POLYCONDENSED ANIONS OF THE TRANSITION METALS: LIGHT SCATTERING AND ULTRACENTRIFUGATION WITH SCHLIEREN AND INTERFERENCE OPTICS OF ALKALINE NIOBIUM (V) SOLUTIONS

1964 ◽  
Vol 42 (4) ◽  
pp. 731-743 ◽  
Author(s):  
Wilfred H. Nelson ◽  
R. Stuart Tobias
Keyword(s):  
Light Scattering ◽  
Experimental Methods ◽  
Degree Of Polymerization ◽  
Potassium Ions ◽  
High Symmetry ◽  
Concentrated Solutions ◽  
Solvent Water ◽  
A Value ◽  
The Stability ◽  
Equilibrium Ultracentrifugation

Alkaline aqueous niobium(V) solutions prepared by dissolving the salt K14Nb12O37•27H2O were studied by means of light scattering and by equilibrium ultracentrifugation by using both schlieren and interference optics. All three experimental methods indicate that the degree of polymerization of the polycondensed niobate anion is no less than 5 and probably has the value 6. The centrifugation data indicate that only one polycondensed species exists in the solutions. The effective charge of the niobate anion appears to be reduced appreciably by the binding of potassium ions to a value of no greater than −2. The behavior of the solutions is very similar to that observed previously with alkaline tantalum(V) solutions, and it appears very likely that the hexameric anion [HNb6O19]−7 found in niobate crystals also exists in aqueous solutions. The niobate is slightly protonated in comparison to the analogous tantalate. The stability of highly concentrated solutions containing this large polycondensed species is probably the result of the existence of a poly-ion with high symmetry which interacts only weakly with the solvent, water.

ANALISIS VARIASI JUMLAH SUDU TURBIN BERPENAMPANG PELAT DATAR PADA TURBIN AIR ALIRAN VORTEX DENGAN TIPE SALURAN MASUK INVOLUTE

2020 ◽  
Vol 7 (2) ◽  
pp. 72-78
Author(s):  
Adnan Al Farisi ◽  
Yopi Handoyo ◽  
Taufiqur Rokhman
Keyword(s):  
Power Plant ◽  
Alternative Energy ◽  
Vortex Flow ◽  
Experimental Methods ◽  
Turbine Efficiency ◽  
A Value ◽  
Current Voltage ◽  
Materials Research ◽  
The One ◽  
Flow Vortex

The One of alternative energy that is environmentally friendly is by untilize water energy and turn it into a Microhydro power plant. Microhydro power plant usually made from utilize the waterfall with the head fell. While utilization for streams with a head small drop is not optimal yet. This is a reference to doing research on harnessing the flow of a river that has a value of head low between 0.7 m – 1.4 m with turning it into a Vortex flow (vortex). The purpose of this research is to know  the effect variation number of blade on power and efficiency in the vortex turbine. This research uses experimental methods to find current, voltage, torque and rpm using a reading instrument. The materials research vortex turbine used 6 blade, 8 blade and 10 blade with flat plate. The result showed the highest efficiency is 29,93 % with produce turbine power is 19,58 W, generated on turbine with variation 10 blade with load 3,315 kg and the capacity of water 10,14 l/s. Followed with an efficiency 24,17% and produce turbine power is 15,81 W, generated on turbine with the variation 8 blade with load 3,315 kg and the capacity of water is 10,14 l/s. The the lowest turbine efficiency 22,32% with produce tuebine power 14,60 W, generated on turbine with the variation 6 blade with load 3,315 kg, the capacity of water is 10,14 l/s.

scholarly journals Regional Coordination and Security of Water–Energy–Food Symbiosis in Northeastern China

2021 ◽  
Vol 13 (3) ◽  
pp. 1326
Author(s):  
Hongfang Li ◽  
Huixiao Wang ◽  
Yaxue Yang ◽  
Ruxin Zhao
Keyword(s):  
External Environment ◽  
Northeastern China ◽  
Decision Makers ◽  
Human Survival ◽  
A Value ◽  
Natural Factors ◽  
Regional Coordination ◽  
Micro Level ◽  
The Stability ◽  
Coordination Degree

The interactions of water, energy, and food, which are essential resources for human survival, livelihoods, production, and development, constitute a water–energy–food (WEF) nexus. Applying symbiosis theory, the economic, social, and natural factors were considered at the same time in the WEF system, and we conducted a micro-level investigation focusing on the stability, coordination, and sustainability of the symbiotic units (water, energy, and food), and external environment of the WEF system in 36 prefecture-level cities across three northeastern provinces of China. Finally, we analyzed the synergistic safety and coupling coordination degree of the WEF system by the combination of stability, coordination, and sustainability, attending to the coordination relationship and influences of the external environment. The results indicated that the synergistic safety of the WEF system in three northeastern provinces need to equally pay attention to the stability, coordination, and sustainability of the WEF system, since their weights were 0.32, 0.36 and 0.32, respectively. During 2010–2016, the synergistic safety indexes of the WEF system ranged between 0.40 and 0.60, which was a state of boundary safety. In the current study, the coupling coordination degree of the WEF system fluctuated around a value of 0.6, maintaining a primary coordination level; while in the future of 2021–2026, it will decline to 0.57–0.60, dropping to a weak coordinated level. The conclusion could provide effective information for decision-makers to take suitable measures for the security development of a WEF system.

scholarly journals Thermally Stimulated Desorption Optical Fiber-Based Interrogation System: An Analysis of Graphene Oxide Layers’ Stability

Photonics ◽  
2021 ◽  
Vol 8 (3) ◽  
pp. 70
Author(s):  
Maria Raposo ◽  
Carlota Xavier ◽  
Catarina Monteiro ◽  
Susana Silva ◽  
Orlando Frazão ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Layer By Layer ◽  
Film Stability ◽  
A Value ◽  
Device Reliability ◽  
Sensor Devices ◽  
Lbl Films ◽  
The Stability

Thin graphene oxide (GO) film layers are being widely used as sensing layers in different types of electrical and optical sensor devices. GO layers are particularly popular because of their tuned interface reflectivity. The stability of GO layers is fundamental for sensor device reliability, particularly in complex aqueous environments such as wastewater. In this work, the stability of GO layers in layer-by-layer (LbL) films of polyethyleneimine (PEI) and GO was investigated. The results led to the following conclusions: PEI/GO films grow linearly with the number of bilayers as long as the adsorption time is kept constant; the adsorption kinetics of a GO layer follow the behavior of the adsorption of polyelectrolytes; and the interaction associated with the growth of these films is of the ionic type since the desorption activation energy has a value of 119 ± 17 kJ/mol. Therefore, it is possible to conclude that PEI/GO films are suitable for application in optical fiber sensor devices; most importantly, an optical fiber-based interrogation setup can easily be adapted to investigate in situ desorption via a thermally stimulated process. In addition, it is possible to draw inferences about film stability in solution in a fast, reliable way when compared with the traditional ones.

scholarly journals Marine Exopolysaccharide Complexed With Scandium Aimed as Theranostic Agents

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 1143 ◽  
Author(s):  
Mattia Mazza ◽  
Cyrille Alliot ◽  
Corinne Sinquin ◽  
Sylvia Colliec-Jouault ◽  
Pascal E. Reiller ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
Light Scattering ◽  
Molar Mass ◽  
Field Flow Fractionation ◽  
High Concentration ◽  
New Class ◽  
Free Ion ◽  
Theranostic Agents ◽  
The Stability ◽  
Drug Reference

(1) Background: Exopolysaccharide (EPS) derivatives, produced by Alteromonas infernus bacterium, showed anti-metastatic properties. They may represent a new class of ligands to be combined with theranostic radionuclides, such as 47Sc/44Sc. The goal of this work was to investigate the feasibility of such coupling. (2) Methods: EPSs, as well as heparin used as a drug reference, were characterized in terms of molar mass and dispersity using Asymmetrical Flow Field-Flow Fractionation coupled to Multi-Angle Light Scattering (AF4-MALS). The intrinsic viscosity of EPSs at different ionic strengths were measured in order to establish the conformation. To determine the stability constants of Sc with EPS and heparin, a Free-ion selective radiotracer extraction (FISRE) method has been used. (3) Results: AF4-MALS showed that radical depolymerization produces monodisperse EPSs, suitable for therapeutic use. EPS conformation exhibited a lower hydrodynamic volume for the highest ionic strengths. The resulting random-coiled conformation could affect the complexation with metal for high concentration. The LogK of Sc-EPS complexes have been determined and showing that they are comparable to the Sc-Hep. (4) Conclusions: EPSs are very promising to be coupled with the theranostic pair of scandium for Nuclear Medicine.

Study on Influence of Silicate Morphology Based on pH Value

2012 ◽  
Vol 454 ◽  
pp. 324-328
Author(s):  
Yan He ◽  
Ya Jing Liu ◽  
Yong Lin Cao ◽  
Li Xia Zhou
Keyword(s):  
Silicic Acid ◽  
Ph Value ◽  
Colorimetric Method ◽  
Absorption Spectrometry ◽  
Degree Of Polymerization ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
The Stability

Infra-red absorption spectrometry, X-ray diffraction observations and characterization tests based on silicon molybdenum colorimetric method were used to investigate the optimal pH value controlling the stability of the silicic acid form. The experiment process was done by using sodium silicate as raw material. The results showed that the solution of silicate influenced the polymerization. The active silicic acid solution with a certain degree of polymerization was obtained by controlling the pH values.

Effect of operating parameters on functional fatigue characteristics of an Ni-Ti shape memory alloy on partial thermomechanical cycling

2022 ◽  
pp. 1045389X2110722
Author(s):  
Swaminathan Ganesan ◽  
Sampath Vedamanickam
Keyword(s):  
Yield Strength ◽  
Applied Stress ◽  
Stress Level ◽  
Crack Nucleation ◽  
Maximum Temperature ◽  
Thermomechanical Cycling ◽  
Permanent Strain ◽  
A Value ◽  
The Stability ◽  
Cycle Temperature

In this study, the influence of upper cycle temperature (maximum temperature in a cycle) and the magnitude of applied stress on the functional properties of an SMA during partial thermomechanical cycling has been studied. A near-equiatomic NiTi SMA was chosen and tested under different upper cycle temperatures (between martensite finish (Mf) and austenite finish (Af) temperatures) and stress level (below and above the yield strength of the martensite). The upper cycle temperature was varied by controlling the magnitude of the current supply. The results show that a raise in the upper cycle temperature causes the permanent strain to increase and also lowers the stability. However, decreasing the stress imposed to a value lower than the yield strength of the martensite improves cyclic stability. The upper cycle temperature was found to influence the crack nucleation, whereas the applied stress level the crack propagation during partial thermomechanical cycling of SMAs. Therefore, decreasing the upper cycle temperature as well as the magnitude of stress applied to lower than the yield stress of martensite have been found to be suitable strategies for increasing the lifespan of SMA-based actuators during partial thermomechanical cycling.

The stability of onoratoite, Sb8O11Cl2, in the supergene environment

2014 ◽  
Vol 78 (7) ◽  
pp. 1671-1675 ◽  
Author(s):  
Adam J. Roper ◽  
Peter Leverett ◽  
Timothy D. Murphy ◽  
Peter A. Williams
Keyword(s):  
Significant Influence ◽  
Secondary Phase ◽  
Low Ph ◽  
Stable Phase ◽  
Supergene Zone ◽  
A Value ◽  
Solubility Studies ◽  
The Stability ◽  
Very High

AbstractSynthesis and solubility studies of onoratoite have been undertaken to determine the role of this rare secondary phase in the immobilization of Sb and the conditions responsible for its formation in the supergene zone. Solubility studies were undertaken at 298.15 K. A value of ΔGfθ (Sb8O11Cl2, s, 298.15 K) = –2576 ±12 kJ mol–1 was derived. Calculations involving sénarmontite, Sb2O3, klebelsbergite, Sb4O4SO4(OH)2 and schafarzikite, FeSb2O4, show that onoratoite is a thermodynamically stable phase only at negligible activities of SO42–(aq) and low activities of Fe2+(aq), at low pH and very high activities of Cl–(aq). This explains why onoratoite is such a rare secondary phase and why it cannot exert any significant influence on the dispersion of Sb in the supergene environment.

The Stability of an Axially–Loaded Continuous Beam

1955 ◽  
Vol 59 (535) ◽  
pp. 506-509
Author(s):  
A. M. Dobson
Keyword(s):  
Axial Load ◽  
Classical Method ◽  
Complete Solution ◽  
Critical Value ◽  
Continuous Beam ◽  
Independent Variables ◽  
A Value ◽  
Method Of Solution ◽  
Axially Loaded ◽  
The Stability

The Classical method of solution of the stability of an axially–loaded continuous beam is by means of the three moments equation, using the Berry Functions, which are functions of the axial load. As the axial load approaches a value equal to the critical value for a pin–jointed beam, the Berry Functions tend to infinity, and the use of the three moments equations —(i. e. treating the end fixing moments as the independent variables)—leads to certain difficulties in the complete solution of the problem.The major difficulty lies in the question of stability. The critical value is determined by the vanishing of the determinant of the coefficients of the fixing moments in the three moments equations. This value could be found by plotting the determinant against end load (c. f. Pippard and Pritchard). However, in a problem involving a large number of bays, the calculation necessary to do this is likely to be considerable, for there may be many branches to the curve.

scholarly journals UJI TOKSISITAS AKUT MINUMAN PROBIOTIK SIRSAK GUNUNG (Annona montana Macf.) DENGAN METODE BSLT (Brine Shrimp Lethality Test)

2020 ◽  
Vol 1 (5) ◽  
pp. 941-948
Author(s):  
Ambar Fidyasari ◽  
Sentot Joko Raharjo ◽  
Melani Setyowati
Keyword(s):  
Acute Toxicity ◽  
Traditional Medicine ◽  
Brine Shrimp ◽  
Experimental Methods ◽  
Test Method ◽  
Toxic Effects ◽  
Brine Shrimp Lethality ◽  
Lc50 Value ◽  
A Value ◽  
Acute Toxic

Soursop fruit (Annona montana Macf.) is one of the plants can be used as as traditional medicine. This plant contains terpenoid and acetogenin which can cause toxicity. The fruit has a flavor that is tasteless so the innovation becomes probiotic drinks. This drink has been proven as an antioxidant, antibacterial, antihyperuricemia and antidiarrheal. The aim of this study was to know about acute toxicity of probiotic drink of soursop juice using brine shrimp lethality test method which will be indicated by LC50 value. This study used experimental methods conducted in the Laboratory of Farmakoknosi. There are several variations in concentration in this study, namely 10000 ppm, 20000 ppm, 30000 ppm, 40000 ppm, 50000 ppm, 60000 ppm, 70000 ppm, 80000 ppm and replication was done 3 times with total number of test animals used was 270. The results showed that probiotic drink of soursop juice can provide acute toxic effects on test animals with LC50 value of 29717,23 ppm. LC50 values ​​indicate that the mountain soursop probiotic drink is not potentially toxic because it has a value of >1000 ppm.

On the stability of viscous flow in a curved channel

1958 ◽  
Vol 244 (1237) ◽  
pp. 186-198 ◽  
Keyword(s):  
Approximate Solution ◽  
Pressure Gradient ◽  
Viscous Flow ◽  
Close Agreement ◽  
Curved Channel ◽  
A Value ◽  
Concentric Cylinders ◽  
The Stability ◽  
Pattern Of Motion

In this paper the stability of viscous flow between two concentric cylinders due to a pressure gradient acting round the cylinders is considered when the spacing between the cylinders is small compared with their radii. Two methods of approximate solution are described, both of which show that instability first sets in when the parameter R √( d / R 1 ) attains a value of about 36 in close agreement with earlier results of Dean (1928). The pattern of motion which then sets in is of the familar cellular type but with a marked asymmetry.

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