Assessing the efficiency of low-cost cleaning methods for diatoms from intertidal sediment samples

2021 ◽  
pp. 106255
Author(s):  
Jéssica C.E. Vilhena ◽  
Ana Amorim ◽  
Lourenço Ribeiro ◽  
Irlon M. Ferreira ◽  
Maíra Pombo
Keyword(s):  
Low Cost ◽  
Intertidal Sediment ◽  
Sediment Samples ◽  
Cleaning Methods

Microdebris analysis in Early Bronze Age Mesopotamian households

Antiquity ◽  
2000 ◽  
Vol 74 (284) ◽  
pp. 291-292 ◽  
Author(s):  
Lynn Rainville
Keyword(s):  
Bronze Age ◽  
Daily Activities ◽  
Site Formation ◽  
Early Bronze Age ◽  
Original Activity ◽  
Sediment Samples ◽  
Cleaning Methods ◽  
Activity Areas

I am interested in the daily activities of the non-Blites to understand ancient Mesopotamian society.Analysing the activities performed within thehouses of the non-6lites is the first step in definingthe social and economic differentiation amonghouseholds and, in turn, a better understanding ofthe role of these households within ancient communities.1 analyse activity areas using a relativelynew method - micro-debris analysis - which analysessmall artefactual and ecofactual remains(Fladmark 1982; Rosen 1989; Matthews 1995).In my dissertation, 365 sediment samples (10litres each) were taken from over 20 structures.The rationale for sampling deposits and countingand weighing the small remains found withinthe earthen matrix is based on a model of depositionalforces. Site formation theorists suggestthat macro-debris left by daily activities are usuallydisturbed and often discarded far from theloci of the original activity. Whereas the large findsmay be scavenged, discarded, or curated in periodsof abandonment, smaller debris is often sweptinto corners or trampled into the surface of afloor. These small items are more likely thanlarge items to remain where they were droppeddue to the difficulty in removing small debriswith traditional cleaning methods (Schiffer 1983;Dunnell & Stein 1989). My research focused onthe analysis of artefacts under 1 cm in dimensionfound in occupational surfaces and featuresin order to define activity areas at severalEarly Bronze Age (c. 3100-1900 BC) sites insoutheastern Turkey

scholarly journals Testing the efficiency of abrasive treatment of reconditioned parts using coolant cleaning in a magnetic sump

2019 ◽  
Vol 298 ◽  
pp. 00115 ◽  
Author(s):  
Boris Avdeyev ◽  
Aleksey Vyngra ◽  
Aleksander Bordiug
Keyword(s):  
Laboratory Tests ◽  
High Efficiency ◽  
Structural Parameters ◽  
Low Cost ◽  
Abrasive Machining ◽  
Abrasive Treatment ◽  
Operation And Maintenance ◽  
Cooling Lubricant ◽  
Cleaning Methods ◽  
Engine Crankshaft

This article discusses pilot study of effectiveness of abrasive machining of the recoverable parts for cleaning cooling lubricants involved in technological processes of processing of the parts. One of the cleaning methods is a magnetic sump, which has high efficiency at relatively low cost of operation and maintenance. Laboratory tests of the magnetic sump were carried out according to a full-factor experiment, varying with certain parameters in order to identify the purity index of cooling lubricant when cleaning from mechanical impurities. Dependencies are obtained that connect the value of purity index of coolant with the technological and structural parameters of the magnetic sump. The influence of the cooling lubricant purity index in the magnetic sump on the roughness of grinded surface of the samples was revealed. The most rational parameters of the magnetic sump have been determined at which optimum surface roughness is observed when processing the engine crankshaft using cooling lubricant cleaned in the magnetic sump.

scholarly journals TIDAL AREA DISPERSANT EXPERIMENT, SEARSPORT MAINE: AN OVERVIEW

1985 ◽  
Vol 1985 (1) ◽  
pp. 553-559 ◽  
Author(s):  
Edward S. Gilfillan ◽  
David S. Page ◽  
Sherry A. Hanson ◽  
Judith C. Foster ◽  
Janet Hotham ◽  
...  
Keyword(s):  
Oil Spill ◽  
Biological Effects ◽  
Animal Tissue ◽  
Community Level ◽  
Intertidal Sediment ◽  
Tissue Samples ◽  
Scope For Growth ◽  
Sediment Samples ◽  
Dispersed Oil ◽  
Biochemical Level

ABSTRACT On August 19, 1981, two test spills of Murban crude oil were carried out in Long Cove, Searsport, Maine. One spill was chemically dispersed; the other was not. Measurements were made to make quantitative comparisons of the chemical fates and biological effects of the two spills. Hydrocarbon analyses were carried out on water samples, animal tissue samples, intertidal sediment samples, and subtidal sediment samples. Biological measurements were carried out at the community level, whole animal level, and biochemical level of organization. No significant biological effects attributable to the dispersed oil spill were observed. This lack of effects is, in part, a result of changes in the physical and chemical properties of dispersed oil which help limit its availability and toxicity. The chemical fate and biological effects of the undispersed oil spill were typical of those reported from actual oil spill sites. Oil was incorporated into sediments and animal tissue. On the community level of organization mortality, reduced diversity and evenness, increased population density, and increased dominance by opportunists were all observed immediately after the spill, and up to 1 year later. On the whole animal level of organization, no effects on scope-for-growth were observed in two filter feeding bivalves. On the biochemical level of organization, activities of two sensitive enzyme systems were elevated.

Decomposition of the metastable beta titanium alloy Ti-15-3

1983 ◽  
Vol 41 ◽  
pp. 264-265
Author(s):  
Y. L. Chen ◽  
S. Fujlshiro
Keyword(s):  
Low Cost ◽  
High Strength ◽  
Alpha Phase ◽  
Thick Sheet ◽  
Omega Phase ◽  
Beta Titanium Alloy ◽  
Beta Titanium ◽  
Beta Matrix ◽  
Metastable Beta ◽  
Very High

Metastable beta titanium alloys have been known to have numerous advantages such as cold formability, high strength, good fracture resistance, deep hardenability, and cost effectiveness. Very high strength is obtainable by precipitation of the hexagonal alpha phase in a bcc beta matrix in these alloys. Precipitation hardening in the metastable beta alloys may also result from the formation of transition phases such as omega phase. Ti-15-3 (Ti-15V- 3Cr-3Al-3Sn) has been developed recently by TIMET and USAF for low cost sheet metal applications. The purpose of the present study was to examine the aging characteristics in this alloy.The composition of the as-received material is: 14.7 V, 3.14 Cr, 3.05 Al, 2.26 Sn, and 0.145 Fe. The beta transus temperature as determined by optical metallographic method was about 770°C. Specimen coupons were prepared from a mill-annealed 1.2 mm thick sheet, and solution treated at 827°C for 2 hr in argon, then water quenched. Aging was also done in argon at temperatures ranging from 316 to 616°C for various times.

Chromic Acid Etching of Polyethylene

1973 ◽  
Vol 31 ◽  
pp. 72-73
Author(s):  
J. D. Muzzy ◽  
R. D. Hester ◽  
J. L. Hubbard
Keyword(s):  
Chromic Acid ◽  
Low Cost ◽  
Acid Etching ◽  
Crystalline Morphology ◽  
Bulk Specimen ◽  
Morphological Studies ◽  
Perfect Form ◽  
Molecular Length ◽  
Lamellar Texture ◽  
Cost Studies

Polyethylene is one of the most important plastics produced today because of its good physical properties, ease of fabrication and low cost. Studies to improve the properties of polyethylene are leading to an understanding of its crystalline morphology. Polyethylene crystallized by evaporation from dilute solutions consists of thin crystals called lamellae. The polyethylene molecules are parallel to the thickness of the lamellae and are folded since the thickness of the lamellae is much less than the molecular length. This lamellar texture persists in less perfect form in polyethylene crystallized from the melt.Morphological studies of melt crystallized polyethylene have been limited due to the difficulty of isolating the microstructure from the bulk specimen without destroying or deforming it.

Glass Knife Geometry as Seen by the SEM

1971 ◽  
Vol 29 ◽  
pp. 454-455
Author(s):  
J. Temple Black
Keyword(s):  
Low Cost ◽  
Amorphous Material ◽  
Stress Concentrations ◽  
Basic Tool ◽  
Tool Materials ◽  
Optical Inspection ◽  
Surface Flaws ◽  
Slip Planes ◽  
Glass Knife ◽  
Diamond Knife

In ultramicrotomy, the two basic tool materials are glass and diamond. Glass because of its low cost and ease of manufacture of the knife itself is still widely used despite the superiority of diamond knives in many applications. Both kinds of knives produce plastic deformation in the microtomed section due to the nature of the cutting process and microscopic chips in the edge of the knife. Because glass has no well defined slip planes in its structure (it's an amorphous material), it is very strong and essentially never fails in compression. However, surface flaws produce stress concentrations which reduce the strength of glass to 10,000 to 20,000 psi from its theoretical or flaw free values of 1 to 2 million psi. While the microchips in the edge of the glass or diamond knife are generally too small to be observed in the SEM, the second common type of defect can be identified. This is the striations (also termed the check marks or feathers) which are always present over the entire edge of a glass knife regardless of whether or not they are visable under optical inspection. These steps in the cutting edge can be observed in the SEM by proper preparation of carefully broken knives and orientation of the knife, with respect to the scanning beam.

TEM characterization of silicon epitaxial layer grown on Si-TaS2, eutectic composites

1991 ◽  
Vol 49 ◽  
pp. 802-803
Author(s):  
C.M. Sung ◽  
M. Levinson ◽  
M. Tabasky ◽  
K. Ostreicher ◽  
B.M. Ditchek
Keyword(s):  
Substrate Surface ◽  
Bulk Sample ◽  
Surface Cleaning ◽  
Native Oxide ◽  
Czochralski Growth ◽  
Ion Milling ◽  
Cross Sectional ◽  
Cleaning Methods ◽  
Field Emission Cathodes

Directionally solidified Si/TaSi2 eutectic composites for the development of electronic devices (e.g. photodiodes and field-emission cathodes) were made using a Czochralski growth technique. High quality epitaxial growth of silicon on the eutectic composite substrates requires a clean silicon substrate surface prior to the growth process. Hence a preepitaxial surface cleaning step is highly desirable. The purpose of this paper is to investigate the effect of surface cleaning methods on the epilayer/substrate interface and the characterization of silicon epilayers grown on Si/TaSi2 substrates by TEM.Wafers were cut normal to the <111> growth axis of the silicon matrix from an approximately 1 cm diameter Si/TaSi2 composite boule. Four pre-treatments were employed to remove native oxide and other contaminants: 1) No treatment, 2) HF only; 3) HC1 only; and 4) both HF and HCl. The cross-sectional specimens for TEM study were prepared by cutting the bulk sample into sheets perpendicular to the TaSi2 fiber axes. The material was then prepared in the usual manner to produce samples having a thickness of 10μm. The final step was ion milling in Ar+ until breakthrough occurred. The TEM samples were then analyzed at 120 keV using the Philips EM400T.

Spectraplot: A PC-based spectrum translation and display program

1988 ◽  
Vol 46 ◽  
pp. 918-919
Author(s):  
H. O. Colijn
Keyword(s):  
Low Cost ◽  
Transfer Program ◽  
File Transfer ◽  
Transfer Data ◽  
Error Checking ◽  
Data Files ◽  
The University

Many labs today wish to transfer data between their EDS systems and their existing PCs and minicomputers. Our lab has implemented SpectraPlot, a low- cost PC-based system to allow offline examination and plotting of spectra. We adopted this system in order to make more efficient use of our microscopes and EDS consoles, to provide hardcopy output for an older EDS system, and to allow students to access their data after leaving the university.As shown in Fig. 1, we have three EDS systems (one of which is located in another building) which can store data on 8 inch RT-11 floppy disks. We transfer data from these systems to a DEC MINC computer using “SneakerNet”, which consists of putting on a pair of sneakers and running down the hall. We then use the Hermit file transfer program to download the data files with error checking from the MINC to the PC.

Transmission Electron Microscopy of oriented Co84Cr14Ta2 thin films for longitudinal magnetic recording

1991 ◽  
Vol 49 ◽  
pp. 756-757
Author(s):  
T. P. Nolan
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Low Cost ◽  
Low Noise ◽  
Information Storage ◽  
High Coercivity ◽  
Magnetic Alloy ◽  
Magnetic Media ◽  
Transmission Electron

Thin film magnetic media are being used as low cost, high density forms of information storage. The development of this technology requires the study, at the sub-micron level, of morphological, crystallographic, and magnetic properties, throughout the depth of the deposited films. As the microstructure becomes increasingly fine, widi grain sizes approaching 100Å, the unique characterization capabilities of transmission electron microscopy (TEM) have become indispensable to the analysis of such thin film magnetic media.Films were deposited at 225°C, on two NiP plated Al substrates, one polished, and one circumferentially textured with a mean roughness of 55Å. Three layers, a 750Å chromium underlayer, a 600Å layer of magnetic alloy of composition Co84Cr14Ta2, and a 300Å amorphous carbon overcoat were then sputter deposited using a dc magnetron system at a power of 1kW, in a chamber evacuated below 10-6 torr and filled to 12μm Ar pressure. The textured medium is presently used in industry owing to its high coercivity, Hc, and relatively low noise. One important feature is that the coercivity in the circumferential read/write direction is significandy higher than that in the radial direction.

Influence of MBE Growth Conditions on Dislocation Densities of GaAs/Ge Epilayers Grown on Silicon Substrates

1985 ◽  
Vol 43 ◽  
pp. 364-365
Author(s):  
K.M. Hones ◽  
P. Sheldon ◽  
B.G. Yacobi ◽  
A. Mason
Keyword(s):  
High Efficiency ◽  
Lattice Mismatch ◽  
Low Cost ◽  
Growth Conditions ◽  
Nonradiative Recombination ◽  
Device Structure ◽  
Si Substrates ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Dislocation Type

There is increasing interest in growing epitaxial GaAs on Si substrates. Such a device structure would allow low-cost substrates to be used for high-efficiency cascade- junction solar cells. However, high-defect densities may result from the large lattice mismatch (∼4%) between the GaAs epilayer and the silicon substrate. These defects can act as nonradiative recombination centers that can degrade the optical and electrical properties of the epitaxially grown GaAs. For this reason, it is important to optimize epilayer growth conditions in order to minimize resulting dislocation densities. The purpose of this paper is to provide an indication of the quality of the epitaxially grown GaAs layers by using transmission electron microscopy (TEM) to examine dislocation type and density as a function of various growth conditions. In this study an intermediate Ge layer was used to avoid nucleation difficulties observed for GaAs growth directly on Si substrates. GaAs/Ge epilayers were grown by molecular beam epitaxy (MBE) on Si substrates in a manner similar to that described previously.

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