Penetration of polyethylene into semi-infinite 2024-T351 aluminum up to velocities of 37,000 feet per second

Light gas projector used in penetration of polyethelene into semiinfinite aluminu

Induced gravity and gauge interactions revisited

It has been shown that the primary, old-fashioned idea of Sakharov's induced gravity and gauge interactions, in the "one-loop dominance" version, works astonishingly well yielding phenomenologically reasonable results. As a byproduct, the issue of the role of the UV cutoff in the context of the induced gravity has been reexamined (an idea of self-cutoff induced gravity). As an additional check, the black hole entropy has been used in the place of the action. Finally, it has been explicitly shown that the induced coupling constants of gauge interactions of the standard model assume qualitatively realistic values.Comment: 15 pages, 2 figures (including 1 table); improved version - fina

Additive manufacturing of carbon fiber-reinforced thermoplastic composites

Additive manufacturing, or 3D printing, encompasses manufacturing processes that construct a geometry by depositing or solidifying material only where it is needed in the absence of a mold. The ability to manufacture complex geometries on demand directly from a digital file, as well as the decreasing equipment costs due to increased competition in the market, have resulted in the AM industry experiencing rapid growth in the past decade. Many companies have emerged with novel technologies well suited to improve products and/or save costs in various industries. Until recently, the applications of polymer additive manufacturing have been mainly limited to prototyping. This can be attributed to multiple factors, namely the high cost of the machines and materials, long print times, and anisotropy of printed parts. In addition, the low unit cost and cycle time of competing processes such as injection molding further skew the economics in favor of other processes. The addition of fiber-reinforcement into polymers used in additive manufacturing processes significantly increases the strength of parts, and also allows larger parts to be manufactured. In 2014, large-scale additive manufacturing of fiber-reinforced polymers was pioneered, and has generated significant attention from both academia and industry. Commercial machines that incorporate high throughput extruders on gantry systems are now available. New applications that require high temperature polymers with low coefficients of thermal expansion and high stiffness are being targeted, for example tooling used in the manufacturing of composite components. The state of the art of this new paradigm in additive manufacturing as well as the target applications will be discussed in detail. Many new challenges arise as AM scales and reinforced polymers are incorporated. One of the most notable challenges is the presence of large temperature gradients induced in parts during the manufacturing process, which lead to residual stresses and sometimes detrimental warpage. The current solution to this problem has been to print faster in order to lessen the temperature gradients, however very high extrusion speeds are likely not ideal for achieving optimal material properties. The high shear rates induce further damage to fibers, and entrapped air during the extrusion process may not escape, leading to high void content. Another significant challenge is overcoming the anisotropy in printed parts, which arises due to the stiff reinforcing fibers orienting primarily in the print direction. This complicates the use in demanding applications such as composite tooling, where high stiffness and low CTE are desirable in all directions. In 2014, a group of graduate students at Purdue University was formed to develop a better understanding of large-scale additive manufacturing processes incorporating high temperature and high fiber content polymer composites. The team spent more than one year designing, developing, and optimizing a lab-scale system that offers full control over all processing parameters, and has begun studying the relevant phenomena and developing models to predict the outcome of printing processes. This thesis will summarizes the system development process, printing process, composite tooling applications, as well as the mechanical, structural, and viscoelastic properties of printed materials, making it one of the most comprehensive documents written in large-scale additive manufacturing of fiber-reinforced polymers to date. The properties of 50 weight percent carbon fiber-reinforced PPS, a material of high interest in the field, will be presented in detail. The viscoelastic properties will be measured and discussed in the context of both stress relaxation during the printing process and the required performance metrics of composite tooling. A summary of the major results and recommendations can be found in chapter 7

Paternity Determinations in Washington: Balancing the Interests of All Parties

The state and all parties in a paternity proceeding may benefit from a more efficient, administrative approach to paternity adjudication if certain procedural safeguards are assured the defendant. Section II of this Comment sketches the development of common-law and statutory rights of paternity actions in Washington. Section III examines the interests of each party in a paternity action. Section IV discusses the advantages of an administrative hearing. Section V suggests procedural safeguards for the defendant and proposes a framework for administrative determinations of paternity that is consistent with the interests of all parties. Administrative hearings in such circumstances are preferable because the overwhelming number of paternity actions are prosecuted by the state in an effort to recover the funds that it expends on Aid to Families of Dependent Children (AFDC) children. Administrative law judges specializing in paternity determinations would provide prompt, efficient case handling in an informal, less expensive environment

Paternity Determinations in Washington: Balancing the Interests of All Parties

The state and all parties in a paternity proceeding may benefit from a more efficient, administrative approach to paternity adjudication if certain procedural safeguards are assured the defendant. Section II of this Comment sketches the development of common-law and statutory rights of paternity actions in Washington. Section III examines the interests of each party in a paternity action. Section IV discusses the advantages of an administrative hearing. Section V suggests procedural safeguards for the defendant and proposes a framework for administrative determinations of paternity that is consistent with the interests of all parties. Administrative hearings in such circumstances are preferable because the overwhelming number of paternity actions are prosecuted by the state in an effort to recover the funds that it expends on Aid to Families of Dependent Children (AFDC) children. Administrative law judges specializing in paternity determinations would provide prompt, efficient case handling in an informal, less expensive environment

I-fibrinogen as an oncophilic radiodiagnostic agent: distribution kinetics in tumour-bearing mice.

Fibrinogen radioiodinated by the iodine monochloride method was tested as a tumour radiodiagnostic agent in mice. The I-fibrinogen cleared from the blood of tumour-bearing mice more rapidly than from that of normal mice, but it cleared from the whole body more slowly, suggesting it accumulated in a substantial tumour-related compartment in the abnormal mice. The tumour concentration steadily increased for 4 h after injection, at which time it reached a peak concentration of 11-4% of the injected dose/g. This concentration was higher than the peak concentration for Ga-citrate (not reached until 24 h) or any other oncophilic radiopharmaceutical tested in this tumour model. The early accumulation is consistent with the use of 123I as a tracer label for fibrinogen. A combination of the large tumour concentration of I-fibrinogen, an increased catabolic rate induced by chemical modification, and the exceptional nuclear properties of 123I for scintigraphic imaging, could lead to a very useful radiodiagnostic procedure for cancer

Vacuum polarization for lukewarm black holes

We compute the renormalized expectation value of the square of a quantum scalar field on a Reissner-Nordström–de Sitter black hole in which the temperatures of the event and cosmological horizons are equal (“lukewarm” black hole). Our numerical calculations for a thermal state at the same temperature as the two horizons indicate that this renormalized expectation value is regular on both the event and cosmological horizons. We are able to show analytically, using an approximation for the field modes near the horizons, that this is indeed the case