Flame Retardant Intumescent Polyamide 11 Nanocomposites – Further Study

The objective of this research is to develop improved polyamide 11 and 12 polymers with enhanced flame retardancy, thermal, and mechanical properties for selective laser sintering (SLS) rapid manufacturing (RM). In the present study, a nanophase was introduced into the polyamide 11 and combine with a conventional intumescent flame retardant (FR) additive via twin screw extrusion. Arkema Rilsan® polyamide 11 molding polymer pellets were used with two types of nanoparticles such as: chemically modified montmorillonite (MMT) organoclays and carbon nanofibers (CNFs). Two types of Clariant’s Exolit® OP 1311 and 1312 intumescent FR additives were used to generate a family of FR intumescent polyamide 11 nanocomposites with anticipated synergism.Mechanical Engineerin

Purposes, concepts, misfits, and a redesign of git

Git is a widely used version control system that is powerful but complicated. Its complexity may not be an inevitable consequence of its power but rather evidence of flaws in its design. To explore this hypothesis, we analyzed the design of Git using a theory that identifies concepts, purposes, and misfits. Some well-known difficulties with Git are described, and explained as misfits in which underlying concepts fail to meet their intended purpose. Based on this analysis, we designed a reworking of Git (called Gitless) that attempts to remedy these flaws. To correlate misfits with issues reported by users, we conducted a study of Stack Overflow questions. And to determine whether users experienced fewer complications using Gitless in place of Git, we conducted a small user study. Results suggest our approach can be profitable in identifying, analyzing, and fixing design problems.SUTD-MIT International Design Centre (IDC

Reconfigurable logic for hardware IP protection: Opportunities and challenges

Protecting the intellectual property (IP) of integrated circuit (IC) design is becoming a significant concern of fab-less semiconductor design houses. Malicious actors can access the chip design at any stage, reverse engineer the functionality, and create illegal copies. On the one hand, defenders are crafting more and more solutions to hide the critical portions of the circuit. On the other hand, attackers are designing more and more powerful tools to extract useful information from the design and reverse engineer the functionality, especially when they can get access to working chips. In this context, the use of custom reconfigurable fabrics has recently been investigated for hardware IP protection. This paper will discuss recent trends in hardware obfuscation with embedded FPGAs, focusing also on the open challenges that must be necessarily addressed for making this solution viable

Innovative technology for cancer risk analysis

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Invited: High-level design methods for hardware security: Is it the right choice?

Due to the globalization of the electronics supply chain, hardware engineers are increasingly interested in modifying their chip designs to protect their intellectual property (IP) or the privacy of the final users. However, the integration of state-of-the-art solutions for hardware and hardware-assisted security is not fully automated, requiring the amendment of stable tools and industrial toolchains. This significantly limits the application in industrial designs, potentially affecting the security of the resulting chips. We discuss how existing solutions can be adapted to implement security features at higher levels of abstractions (during high-level synthesis or directly at the register-transfer level) and complement current industrial design and verification flows. Our modular framework allows designers to compose these solutions and create additional protection layers

Using Static Analysis for Enhancing HLS Security

Due to the increasing complexity of modern integrated circuits, High-Level Synthesis (HLS) is becoming a key technology in hardware design. HLS uses optimizations to assist during design space exploration. However, some of them can introduce security weaknesses. We propose an approach that leverages static analysis to identify a class of weaknesses in HLS-generated code. We show that some of these weaknesses can be corrected through the automatic generation of HLS directives. We evaluate our approach by comparing the static analysis results with formal verification. Our results show that the static approach has the same accuracy as formal methods while being 3× to 200× faster

Pyrolysis Gas Composition for a Phenolic Impregnated Carbon Ablator Heatshield

Published physical properties of phenolic impregnated carbon ablator (PICA) are compiled, and the composition of the pyrolysis gases that form at high temperatures internal to a heatshield is investigated. A link between the composition of the solid resin, and the composition of the pyrolysis gases created is provided. This link, combined with a detailed investigation into a reacting pyrolysis gas mixture, allows a consistent, and thorough description of many of the physical phenomena occurring in a PICA heatshield, and their implications, to be presented

Designing ML-resilient locking at register-transfer level

Various logic-locking schemes have been proposed to protect hardware from intellectual property piracy and malicious design modifications. Since traditional locking techniques are applied on the gate-level netlist after logic synthesis, they have no semantic knowledge of the design function. Data-driven, machine-learning (ML) attacks can uncover the design flaws within gate-level locking. Recent proposals on register-transfer level (RTL) locking have access to semantic hardware information. We investigate the resilience of ASSURE, a state-of-the-art RTL locking method, against ML attacks. We used the lessons learned to derive two ML-resilient RTL locking schemes built to reinforce ASSURE locking. We developed ML-driven security metrics to evaluate the schemes against an RTL adaptation of the state-of-the-art, ML-based SnapShot attack

Flammability and Thermal Properties of Polyamide 11-Alumina Nanocomposites

Neat polyamides 11 and 12 lack high strength/high heat resistance and flame retardancy. The incorporation of selected nanoparticles is expected to enhance these properties to a level that is desired and required for performance driven applications. This enhancement may result in additional market opportunities for the polyamide 11 and 12 polymer manufacturers. The objective of this study is to develop polyamide 11 polymer nanocomposites with enhanced thermal, flammability, and mechanical performance for selective laser sintering (SLS) rapid manufacturing. Three types of nano-alumnia (X-0 needle, X-25SR, and X-0SR) with different organic treatments were melt-compounded into polyamide 11 in three different weight loadings of the nanoparticles (2.5%, 5%, and 7.5%). Injection molded specimens were fabricated for thermal, flammability, and mechanical properties characterization. Although nano-alumina was uniformly dispersed in polyamide 11 and better thermal stability of the nanomodified materials was observed, the desired FR characteristics of the nanomodified polyamide 11 was not achieved. None of the materials passed the desired UL 94 V0 rating.Mechanical Engineerin

A Rare Case of Effusive-Constrictive Pericarditis Caused by Streptococcus agalactiae: Emergency Surgical Treatment

A 70-year-old male patient was admitted to the emergency room in cardiac arrest. The patient was resuscitated and then referred to our cardiac surgery department, where he was diagnosed with suspected effusive constrictive pericarditis. A failed trial of TEE-guided pericardiocentesis led to the decision of surgical intervention. Sternotomy was performed and revealed pericardial thickening and very dense adhesions involving the pericardium and both pleurae, suggesting a neoplastic disease. An extensive pericardiectomy and bilateral pleural decortication were performed. After surgery, the patient improved significantly and was discharged from the intensive care unit 24 h later. Pericardial thickening, dense adhesions, the amount and color of pericardial fluid and the aspect of epicardial tissue increased our suspicion of neoplastic disease. Histological samples were sent to be analyzed immediately; a few days later, they were unexpectedly negative for any neoplastic disease but showed a group-B-hemolytic Streptococcus agalactiae infection, which causes pericarditis in extremely rare cases. Postoperatively, the patient, under intravenous antibiotic and anti-inflammatory therapy, remained asymptomatic and was discharged ten days after the surgery. At the three-month follow-up, transthoracic echocardiography showed a normal right and left ventricular function with no pericardial effusion