scholarly journals Iron’s Wake: The Performance of Quantum Mechanical-Derived Versus General-Purpose Force Fields Tested on a Luminescent Iron Complex

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3084 ◽  
Author(s):  
Valentin Diez-Cabanes ◽  
Giacomo Prampolini ◽  
Antonio Francés-Monerris ◽  
Antonio Monari ◽  
Mariachiara Pastore
Keyword(s):  
Force Fields ◽  
Low Cost ◽  
Md Simulations ◽  
General Purpose ◽  
Iron Complex ◽  
Chemical Environment ◽  
Quantum Mechanical ◽  
Minor Role ◽  
Transient Spectroscopy ◽  
A Minor

Recently synthetized iron complexes have achieved long-lived excited states and stabilities which are comparable, or even superior, to their ruthenium analogues, thus representing an eco-friendly and cheaper alternative to those materials based on rare metals. Most of computational tools which could help unravel the origin of this large efficiency rely on ab-initio methods which are not able, however, to capture the nanosecond time scale underlying these photophysical processes and the influence of their realistic environment. Therefore, it exists an urgent need of developing new low-cost, but still accurate enough, computational methodologies capable to deal with the steady-state and transient spectroscopy of transition metal complexes in solution. Following this idea, here we focus on the comparison between general-purpose transferable force-fields (FFs), directly available from existing databases, and specific quantum mechanical derived FFs (QMD-FFs), obtained in this work through the Joyce procedure. We have chosen a recently reported FeIII complex with nanosecond excited-state lifetime as a representative case. Our molecular dynamics (MD) simulations demonstrated that the QMD-FF nicely reproduces the structure and the dynamics of the complex and its chemical environment within the same precision as higher cost QM methods, whereas general-purpose FFs failed in this purpose. Although in this particular case the chemical environment plays a minor role on the photo physics of this system, these results highlight the potential of QMD-FFs to rationalize photophysical phenomena provided an accurate QM method to derive its parameters is chosen.

On the Influence of Illumination During Ion Damage Defect Anneal of Silicon

1995 ◽  
Vol 396 ◽  
Author(s):  
A. Tanabe ◽  
S. Ashok
Keyword(s):  
Electron Cyclotron Resonance ◽  
Deep Level ◽  
Hydrogen Plasma ◽  
Minor Role ◽  
Extended Defects ◽  
Rapid Thermal Anneal ◽  
Thermal Generation ◽  
Ion Damage ◽  
Transient Spectroscopy ◽  
A Minor

AbstractAn exploratory deep level transient spectroscopy (DLTS) study on the possible role of illumination during thermal annealing has been carried out on Si with extended defects generated by Ar implantation and electron cyclotron resonance (ECR) hydrogen plasma. Experiments with rapid thermal anneal (RTA) using quartz-halogen lamps show only a minor role for illumination on anneal of defects generated by Ar ion damage as well as thermal generation of defects under post-hydrogenation anneal. However, significant differences are evident relative to conventional furnace anneal and it appears likely that recombination-assisted defect reactions may be quite significant in Si processing when high intensity sources such as arc lamps are adapted in RTA systems.

The Role of Lubrication in the Cold Heading of Mild Steel

1975 ◽  
Vol 97 (2) ◽  
pp. 144-150 ◽  
Author(s):  
J. L. Tevaarwerk ◽  
A. Plumtree ◽  
R. Sowerby
Keyword(s):  
Mild Steel ◽  
Coefficient Of Friction ◽  
Low Cost ◽  
Steel Wire ◽  
Solid Lubricants ◽  
Minor Role ◽  
Total Force ◽  
Liquid Lubricant ◽  
The Coefficient Of Friction ◽  
A Minor

This work provides information leading to the evaluation of the coefficient of friction for various lubricants during the first blow of a double blow heading operation on AISI 1018 steel wire. A Waterbury-Farrel cold heading machine was instrumented so that the total force and frictional force could be evaluated during the first blow operation. The lubricants investigated fell into four main groups: 1) Lubricants, physically or chemically bonded to the wire; this group included zinc phosphate, 2) Lubricants listed in 1) used together with a petroleum based polar oil, SAE 30 [780 SUS at 80° F (167 × 10−6 m2/s at 27° C)], 3) Liquid lubricants of various viscosities employed with the bare wire, 4) Solid lubricants mixed with a non-polar mineral oil [65 SUS at 80° F (12 × 10−6 m2/s at 27° C)], again used with bare wire. The calculated coefficient of friction was used to indicate the efficiency of the respective lubricants. Liquid lubricants either alone on bare wire or with bonded lubricants proved to be the most successful in reducing the calculated μ value; additives appeared to play a minor role. The results indicate that a low cost liquid lubricant used on bare wire has both economic and operational advantages when cold heading mild steel wire.

scholarly journals Sustainability of conservation agriculture adoption and the role lead farmers play in Zimbabwe

2021 ◽  
Vol 49 (2) ◽  
pp. 1-14
Author(s):  
Joe Stevens ◽  
Nyathi ◽  
Salomons
Keyword(s):  
Low Cost ◽  
Conservation Agriculture ◽  
Farming System ◽  
Small Scale ◽  
Minor Role ◽  
Extension Services ◽  
Governmental Organizations ◽  
Non Governmental Organizations ◽  
A Minor ◽  
Agriculture Extension

Conservation Agriculture (CA) has been promoted widely in Zimbabwe through several organizations, including government and non-governmental organizations, to help address food insecurity. The sustainability of donor led interventions has been questioned as they are of limited duration, and some research has reported that farmers stop practicing CA when a project ends. However, agriculture extension services are reported crucial in adopting new agriculture technologies; hence, continued access to services is crucial for the sustainable uptake of CA. The use of farmer-led extension approaches has been used to reach more farmers at low cost to promote CA and for sustainability. The study evaluates the sustainability of CA practices as well as lead farmers roles after the end of Christian Care project activities. The findings reveal continued adoption of CA principles, albeit on a small scale. We conclude that CA has become part of the traditional farming system and recommend labour-saving technologies for the uptake of CA on a greater scale. Government extension support has also continued, although lead farmers played a minor role in these extension activities. Lead farmers alone cannot sustainably provide extension services without institutional support. The recommendation is that public extension systems work closely with lead farmers in communities to efficiently reach farmers and ensure better coordination between NGOs and government extension activities.

scholarly journals Radiation-produced defects in germanium: experimental data and models of defects

2017 ◽  
Vol 51 (12) ◽  
pp. 1632
Author(s):  
V.V. Emtsev ◽  
D.S. Poloskin ◽  
G.A. Oganesyan ◽  
V.V. Kozlovski
Keyword(s):  
Experimental Data ◽  
Defect Formation ◽  
Deep Level ◽  
Minor Role ◽  
Radiation Defects ◽  
Electrical Measurements ◽  
Group V ◽  
Before And After ◽  
Transient Spectroscopy ◽  
A Minor

The problem of radiation-produced defects in n-Ge before and after n-> p conversion is discussed in the light of electrical data obtained by means of Hall effect measurements as well as Deep Level Transient Spectroscopy. The picture of the dominant radiation defects in irradiated n-Ge before n-> p conversion appears to be complicated, since they turn out to be neutral in n-type material and unobserved in the electrical measurements. It is argued that radiation-produced acceptors at ~ EC-0.2 eV previously ascribed to vacancy-donor pairs (E-centers) play a minor role in the defect formation processes under irradiation. Acceptor defects at ~ EV+0.1 eV are absolutely dominating in irradiated n-Ge after n-> p conversion. All the radiation defects under consideration were found to be dependent on the chemical group-V impurities. Together with this, they are concluded to be vacancy-related, as evidenced positron annihilation experiments. A detailed consideration of experimental data on irradiated n-Ge shows that the present model of radiation-produced defects adopted in literature should be reconsidered. DOI: 10.21883/FTP.2017.12.45178.8599

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

Use of Different Tissue Thromboplastins in the Control of Anticoagulant-Therapy

1958 ◽  
Vol 02 (05/06) ◽  
pp. 462-480 ◽  
Author(s):  
Marc Verstraete ◽  
Patricia A. Clark ◽  
Irving S. Wright
Keyword(s):  
Prothrombin Time ◽  
Anticoagulant Therapy ◽  
Factor Vii ◽  
Rabbit Brain ◽  
Minor Role ◽  
Rabbit Lung ◽  
Coagulation Mechanism ◽  
Time Test ◽  
The One ◽  
A Minor

SummaryAn analysis of the results of prothrombin time tests with different types of thromboplastins sheds some light on the problem why the administration of coumarin is difficult to standardize in different centers. Our present ideas on the subject, based on experimental data may be summarized as follows.Several factors of the clotting mechanism are influenced by coumarin derivatives. The action of some of these factors is by-passed in the 1-stage prothrombin time test. The decrease of the prothrombin and factor VII levels may be evaluated in the 1-stage prothrombin time determination (Quick-test). The prolongation of the prothrombin times are, however, predominantly due to the decrease of factor VII activity, the prothrombin content remaining around 50 per cent of normal during an adequate anticoagulant therapy. It is unlikely that this degree of depression of prothrombin is of major significance in interfering with the coagulation mechanism in the protection against thromboembolism. It may, however, play a minor role, which has yet to be evaluated quantitatively. An exact evaluation of factor VII is, therefore, important for the guidance of anticoagulant therapy and the method of choice is the one which is most sensitive to changes in factor VII concentration. The 1-stage prothrombin time test with a rabbit lung thromboplastin seems the most suitable method because rabbit brain preparations exhibit a factor VII-like activity that is not present in rabbit lung preparations.

Produktivkraft als Versprechen

2016 ◽  
Vol 46 (185) ◽  
pp. 621-638 ◽  
Author(s):  
Christian Siefkes
Keyword(s):  
Private Consumption ◽  
Minor Role ◽  
Progressive Reduction ◽  
Internal Forces ◽  
A Minor

The ‘Fragment on Machines’ from Marx’s Grundrisse is often cited as an argument that the internal forces of capitalism will lead to its doom. But the argument that the progressive reduction of labor must doom capitalism lacks a proper foundation, as a comparison with the ‘Schemes of Reproduction’ given in Capital II shows. The latter, however, aren’t fully convincing either. In reality, more depends on the private consumption of capitalists than either model recognizes. Ultimately, most can be made of the ‘Fragment on Machines’ by reading it not as an exposure of capitalism’s internal contractions, but as a discussion of a possible communist future where labor (or work) will play but a minor role.

Polysaccharide Structures in the Outer Mucilage of Arabidopsis Seeds Visualized by AFM

2020 ◽  
Author(s):  
MAK Williams ◽  
V Cornuault ◽  
AH Irani ◽  
VV Symonds ◽  
J Malmström ◽  
...  
Keyword(s):  
Average Length ◽  
American Chemical Society ◽  
Md Simulations ◽  
Chemical Society ◽  
Side Chains ◽  
Rhamnogalacturonan I ◽  
Afm Imaging ◽  
Minor Population ◽  
The Stability ◽  
A Minor

© 2020 American Chemical Society. Evidence is presented that the polysaccharide rhamnogalacturonan I (RGI) can be biosynthesized in remarkably organized branched configurations and surprisingly long versions and can self-assemble into a plethora of structures. AFM imaging has been applied to study the outer mucilage obtained from wild-type (WT) and mutant (bxl1-3 and cesa5-1) Arabidopsis thaliana seeds. For WT mucilage, ordered, multichain structures of the polysaccharide RGI were observed, with a helical twist visible in favorable circumstances. Molecular dynamics (MD) simulations demonstrated the stability of several possible multichain complexes and the possibility of twisted fibril formation. For bxl1-3 seeds, the imaged polymers clearly showed the presence of side chains. These were surprisingly regular and well organized with an average length of ∼100 nm and a spacing of ∼50 nm. The heights of the side chains imaged were suggestive of single polysaccharide chains, while the backbone was on average 4 times this height and showed regular height variations along its length consistent with models of multichain fibrils examined in MD. Finally, in mucilage extracts from cesa5-1 seeds, a minor population of chains in excess of 30 μm long was observed.

AISI 1030

Alloy Digest ◽  
1983 ◽  
Vol 32 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Low Cost ◽  
Heat Treating ◽  
Plain Carbon Steel ◽  
General Purpose ◽  
Fine Grain ◽  
Steel Mills ◽  
Medium Strength ◽  
Hot Rolled

Abstract AISI 1030 is a plain carbon steel containing nominally 0.30% carbon. It is used in the hot-rolled, normalized, oil-quenched-and-tempered or water-quenched-and-tempered conditions for general-purpose engineering and construction. It provides medium strength and toughness at low cost. Among its many uses are axles, bolts, gears and building sections. All data are on a single heat of fine-grain steel. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-94. Producer or source: Carbon and alloy steel mills.

AISI 1040

Alloy Digest ◽  
1971 ◽  
Vol 20 (6) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
Low Cost ◽  
Heat Treating ◽  
General Purpose ◽  
Medium Carbon Steel ◽  
Medium Carbon ◽  
Steel Mills ◽  
Medium Strength ◽  
Hot Rolled

Abstract AISI 1040 is a medium-carbon steel used in the hot-rolled, normalized, oil quenched and tempered or water quenched and tempered condition for general purpose engineering and construction. It provides medium strength and toughness at low cost. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: CS-41. Producer or source: Carbon and alloy steel mills.

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