The Temporal and Spatial Distribution of Catlinite and Redstone Pipes on Caddo Sites

Catlinite and redstone pipes are widely distributed on post-A.D 1450 native American sites across eastern North America, including the Caddo area of the far Southeast. As Rodning indicates, however, catlinite pipes are much more widespread from the late seventeenth century to the early eighteenth century, where the smoking of catlinite pipes is associated with calumet ceremonialism, and the spread of calumet ceremonialism associated with the “spread of European colonists and colonialism.” In this article, I discuss the temporal and spatial distribution of catlinite and redstone pipes on Caddo sites across the northern and southern Caddo areas. These pipes occur in both pre- and post-European contexts in Caddo sites, and take several forms (disk and elbow pipes), but their widest distribution is on sites that date from ca. A.D. 1690-1780 on Caddo sites in East Texas. Catlinite and redstone pipes are made from argillite found in sources in the Great Plains and the upper Midwest, most notably at Pipestone National Monument in southwestern Minnesota. According to Rodning, the French “colonists are known to have imported argillite and perhaps catlinite from the Midwest or Plains… for the purpose of making calumet pipes to give as gifts to native American groups with whom the French sought alliances.

“Perversity, Futility, Jeopardy”: An Economic Analysis of the Attack on Gun Control

A relatively new way for utilizing the thermal performance of heat pipes is to use nanofluids as working fluids in the heat pipes. Heat pipes are effective heat transfer devices in which the nanofluid operates in the two phases, evaporation and condensation. The heat pipe transfers the heat supplied in e.g. a laptop, from the evaporator to condenser part. Nanofluids are mixtures consisting of nanoparticles (e.g. nano-sized silver particles) and a base fluid (e.g. water). The aim of this bachelor’s thesis has been to examine the effect of nanofluids on heat pipes on the subject of temperature parameters and thermal resistance in the heat pies, through findings in literature and an applied model. The study, based on literature and an applied model, found that higher particle conductivity and higher concentration of nanoparticles consequently decrease the thermal resistance in the heat pipes, resulting in an enhanced thermal performance of the heat pipes with nanofluids as working fluids. It is however concluded that difficulties in finding the optimal synthesis of nanofluids, the concentration level of nanoparticles and the filling ratio of nanofluids in heat pipes, set bounds to the commercial use of nanofluids in heat pipes. It is suggested that, in order to enhance the heat transfer performance of nanofluids in heat pipes, to conduct further research concerning e.g. synthesis of nanofluids and concentration level of nanoparticles in nanofluids

Modeling and analysis of water-hammer in coaxial pipes

The fluid-structure interaction is studied for a system composed of two coaxial pipes in an annular geometry, for both homogeneous isotropic metal pipes and fiber-reinforced (anisotropic) pipes. Multiple waves, traveling at different speeds and amplitudes, result when a projectile impacts on the water filling the annular space between the pipes. In the case of carbon fiber-reinforced plastic thin pipes we compute the wavespeeds, the fluid pressure and mechanical strains as functions of the fiber winding angle. This generalizes the single-pipe analysis of J. H. You, and K. Inaba, Fluid-structure interaction in water-filled pipes of anisotropic composite materials, J. Fl. Str. 36 (2013). Comparison with a set of experimental measurements seems to validate our models and predictions

Looped and Perforated Elbow Pipes in Northeast Texas

Todd presented a general chronology for the presence of aboriginal-manufactured clay elbow pipes in Northeast Texas Caddo sites. Most of the pipe types have an extensive range in time; however, this may be true for thong elbow pipes. This paper looks further at the time range for; and the variety, of thong pipes. Jackson refers to elbow pipes that have a hole between the keel and the bowl as thong pipes. A string appears to have been run through the holes. He refers to the two types of pipes as handled and holed, but I use the terms looped and perforated. Perino mentions that the perforation in the pipe\u27s keel may have been so that a cord could be fastened to the stem, similar to some French and Native American micmac pipes

Synchronization of organ pipes: experimental observations and modeling

We report measurements on the synchronization properties of organ pipes. First, we investigate influence of an external acoustical signal from a loudspeaker on the sound of an organ pipe. Second, the mutual influence of two pipes with different pitch is analyzed. In analogy to the externally driven, or mutually coupled self-sustained oscillators, one observes a frequency locking, which can be explained by synchronization theory. Further, we measure the dependence of the frequency of the signals emitted by two mutually detuned pipes with varying distance between the pipes. The spectrum shows a broad ``hump'' structure, not found for coupled oscillators. This indicates a complex coupling of the two organ pipes leading to nonlinear beat phenomena.Comment: 24 pages, 10 Figures, fully revised, 4 big figures separate in jpeg format. accepted for Journal of the Acoustical Society of Americ

A First Look at the Performance of Nano-Grooved Heat Pipes

Passive thermal spreaders utilizing liquid/vapor phase-change mechanism such as heat pipes, have been widely used in the macro-scale thermal management of electronic devices for many years. Micro-fabrication techniques enabled the fabrication micro-scale grooved heat pipes on semiconductors. Recent advances in fabrication techniques, on the other hand, enabled producing nano- and {\AA}ngstr\"om-scale capillaries and cavities, which renders the manufacturing of nanoscale heat pipes possible. In the present study, we have simulated nanoscale heat pipes composed of nano-grooves using molecular dynamics and evaluated their performance based on different operating parameters such as the filling ratio and heat load. Moreover, evaluation of size effect on the thermal performance is made by comparing proportionally scaled heat pipes. Simulation results reveal that efficient operation of nano-grooved heat pipes depend not only on the proper selections of filling ratio and heat load, but also on the geometrical parameters such as cross sectional dimensions and aspect ratio of the groove. The modeling strategy used in this study opens an opportunity for computational experimentation of nanoscale heat pipes

DOD low-thrust mission studies

The space transportation system (STS) will be the principal means of launching USAF spacecraft beginning in the 1980's. Since it is manned and reusable it provides new opportunities for unique approaches for cost effective utilization of its capabilities. The STS also places additional requirements and constraints on advanced spacecraft deployment systems that did not previously exist for expandable launch vehicles. To fully utilize these new capabilities designers must be prepared by having cost effective technologies available. Advanced propulsion technology that would provide flexibility, performance, and economic benefits to future Air Force missions was identified. Both electric and chemical propulsion systems are discussed. An LO2/LH2 stage with a torus LO2 tank and 500 lbf pumb fed engine is high on the list of propulsion technology

Literature review and experimental investigation of heat pipes

Tests on heat pipes determine operational limits, external boundary conditions, noncondensable gas effects, startup behavior, and geometric configurations. Experiment consists of design, construction, and testing of an apparatus for measuring wick properties, conventional heat pipes and coplanar heat pipes

Solar thermal energy receiver

A plurality of heat pipes in a shell receive concentrated solar energy and transfer the energy to a heat activated system. To provide for even distribution of the energy despite uneven impingement of solar energy on the heat pipes, absence of solar energy at times, or failure of one or more of the heat pipes, energy storage means are disposed on the heat pipes which extend through a heat pipe thermal coupling means into the heat activated device. To enhance energy transfer to the heat activated device, the heat pipe coupling cavity means may be provided with extensions into the device. For use with a Stirling engine having passages for working gas, heat transfer members may be positioned to contact the gas and the heat pipes. The shell may be divided into sections by transverse walls. To prevent cavity working fluid from collecting in the extensions, a porous body is positioned in the cavity