Manufacturing Test Research Articles

A Low-overhead Solution for Obfuscating Scan Data Against Scan-based Side-channel Attacks

Scan-based design has been used normally to simplify the manufacturing test. However, the convenience brought by the design also becomes the weakness that increases the vulnerability of crypto chips. Many attacks have been proved effective to steal secret information stored inside chips through this structure. In this paper, we will propose a secure scan design with very low overhead and high security. The proposed scheme chooses some scan cells in the front part of the original scan chain to store the test key. The output of these scan cells will be transmitted to a multiple-input AND gate to realize authentication. If the input test key is incorrect, the data of the subchain in the front part of the scan chain will be shifted circularly and the values of those scan cells used to store the test key will be dynamically transmitted to the latter part of the scan chain to realize dynamic data obfuscation. The scheme excellently resists existing scan attacks.

Влияние человеческого фактора при создании авиационных двигателей

Ensuring the safety of the civil aviation system is the main goal of the International Civil Aviation Organization (ICAO) activities and the "human factor" was define as a priority in the field of flight safety. Given the variety of factors potentially affecting human performance, it is not surprising, that human error has been recognized as a major causative factor in virtually all air crashes and accidents since the inception of aviation. The reliability and safety of flights are influenced by: the quality of preparation of aviation equipment for flight, the quality of manufacture, assembly, acceptance, and pre-flight tests, the quality of design of aircraft and engines. The quality of workmanship is confirmed by the execution of control at each stage of manufacture. In any activity, the "human factor" is manifested by mistakes, oversights, and omissions, or miscalculations that a person makes when doing his job under certain conditions. The theory of the occurrence and prevention of errors associated with human physiology and the environment were described by H. Heinrich's "domino theory". Human errors form sequences in which the first error causes a chain of subsequent ones, keeping one of the dominoes standing behind each other, it is possible to prevent the consequences of an accident in the form of material damage or an accident. Human physiological features such as vision can be one of the dominoes and lead to erroneous actions. In the modern world, non-destructive testing methods are relevant and the role of a defectoscopistꞌs in determining the nature of a defect is quite large. Regular monitoring of vision (prophylactic examination) allows you to identify potential vision problems with a specialist, which can lead to erroneous actions. Human factors research is fundamental to understanding the context in which normal, healthy, skilled, well-equipped and reasonably motivated personnel make mistakes, some of which are fatal and, if the causes of human error are correctly understood, it will be possible to develop more effective prevention strategies errors, their control, and safe elimination.

Benchmarking of Nondestructive Testing for Additive Manufacturing.

Defect detection in additive manufacturing (AM) is of paramount importance to improve the reliability of products. Nondestructive testing is not yet widely used for defect detection. The main challenges are a lack of standards and methods, the types and location of defects, and the complex geometry of many parts. During selective laser melting (SLM), several types of defects can occur such as porosity, cracking, and lack of fusion. In this study, several nondestructive tests were conducted in a highly complex shaped part in AISI 316L stainless steel with real defects manufactured by SLM. Two additional artificial defects (one horizontal and one flat bottom hole) were produced and the defect detectability was evaluated. The techniques used were as follows: dye penetrant, infrared thermography, immersion ultrasonic, eddy current, and X-ray microcomputed tomography to assess different types of defects in the as-built part. We conclude that no single technique can detect every type of defect, although multiple techniques provide complementary and redundant information to critically evaluate the integrity of the parts. This approach is fundamental for improving the reliability of defect detection, which will help expand the potential for using AM to produce parts for critical structural applications.

Effect of size and shape of nanofillers on electrostatic and thermal behavior of epoxy-based composites

The role of nanodielectrics in the electrical power system is becoming crucial owing to its superior properties and potential applications in the field. Yet, the materials face limited breakdown strength and thermal properties. Further, the nanodielectrics have not found a comprehensive commercial platform because of the costly manufacturing process, and characterization and testing facilities. Therefore, to reduce the involved cost, in this work, an FE (finite element) based computational technique has been implemented to visualize the effect of shape, size, and filler concentration under the application of high voltage (HV). The epoxy-based nanodielectrics have been modeled incorporating a range of different shapes and size nanofillers—Al2O3, BN, BeO, SiO2, and TiO2. The paper discusses the 2D-analysis of the modeled nanodielectric in the steady-state electrostatic fields and thermal domains. It shows the insights of the nanofillers’ choice to ensure a perfect blend of electrical and thermal properties. The epoxy with square-shaped BeO fillers showed a rise in the electric field of nearly 1.5 times than unfilled neat epoxy, which indicates a significant surge in thermal conductivity at specific filler loading.

Transfusions in Aplastic Anemia Patients Cause HLA Alloimmunization: Comparisons of Current and Past Cohorts Demonstrate Progress

Transfusions are the mainstay of supportive therapy in patients with aplastic anemia (AA) and may lead to anti- HLA alloimmunization, thereby also increasing the risk for donor-specific antibodies in the setting of HLA-mismatched transplantation. Historically, AA patients were thought to be at particularly high risk for HLA alloimmunization. In past decades, blood product manufacturing (leukoreduction) and HLA antibody testing have improved significantly by single antigen bead (SAB) technology. It is currently unknown how those developments have impacted HLA alloimmunization and treatment outcome in patients with AA. We retrospectively investigated 54 AA patients treated by immunosuppressive therapy or allogeneic hematopoietic cell transplantation after the introduction of the SAB assay at our center. We compared the HLA antibody results to a historical AA cohort (n = 26), treated before introduction of leukoreduced blood products from 1975 to 1995. HLA alloimmunization was detected in 43 of 54 (80%) recently treated patients. Past pregnancy, female gender, disease severity, age, and a history of other transfusions were significantly associated with a larger number or higher intensity (mean fluorescence intensity) of HLA antibodies. Treatment outcome including bleeding episodes, response to treatment, engraftment, graft-versus-host disease, and overall survival was not associated with HLA alloimmunization. In the historical cohort a significantly higher number of HLA antibodies (P < .01) with a higher mean fluorescent intensity (P < .01) was observed. HLA alloimmunization remains frequent in AA tested by current techniques, but it has significantly decreased since prior decades and does not affect treatment outcome.© 2021 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.

Functional mechanical metamaterial with independently tunable stiffness in the three spatial directions

Mechanical metamaterials with variable stiffness recently gained a lot of research interest, as they allow for structures with complex boundary and load conditions. Herein, we highlight the design, additive manufacturing, and mechanical testing of a new kind of bending-dominated metamaterial. By advancing from well-established mechanical metamaterials, the proposed geometry allows for varying the stiffness in the three spatial directions independently. Therefore, structures with different orientational properties can be designed, ranging from isotropic to anisotropic structures, including orthotropic structures. The compression modulus can be varied in the range of several orders of magnitude. Gradual transitions from one unit cell to the next can be realized, enabling smooth transitions from soft to hard regions. Specimens have been additively manufactured with acrylic resins and polylactic acid using Digital Light Processing and Fused Filament Fabrication, respectively. Two different numerical models have been employed using ABAQUS to describe the mechanical properties of the structure and verified by the experiments. Compression tests were performed to investigate the linear elastic properties of isotropic structures. Numerical models, based on three-point-bending test data, have been employed to study orthotropic structures. Compression test results for orthotropic and anisotropic structures are shown to highlight the independent variability. The manufacturing of the structures is not limited to the presented techniques and materials but can be expanded to all available additive manufacturing techniques and their respective materials. For a video of the compression tests of a specimen with three different compression moduli along the spatial axes, see the Supplementary Data available online.

Co-relation scan attack analysis (COSAA) on AES: A comprehensive approach

Scan based DfT is indispensable for IC testing in the semiconductor chip industry to ensure correctness of chip, both functionally and structurally. Since a higher degree of fault coverage is essential, cryptographic ICs rely on it as a standard technique during manufacturing test. Yet an invaluable tradeoff needs to be met between security and testability, because it is the observability and controllability of the sequential memory elements in the scan chain which are enhanced to facilitate testing. Well designed differential scan attacks which make use of this feature can prove to be critically pervasive to leak secret keys embedded in cryptochips. Use of response compactors ensure test cost reduction. Existing differential scan attacks target Hamming weight pairs that are unique. The motivation of our work lies in the fact that carefully fabricating additional bits in order to transform a unique Hamming weight to a non-unique one, existing attacks can be defended. In this paper, we propose Co-relation scan attack (COSAA) on AES crypto-system which can work even in the presence of test response compaction. We show our attack technique to be lethal against any possible Hamming weight model which means that the designer needs to prevent the circuit under test from a relatively broader attack surface. Our experiments show the proposed attack can successfully recover the secret key of AES with XOR compaction in 24 milliseconds using an average desktop machine.

Fabric steering technology for variable stiffness panels: Manufacture and mechanical testing

A novel low-cost manufacturing process is introduced, referred to as ‘Fabric Steering’. By manipulating biaxial fabrics, curvilinear fibre paths can be created to manufacture variable stiffness panels, similar to those produced using Automated Fibre Placement [1]. With low equipment costs and the capability to steer multiple-layers of fabrics simultaneously, this technique potentially offers faster production rates and lower manufacturing costs compared to Automated Fibre Placement. A computer aided engineering tool, SteerFab [2,3], is used to guide the design and manufacture process by predicting: (a) the optimum 2D fibre paths, (b) the subsequent mechanical behaviour of the resulting variable stiffness panel (including improvements in buckling resistance and strength) and (c) step-by-step manufacturing instructions. Compared to conventional quasi-isotropic straight-fibre laminates, experimental buckling tests show slightly heavier (by 4.6%) steered-fibre laminates achieve improvements of ~9% and ~17% in buckling resistance load and failure load, findings that fit well with numerical predictions.

Hierarchical sheet triply periodic minimal surface lattices: Design, geometric and mechanical performance

Lattices with hierarchical architectures exhibit unique geometric and mechanical properties compared with single scale ones. While numerous research efforts have focused on hierarchical strut lattices, hierarchical sheet lattices have yet to be studied in detail. This paper proposes a systemic framework including geometric design, finite element modelling, additive manufacturing, and mechanical testing for hierarchical sheet triply periodic minimal surface (TPMS) lattices such that the lattice walls comprise successively smaller scale TPMS architectures. Geometric properties including relative densities and volume-specific surface areas of hierarchical lattices are analytically calculated and verified via numerical calculations. The compressive properties of 2-order sheet Gyroid lattices are investigated with finite element simulations and experimentally validated using micro-selective laser melting fabricated stainless-steel specimens. Geometric analysis shows that hierarchical sheet lattices have great potential to achieve a wide range of controllable geometric properties including hierarchical porosities, ultralow densities, and significantly enlarged surface areas. Simulation results indicate that 2-order lattices have superior buckling strength over single scale lattices at ultralow densities. At moderate densities, 2-order lattices exhibit reduced modulus and strength, but more stable failure behaviour. With these unique combinations of geometric and mechanical properties, hierarchical sheet TPMS designs are shown to be desirable structural configurations for biomedical scaffolds.

Fundamentals of Capillary Electrophoretic Migration and Separation of SDS Proteins in Borate Cross-Linked Dextran Gels.

Recent progress in the development and production of new, innovative protein therapeutics require rapid and adjustable high-resolution bioseparation techniques. Sodium dodecyl sulfate capillary gel electrophoresis (SDS-CGE) using a borate (B) cross-linked dextran (D) separation matrix is widely employed today for rapid consistency analysis of therapeutic proteins in manufacturing and release testing. Transient borate cross-linking of the semirigid dextran polymer chains leads to a high-resolution separation gel for SDS-protein complexes. To understand the migration and separation basis of the D/B gel, the present work explores various gel formulations of dextran monomer (2, 5, 7.5, and 10%) and borate cross-linker (2 and 4%) concentrations. Ferguson plots were analyzed for a mixture of protein standards with molecular weights ranging from 20 to 225 kDa, and the resulting nonlinear concave curves pointed to nonclassical sieving behavior. While the 2% D/4% B gel resulted in the fastest analysis time, the 10% D/2% B gel was found to produce the greatest separation window, even higher than with the 10% D/4% B gel, due to a significant increase in the electroosmotic flow of the former composition in the direction opposite to SDS-protein complex migration. The study then focused on SDS-CGE separation of a therapeutic monoclonal antibody and its subunits. A combination of molecular weight and shape selectivity as well as, to a lesser extent, surface charge density differences (due to glycosylation on the heavy chain) influenced migration. Greater molecular weight selectivity occurred for the higher monomer concentration gels, while improved glycoselectivity was obtained using a more dilute gel, even as low as 2% D/2% B. This latter gel took advantage of the dextran-borate-glycoprotein complexation. The study revealed that by modulating the dextran (monomer) and borate (cross-linker) concentration ratios of the sieving matrix, one can optimize the separation for specific biopharmaceutical modalities with excellent column-to-column, run-to-run, and gel-to-gel migration time reproducibilities (<0.96% relative standard deviation (RSD)). The widely used 10% dextran/4% borate gel represents a good screening option, which can then be followed by a modified composition, optimized for a specific separation as necessary.

Optimal propeller blade design, computation, manufacturing and experimental testing

PurposeModern unmanned air vehicles (UAVs) are usually equipped with rotors connected to electric motors that enable them to hover and fly in all directions. The purpose of the paper is to design optimal composite rotor blades for such small UAVs and investigate their aerodynamic performances both computationally and experimentally.Design/methodology/approachArtificial intelligence method (genetic algorithm) is used to optimize the blade airfoil described by six input parameters. Furthermore, different computational methods, e.g. vortex methods and computational fluid dynamics, blade element momentum theory and finite element method, are used to predict the aerodynamic performances of the optimized airfoil and complete rotor as well the structural behaviour of the blade, respectively. Finally, composite blade is manufactured and the rotor performance is also determined experimentally by thrust and torque measurements.FindingsComplete process of blade design (including geometry definition and optimization, estimation of aerodynamic performances, structural analysis and blade manufacturing) is conducted and explained in detail. The correspondence between computed and measured thrust and torque curves of the optimal rotor is satisfactory (differences mostly remain below 15%), which validates and justifies the used design approach formulated specifically for low-cost, small-scale propeller blades. Furthermore, the proposed techniques can easily be applied to any kind of rotating lifting surfaces including helicopter or wind turbine blades.Originality/valueBlade design methodology is simplified, shortened and made more flexible thus enabling the fast and economic production of propeller blades optimized for specific working conditions.

Improving Quality of Manufacturing Test using Cell-Aware ATPG

The existing fault models like stuck-at, small delay defect, transition, and bridge fault models and their associated patterns are becoming less efficient, as the technology moves to increasingly smaller geometries. It is because traditional defect models target the faults only on IC gate boundaries, and the interconnects between the cells, but a significant population of defects (perhaps up to 50%) occurs within the cells or gates which are not specifically targeted by existing ATPG fault models. In this paper, a new ATPG methodology known as the Cell-aware test is implemented explicitly to target the defects caused by cell-internal open and short faults and improve the manufacturing test quality by minimizing the test escapes. This work explains how a Cell-Aware ATPG method performs a characterization on the GDSII data of library cell`s to produce a CAT library view (UDFM), test Pattern generation, and comparison between Traditional and Cell-Aware ATPG. The Cell-Aware ATPG is implemented using Tessent Testkompress, traditional ATPG is also developed to study and analyze both ATPG methodologies comparatively. Experiment results show a significant improvement in faults being targeted at an expense of an increase in pattern count and run-time. Obtained 71.28% and 59.38% test coverage for UDFM static and UDFM delay respectively. Achieved significant improvement in the test escapes with Cell-Aware Patterns when compared to traditional ATPG patterns.

Strength and elastic properties of 3D printed PVDF-based parts for lightweight biomedical applications

Research results on 3D printed fluoropolymers are scarce since the filaments were introduced commercially only in the last several years to enable fused filament fabrication (FFF) of structural components for more demanding service conditions, where chemical, UV or fire resistance, high purity, sterilizability or biocompatibility are critical such as in biomedical industry. This experimental study reports on additive manufacturing and quasi-static mechanical testing of polyvinylidene fluoride (PVDF) and in-vitro cytocompatible polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) specimens that were 3D printed with different infill patterns at 75% density (linear, cubic, cross, concentric, octet, zigzag, triangular). Recommendations are provided for addressing issues related to weak adhesion and obtrusive warping, which occur in open-chamber FFF printer due to semi-crystalline and hydrophobic nature of PVDF-based thermoplastics. The measured tensile and flexural stress-strain curves are analyzed to determine the influence of strut-based infills on the strength and elastic performance by including comparisons in ratios between strength, modulus of elasticity and weight of the specimens. The concentric pattern demonstrates the highest tensile strength, while the cross and triangular lattices – the lowest one. In three-point bending, the linear pattern delivers the lowest strength, while the rest exhibit comparable mechanical properties. The results are conducive to the design of 3D printable PVDF homopolymer and copolymer load-bearing structures serving as lightweight high-performance components in biomedical applications.

Process evolution in cell and gene therapy from discovery to commercialization

AbstractThe field of cell and gene therapy (CGT) is maturing at a rapid rate. Manufacturing remains a major challenge and manufacturing failures and limitations are a notable source of CGT products not meeting specification or being held back from regulatory approvals. To ensure that products remain compliant and competitive throughout their lifecycle, CGT process development requires both ongoing advancement of fit‐for‐purpose technologies to allow for and support well‐designed development studies, and a methodology that enables these studies to occur effectively during focused product development campaigns. We describe a framework for ongoing innovation in CGT process development, manufacturing, and clinical testing, based on the quality by design (QbD) approach. We propose use of the concepts of process discovery, process characterization, and process development in an iterative way to refine the design space as a product matures. This strategy is enabled by the early implementation of broad and robust analytics, and a modular approach to accelerate optimization. With these strategies, CGT developers can prospectively plan for comparability studies and develop in a stage‐appropriate manner, to allow for ongoing innovation and improvements from discovery through to commercialization.

A GMP process for the manufacture and quality control release testing of metabolically fit autologous IFNy-stimulated mscs for xerostomia (TC-MSC(M)-IFNy)

A GMP process for the manufacture and quality control release testing of metabolically fit autologous IFNy-stimulated mscs for xerostomia (TC-MSC(M)-IFNy)

Toward Better and Smarter Batteries by Combining AI with Multisensory and Self‐Healing Approaches

AbstractWith an exponentially growing demand for rechargeable batteries, the development of new ultra‐performant, fully scalable, and sustainable battery technologies and materials must be accelerated. Creating a holistic, closed‐loop infrastructure for materials discovery, manufacturing, and battery testing that utilizes a common data infrastructure and autonomous workflows to bridge big data from all domains of the battery value chain, can pave the way for a transformative reduction in the required time to discovery. By embedding multisensory and self‐healing capabilities in future battery technologies and integrating these with AI and physics‐aware machine learning models capable of predicting the spatio‐temporal evolution of battery materials and interfaces, it will, in time, be possible to identify, predict and prevent potential degradation and failure modes. This will facilitate enhanced battery quality, reliability, and life, for example, by preemptively changing the battery charging conditions or releasing self‐healing additives from the separator membrane, akin to preemptive medicine, and form the basis for inverse design of new battery materials, interfaces, and additives. The large‐scale and long‐term European research initiative BATTERY 2030+ seeks to make this longer‐than ten‐year vision a reality through the development of a versatile and chemistry neutral “Battery Interface Genome—Materials Acceleration Platform” infrastructure (BIG‐MAP).

Recycled cotton/polyester and polypropylene nonwoven hybrid composite materials for house hold applications

ABSCRACT Renewable raw materials and recyclable thermoplastic polymers provide attractive eco-friendly quality as well as environmental sustainability to the resulting recycled cotton/polyester and polypropylene fiber reinforced nonwoven composites. We studied the possibility of using recycled polypropylene (PP) for the production of nonwoven composites based on recycled cotton (RC) and recycled polyester (RP) as reinforcements. This research focuses on optimizing the manufacturing techniques and testing of both air-laid nonwoven and melt-bonded recycled nonwoven composite materials. Each series of experimentation was to be combined with a specific amount of copolymer chemical agent, the recycled post-industrial polypropylene powder, and recycled fiber. The physical and mechanical properties can be tested in accordance with ASTM standards. The results exposed that physical properties can be determined for both conditions like 24 h soak and 2 h boil. The air-laid materials have more properties than melt extrusion. The air-laid and melt- bond has deviation likewise coupling agent can change the properties. The results obtained report the possibility of exploitation of recycled PP for the production of recycled cotton/polyester reinforcements based on nonwoven composites with good mechanical characteristics to utilize as construction building materials in housing systems.

Hard-to-Detect Fault Analysis in FinFET SRAMs

Manufacturing defects can cause hard-to-detect (HTD) faults in fin field-effect transistor (FinFET) static random access memories (SRAMs). Detection of these faults, such as random read outputs and out-of-spec parametric deviations, is essential when testing FinFET SRAMs. Undetected HTD faults result in test escapes, which lead to early in-field failures. This article presents a detailed analysis of HTD faults in FinFET SRAMs by exploring their sensitization and discussing solutions to improve HTD fault coverage during manufacturing testing. We first define the fault space for SRAMs and classify all faults in the space. Following this, we perform a systematic fault analysis based on injecting resistive defects in a memory cell, inspecting its behavior, and identifying HTD faults. Furthermore, we survey existing test solutions and discuss their HTD fault coverage and limitations. Based on our analysis, it is clear that no single test solution can fully detect all HTD faults, thus leading to test escapes. Hence, there is a need for new and more efficient test solutions. Improved detection of HTD faults could be achieved by using parametric test solutions, proposing solutions that cover yet-untargeted HTD faults, combining multiple test approaches into a single solution, and further exploring stress conditions. These new approaches would reduce test escapes and therefore improve the quality of FinFET SRAMs.

Directions for the development of the existing concept of assessing the relevance of information leakage through technical channels in the current trends of improving technical intelligence

Problem statement. The rationale for confidentiality requirements in the process of manufacturing and production testing of aviation equipment samples. There is a need to assess the effectiveness of measures to prevent information leakage through the channels of incidental electromagnetic radiation and interference and vibroacoustic channels. This situation is characteristic both for the technological equipment of the aviation industry enterprises and the equipment of the produced aircraft models.Objective. The rationale for developing the existing concept of assessing the relevance of the threats of information leakage through technical channels in the current trends of improving technical reconnaissance.Results. The article presents the analysis results of the existing regulatory and existing base of FSTEC Russia for sufficient assessment of measures to prevent information leakage through the channels of incidental electromagnetic radiation and interference and vibroacoustic channels at the enterprises of the aircraft industry in the implementation of production technologies and testing of manufactured products.Practical implications. The substantiated directions of improving the methodological basis for determining the current threats can be used in the development of methods and models for assessment of measures to prevent information leakage through the channels of electromagnetic emissions and interference and vibroacoustic channels at aircraft industry enterprises in the implementation of production technologies and testing of manufactured products.

공중 통신용 송신 다중빔 능동 위상배열 안테나 시스템의 설계

In this paper, we describe the design, manufacture, and performance test results of a highly integrated Tx multi-beam active phased array antenna for aerial communications. The proposed Tx phased array antenna is composed of three tile phased array antennas, which consist of an array antenna, RF, and beamforming units. In the performance test of the Tx antenna system, an EIRP of 21 dBW and a beam pointing accuracy of less than 0.4° were achieved with four independently operable multi-beams. It is expected that the Tx multi-beam antenna system can be applied to common data link (CDL) communications for aerial networks.