scholarly journals Long-Term Embrittlement of Ancient Copper and Silver Alloys

Heritage ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 2287-2319 ◽  
Author(s):  
Omid Oudbashi ◽  
Russell Wanhill
Keyword(s):  
Copper Alloy ◽  
Chemical Analyses ◽  
Silver Alloy ◽  
Old World ◽  
Silver Alloys ◽  
Fracture Surfaces ◽  
A Minor ◽  
Microstructural Studies ◽  
High Silver

The manifestations of ancient metals’ embrittlement, cracking and fracture, are challenging problems for restorers and conservators, yet the scientific understanding of these problems is limited. In particular, the study and interpretation of fracture surfaces, fractography, is a minor or non-existent consideration for most archaeometallurgical investigations. This paper presents a survey of fractographic analyses, in combination with the more widely used disciplines of microstructural studies, metallography, and chemical analyses for some Old-World copper alloy (bronzes) and high-silver alloy artifacts that have undergone long-term corrosion and embrittlement damage. We show that fractography, as an adjunct to metallography, can improve the interpretation of these types of damage and assist in selecting the best methods for restoration and conservation of the objects made from these alloys.

A non-cyanide method of electropolishing silver

1978 ◽  
Vol 36 (1) ◽  
pp. 146-147
Author(s):  
R. L. Lyles ◽  
S. J. Rothman ◽  
W. Jäger
Keyword(s):  
Electron Microscopy ◽  
Sulphuric Acid ◽  
Methyl Alcohol ◽  
Health Hazards ◽  
Silver Alloy ◽  
High Quality ◽  
Silver Alloys ◽  
Free Sample ◽  
Specimen Quality ◽  
Standard Techniques

Standard techniques of electropolishing silver and silver alloys for electron microscopy in most instances have relied on various CN recipes. These methods have been characteristically unsatisfactory due to difficulties in obtaining large electron transparent areas, reproducible results, adequate solution lifetimes, and contamination free sample surfaces. In addition, there are the inherent health hazards associated with the use of CN solutions. Various attempts to develop noncyanic methods of electropolishing specimens for electron microscopy have not been successful in that the specimen quality problems encountered with the CN solutions have also existed in the previously proposed non-cyanic methods.The technique we describe allows us to jet polish high quality silver and silver alloy microscope specimens with consistant reproducibility and without the use of CN salts.The solution is similar to that suggested by Myschoyaev et al. It consists, in order of mixing, 115ml glacial actic acid (CH3CO2H, specific wt 1.04 g/ml), 43ml sulphuric acid (H2SO4, specific wt. g/ml), 350 ml anhydrous methyl alcohol, and 77 g thiourea (NH2CSNH2).

NICKEL SILVER 55-18

Alloy Digest ◽  
1958 ◽  
Vol 7 (3) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Physical Properties ◽  
Tensile Properties ◽  
High Resistance ◽  
Copper Alloy ◽  
Heat Treating ◽  
Silver Alloy ◽  
Nickel Silver

Abstract NICKEL SILVER, 55-18 is a spring quality nickel silver alloy having high resistance to corrosion and tarnish. It is used primarily for springs and electrical resistances. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Cu-61. Producer or source: Copper alloy mills.

scholarly journals Life Cycle Cost Analysis of a Single-Family House in Sweden

Buildings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 215
Author(s):  
Bojana Petrović ◽  
Xingxing Zhang ◽  
Ola Eriksson ◽  
Marita Wallhagen
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Single Family ◽  
Labor Costs ◽  
Construction Costs ◽  
Economic Parameters ◽  
A Minor ◽  
Family House ◽  
Replacement Operation

The objective of this paper was to explore long-term costs for a single-family house in Sweden during its entire lifetime. In order to estimate the total costs, considering construction, replacement, operation, and end-of-life costs over the long term, the life cycle cost (LCC) method was applied. Different cost solutions were analysed including various economic parameters in a sensitivity analysis. Economic parameters used in the analysis include various nominal discount rates (7%, 5%, and 3%), an inflation rate of 2%, and energy escalation rates (2–6%). The study includes two lifespans (100 and 50 years). The discounting scheme was used in the calculations. Additionally, carbon-dioxide equivalent (CO2e) emissions were considered and systematically analysed with costs. Findings show that when the discount rate is decreased from 7% to 3%, the total costs are increased significantly, by 44% for a 100-year lifespan, while for a 50 years lifespan the total costs show a minor increase by 18%. The construction costs represent a major part of total LCC, with labor costs making up half of them. Considering costs and emissions together, a full correlation was not found, while a partial relationship was investigated. Results can be useful for decision-makers in the building sector.

Dropouts and Aftereffects: Examining General Accessibility to Virtual Environment Technology

2002 ◽  
Vol 46 (26) ◽  
pp. 2114-2118 ◽  
Author(s):  
Kay M. Stanney ◽  
Kelly S. Kingdon ◽  
Robert S. Kennedy
Keyword(s):  
Virtual Environments ◽  
Virtual Environment ◽  
Broad Spectrum ◽  
General Public ◽  
Dropout Rates ◽  
Environment Exposure ◽  
Oculomotor Disturbances ◽  
A Minor

Are current virtual environments (VEs) usable by the broad spectrum of people who may wish to utilize this technology? The current study, which examined over 1000 participants, indicates the answer to this question is a definitive ‘no’. Virtual environment exposure was found to cause people to vomit (1.1%), experience nausea (71%), disorientation (70%), and oculomotor disturbances (79%). Overall, 88% of participants reported some level of adverse symptomatology, ranging from a minor headache to vomiting and intense vertigo. These disturbances led 12% of those exposed to prematurely cease their interaction. Dropout rates as high as nearly 50% were found in exposures of 1 hr in length. In addition, long-term aftereffects were found, including headaches, drowsiness, nausea, and fatigue. These problems could substantially reduce the accessibility of VE technology by the general public and thus must be resolved if this technology is to be widely adopted.

Factors affecting the future of the Scottish hydrometric network

1987 ◽  
Vol 78 (4) ◽  
pp. 269-274 ◽  
Author(s):  
T. Poodle
Keyword(s):  
Data Acquisition ◽  
Computer Systems ◽  
Economic Recession ◽  
Data Standards ◽  
Factors Affecting ◽  
Economic Climate ◽  
A Minor ◽  
The Cost ◽  
Minor Extent

ABSTRACTThe Scottish Hydrometric Network consists of a number of river gauging stations which have been located at sites considered suitable to provide long term flow records. Economic recession has placed some stress on the gauging programme, and has given rise to extensive closures of gauging stations in England and, to a minor extent so far, in Scotland. The way in which the network became established provides a mixture of strengths and weaknesses which could have unpredictable consequences in an adverse economic climate. Changing technology provides some opportunity to reduce the cost of data acquisition and improve the deployment of manpower, while maintaining data standards. In these changing circumstances, particularly with extensive use of computer systems, it is important that standards are established for data returned to the Water Archive and that the network is not allowed to degenerate by default.

NgCAM and VAMP2 Reveal that Direct Delivery and Dendritic Degradation Maintain Axonal Polarity

2021 ◽  
Author(s):  
Alec T. Nabb ◽  
Marvin Bentley
Keyword(s):  
Membrane Proteins ◽  
Molecular Mechanisms ◽  
Minor Role ◽  
Axonal Membrane ◽  
Quantitative Analyses ◽  
Direct Delivery ◽  
Novel Strategy ◽  
Extreme Scale ◽  
A Minor

Neurons are polarized cells of extreme scale and compartmentalization. To fulfill their role in electrochemical signaling, axons must maintain a specific complement of membrane proteins. Despite being subject of considerable attention, the trafficking pathway of axonal membrane proteins is not well understood. Two pathways, direct delivery and transcytosis, have been proposed. Previous studies reached contradictory conclusions about which of these mediates delivery of axonal membrane proteins to their destination, in part because they evaluated long-term distribution changes and not vesicle transport. We developed a novel strategy to selectively label vesicles in different trafficking pathways and determined the trafficking of two canonical axonal membrane proteins, NgCAM and VAMP2. Results from detailed quantitative analyses of transporting vesicles differed substantially from previous studies and found that axonal membrane proteins overwhelmingly undergo direct delivery. Transcytosis plays only a minor role in axonal delivery of these proteins. In addition, we identified a novel pathway by which wayward axonal proteins that reach the dendritic plasma membrane are targeted to lysosomes. These results redefine how axonal proteins achieve their polarized distribution, a crucial requirement for elucidating the underlying molecular mechanisms. [Media: see text] [Media: see text] [Media: see text] [Media: see text]

scholarly journals Occurrence of L1014F and L1014S mutations in insecticide resistant Culex quinquefasciatus from filariasis endemic districts of West Bengal, India

2022 ◽  
Vol 16 (1) ◽  
pp. e0010000
Author(s):  
Priyanka Rai ◽  
Dhiraj Saha
Keyword(s):  
Culex Quinquefasciatus ◽  
West Bengal ◽  
Economic Status ◽  
Minor Role ◽  
Resistance Development ◽  
Vector Population ◽  
A Minor ◽  
First Time

Introduction Lymphatic filariasis causes long term morbidity and hampers the socio-economic status. Apart from the available treatments and medication, control of vector population Culex quinquefasciatus Say through the use of chemical insecticides is a widely applied strategy. However, the unrestrained application of these insecticides over many decades has led to resistance development in the vectors. Methods In order to determine the insecticide susceptibility/resistance status of Cx. quinquefasciatus from two filariasis endemic districts of West Bengal, India, wild mosquito populations were collected and assayed against six different insecticides and presence of L1014F; L1014S kdr mutations in the voltage-gated sodium channel gene was also screened along with the use of synergists to evaluate the role of major detoxifying enzymes in resistance development. Results The collected mosquito populations showed severe resistance to insecticides and the two synergists used–PBO (piperonyl butoxide) and TPP (triphenyl phosphate), were unable to restore the susceptibility status of the vector thereupon pointing towards a minor role of metabolic enzymes. kdr mutations were present in the studied populations in varying percent with higher L1014F frequency indicating its association with the observed resistance to pyrethroids and DDT. This study reports L1014S mutation in Cx. quinquefasciatus for the first time.

scholarly journals SARS-CoV-2 and the Brain: What Do We Know about the Causality of ‘Cognitive COVID?

2021 ◽  
Vol 10 (15) ◽  
pp. 3441
Author(s):  
Hashir Ali Awan ◽  
Mufaddal Najmuddin Diwan ◽  
Alifiya Aamir ◽  
Muneeza Ali ◽  
Massimo Di Giannantonio ◽  
...  
Keyword(s):  
Olfactory Pathway ◽  
Cognitive Sequelae ◽  
Significant Burden ◽  
Inflammatory State ◽  
Underlying Mechanisms ◽  
Acute Changes ◽  
A Minor

The second year of the COVID-19 (coronavirus disease) pandemic has seen the need to identify and assess the long-term consequences of a SARS-CoV-2 infection on an individual’s overall wellbeing, including adequate cognitive functioning. ‘Cognitive COVID’ is an informal term coined to interchangeably refer to acute changes in cognition during COVID-19 and/or cognitive sequelae with various deficits following the infection. These may manifest as altered levels of consciousness, encephalopathy-like symptoms, delirium, and loss of various memory domains. Dysexecutive syndrome is a peculiar manifestation of ‘Cognitive COVID’ as well. In the previous major outbreaks of viruses like SARS-CoV, MERS-CoV and Influenza. There have been attempts to understand the underlying mechanisms describing the causality of similar symptoms following SARS-CoV-2 infection. This review, therefore, is attempting to highlight the current understanding of the various direct and indirect mechanisms, focusing on the role of neurotropism of SARS-CoV-2, the general pro-inflammatory state, and the pandemic-associated psychosocial stressors in the causality of ‘Cognitive COVID.’ Neurotropism is associated with various mechanisms including retrograde neuronal transmission via olfactory pathway, a general hematogenous spread, and the virus using immune cells as vectors. The high amounts of inflammation caused by COVID-19, compounded with potential intubation, are associated with a deleterious effect on the cognition as well. Finally, the pandemic’s unique psychosocial impact has raised alarm due to its possible effect on cognition. Furthermore, with surfacing reports of post-COVID-vaccination cognitive impairments after vaccines containing mRNA encoding for spike glycoprotein of SARS-CoV-2, we hypothesize their causality and ways to mitigate the risk. The potential impact on the quality of life of an individual and the fact that even a minor proportion of COVID-19 cases developing cognitive impairment could be a significant burden on already overwhelmed healthcare systems across the world make it vital to gather further evidence regarding the prevalence, presentation, correlations, and causality of these events and reevaluate our approach to accommodate early identification, management, and rehabilitation of patients exhibiting cognitive symptoms.

scholarly journals Effects of Long-Term Triclosan Exposure on Microbiota in Zebrafish

2021 ◽  
Vol 12 ◽  
Author(s):  
Ning Tang ◽  
Pianpian Fan ◽  
Xiaogang Yu ◽  
Rui Ma ◽  
Yexuan Tao ◽  
...  
Keyword(s):  
Gastrointestinal Tract ◽  
Early Adulthood ◽  
Rrna Gene ◽  
Adult Zebrafish ◽  
Short Term ◽  
Microbial Composition ◽  
Short Term Exposure ◽  
Embryonic Life ◽  
A Minor

Background: Triclosan (TCS) is a widely used antibacterial agent in personal care products and is ubiquitous in the environment. We aimed to examine whether TCS exposure affects microbiota in the gastrointestinal tract of zebrafish.Methods: After exposure to TCS 0 (Dimethyl Sulphoxide, DMSO control), 0.03, 0.3, 3, 30, 100, and 300ng/ml, respectively, from day 0 to 120days post fertilization (dpf), or for 7days in adult 4-month zebrafish, the long- and short-term impact of TCS exposure on the microbiome in the gastrointestinal tract was evaluated by analyzing 16S rRNA gene V3-V4 region sequencing.Results: The top two most dominant microbiota phyla were Proteobacteria and Fusobacteria phylum in all zebrafish groups. In TCS exposure 0–120 dpf, compared with DMSO control, the mean number of microbial operational taxonomic units (OTUs) was 54.46 lower (p<0.0001), Chao indice 41.40 lower (p=0.0004), and Ace indice 34.10 lower (p=0.0044) in TCS 300ng/ml group, but no change was observed in most of the other TCS concentrations. PCoA diagram showed that the microbial community in the long-term TCS 300ng/ml exposure group clustered differently from those in the DMSO control and other TCS exposure groups. A shorter body length of the zebrafish was observed in the long-term TCS exposure at 0.03, 100, and 300ng/ml. For 7-day short-term exposure in adult zebrafish, no difference was observed in alpha or beta diversity of microbiota nor the relative abundance of Proteobacteria or Fusobacteria phylum among DMSO control and any TCS levels, but a minor difference in microbial composition was observed for TCS exposure.Conclusions: Long-term exposure to high TCS concentration in a window from early embryonic life to early adulthood may reduce diversity and alter the composition of microbiota in the gastrointestinal tract. The effect of short-term TCS exposure was not observed on the diversity of microbiota but there was a minor change of microbial composition in adult zebrafish with TCS exposure.

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