety of the National Airspace System (NAS) in the context of an IASMS. This assessment includes understanding the nature of the data themselves and using some data analytics tools on these data to show how they can be used to identify potential safety issues. We also describe how the data and analytics are part of a system that can allow for other data and analytics to be performed and for the results to be visualized for use by appropriate operators to identify potential safety issues and develop mitigations. This report is a step toward the ultimate goal of TC-6, which is to develop a prototype IASMS system that demonstrates the potential of an IASMS and inspire operators to build analogous systems to make the best possible use of the significant investments that they make in collecting, storing, and managingdata related to their operations.

aviation safety↗
DOE OSTI2022

Detecting missing struts in metallic micro-lattices using high speed melt pool thermal monitoring

Metal lattices are an important class of cellular materials that offer great advantages by providing high-strength and lightweight structures as compared to bulk materials. Progress in additive manufacturing techniques has led to increased complexity in design and shape of produced objects and is greatly beneficial for the development of metallic lattice structures. However additive manufacturing of lattices suffers from unpredictable defect creation that can compromise its mechanical integrity. Although post-build inspection techniques can provide quality assurance of the process, accurate assessment can be technically challenging, time consuming and costly. In this work, we investigate the use of high-speed measurements of thermal emission from the melt pool to identify defective individual struts formed with a missing bottom half in an otherwise fully built lattice structure produced with laser powder bed fusion. Surprisingly, results indicate lower photodiode signal, suggesting colder melt pool surface temperature, when printing struts with missing bottom half as compared to nominal struts. Additional thermographic imaging and multi-physics simulations reveal that the low photodiode signal is accompanied by presence of hot spatters carrying heat away from detection and continuous avalanche of powder on the melt pool. Based on these observations, a method was developed to identify defective individual struts with missing bottom half in full built lattices. This prediction approach provides valuable insights about part quality which are important for process qualification and illustrates the utility of melt pool thermal emission monitoring for identifying specific defects introduced by laser powder bed fusion.

36 MATERIALS SCIENCE↗
NASA NTRS2010

Building on the Past - Looking to the Future: A Focus on Expanding Horizons - Part 2

The history of space endeavors stretches far from Robert Goddard s initial flights and will certainly extend far beyond the construction of the International Space Station. As society grows in knowledge of and familiarity with space, the focus of maintaining the safety of the crews and the habitability of the vehicles will be of the utmost importance to the National Aeronautics and Space Administration (NASA) community. Through the years, Payload Safety has developed not only as a Panel, but also as part of the NASA community, striving to enhance the efficiency and understanding of how business should be conducted as more International Partners become involved. The recent accomplishments of the first docking of the Japan Aerospace Exploration Agency (JAXA) HII Transfer Vehicle (HTV 1) and completion of the Japanese Experiment Module (JEM) or KIBO and the Russian MRM2 to the International Space Station (ISS) mark significant steps for the future of ISS. 2010 will mark the final flights of the Shuttle and the completion of ISS assembly. Future delivery of humans and hardware will rely on the Russian Progress and Soyuz, the Japanese HII Transfer Vehicle (HTV), the European Automated Transfer Vehicle (ATV) and US "Commercial Off-The-Shelf" (COTS) and Constellation vehicles. The International Partners (IPs) will have more capability in delivery as well as responsibility for review of hardware they deliver to assure safe operation. This is the second in a series of papers and presentations in what is hoped to be an annual update that illustrates challenges and lessons learned in the areas of communication (how hazard reports can be misunderstood), safety requirements (transitioning from Shuttle-centric to ISS-centric), and processes (review of hardware by RSC-E and Franchised ESA and JAXA PSRP) which have been vital in conducting the business of the Payload Safety Review Panel (PSRP). This year will focus on the items annotated above.

Guidry, Richard W.↗
NASA NTRS2019

Evaluation of MODIS and VIIRS Cloud-Gap-Filled Snow-Cover Products for Production of an Earth Science Data Record

MODerate resolution Imaging Spectroradiometer (MODIS) cryosphere products have been available since 2000 – following the 1999 launch of the Terra MODIS and the 2002 launch of the Aqua MODIS – and include global snow-cover extent (SCE) (swath, daily, and 8 d composites) at 500 m and ∼5 km spatial resolutions. These products are used extensively in hydrological modeling and climate studies. Reprocessing of the complete snow-cover data record, from Collection 5 (C5) to Collection 6 (C6) and Collection 6.1 (C6.1), has provided improvements in the MODIS product suite. Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) Collection 1 (C1) snow-cover products at a 375 m spatial resolution have been available since 2011 and are currently being reprocessed for Collection 2 (C2). Both the MODIS C6.1 and the VIIRS C2 products will be available for download from the National Snow and Ice Data Center beginning in early 2020 with the complete time series available in 2020. To address the need for a cloud-reduced or cloud-free daily SCE product for both MODIS and VIIRS, a daily cloud-gap-filled (CGF) snow-cover algorithm was developed for MODIS C6.1 and VIIRS C2 processing. MOD10A1F (Terra) and MYD10A1F (Aqua) are daily, 500 m resolution CGF SCE map products from MODIS. VNP10A1F is the daily, 375 m resolution CGF SCE map product from VIIRS. These CGF products include quality-assurance data such as cloud-persistence statistics showing the age of the observation in each pixel. The objective of this paper is to introduce the new MODIS and VIIRS standard CGF daily SCE products and to provide a preliminary evaluation of uncertainties in the gap-filling methodology so that the products can be used as the basis for a moderate-resolution Earth science data record (ESDR) of SCE. Time series of the MODIS and VIIRS CGF products have been developed and evaluated at selected study sites in the US and southern Canada. Observed differences, although small, are largely attributed to cloud masking and differences in the time of day of image acquisition. A nearly 3-month time-series comparison of Terra MODIS and S-NPP VIIRS CGF snow-cover maps for a large study area covering all or parts of 11 states in the western US and part of southwestern Canada reveals excellent correspondence between the Terra MODIS and S-NPP VIIRS products, with a mean difference of 11 070 sqkm, which is ∼0.45 % of the study area. According to our preliminary validation of the Terra and Aqua MODIS CGF SCE products in the western US study area, we found higher accuracy of the Terra product compared with the Aqua product. The MODIS CGF SCE data record beginning in 2000 has been extended into the VIIRS era, which should last at least through the early 2030s.

Hall, Dorothy K.↗
NASA NTRS1991

Validation of lidar and satellite remote sensing

Validation of observations is an important part of any remote sensing program. With respect to aerosols this is exceedingly difficult because each technique typically measures a different aerosol parameter. Correlative sensors, therefore, must be capable of measuring the same parameter over the same size range or include enough measurements to properly characterize the aerosol, possibly with the assistance of models. In any correlative measurement program, simultaneity in space and time is required. This can be less restrictive during periods of atmospheric stability. The discussion is presented which is focused on the validation programs developed for NASA's Stratospheric Aerosol Measurement (SAM II), and the Stratospheric Aerosol and Gas Experiments I and II (SAGE I and II). To date these were limited to the stratosphere. Since satellite sensors are capable of providing near-global and long-term observations, periodic correlative observations over various global locations and seasons are required for assuring that data quality is unchanged, or for understanding any changes observed.

Mccormick, M. P.↗
DOE OSTI2023

2022 Site Environmental Report: Idaho National Laboratory

The INL Site’s operations, as well as the ongoing cleanup mission involve a commitment to environmental stewardship and full compliance with environmental protection laws. As part of this commitment, the INL Site Environmental Report is prepared annually to inform the public, regulators, stakeholders, and other interested parties of the INL Site’s environmental performance during the year. This report is published for U.S. Department of Energy, Idaho Operations Office (DOE-ID) in compliance with DOE O 231.1B, “Environment, Safety and Health Reporting.” The purpose of the report is to provide the following: (1) Present the INL Site, mission, and programs, (2) Report compliance status with applicable federal, state, and local regulations, (3) Describe the INL Site environmental programs and activities, (4) Summarize results of environmental monitoring, (5) Discuss potential radiation doses to the public residing in the vicinity of the INL Site, (6) Report on ecological monitoring and research conducted by contractors and affiliated agencies and by independent researchers through the Idaho National Environmental Research Park, (7) Describe quality assurance methods used to ensure confidence in monitoring data, and (8) Provide supplemental technical data and reports that support the INL Site Environmental Report (https://idahoeser.inl.gov/publications.html).

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2000

Continuing Measurements of CO2 Crystals with a Hand-Held 35 GHz Radiometer

In order to increase our knowledge of the Martian polar caps, an improved understanding of the behavior of both frozen H2O and CO2 in different parts of the electromagnetic spectrum is needed. The thermal microwave part of the spectrum has received relatively little attention compared to the visible and infrared wavelengths. A simple experiment to measure the brightness temperature of frozen CO2 was first performed in the winter of 1998 using a 35 GHz radiometer. in experiments performed during the winter of 1999 and 2000, passive microwave radiation emanating from within layers of manufactured CO2 (dry ice) crystals was again measured with a 35 GHz handheld radiometer. Both large (0.8 cm) and small (0.3 cm) cylindrical-shaped dry ice pellets, at a temperature of 197 K (-76 C), were measured. A 1 sq m plate of aluminum sheet metal was positioned beneath the dry ice so that microwave emissions from the underlying soil layers would be minimized. Non-absorbing foam was positioned around the sides of the plate in order to keep the dry ice in place and to assure that the incremental deposits were level. Thirty-five GHz measurements of this plate were made through the dry ice deposits in the following way. Layers of dry ice were built up and measurements were repeated for the increasing CO2 pack. First, 7 cm of large CO2 pellets were poured onto the sheet metal plate, then an additional 7 cm were added, and finally, 12 cm were added on top of the 14 cm base. Hand-held 35 GHz measurements were made each time the thickness of the deposit was increased. The same process was repeated for the smaller grain pellets. Furthermore, during the past winter, 35 GHz measurements were taken of a 25 kg (27 cm x 27 cm x 27 cm) solid cube Of CO2, which was cut in half and then re-measured. Additional information is contained in the original extended abstract.

Foster, J.↗
NASA NTRS1989

Product assurance technology for procuring reliable, radiation-hard, custom LSI/VLSI electronics

Advanced measurement methods using microelectronic test chips are described. These chips are intended to be used in acquiring the data needed to qualify Application Specific Integrated Circuits (ASIC's) for space use. Efforts were focused on developing the technology for obtaining custom IC's from CMOS/bulk silicon foundries. A series of test chips were developed: a parametric test strip, a fault chip, a set of reliability chips, and the CRRES (Combined Release and Radiation Effects Satellite) chip, a test circuit for monitoring space radiation effects. The technical accomplishments of the effort include: (1) development of a fault chip that contains a set of test structures used to evaluate the density of various process-induced defects; (2) development of new test structures and testing techniques for measuring gate-oxide capacitance, gate-overlap capacitance, and propagation delay; (3) development of a set of reliability chips that are used to evaluate failure mechanisms in CMOS/bulk: interconnect and contact electromigration and time-dependent dielectric breakdown; (4) development of MOSFET parameter extraction procedures for evaluating subthreshold characteristics; (5) evaluation of test chips and test strips on the second CRRES wafer run; (6) two dedicated fabrication runs for the CRRES chip flight parts; and (7) publication of two papers: one on the split-cross bridge resistor and another on asymmetrical SRAM (static random access memory) cells for single-event upset analysis.

Buehler, M. G.↗
DOE OSTI2022

Code of Record: DOE Standard Canister (DOESC)

The United States Department of Energy (DOE) Spent Nuclear Fuel (SNF) Packaging Demonstration seeks to develop and demonstrate the designs, technology, processes, and regulatory framework for packaging DOE SNF for road-ready dry storage (RRDS); and establish the processes that will be used in a future production facility. The Packaging Demonstration will utilize the DOE Standard Canister (DOESC) for packaging select DOE-managed SNF types for interim storage, transportation and disposal as part of RRDS. Placing DOE-managed SNF into RRDS is part of the strategic framework for SNF on the Idaho National Laboratory (INL) site. To comply with DOE, INL and Nuclear Regulatory Commission (NRC) requirements, this Code of Record establishes the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC), Section III, Division 3 as the Code that will govern DOESC and internal support structure constructioni, with certain clarifications. This Code of Record establishes a rationale for proceeding without construction certification of the DOESC (i.e., “N-stamping) and the extent to which a Registered Professional Engineer is required for the DOE Spent Fuel Packaging Demonstration. Given the (i) standard industry practice to pursue independent licensure of commercial storage casks and transportation packages by the NRC in lieu of ASME certification and (ii) guidance provided by 10 CFR 830, DOESC construction activities need not be certified (i.e., “stamped”) to the ASME BPVC. However, additional quality assurance requirements will apply as outlined in this Code of Record.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Strategic roadmap to assess forest vulnerability under air pollution and climate change

Abstract Although it is an integral part of global change, most of the research addressing the effects of climate change on forests have overlooked the role of environmental pollution. Similarly, most studies investigating the effects of air pollutants on forests have generally neglected the impacts of climate change. We review the current knowledge on combined air pollution and climate change effects on global forest ecosystems and identify several key research priorities as a roadmap for the future. Specifically, we recommend (1) the establishment of much denser array of monitoring sites, particularly in the South Hemisphere; (2) further integration of ground and satellite monitoring; (3) generation of flux‐based standards and critical levels taking into account the sensitivity of dominant forest tree species; (4) long‐term monitoring of N, S, P cycles and base cations deposition together at global scale; (5) intensification of experimental studies, addressing the combined effects of different abiotic factors on forests by assuring a better representation of taxonomic and functional diversity across the ~73,000 tree species on Earth; (6) more experimental focus on phenomics and genomics; (7) improved knowledge on key processes regulating the dynamics of radionuclides in forest systems; and (8) development of models integrating air pollution and climate change data from long‐term monitoring programs.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS2007

Build-up Approach to Updating the Mock Quiet Spike(TM)Beam Model

A crucial part of aircraft design is ensuring that the required margin for flutter is satisfied. A trustworthy flutter analysis, which begins by possessing an accurate dynamics model, is necessary for this task. Traditionally, a model was updated manually by fine tuning specific stiffness parameters until the analytical results matched test data. This is a time consuming iterative process. The NASA Dryden Flight Research Center has developed a mode matching code to execute this process in a more efficient manner. Recently, this code was implemented in the F-15B/Quiet Spike (Gulfstream Aerospace Corporation, Savannah, Georgia) model update. A build-up approach requiring several ground vibration test configurations and a series of model updates was implemented to determine the connection stiffness between aircraft and test article. The mode matching code successfully updated various models for the F-15B/Quiet Spike project to within 1 percent error in frequency and the modal assurance criteria values ranged from 88.51-99.42 percent.

Herrera, Claudia Y.↗