Qualification Method Research Articles

Chemical Isotope Labeling Exposome (CIL-EXPOSOME): One High-Throughput Platform for Human Urinary Global Exposome Characterization.

Human exposure to hundreds of chemicals, a primary component of the exposome, has been associated with many diseases. Urinary biomarkers of these chemicals are commonly monitored to quantify their exposure. However, because of low concentrations and the great variability in physicochemical properties of exposure biomarkers, exposome research has been limited by low-throughput and costly methods. Here, we developed a sensitive and high-throughput exposome analytical platform (CIL-EXPOSOME) by isotopically labeling urinary biomarkers with common functional groups (phenolichydroxyl/carboxyl/primary amine). After a simple cleanup, we used mass spectrometry to perform a screening for both targeted and untargeted biomarkers, which was further processed by an automatic computational pipeline method for qualification and quantification. This platform has effectively introduced an isotope tag for the absolute quantification of biomarkers and has improved sensitivity of 2-1184 fold compared to existing methods. For putative identification, we built a database of 818 urinary biomarkers with MS/MS fragmentation information from either standards or in silico predictions. Using this platform, we have found 671 urinary exposure biomarker candidates from a 2 mL pooled urine sample. The exposome data acquisition and analysis time has also been greatly shortened. The results showed that CIL-EXPOSOME is a useful tool for global exposome analysis of complex samples.

Applying time domain reflectometry to quantification of slope deformation by shear failure in a landslide

This study employed time domain reflectometry (TDR) to monitor the deformation of grouted coaxial cables in a landslide over an extended period. Laboratory experiments were performed to quantify the magnitude of the deformation by shear failure to simulate types of cable deformation in the field when two localized shear types had been detected using TDR. The study applied two qualification methods to measure the magnitude of the laboratory shear deformation. The integration method of the TDR reflection coefficients demonstrated a stronger significant positive correlation with the shear displacement than did the linear regression method of reflection coefficients in relation to the deformation magnitude of the cables. The integration method indicated increases of localized shear displacements from 15 to 47 mm over time at 10.33- and 13.36-m depths in the landslide. The average maximum magnitude of the cable deformation by shearing was 47 mm corresponding to a 210-mρ reflection coefficient when the cable ruptured in the case study. Overall, the location and magnitude of shear deformation in the landslide can be determined using changes in the TDR waveforms and calculations of the integration method of reflection coefficients.

Advanced qualification method for patterns with irregular edges in printed electronics

To evaluate the pattern transfer completeness (PTC) with respect to the line edge roughness (LER), this paper proposes an advanced method which statistically quantifies the deviations of printed patterns from their corresponding designed patterns. Complex patterns of Archimedean, logarithmic, and hyperbolic spirals are demonstrated using inkjet printing under various conditions to show different LERs and the effectiveness of the advanced method. The advanced method analyzes patterns using parametric forms in Cartesian coordinates instead of standard forms in polar coordinates, thus enabling evaluations with negligible errors which outperform existing methods. This study involved comprehensive analyses of the impacts of digitized patterns with serrated curves, different orientations of the asymmetric pattern, curvatures of the pattern, and the detection range and its movement. The results show that the advanced method not only correctly reflected the PTC, but also exhibited operational flexibilities, e.g. the evaluation efficiency may be enhanced by introducing an enlarged detection range or an increased movement of the detection range.

Risk Based Technology Qualification Method for HPHT Well

With the increasing demand for new technologies in HPHT (high pressure high temperature) wells, more and more attention has been paid to the system of technical qualifications. Most established norms, standards and recommended practices are written in prescribed formats, setting out methods, procedures and acceptance criteria for product design, manufacture and testing. However, established norms, standards or recommended practices may not adequately cover new technologies or applications. The technical qualification system is established in this paper, which can identify the potential failure modes and some activities in order to control the uncertainties and increase confidence of using new technology. A risk-based technical qualification system is used to assess non-traditional operations. It includes following seven main steps: system breakdown, technology assessment and classification, technical novelty, failure model and risk analysis, risk-based qualification planning and participation level development. The core of technical qualification system is to understand the ways and causes of system failure, and to carry out corresponding activities to provide evidence that the system will not fail. Through the technical identification process, the detailed equipment/operation specifications and identification requirements have been formulated. Different levels of participation are assigned for each eligibility activity, depending on the hazard and risk. It is proved that the application of the technical qualification principle in the systematic evaluation and control of the risks of new technologies or new applications is successful. In HPHT wells in particular, operators can move from a reactive approach to a proactive approach.

Verification of Redox Flow Batteries’ Functionality by Electrochemical Impedance Spectroscopy Tests

The state-of-the-art functionality test of classic redox-flow-stacks measures the current–voltage characteristic with the technical electrolyte. This research paper aims to simplify the validation of redox flow batteries’ functionality by conducting electrochemical impedance spectroscopy (EIS) on redox flow stacks. Since the electrolyte used in the batteries is usually toxic and aggressive, it would be a significant simplification to verify the functionality with an alternative, non-toxic fluid. EIS measurements on batteries with larger sized electrodes, multiple cells, and different fluids were performed. It was demonstrated that all impedances are repeatable, thereby validating this procedure as a qualification method for full-size and complex batteries with an alternative fluid. EIS measurements were able to detect deliberately manipulated cells. This research uses three different analysis methods for the acquired data to identify errors. The respective approaches are, firstly, (1) a comparison of the Nyquist plots; secondly, (2) a comparison of the Bode plots; and thirdly, (3) a comparison of the calculated characteristic values of the equivalent circuits. The analysis found that all methods are suitable to detect errors in the batteries. Nevertheless, the bode-plot comparison method proves to be especially advantageous, because it enables a quantitative statement.

In situ defect detection in selective laser melting via full-field infrared thermography

Selective laser melting (SLM) has become one of the most commonly utilized processes in metal additive manufacturing (AM). Despite its widespread use and capabilities, SLM parts are still being produced with excessive volumetric defects and flaws. The complex dependence of defect formation on process parameters, geometry, and material properties has inhibited effective quality assurance in SLM production. Exacerbating these issues are the difficulties thus far in accurately detecting and identifying defects in-process so that parts may be qualified without destructive testing. Some of the most detrimental defects produced during SLM processing are lack of fusion (LoF) defects, which are frequently found to be in excess of 100 μm in size, thus these defects are of critical importance to detect and remove. In this work, we have developed and demonstrated the capabilities of a novel in situ monitoring system using full-field infrared (IR) thermography to monitor AlSi10Mg specimens during SLM production. Using layerwise relative surface temperature measurements, subsurface defects were identified via their retained thermal signature at the surface; transient thermal modeling was performed, which supported these observations. Parts were characterized using ex situ scanning electron microscopy (SEM) to validate data identified defects and, critically, to estimate detection success. The IR defect detection method was highly effective in identifying defects, with an 82% total success rate for LoF defects; detection success improved with increasing defect size. The method was also used statistically to analyze the presence of systematic process errors during SLM production, expanding the capabilities of IR monitoring methods. This unique analysis method and simple integration for in situ IR monitoring can immediately improve non-destructive qualification methods in SLM processing.

Quality evaluation of postal address datasets measuring their autocorrelation

Many spatial applications related to land and titles like land use management, registering, and utility and health service providers are using postal addresses as their main or their supplementary georeferencing method. Evaluation of postal address datasets quality is important when controlling their changes due to manipulations (like add or update), comparing them, or merging them, that is one of the main strategies of developing countries like Iran, to form a unified addressing structure and database. Despite the costly and time consuming formal methods of postal addresses qualification that are based on address matching, the method proposed in this paper provides an evaluation of a postal address quality not requiring any preprocessing like standardization or ancillary data like streets and their addressing scheme data. The proposed method is based on measuring the autocorrelation of a postal address dataset content where higher level of autocorrelation indicates more standardization and less spatial sparsity of the addresses. The method processes the adjacency graph formed measuring Damerau–Levenstein distance between records of a postal address dataset. Evaluation of 5 statistics for 4 postal address datasets of Tehran City of Iran shows that the cumulative frequency of values and the maximum size of the components (sub-graphs) in the adjacency graph could be used. These statistics both show stable S-Shaped patterns that their threshold at the first extremum of their second derivative represents the desired quality of a postal address dataset. The results show that the measured threshold of postal address dataset corresponds with its topological structure of the streets that cover its addresses. The method can define characteristics of a standard address structure for one or more postal address datasets as the results propose 5 components for the standard address of the evaluated datasets which is the same as the number of components defined for Iranian national structure of postal addresses.

Cyclic robustness of heavy wire bonds: Al, AlMg, Cu and CucorAl

Development of advanced electronic packages can be drastically affected by implementation of new materials. The ever increasing demands for high performance and reliable power electronics, raise the need for rapid robustness evaluation of interconnects. In this study the lifetime of heavy wire bonded interconnects, fabricated with different wire material types Al, AlMg, Cu and Al coated Cu (CucorAl) bonded onto direct copper bonded ceramic substrates was investigated. The tests were performed using an accelerated mechanical fatigue testing system, which allows to determine the lifetime of the interconnects with regard to wire bond lift-off failure in a short period of time. Thus, the influence of ultrasonic power variation and the impact of aging on the performance of wire bonds with different material combinations was studied. Cu wire bonds showed clearly the best fatigue performance as well as static shear strength followed by AlMg and Al bonds. Increasing the ultrasonic power results in a higher fatigue resistance of CucorAl in comparison to pure Al wires. In certain cases, the results of the fatigue experiments and static shear tests were found to be contradictory. The presented results suggest that accelerated mechanical fatigue testing can be used as an additional fast method for qualification of interconnects and assessment of the influence of wire material, bond parameter and aging.

Application of multi-output Gaussian process regression for remaining useful life prediction of light emitting diodes

Light-emitting diodes (LEDs) are the preferred technology today when it comes to lighting both for indoor and outdoor applications, predominantly due to their high efficiency, environmental resilience and prolonged lifetime. Given their widespread use, there is a need to quickly qualify them and accurately predict the reliability of these devices. Due to their inherently long operational life, most LED reliability studies involve the use of degradation tests and application of filter-based prognostic techniques for dynamic update of degradation model parameters and estimation of the remaining useful life (RUL). Although they are in general very effective, the main drawback is the need for a specific state-space model that describes the degradation. In many cases, LED degradation trends are affected by a multitude of unknown factors such as unidentified failure modes, varying operational conditions, process and measurement variance, and environmental fluctuations. These variable factors that are hard to control tend to complicate the selection of a suitable state-space model and in some cases; there may not be a single model that could be used for the entire lifespan of the device. If the degradation patterns of LEDs under test deviate from the state space models, the resulting predictions will be inaccurate. This paper introduces a prognostics-based qualification method using a multi-output Gaussian process regression (MO-GPR) and applies it to RUL prediction of high-power LED devices. The main idea here is to use MO-GPR to learn the correlation between similar degradation patterns from multiple similar components under test and thereby, bypass the need for a specific state space model using available data of past units tested to failure.

Qualification Strategy of New Technologies for Safety Instrumentation in Harsh Radiation Environments

Qualification of safety instrumentation for nuclear reactors is a challenging issue in harsh radiation environments; the task is further complicated when new technologies are introduced. In this paper, we present two qualification strategies for new developments qualified to the highest safety standards. In the first case study, we develop a qualification method that quantifies the aging rate of a polymer during different aging steps, thus paving the way to predictive maintenance for safety qualified instrumentation. In the second case study, we propose a qualification strategy for a fiber optic-based probe which is supposed to implement a safety function in an extreme radiation environment that will expose the probe to 800 MGy over its lifetime.

Universal HPLC Detector for Hydrophilic Organic Compounds by Means of Total Organic Carbon Detection.

Most quantifications are achieved by comparison of the signals obtained with the sample to those from a standard. Thus, the purity and stability of the standard are key in chemical analysis. Furthermore, if an analyte standard cannot be obtained, quantification cannot be achieved, even if the chemical structures are identified by a qualification method (e.g., high-resolution mass spectrometry). Herein, we describe a universal and analyte standard-free detector for aqueous-eluent-based high-performance liquid chromatography. This universal carbon detector (UCD) was developed based on total organic carbon detection. Separated analytes were oxidized in-line and converted to carbon dioxide (CO2). Generated CO2 was transferred into the gas phase and collected into ultrapure water, which was followed by conductivity detection. The system can be applied as a HPLC detector that does not use an organic solvent as an eluent. The system can be calibrated with a primary standard of sodium bicarbonate for organic compounds. The universality and quantification were evaluated with organic compounds, including organic acids, sugars, and amino acids. Furthermore, the system was successfully applied to evaluation of the purity of formaldehyde in formalin solution, and determination of sugars in juices. The results show the universal carbon detector has good universality and can quantify many kinds of organic compounds with a single standard such as sodium bicarbonate.

Comparison and Research on Seismic Design Practice for Elec-tric Substation Equipment in China, Japan, USA and Europe

This paper compares the key aspects, i.e. the objectives, methods of seismic qualification, site classification and required response spectra (RRS) of GB 50260, JEAG 5003, IEEE Std 693 and IEC 62271-300. This study provides an understanding of the similarities and differences among Chinese, Japanese, U.S. and European seismic design practice. In terms of the performance objectives, site assignments and RRS, IEEE Std 693 and IEC 62271-300 present numerous similar standards, although there are many minor differences in the detailed provisions, while GB 50260 and JEAG 5003 are different in definition of ground types and determination of design response spectra. Among the four codes, the IEEE standard is generally the most restrictive, particularly at higher qualification levels. The four have strengths as well as shortcomings, and may benefit from learning each other's experience. This study may provide linkages among these standards for seismic qualification, as well as potential modifications and unification of these criteria, which could result in better performance.

A Novel Method for Qualification of a Potency Assay through Partial Computer Simulation.

For biotherapeutics and vaccines, potency is measured in a bioassay that compares the concentration-response curves of a new batch to that of a reference standard. Acceptable accuracy and precision of potency measurement is critical to the manufacturing of these products. These characteristics of a bioassay are typically assessed in a procedure that is carried out with samples spanning the acceptable range for the product. During early development, however, a full validation study such as that which is carried out in late development can be costly as it relates to the likelihood of eventual program success. For these reasons, the laboratory may look for alternative ways to ensure the validity of the bioassay across a range that will support product development. One such alternative combines information from a reduced procedure using only reference standard and 100% relative potency concentration-response data sets, together with computer simulation, to estimate missing relative potency values across the desired range. Fits to the reduced dataset provide estimates of bioassay model parameters such as those for an S-shaped potency assay that follows a four-parameter logistic relationship, along with estimates of their variance-covariance structure and independent experimental unit (e.g., well-to-well or animal-to-animal) errors. Using Bayesian Markov Chain Monte Carlo modeling, the predictive distribution of the concentration-response data for the desired levels of relative potency is generated. Results from use of the reduced procedure are compared to results calculated from a full dataset in Monte Carlo simulation and in a motivating example.LAY ABSTRACT: For biotherapeutics and vaccines, potency is measured in a bioassay that compares the concentration-response curves of a new batch to that of a reference standard. Acceptable accuracy and precision of potency measurement is critical to the manufacturing of these products. These characteristics of a bioassay are typically assessed in a procedure that is carried out with samples spanning the acceptable range for the product. During early development, however, a full validation study such as that which is carried out in late development can be costly as it relates to the likelihood of eventual program success. For these reasons, the laboratory may look for alternative ways to ensure the validity of the bioassay across a range that will support product development. One such alternative combines information from a reduced procedure using only reference standard and 100% relative potency concentration-response data sets, together with computer simulation, to estimate missing relative potency values across the desired range. Bayesian Markov Chain Monte Carlo modeling is used to generate the distributions of the missing potency levels. Results from use of the reduced procedure are compared to results calculated from a full dataset in Monte Carlo simulation and in a motivating example.

The Role of Regulators in Mitigating Uncertainty within the Valley of Death

The essential cause of the ‘Valley of Death’ is the reluctance of the private sector to invest in technologies which are perceived as too risky. This risk has usually been assessed in terms of technology maturity. However, uncertainty about whether a new product or technology complies with regulatory frameworks may also have an important effect on private sector investments. We study how regulatory agencies engage with public sector researchers and the private sector actors to create new tools and guidelines to reduce regulatory uncertainty, and how their efforts impact investment across the Valley of Death. We use the cases of the Critical Path Initiative, in the pharmaceutical industry, and the Advanced General Aviation Transportation Experiments, in the general aviation industry, to analyze how the role of regulators may vary across different industry contexts. Based on our findings, we create a taxonomy with three different types of regulatory uncertainty, which we designate as ‘Framework Dynamics Uncertainty,’ ‘Final Compliance Uncertainty’ and ‘Qualification Method Uncertainty.’ Analyzing the dominant types of uncertainty in each industry and technology case may help better design public-private partnerships by incorporating the appropriate technical expertise from a variety of stakeholders, and align program outcomes to regulatory goals so that the tools created in those programs enjoy the appropriate regulatory endorsement.

Robotics in securities operations

With widespread interest in robotics, more and more firms are beginning to explore automation through proof-of-concepts and pilots. Traditionally, shared services has been the primary target of such ventures; however, investment banks are increasingly exploring if robotics could be extended into core processing functions. This paper, written on the basis of implementation experiences, examines activities across securities operations from trade processing, corporate actions, clearing and settlements, data management and onboarding to provide practical use cases for automation. Specifically, the paper identifies common repetitive and rule-based manual tasks across the areas mentioned above and discusses how robotic process automation can be used to reimagine the processes for greater efficiencies and control. Nevertheless, as with any new technology, there are challenges that may impede benefit realisation. Some of the challenges are structural in nature, such as process fragmentation, which may require front-to-back process redesign along with automation. Other challenges could be addressed with the right operating model, governance, opportunity qualification methods and infrastructure. Beyond cost savings, starting this journey and getting it right could position investment banks to benefit from the application of the next generation of exponential technologies.

Analysis of the new examination process and German tests for sworn translators in Spain

Abstract The recent changes in the legislation on sworn translators and interpreters in Spain (Royal Decree 2002/2009, Order AEC/2125/2014) have brought about some modifications in the requisites and the access tests for this professional figure. Following the Resolution of 19 January 2015, new tests were conducted in 2015 in order to qualify translators and interpreters. This paper aims to analyze the new format of examination and the statistics of success of the candidates, with special focus on the German language. The current process shall also be compared to the now extinct academic process of qualification of sworn translators and interpreters in the framework of official translation degrees in Spain, in order to ascertain the most appropriate qualification method.

Performance qualification for reproducible Surface Plasmon Resonance analysis

Surface Plasmon Resonance Biosensors (SPR) are one of the most powerful tools to characterize protein binding, e.g. for drug discovery, like target identification, ligand fishing, assay development, lead selection and manufacturing quality control. However, there is increasing concern about its reproducibility in the light of the reproducibility crisis. Therefore an appropriate analytical instrument qualification (AIQ) is required for quality assurance of SPR instruments. AIQ is a prerequisite for analytical method validation and it is consisting of four parts, Design Qualification (DQ), Installation Qualification (IQ), Operational Qualification (OQ) and Performance Qualification (PQ). PQ regularly executed is supposed to continuously control the performance of the instrument under actual running conditions.In this work a performance qualification method was developed for the SPR instrument Biacore X100. This method is suitable for the routinely control of the instrument performance for antibody-antigen binding measurements. Control charts were designed to get a clearly representable and easy implementable tool to check the critical parameters. These control charts and a straightforward protocol now allow the design and application of an individual performance qualification procedure that can be used in the laboratory routine. They serve as reference for individual standard operation procedures (SOPs).

Multiple perspectives of qingkailing injection-fraction-single compound in revealing the hepatotoxicity of baicalin and hyodeoxycholic acid

Ethnopharmacological relevanceThe complexity of ingredients in traditional Chinese medical formulas and the limited consideration of toxicological responses are fundamental issues that hamper prognostic information of drug quality control. Materials and methodsA multidisciplinary approach for quality control of Qingkailing injection (QKL) regarding drug induced liver toxicity was described for the first time. High content image analysis (HCA) was combined with reverse-phase chromatographic separation and high-resolution MS detection technologies to provide the dynamic responses of drug induced HepG2 cell injury. Firstly, a simple and rapid method for simultaneous qualification and quantification of 21 major constituents in QKL was established and validated using ultra-high performance liquid chromatography-hybrid quadrupole-Orbitrap mass spectrometer (UHPLC-Q-Orbitrap), which were operated in full MS/dd-MS2 mode and thus simultaneously acquired quantitative high resolution (HR) full scan data and confirmatory HR MS2 data. Secondly, repeated semi-preparation HPLC was applied to obtain four fractions (F1-F4) for HCS analysis. Finally, potential hepatotoxicity was determined by five hepatotoxicity biomarkers, including cell loss, DNA condense, glutathione (GSH) depletion, reactive oxygen species (ROS) formation, and mitochondria membrane potential (MMP) depolarization. ResultsThe detection in polarity switching mode empowered the coverage of comprehensive constituents with different chemical properties. Satisfactory linearity precisions, repeatability, stability, and recovery were achieved. QKL injection significantly induced HepG2 cell injury above the concentration of 1.25% (v/v). Meanwhile, flavone glycosides (F3) and stinasterols (F4) fractions exhibited hepatotoxicity above 75μg/mL and 50μg/mL, respectively. Still further, baicalin originated from F3 significantly caused cell loss and glutathione (GSH) depletion. In parallel, hyodeoxycholic acid from F4 induced cell loss, nucleus condense, and GSH reduction as well. ConclusionsOur work provides multiple perspectives based on injection-fractions-single compound format to improve QKL pharmacovigilance through revealing the potential hepatotoxic material basis. Additionally, our study provides an integrating paradigm for the comprehensive and systematic quality control of traditional Chinese medical formulas.

Flow Cytometric Aldehyde Dehydrogenase Assay Enables a Fast and Accurate Human Umbilical Cord Blood Hematopoietic Stem Cell Assessment.

Objective:Colony-forming units of granulocytes/macrophages (CFU-GM) analysis is the most widely used method to determine the hematopoietic stem cell (HSC) content of human umbilical cord blood (CB) for prediction of engraftment potential. The measurement of aldehyde dehydrogenase (ALDH) activity is a more recent method for HSC qualification. Our aim was to correlate phenotypic and functional assays to find the most predictive method.Materials and Methods:In this study, flow cytometric quantitation of CD34+ cells and ALDH positivity along with CFU-GM capacity were assessed in fresh and post-thaw CB units.Results:Among 30 post-processing samples, for each CB unit the mean total number of nucleated cells (TNCs) was (93.8±30.1)x107, CD34+ cells were (3.85±2.55)x106, ALDH+ cells were (3.14±2.55)x106, and CFU-GM count was (2.64±1.96)x105. Among an additional 19 post-thaw samples the cell counts were as follows: TNCs, (32.79±17.27)x107; CD34+, (2.18±3.17)x106; ALDH+, (2.01±2.81)x106; CFU-GM, (0.74±0.92)x105. Our findings showed that in fresh samples TNCs, CD34+ cells, and ALDH correlated highly with counts of CFU-GM, CFU-erythroids/granulocytes-macrophages/megakaryocytic cells (GEMM), and burst forming units of erythroids (BFU-E) as follows: TNCs, r=0.47, r=0.35, r=0.41; CD34+, r=0.44, r=0.54, r=0.41; and ALDH, r=0.63, r=0.45, r=0.6, respectively. In terms of post-thaw samples, the correlations were as follows: TNCs, r=0.59, r=0.46, r=0.56; CD34+, r=0.67, r=0.48, r=0.61; and ALDH, r=0.61, r=0.67, r=0.67, for CFU-GM, CFU-GEMM, and BFU-E, respectively. All correlations were statistically significant.Conclusion:In our experience, HSC assessment by ALDH activity yields the highest correlation with conventional analytical methods, particularly for post-thaw samples. Thus, this fast, inexpensive method has the potential to overcome the weaknesses of other techniques.

Reliability of Solid-State Drives Based on NAND Flash Memory

This paper reviews the reliability of solid-state drives (SSDs) based on NAND Flash memory from the perspectives of failure mechanisms, design mitigations, qualification methods, and field failure rates. NAND reliability is dominated by gradual memory-cell degradation in late life and defects such as interconnect shorts earlier in life. Design mitigations exist for these mechanisms. Qualification methods standardized in JEDEC JESD218 are designed to evaluate the mechanisms and mitigations, over a full drive lifetime, in the laboratory. Full-lifetime qualification provides confidence in the long-term reliability of SSDs that cannot be achieved by the early-life qualifications performed on hard disk drives. If NAND mechanisms are sufficiently suppressed, field reliability will be dominated by non-NAND mechanisms such as firmware bugs, power-loss events, radiation-induced soft errors, and failures in non-NAND components. A wide range of design validation and qualification tests are necessary to evaluate these non-NAND mechanisms. Published field reliability statistics indicate that SSDs are more reliable on average than HDDs, but they are not immune to failure, and there is wide variation among models. The NAND and non-NAND mechanisms are illustrated through new case studies of SSD internal qualification and field reliability data.