Perhitungan Laju Korosi Pada Material Baja A36 Akibat Proses Pengelasan Smaw (Shielded Metal Arc Welding)

Corrosion is one of the causes of deterioration of a metal material, the process of degradation / deteorisation. Some environmental conditions can accelerate the corrosion of metal materials such as sea water. Sea water containing NaCl can accelerate the corrosion. Testing done by preparing specimens that have been measured and weighed in advance and will be dyed and steamed in a water solution of the Sea, 10% NaCl, NaCl 20% and 30% NaCl. There are eight specimens in doing welding with SMAW welding current 80 A and 8 specimens that did not do the welding results showed that the corrosion rate of the highest value found in SMAW welding specimens made and steamed above the 20% NaCl solution with the corrosion rate of 0.002066 MPY

Thermal Analysis of the Mound One Kilowatt Package

The Mound One Kilowatt (1 KW) package was designed for the shipment of plutonium (Pu-238) with not more than 1 kW total heat dissipation. To comply with regulations, the Mound 1 kW package has to pass all the requirements under Normal Conditions of Transport (NCT; 38 degrees C ambient temperature) and Hypothetical Accident Conditions (HAC; package engulfed in fire for 30 minutes). Analytical and test results were presented in the Safety Analysis Report for Packaging (SARP) for the Mound 1 kW package, revision 1, April 1991. Some issues remained unresolved in that revision. In March 1992, Fairchild Space and Defense Corporation was commissioned by the Department of Energy to perform the thermal analyses. 3-D thermal models were created to perform the NCT and HAC analyses. Four shipping configurations in the SARP revision 3 were analyzed. They were: (1) The GPHS graphite impact shell (GIS) in the threaded product can (1000 W total heat generation); (2) The fueled clads in the welded product can (1000 W total heat generation); (3) The General Purpose Heat Source (GPHS) module (750 W total heat generation); and (4) The Multi-Hundred Watt (MHW) spheres (810 W total heat generation). Results from the four cases show that the GIS or fuel clad in the product can is the worse case. The temperatures predicted under NCT and HAC in all four cases are within the design limits. The use of helium instead of argon as cover gas provides a bigger safety margin. There is a duplicate copy

Prefect Klein tunneling in anisotropic graphene-like photonic lattices

We study the scattering of waves off a potential step in deformed honeycomb lattices. For small deformations below a critical value, perfect Klein tunneling is obtained. This means that a potential step in any direction transmits waves at normal incidence with unit transmission probability, irrespective of the details of the potential. Beyond the critical deformation, a gap in the spectrum is formed, and a potential step in the deformation direction reflects all normal-incidence waves, exhibiting a dramatic transition form unit transmission to total reflection. These phenomena are generic to honeycomb lattice systems, and apply to electromagnetic waves in photonic lattices, quasi-particles in graphene, cold atoms in optical lattices

Dynamic magnetomechanical properties of Terfenol-D/epoxy pseudo 1-3 composites

2004-2005 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Indigenous silk moth farming as a means to support Ranomafana National Park

We envisage a world where the rural poor can derive a livelihood from protecting forests instead of cutting them down; where development planners understand that habitat health is the keystone for human health and survival, and where conservation biologists understand that long - term solutions to biodiversity loss must be built around social programs which enable local people to thrive. Our vision, however, can only be achieved when scientists express the role of biodiversity conservation in economic terms (Baird and Dearden 2003), and development planners understand environmental complexity and its role in poverty alleviation. Our long - term goal is to develop a generalized approach to biodiversity conservation that will enable scientists and development professionals to identify, plan and initiate sustainable, small - scale businesses in ecologically important areas. This paper reports on a recent study to expand current production of wild silk and explore new types of silk as one economic means of biodiversity protection in Madagascar. Madagascar is one of the most important centers of world biodiversity and 90% of its species are forest dwelling. Nevertheless, 80% of the population are subsistence farmers (Kistler and Spack 2003), and the predominant agricultural practice is “tavy” or slash and burn. Less than 10 % of the original forest remains. Development and conservation communities can effectively prevent deforestation only when they counter the macroeconomic forces that drive people to clear land. Small-scale farmers cut down forests because national and international policies, market conditions or local institutions do not provide them with reasonable alternatives (Tomich et al. 2005). Furthermore, even when alternatives are made available, results are difficult to achieve in a short time. At least some actions need to be implemented pro-actively, in sites that are currently healthy but near areas of potential population growth. We have been working for the past year to develop an approach to identify high value export products (i.e. products whose value is likely to be least vulnerable to macroeconomic shock; Castellano and San 2005), that can be found in areas of high biodiversity and conservation importance. One such product may be wild silk. Wild silk can be sustainably harvested in remote areas and easily transported to commercial centers. To determine if wild silk is a potential means of income generation for people living in areas of Madagascar where silk has not been traditionally produced, we gathered three types of information: 1. The diversity of silk producing larvae in the Eastern Forest Corridor and specifically in Ranomafana 2. The physical properties of larval silk and their estimated commercial value 3. How to apply our data in order to select sites where wild silk production could have a maximum economic and conservation effect We emphasize that the work reported here is preliminary and that we are working to expand our database for silkworm larvae and potential projects sites. All of these data will be posted on the website for Conservation through Poverty Alleviation (www.cpali.org) as we progress. Elsewhere we report the life-history biology of the species found to date and analyze the economic resources that will need to be generated by local com-munities to engage in silk production for commercial markets (Craig and Weber, in prep.)

In Vitro Antimicrobial Activity Of Crude Extracts From Plants Bryophyllum pinnatum And Kalanchoe crenata

Extracts from the leaves of Bryophyllum pinnatum and Kalanchoe crenata were screened for their antimicrobial activities. Solvents used included water, methanol, and local solvents such as palmwine, local gin (Seaman's Schnapps 40% alcoholic drink,) and “omi ekan-ogi” (Sour water from 3 days fermented milled maize). Leaves were dried and powdered before being soaked in solvents for 3 days. Another traditional method of extraction by squeezing raw juice from the leaves was also employed. All extracts were lyophilized. These extracts were tested against some Gram-negative organisms (Escherichia coli ATCC 25922, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Shigella flexneri, Salmonella paratyphi, Citrobacter spp); Gram-positive organisms Staphylococcus aureus ATCC 25213, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis) and a fungus (Candida albicans). Agar well diffusion and broth dilution methods were used to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) at concentrations of 512mg/ml to 4mg/ml. All the organisms except Candida albicans were susceptible to the extracts obtained from the traditional method. The squeezed-leaf juice of Kalanchoe crenata was the most active one with MIC of 8 mg/ml against Pseudomonas aeruginosa, Klebsiella pneumoniae and Bacillus subtilis, 32 mg/ml against Shigella flexneri, 64 mg/ml against Escherichia coli and 128 mg/ml against the control strain Staphylococcus aureus while its MBC is 256 mg/ml against these organisms except Bacillus subtilis and Klebsiella pneumoniae. The Gram-positive organisms were more sensitive to the methanol and local gin-extract of Bryophyllum pinnatum. Extracts from other solvents showed moderate to weak activity. Keywords:Antimicrobial, Bryophyllum pinnatum, Kalanchoe crenata, Local solvents, Gram-positive organism, Gram-negative organism African Journal of Traditional and Complementary Medicine Vol. 4 (3) 2007: pp. 338-34

Analysis of Possible Stratagems for Enhancing the EOM Power of RTGs for the CRAF Mission

Paper presented at the 26th IECEC in Boston, MA August 4-9, 1991. This paper describes the various stratagems investigated and discusses their drawbacks and their effectiveness. The analytical results indicated that a combination of relatively modest RTG modifications that could be implemented in time for the mission could come very close to meeting the CRAF power demand goals specified by JPL. However, since even with the modifications the two RTGs did not provide sufficient margin for possible further growth in power demand, the JPL project team ultimately decided to use 3 RTGs for the CRAF mission also. This had the decisive advantage of eliminating the need for load switching to reduce the power demand peaks. The purpose of this paper is to document the various power enhancement schemes analyzed and their computed effectiveness, for possible future applications. There are three copies in the file