Search

This research paper will mainly consist of the unreported Neolithic site and rock art sites of Simdega district. In this paper there will be the detailed information about the rock paintings. The detailed study will be done of the various figures of the paintings. This paper will also describe the associated remains found along with the rock paintings. The research paper also consists of the developing phase of the rock art which can be seen in the tribal communities. Paper will also consist of the study of saddle quern, its various uses and how it is related to the tribal community. There will the content about the importance of the rock art in the tribal society. Various rituals are performed on the rock art site by the tribal people till today. This research paper will describe these rituals which are performed by the tribal people. The paper will consists of the study of correlation between the rock art and the various arts forms and cultures present in the tribal community.

Although microliths are regarded as small standardized tools for complex composite technology, it is still not fully understood whether this schematic understanding developed in Old World prehistor...

Pulmonary alveolar microlithiasis (PAM) is a rare genetic disease caused by mutations in sodium-phosphate co-transporter (SLC34A2), which encodes a type 2b sodium phosphate co-transporter. Disease is characterized by intra-alveolar microlith formation of phosphate. Turkey has a high prevalence of PAM. Herein, we report the clinical and radiological findings of three patients diagnosed with PAM and treated with disodium etidronate.

Fuel cell technology has yet to realize widespread deployment, in part because of the hydrogen fuel infrastructure required for proton exchange membrane systems. One option to overcome this barrier is to produce hydrogen by reforming propane, which has existing widespread infrastructure, is widely used by the general public, easily transported, and has a high energy density. The present work combines thermodynamic modeling of propane catalytic partial oxidation (cPOx) and experimental performance of a Precision Combustion Inc. (PCI) Microlith ® reactor with real-time soot measurement. Much of the reforming research using Microlith-based reactors has focused on fuels such as natural gas, JP-8, diesel, and gasoline, but little research on propane reforming with Microlith-based catalysts can be found in literature. The aim of this study was to determine the optimal operating parameters for the reformer that maximizes efficiency and minimizes solid carbon formation. The primary parameters evaluated were reformate composition, carbon concentration in the effluent, and reforming efficiency as a function of catalyst temperature and O 2 /C ratio. Including the lower heating values for product hydrogen and carbon monoxide, efficiency of 84% was achieved at an O 2 /C ratio of 0.53 and a catalyst temperature of 940 °C, resulting in near equilibrium performance. Significant solid carbon formation was observed at much lower catalyst temperatures, and carbon concentration in the effluent was determined to have a negative linear relationship at T

Precision Combustion, Inc. (PCI) has developed autothermal reformer (ATR) units based on its patented Microlith ® technology and demonstrated stable, coke-free operation using JP-8 consisting of up to 70 ppm w sulfur for 1100 h with complete fuel conversion and reforming efficiency of ∼85%. The feasibility of operating ATR reformers with distillate fuels containing higher sulfur (up to 400 ppm w ) has also been demonstrated for 55 h, while producing syngas (i.e., H 2 and CO) at >80% reforming efficiency and at complete fuel conversion. Reformer test results, demonstrating water neutral operation, catalyst sulfur tolerance, removal of sulfur to v , and maintenance of higher hydrocarbons to levels acceptable for fuel cell stacks, provide a measure of the ATR performance that can be expected under realistic conditions with readily available fuels. The results also give valuable insights to the system design and operation strategy for integrated power generation systems.

The paper describes the design and performance of a breadboard prototype for a 5 kW fuel-processor for powering a solid oxide fuel cell (SOFC) stack. The system was based on a small, modular catalytic Microlith auto-thermal (ATR) reactor with the versatility of operating on diesel, Jet-A or JP-8 fuels. The reforming reactor utilized Microlith substrates and catalyst technology (patented and trademarked). These reactors have demonstrated the capability of efficiently reforming liquid and gaseous hydrocarbon fuels at exceptionally high power densities. The performance characteristics of the auto-thermal reactor (ATR) have been presented along with durability data. The fuel processor integrates fuel preparation, steam generation, sulfur removal, pumps, blowers and controls. The system design was developed via ASPEN® Engineering Suite process simulation software and was analyzed with reference to system balance requirements. Since the fuel processor has not been integrated with a fuel cell, aspects of thermal integration with the stack have not been specifically addressed.

Recent advances in the development of short contact time (SCT) reactor design approaches allow reformers capable of overcoming current barriers of cost, size, weight, complexity and efficiency associated with conventional reactor design approaches. PCI has developed an SCT based approach using a patented substrate (trademarked Microlith ® ) and proprietary coating technology [1] . The high heat and mass transport properties of the substrate have been shown to significantly reduce reactor size while improving performance. Resistance to coking, especially at low H 2 O:C ratios, has also been observed with these reactors. This paper summarizes the results of auto thermal reforming (ATR) of an iso -octane-based liquid fuel. In addition Microlith-based water gas shift (WGS) and preferential CO oxidation (PROX) reactors were also examined for fuel processing applications. Surprisingly, selectivity advantages for these kinetically controlled reactions were observed [2] . Examples described here include low methanation selectivity in WGS applications and large operating windows for PROX at very high space velocities. A complete reformer system with Microlith ATR, WGS and PROX reactors has been identified. Sensitivity of system size with regard to steam:carbon ratios, and the resulting implications for reactor/heat exchanger sizes were documented and a compact system identified.

Oxidative steam reforming (OSR) of methanol is shown to produce extremely high hydrogen yield. Specific hydrogen production rates as high as 425 kWt per liter of reactor volume were demonstrated in a novel Microlith ® -based catalytic reactor. At reduced space velocities hydrogen concentration in the reformate stream was as high as 50%, while CO concentration was as low as 1.2%. The thermal efficiency of the OSR process is greater than 80%. It is shown that the autothermal OSR process consists of three reactions – methanol oxidation, methanol decomposition and water gas shift. These reactions have different kinetic rates and progress in an overlapping sequence along the catalyst bed. A radial flow catalyst configuration enables varying gas flow velocity to accommodate the different kinetic rates and heat release characteristics of these reactions. This allows a flat temperature profile and approach to equilibrium product composition to be achieved in a single catalyst bed. © 2004 Elsevier B.V. All rights reserved.

The development of improved substrate properties for catalytic combustion has been an area of much interest in recent years. Towards this end, Precision Combustion Inc. has developed novel short channel length, high cell density substrates (trademarked Microlith ® ) and high surface area ceramic coatings for them. These substrates avoid substantial boundary layer buildup and greatly enhance heat and mass transfer rates in reactors. The high cell density of these substrates results in high amount of the catalyst per unit of reactor volume. In this paper we examine the performance of these substrates coated with precious metal catalysts for the catalytic combustion and reforming of methane. Under fuel-lean operating conditions the surface temperature of Pd-based catalyst supported on Microlith ® substrate and the temperature of the gas exiting the reactor remain stable at ∼800 ◦ C over a wide range of inlet conditions. This is attributed to combination of enhanced transport properties and characteristics of Pd–PdO transformation. Preheating of the gas mixture in the Microlith ® reactor was sufficient to stabilize a downstream premixed flame with NO x, CO, and UHC emissions in the single digit ppm range. Microlith ® substrates were also examined for partial oxidation of methane under fuel-rich conditions. The enhanced transport properties of the Microlith ® substrate allowed complete conversion of methane with surface temperature not exceeding material limits at 93% selectivity to partial oxidation products. High flow rate of reactants result in extremely high power densities and syngas output. The catalyst performance was observed to be stable over 500 h of operation. © 2003 Elsevier B.V. All rights reserved.

Image simulation remains under-exploited for the most widely used biological phase microscopy methods, because of difficulties in simulating partially coherent illumination. We describe an open-source toolbox, microlith (https://code.google.com/p/microlith), which accurately predicts three-dimensional images of a thin specimen observed with any partially coherent imaging system, including coherently illuminated and incoherent, self-luminous specimens. Its accuracy is demonstrated by comparing simulated and experimental bright-field and dark-field images of well-characterized amplitude and phase targets, respectively. The comparison provides new insights about the sensitivity of the dark-field microscope to mass distributions in isolated or periodic specimens at the length-scale of 10nm. Based on predictions using microlith, we propose a novel approach for detecting nanoscale structural changes in a beating axoneme using a dark-field microscope., Comment: current: 17 pages, 8 figures, expanded to include biological simulations; previous version: 7 pages, 2 figures; related website: https://code.google.com/p/microlith

The utilization of CO2 to produce (or recycle) life support consumables, such as O2 and H2O, and to generate propellant fuels is an important aspect of NASA's concept for future, long duration planetary exploration. One potential approach is to capture and use CO2 from the Martian atmosphere to generate the consumables and propellant fuels. Precision Combustion, Inc. (PCI), with support from NASA, continues to develop its regenerable adsorber technology for capturing CO2 from gaseous atmospheres (for cabin atmosphere revitalization and in-situ resource utilization applications) and its Sabatier reactor for converting CO2 to methane and water. Both technologies are based on PCI's Microlith(R) substrates and have been demonstrated to reduce size, weight, and power consumption during CO2 capture and methanation process. For adsorber applications, the Microlith substrates offer a unique resistive heating capability that shows potential for short regeneration time and reduced power requirements compared to conventional systems. For the Sabatier applications, the combination of the Microlith substrates and durable catalyst coating permits efficient CO2 methanation that favors high reactant conversion, high selectivity, and durability. Results from performance testing at various operating conditions will be presented. An effort to optimize the Sabatier reactor and to develop a bench-top Sabatier Development Unit (SDU) will be discussed.

Utilizing carbon dioxide to produce water and hence oxygen is critical for sustained manned missions in space, and to support both NASA's cabin Atmosphere Revitalization System (ARS) and In-Situ Resource Utilization (ISRU) concepts. For long term missions beyond low Earth orbit, where resupply is significantly more difficult and costly, open loop ARS, like Sabatier, consume inputs such as hydrogen. The Bosch process, on the other hand, has the potential to achieve complete loop closure and is hence a preferred choice. However, current single stage Bosch reactor designs suffer from a large recycle penalty due to slow reaction rates and the inherent limitation in approaching thermodynamic equilibrium. Developmental efforts are seeking to improve upon the efficiency (hence reducing the recycle penalty) of current single stage Bosch reactors which employ traditional steel wool catalysts. Precision Combustion, Inc. (PCI), with support from NASA, has investigated the potential for utilizing catalysts supported over short-contact time Microlith substrates for the Bosch reaction to achieve faster reaction rates, higher conversions, and a reduced recycle flows. Proof-of-concept testing was accomplished for a staged Bosch process by splitting the chemistry in two separate reactors, first being the reverse water-gas-shift (RWGS) and the second being the carbon formation reactor (CFR) via hydrogenation and/or Boudouard. This paper presents the results from this feasibility study at various operating conditions. Additionally, results from two 70 hour durability tests for the RWGS reactor are discussed.

The utilization of CO2 to produce life support consumables, such as O2 and H2O, via the Sabatier reaction is an important aspect of NASA s cabin Atmosphere Revitalization System and In-Situ Resource Utilization architectures for both low-earth orbit and long-term manned space missions. In the current International Space Station (ISS) and other low orbit missions, metabolically-generated CO2 is removed from the cabin air and vented into space, resulting in a net loss of O2. This requires a continuous resupply of O2 via water electrolysis, and thus highlights the need for large water storage capacity. For long-duration space missions, the amount of life support consumables is limited and resupply options are practically nonexistent, thus atmosphere resource management and recycle becomes crucial to significantly reduce necessary O2 and H2O storage. Additionally, the potential use of the Martian CO2-rich atmosphere and Lunar regolith to generate life support consumables and propellant fuels is of interest to NASA. Precision Combustion, Inc. (PCI) has developed a compact, lightweight Microlith(Registered TradeMark)-based Sabatier (CO2 methanation) reactor which demonstrates the capability of achieving high CO2 conversion and near 100% CH4 selectivity at space velocities of 30,000-60,000 hr-1. The combination of the Microlith(Registered TradeMark) substrates and durable, novel catalyst coating permitted efficient Sabatier reactor operation that favors high reactant conversion, high selectivity, and long-term durability. This paper presents the reactor development and performance results at various operating conditions. Additionally, results from 100-hr durability tests and mechanical vibration tests are discussed.

To support continued manned space exploration, the development of atmosphere revitalization systems that are lightweight, compact, durable, and power efficient is a key challenge. The systems should be adaptable for use in a variety of habitats and should offer operational functionality to either expel removed constituents or capture them for closedloop recovery. As mission durations increase and exploration goals reach beyond low earth orbit, the need for regenerable adsorption processes for continuous removal of CO2 and trace contaminants from cabin air becomes critical. Precision Combustion, Inc. (PCI) and NASA Marshall (MSFC) have been developing an Engineered Structured Sorbents (ESS) approach based on PCI s patented Microlith technology to meet the requirements of future, extended human spaceflight explorations. This technology offers the inherent performance and safety attributes of zeolite and other sorbents with greater structural integrity, regenerability, and process control, thereby providing potential durability and efficiency improvements over current state-of-the-art systems. The major advantages of the ESS explored in this study are realized through the use of metal substrates to provide structural integrity (i.e., less partition of sorbents) and enhanced thermal control during the sorption process. The Microlith technology also offers a unique internal resistive heating capability that shows potential for short regeneration time and reduced power requirement compared to conventional systems. This paper presents the design, development, and performance results of the integrated adsorber modules for removing CO2, water vapor, and trace chemical contaminants. A related effort that utilizes the adsorber modules for sorption of toxic industrial chemicals is also discussed. Finally, the development of a 4-person two-leg ESS system for continuous CO2 removal is also presented.

Under a U.S. Army program, PCI has developed autothermal reforming catalysts for E85 to provide stable performance in the presence of fuel sulfur as well as corrosion inhibitors. The catalysts build on PCI’s Microlith™ catalyst technology and used PCI’s proprietary formulations. A stable performance was demonstrated through short-term testing (70–80h) using high sulfur doped (100ppm) fuel. At 1.11 O:C and 1.25 S:C, nearly complete conversion and 70%+ reforming efficiency (LHV based) were achieved on stabilized catalysts in the presence of 20ppm feed sulfur. The effect of ceria addition into an alumina based support was also examined.

An integrated sorber-based Trace Contaminant Control System (TCCS) and Carbon Dioxide Removal Assembly (CDRA) prototype was designed, fabricated and tested. It corresponds to a 7-person load. Performance over several adsorption/regeneration cycles was examined. Vacuum regenerations at effective time/temperature conditions, and estimated power requirements were experimentally verified for the combined CO2/trace contaminant removal prototype. The current paper details the design and performance of this prototype during initial testing at CO2 and trace contaminant concentrations in the existing CDRA, downstream of the drier. Additional long-term performance characterization is planned at NASA. Potential system design options permitting associated weight, volume savings and logistic benefits, especially as relevant for long-duration space flight, are reviewed. The technology consisted of a sorption bed with sorbent- coated metal meshes, trademarked and patented as Microlith by Precision Combustion, Inc. (PCI). By contrast the current CO2 removal system on the International Space Station employs pellet beds. Preliminary bench scale performance data (without direct resistive heating) for simultaneous CO2 and trace contaminant removal was reviewed in SAE 2004-01-2442. In the prototype, the meshes were directly electrically heated for rapid response and accurate temperature control. This allowed regeneration via resistive heating with the potential for shorter regeneration times, reduced power requirement, and net energy savings vs. conventional systems. A novel flow arrangement, for removing both CO2 and trace contaminants within the same bed, was demonstrated. Thus, the need for a separate trace contaminant unit was eliminated resulting in an opportunity for significant weight savings. Unlike the current disposable charcoal bed, zeolites for trace contaminant removal are amenable to periodic regeneration.

The development of energy efficient, lightweight sorption systems for removal of environmental contaminants in space flight applications is an area of continuing interest to NASA. The current CO2 removal system on the International Space Station employs two pellet bed canisters of 5A molecular sieve that alternate between regeneration and sorption. A separate disposable charcoal bed removes trace contaminants. An alternative technology has been demonstrated using a sorption bed consisting of metal meshes coated with a sorbent, trademarked and patented [1] as Microlith ® by Precision Combustion, Inc. (PCI); these meshes have the potential for direct electrical heating for this application. This allows the bed to be regenerable via resistive heating and offers the potential for shorter regeneration times, reduced power requirement, and net energy savings vs. conventional systems. The capability of removing both CO2 and trace contaminants within the same bed has also been demonstrated. Thus, the need for a separate trace contaminant unit is eliminated resulting in an opportunity for significant weight savings. Unlike the charcoal bed, zeolites for trace contaminant removal are amenable to periodic regeneration. This paper describes the design and performance of a prototype sorber device for simultaneous CO2 and trace contaminant removal and its attendant weight and energy savings.

Use of catalytically coated short contact time (SCT) design approaches for application in mass transfer controlled reactors such as Auto Thermal Reformers (ATR’s) is an area of much recent interest. Precision Combustion, Inc. (PCI) has developed an efficient and compact ATR using ultra-short channel length, high cell density SCT substrates (Microlith ® ). PCI has also extended this Microlith technology to other fuel processor reactors that operate at lower temperatures and are not mass transfer limited. Namely, reactors for the Water Gas Shift (WGS) and Preferential Oxidation (PROX) of CO have been developed. Due to the higher surface area per unit volume of the Microlith substrate compared to conventional monoliths, size advantages have been observed for these reactions, which are more kinetically controlled. This results not only in shortened startup times and quick load following capability but also allows much smaller and lighter reactors – required attributes for automotive fuel cell applications. In this paper, experimental data on the performance of Microlith based ATR, WGSR and PROX reactors for reforming isooctane is presented. Transient and durability characteristics have also been included and compared to Department of Energy (DOE) targets.

The paper concerns a series of Epi-Paleolithic and ante-Natufian sites, with special reference to Nadaouiyeh 2. A controlled collection has enabled us to study the lithic artifacts in detail, and a spatial analysis has brought to light specialised activity areas. Since the collections consisted mainly of microlith fragments, emphasis was on the search for a better idea as to the initial composition of the lithic equipment. It is already apparent that the microliths will play a more important part than a conventional study would have suggested., L'étude concerne une série de sites épipaléolithiques ante-Natoufien, et plus particulièrement Nadaouiyeh 2. Un ramassage contrôlé y a permis une analyse approfondie des artefacts lithiques et une analyse spatiale a mis en évidence des aires d'activité spécialisées. Les fragments de microlithes constituant l'essentiel du matériel recueilli, l'accent a été mis sur la recherche d'une meilleure estimation de la composition initiale de l'équipement lithique. Il est alors apparu que les macrolithes devaient prendre une part plus importante qu'une étude classique l'aurait suggéré., Cauvin Marie-Claire, Coqueugniot Éric. L'Oasis d'El Kowm et le Kébarien géométrique. In: Paléorient, 1988, vol. 14, n°2. Préhistoire du Levant II. Processus des changements culturels. pp. 270-282.

The role of matrix in stone growth has been conclusively proved (1). However, it is not yet established that this matrix is present in the urinary sediment. Crystalluria is more common in stone formers than controls (2). Scanning Electron Microscopy (SEM) can be used to identify a wide variety of materials in urine (3). This paper is based on a detailed study of urinary deposits of patients with urinary stones.