SAFETY PERFORMANCE EVALUATION ON THE NEBRASKA TURNED-DOWN APPROACH TERMlNAL SECTION

One full-scale vehicle crash test was conducted on the Nebraska Turned-Down Approach Terminal Section. Test NETD-1 was conducted with a 1984 Dodge Colt weighing 1,887-lbs (test inertial). Impact conditions were 59.0 mph and 0 degrees with a 1.25-ft offset toward the roadway. The test was conducted and reported in accordance with the requirements specified in the Recommended Procedures for the Safety Performance Evaluation of Highway Appurtenances, National Cooperative Highway Research Program (NCHRP) Report No. 230. The safety performance of the Nebraska Turned-Down Approach Terminal Section was determined to be unacceptable according to the NCHRP 230 criteria

SAFETY PERFORMANCE EVALUATION ON THE NEBRASKA TURNED-DOWN APPROACH TERMlNAL SECTION

One full-scale vehicle crash test was conducted on the Nebraska Turned-Down Approach Terminal Section. Test NETD-1 was conducted with a 1984 Dodge Colt weighing 1,887-lbs (test inertial). Impact conditions were 59.0 mph and 0 degrees with a 1.25-ft offset toward the roadway. The test was conducted and reported in accordance with the requirements specified in the Recommended Procedures for the Safety Performance Evaluation of Highway Appurtenances, National Cooperative Highway Research Program (NCHRP) Report No. 230. The safety performance of the Nebraska Turned-Down Approach Terminal Section was determined to be unacceptable according to the NCHRP 230 criteria

MEMS sensors as physical unclonable functions

A fundamental requirement of any crypto system is that secret-key material remains securely stored so that it is robust in withstanding attacks including physical tampering. In this context, physical unclonable functions (PUFs) have been proposed to store cryptographic secrets in a particularly secure manner. In this thesis, the feasibility of using microelectromechanical systems (MEMS) sensors for secure key storage purposes is evaluated for the first time. To this end, we investigated an off-the-shelf 3-axis MEMS gyroscope design and used its properties to derive a unique fingerprint from each sensor. We thoroughly examined the robustness of the derived fingerprints against temperature variation and aging. We extracted stable keys with nearly full entropy from the fingerprints. The security level of the extracted keys lies in a range between 27 bits and 150 bits depending on the applied test conditions and the used entropy estimation method. Moreover, we provide experimental evidence that the extractable key length is higher in practice when multiple wafers are considered. In addition, it is shown that further improvements could be achieved by using more precise measurement techniques and by optimizing the MEMS design. The robustness of a MEMS PUF against tampering and malicious read-outs was tested by three different types of physical attacks. We could show that MEMS PUFs provide a high level of protection due to the sensitivity of their characteristics to disassembly.Eine grundlegende Anforderung jedes Kryptosystems ist, dass der verwendete geheime Schlüssel sicher und geschützt aufbewahrt wird. Vor diesem Hintergrund wurden physikalisch unklonbare Funktionen (PUFs) vorgeschlagen, um kryptographische Geheimnisse besonders sicher zu speichern. In dieser Arbeit wird erstmals die Verwendbarkeit von mikroelektromechanischen Systemen (MEMS) für die sichere Schlüsselspeicherung anhand eines 3-achsigen MEMS Drehratensensor gezeigt. Dabei werden die Eigenschaften der Sensoren zur Ableitung eines eindeutigen Fingerabdrucks verwendet. Die Temperatur- und Langzeitstabilität der abgeleiteten Fingerabdrücke wurde ausführlich untersucht. Aus den Fingerabdrücken wurden stabile Schlüssel mit einem Sicherheitsniveau zwischen 27 Bit und 150 Bit, abhängig von den Testbedingungen und der verwendeten Entropie-Schätzmethode, extrahiert. Außerdem konnte gezeigt werden, dass die Schlüssellänge ansteigt, je mehr Wafer betrachtet werden. Darüber hinaus wurde die Verwendung einer präziseren Messtechnik und eine Optimierung des MEMS-Designs als potentielle Verbesserungsmaßnahmen identifiziert. Die Robustheit einer MEMS PUF gegen Manipulationen und feindseliges Auslesen durch verschiedene Arten von physikalischen Angriffen wurde untersucht. Es konnte gezeigt werden, dass MEMS PUFs aufgrund der Empfindlichkeit ihrer Eigenschaften hinsichtlich einer Öffnung des Mold-Gehäuses eine hohe Widerstandsfähigkeit gegenüber invasiven Angriffen aufweisen

DEVELOPMENT OF ABUSE DETERRENT FORMULATIONS USING HOT MELT EXTRUSION

In recent years prescription drug diversion, misuse, abuse represent a growing problem for the United States. Oral ingestion, snorting, injection are most commonly employed routes of abuse. To circumvent this problem hot melt extrusion (HME) was employed to prepare abuse deterrent formulation (ADF). Abuse Deterrent Immediate Release Egg-Shaped Tablet Using 3D Printing Technology: Quality by Design to Optimize Drug Release and Extraction. In current work, we developed egg-shaped tablet (egglet) using fused deposition modeling (FDM) 3D printing. Drug-loaded polymeric filaments (1.5 mm) were prepared using HME followed by printing into egglets of different sizes and infill densities. Based on printability, crush resistance polyvinyl alcohol (PVA) was used further. Later, egglets were evaluated for abuse deterrence properties based on USFDA guidance. A multifactorial design was used to optimize solvent extraction, drug release. Extreme hardness (\u3e 500 N), large particle size (\u3e 1 mm) on mechanical manipulation established snorting deterring property while \u3c20% drug extraction in 5 min (% Sext) demonstrated deterrence for injection abuse. Quality target product profile D85 \u3c 30 min, % Sext \u3c 20 was achieved with egglets of 6 mm diameter, 45% infill density, 15% w/w drug loading. Development of Multi-dose Oral Abuse Deterrent Formulation of Loperamide Using Hot melt extrusion. Loperamide, an over the counter anti-diarrheal drug, also referred as poor man\u27s methadone . Abusers consume more than 30 tablets to achieve euphoria and to combat opioid withdrawal. But supratherapeutic doses causes respiratory depression, cardiac dysrhythmia, mortality. Aim is designing a tablet which can immediate release loperamide in diarrheic patients (single tablet) while stops release in case of intentional multi-dose ingestion. Loperamide was molecularly dispersed into gastric soluble cationic polymers - Eudragit® EPO, Kollicoat® Smartseal 100P using HME to obtain filament. Filaments were milled and compressed into tablets ((Eudragit® EPO (SJU1) and Kollicoat® Smartseal (SJU2)) with optimized amount of L-arginine. Dissolution in 250 mL of Fasted state simulated gastric fluid (FaSSGF) revealed that single tablet of Imodium® (marketed formulation) and SJU1 showed \u3e85% of release in 15 min. In multi-unit dissolution (15 tablets), Imodium® exhibited \u3e90% release but SJU tablets showed \u3c5% of release thus demonstrating its ability to deter multi-dose oral abuse

Analysis of Diffusion in Heat Seals Using Energy Dispersive X-ray Spectroscopy

Heat sealing is one of several methods used to weld thermoplastic materials in packaging. Heat seals were made between Dow 501i LDPE and DuPont Nucrel 1202HC poly (ethylene co-methacrylic acid). The seals were exposed to sodium hydroxide solution so that the methacrylic acid sites of the DuPont Nucrel 1202HC were neutralized with a sodium ion. This was done to make diffusion measurements. Two side heated tooling sealing was used to make seals at 40 psi (276kPa), 1.0 second dwell, and temperatures ranging from 200oF (93.3oC) to 300oF (148.9oC). Energy dispersive x-ray spectroscopy, a function of scanning electron microscopy, was used to measure the presence of sodium and therefore diffusion of the methacrylic acid sites. The methacrylic sites are part of the polymer chain, and were tagged from the sodium hydroxide. It was possible to estimate polymer chain diffusion distance based on a sodium trace, as well as an oxygen trace. Then this method was used to measure diffusion on samples of 501i and 1202HC sealed at various temperatures. Diffusion was compared to seal temperature and to seal strength. The results of this study are different from previous findings. It was found that with this system diffusion distance is not correlated to seal strength. It was also found that for this system diffusion distance is not correlated with sealing temperature. However, it was found that both sodium and oxygen can be used to estimate diffusion in this polymer system

Plasma-activated fusion bonding for vacuum encapsulation of microdevices

A fabrication process for vacuum-encapsulating PZT microcantilevers was designed in this dissertation. Initially, a low temperature wafer-bonding recipe was optimized with the help of plasma-activation. Conventional direct fusion bonding temperature was reduced from 400°C to 85°C, and final thermal annealing temperature and time of 1000°C for 4 hours (hr) were significantly reduced to 300°C and 1 hr respectively. Tensile tests conducted on dies diced from the bonded wafer stack revealed bond strengths of 22.15 MPa, which was close to the bulk fracture strength of 24 MPa for silicon. Near infrared images of the wafer stack showed no debonded regions at the interface. Surface and interface chemistry of oxygen plasma-activated wafers before, during, and after bonding were investigated. Significance of wet chemical activation technique, like RCA (Radio Corporation of America) cleaning, was studied. The time interval between plasma-activation and fusion bonding was varied, and its effect on the bond quality and bond strength was investigated. Decrease in the bond-quality and strength was observed with an increase in storage time. However, an unexpected increase in the bond quality was observed after 48 hr, and was attributed to the increase in the interfacial oxide layer. Further investigations revealed that the interfacial oxide layer was capable of absorbing gas molecules released as a byproduct of ongoing reactions at the interface of the two wafers. Gettering capability of the interfacial oxide layer was confirmed through the bonding of plasma-activated and 48 hr stored silicon (Si) and silicon dioxide (SiO2) wafers. Infrared images showed a good bond for the wafer stack. Since designing a fabrication process flow for vacuum-encapsulation of microdevices was the primary objective, lead zirconate titanate microcantilevers were fabricated onto a silicon substrate. The microdevices were actuated in ambient air pressure as well as in a vacuum environment. Broadening of the resonance curve was observed with an increase in the magnitude of ambient pressure, and is a result of increased air-damping. Experimental results obtained were compared to theoretical results from finite element modeling analyses. Vacuum cavities were fabricated between two Si wafers. Optical lid-deflection method of measuring internal cavity pressure was explored and employed with the help of high aspect ratio pressure diaphragms on a capping wafer. An investigation of seal integrity of the vacuum package revealed real/virtual leaks. The gettering capability of the SiO2 layer was employed in order to preserve the vacuum-level in the cavities. Two types of gettering patterns were investigated. It was concluded that an SiO2 getter layer at the interface increased the seal-integrity of the vacuum packages, while getter rings still showed signs of real leaks. In addition, it was observed that the internal vacuum-level was higher for cavities with getter rings as compared to cavities without getters. It was concluded that getter rings were capable of preventing virtual leaks but not real leaks. A thick interfacial getter layer, however, prevented both the real and virtual leaks. Finally, a vacuum-packaging fabrication method to encapsulate lead zirconate titanate microcantilevers was proposed. In addition, more accurate methods of measuring package vacuum pressure magnitudes were proposed