scholarly journals THE MINOR INFLUENCE OF CALCIUM DOPED PHOSPHATE TUNGSTEN BRONZE ON THE BRIGGS-RAUSCHER REACTION DYNAMICS

2018 ◽  
Vol 9 (2) ◽  
Author(s):  
Jelena P. Maksimović ◽  
Tijana V. Maksimović ◽  
Zoran P. Nedić ◽  
Maja C. Pagnacco
Keyword(s):  
Thermal Treatment ◽  
Tungsten Bronze ◽  
Reaction Dynamics ◽  
Added Mass ◽  
Oscillatory Reactions ◽  
Minor Influence ◽  
The Subject ◽  
Calcium Doped ◽  
Future Work ◽  
Oscillatory Period

The Briggs-Rauscher (BR) oscillatory reaction is the oxidation of malonic acid in the presence of hydrogen peroxide and iodate in the acidic environment, which is catalyzed by ions of manganese. This reaction is very sensitive to the presence of additives. In this paper, the BR reaction has been used to investigate the phosphate tungsten bronze as well as calcium doped tungsten bronze, obtained by thermal treatment. The addition (0.01-0.08 g) of phosphate tungsten bronze and calcium doped phosphate tungsten bronze has a different effect on the dynamics of the Briggs-Rauscher reaction. In the case of the addition of phosphate tungsten bronze in the Briggs-Rauscher reaction, the linear dependence of the length of the oscillatory period on the mass of the added bronze was obtained, while in the case of addition of calcium doped phosphate tungsten bronze, the oscillatory period does not significantly change with an increase of added mass. The mechanism of calcium doped and undoped phosphate tungsten bronze action in BR reaction is probably adsorptive, and it will be the subject of future work. Keywords: oscillatory reactions, Briggs-Rauscher reaction, phosphate tungsten bronze, calcium doped phosphate tungsten bronze, thermal treatment.

scholarly journals Sensorimotor impairment from a new analog of spaceflight-altered neurovestibular cues

2020 ◽  
Vol 123 (1) ◽  
pp. 209-223
Author(s):  
Jordan B. Dixon ◽  
Torin K. Clark
Keyword(s):  
Head Tilt ◽  
Semicircular Canals ◽  
Control Groups ◽  
Head Restraint ◽  
The Subject ◽  
Sensorimotor Impairment ◽  
Self Motion ◽  
Future Work ◽  
Extended Exposure ◽  
Sensorimotor Performance

Exposure to microgravity during spaceflight causes central reinterpretations of orientation sensory cues in astronauts, leading to sensorimotor impairment upon return to Earth. Currently there is no ground-based analog for the neurovestibular system relevant to spaceflight. We propose such an analog, which we term the “wheelchair head-immobilization paradigm” (WHIP). Subjects lie on their side on a bed fixed to a modified electric wheelchair, with their head restrained by a custom facemask. WHIP prevents any head tilt relative to gravity, which normally produces coupled stimulation to the otoliths and semicircular canals, but does not occur in microgravity. Decoupled stimulation is produced through translation and rotation on the wheelchair by the subject using a joystick. Following 12 h of WHIP exposure, subjects systematically felt illusory sensations of self-motion when making head tilts and had significant decrements in balance and locomotion function using tasks similar to those assessed in astronauts postspaceflight. These effects were not observed in our control groups without head restraint, suggesting the altered neurovestibular stimulation patterns experienced in WHIP lead to relevant central reinterpretations. We conclude by discussing the findings in light of postspaceflight sensorimotor impairment, WHIP’s uses beyond a spaceflight analog, limitations, and future work. NEW & NOTEWORTHY We propose, implement, and demonstrate the feasibility of a new analog for spaceflight-altered neurovestibular stimulation. Following extended exposure to the analog, we found subjects reported illusory self-motion perception. Furthermore, they demonstrated decrements in balance and locomotion, using tasks similar to those used to assess astronaut sensorimotor performance postspaceflight.

Structures and phase transitions in barium sodium niobate tungsten bronze (BNN)

2021 ◽  
Vol 77 (6) ◽  
Author(s):  
Thomas A. Whittle ◽  
Christopher J. Howard ◽  
Siegbert Schmid
Keyword(s):  
Phase Transitions ◽  
Room Temperature ◽  
Tungsten Bronze ◽  
Standard Setting ◽  
Experimental Results ◽  
Temperature Structure ◽  
Sodium Niobate ◽  
Tetragonal Tungsten Bronze ◽  
Space Group ◽  
The Subject

The room-temperature structure of the filled tetragonal tungsten bronze, Ba2NaNb5O15 (BNN), has been the subject of a number of studies, and these studies have given an almost corresponding number of different results. From a group theoretical examination of the different possibilities and a review of the published experimental results we conclude that the room-temperature structure is that proposed by Labbé et al. [J. Phys. Condens. Matter (1989), 2, 25–43] in the space group Bbm2 (Ama2 in standard setting) on a 2\sqrt{2}a × \sqrt{2}a × 2c cell. Upon heating, the structure remains ferroelectric but becomes tetragonal (space group P4bm) at 550 K, then paraelectric (space group P4/mbm) at and above 860 K.

scholarly journals A possible connection between phosphate tungsten bronzes properties and Briggs-Rauscher oscillatory reaction response

2021 ◽  
Vol 53 (2) ◽  
pp. 223-235
Author(s):  
Tijana Maksimovic ◽  
Jelena Maksimovic ◽  
Pavle Tancic ◽  
Nebojsa Potkonjak ◽  
Zoran Nedic ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Calcium Phosphate ◽  
Active Site ◽  
Unit Cell Volume ◽  
Tungsten Bronze ◽  
Reaction Dynamics ◽  
Unit Cell ◽  
Oscillatory Reaction ◽  
Innovative Method ◽  
Cell Volumes

The calcium phosphate tungsten bronze (Ca-PWB) has been synthesized and characterized (TGA, DSC, XRPD, FTIR, SEM). The influence of solid insoluble materials Ca- PWB, as well as lithium doped (Li-PWB) and cation free phosphate tungsten (PWB) bronzes on the oscillatory Briggs-Rauscher (BR) reaction dynamics, is compared. The results show that doping with Li and Ca reduces sensitivity of the BR reaction towards bronzes addition. These findings suggest the usage of the BR reaction as an innovative method for testing of different properties of bronze material. The behavior of PWB in the BR reaction is significantly changed with divalent cation (Ca2+) doping. The reasons for the different bronzes behavior were found in their calculated unit cell volumes. Namely, the compressed Ca-PWB unit cell volume indicates the difficult availability of the active site for heterogeneous catalysis. Hence, the linear correlation (slope) of the BR oscillogram?s length (?osc) vs. mass of bronze in BR reaction might be considered as a new parameter for the evaluation of the bronzes catalytic activity.

A Program for an Investigation of the Rudder-Torque Problem

1965 ◽  
Vol 2 (03) ◽  
pp. 282-298
Author(s):  
Karl E. Schoenherr
Keyword(s):  
Research Program ◽  
Current Knowledge ◽  
Lateral Force ◽  
The Status ◽  
The Subject ◽  
Future Work ◽  
Marine Engineers

Panel H-10 (Controllability) of The Society of Naval Architects and Marine Engineers Technical and Research Program was requested to undertake an investigation of existing uncertainties in pre-calculating rudder torque and lateral force. In order to become quickly familiar with the subject and prospects therein, the Panel commissioned the author of this paper to survey the status of current knowledge of the subject and prepare a report of the findings. In particular, this report was to identify the most promising approaches for future work leading to an ultimate solution of the problem and to include technical descriptions of proposed programs for an exhaustive investigation, all of which are discussed in this paper.

scholarly journals In-Fiber Structured Particles and Filament Arrays from the Perspective of Fluid Instabilities

2020 ◽  
Vol 2 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Bingrui Xu ◽  
Shuqi Ma ◽  
Yuanzhuo Xiang ◽  
Jing Zhang ◽  
Meifang Zhu ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Large Scale ◽  
The Other ◽  
Materials Selection ◽  
Capillary Instability ◽  
Fluid Instabilities ◽  
Fiber Devices ◽  
Filamentation Instability ◽  
Future Work ◽  
Thermal Drawing

AbstractIn-fiber structured particles and filament array have been recently emerging, providing unique advantages of feasible fabrication, diverse structures and sophisticated functionalities. This review will focus on the progress of this topic mainly from the perspective of fluid instabilities. By suppressing the capillary instability, the uniform layered structures down to nanometers are attained with the suitable materials selection. On the other hand, by utilizing capillary instability via post-drawing thermal treatment, the unprecedent structured particles can be designed with multimaterials for multifunctional fiber devices. Moreover, an interesting filamentation instability of a stretching viscous sheet has been identified during thermal drawing, resulting in an array of filaments. This review may inspire more future work to produce versatile devices for fiber electronics, either at a single fiber level or in large-scale fabrics and textiles, simply by manipulating and controlling fluid instabilities.

Lax and Dense-Eared Wheats

1914 ◽  
Vol 6 (3) ◽  
pp. 371-386
Author(s):  
W. H. Parker
Keyword(s):  
Quantitative Character ◽  
General Importance ◽  
External Conditions ◽  
The Subject ◽  
Future Work

The present paper is written with no pretence at finality, and consequently some excuse is due for its publication at the present time. The author was induced to write it since the results so far obtained by him do not seem to agree, in all points, with the work previously done on the subject, and tend to show that there is much scope for future work both on this matter and also on a matter of much greater general importance, namely, on the influence of external conditions on a quantitative character.

Leach Resistant Cesium and Strontium-bearing Wasteforms from Hexagonal Tungsten Bronze-Polyacrylonitrile Composite Adsorbers

2006 ◽  
Vol 932 ◽  
Author(s):  
Christopher S. Griffith ◽  
Vittorio Luca ◽  
Ferdinand Sebesta ◽  
Patrick Yee ◽  
Elizabeth Drabarek
Keyword(s):  
Composite Material ◽  
Thermal Treatment ◽  
Strontium Titanate ◽  
Tungsten Bronze ◽  
Composite Adsorbent ◽  
Spherical Morphology ◽  
Sodium Cations ◽  
Full Complement ◽  
High Concentrations ◽  
Better Than

ABSTRACTImmobilization of adsorbed Cs+ and Sr2+ on a molybdenum-doped, hexagonal tungsten bronze (HTB)-polyacrylonitrile (PAN) composite adsorbent can be achieved by heating in air at temperatures in the range 600 - 1200 °C. Thermal treatment of the parent composite material at 800 – 1000 °C undergoes a ca. 60% reduction in volume and retains its spherical morphology. For materials prepared at 800 – 1200 °C the full complement of Cs+ and the majority of Sr2+ partition into HTB phases (A∼0.16-0.3MO3; A = Cs, Sr, Na; M = Mo,W), along with sodium cations. The presence of high concentrations of Na+ relative to either Cs+ or Sr2+ does not appear to interfere with the formation of the HTB phase. The fraction (f) of Cs+ and Sr2+ leached from the tungstate phase assemblages is better or comparable with cesium hollandite (Cs0.8Ba0.4Ti8O18; f = ca. 8 × 10−5; rate = <1.2 × 10−4 g m−2d−1) and strontium titanate (SrTiO3; f = 3.1 × 10−3; rate = 2.63 × 10−4 g m−2day−1), respectively, using a modified PCT test. Furthermore, where aggressive leaching conditions are employed (0.1M HNO3; 150 °C; 4 days), the tungstate phase assemblages display leach resistance orders of magnitude better than the reference phases (Cs+ - f = ca. 5 × 10−3; rate = ca. 1.4 × 10−3 g m−2day−1; Sr2+ - f = ca. 8 × 10−2; rate = ca. 2.5 × 10−2 g m−2day−1).

scholarly journals Mid-Cretaceous acanthomorph fishes with the description of a new species from the Turonian of Lac des Bois, Northwest Territories, Canada

2016 ◽  
Vol 1 ◽  
pp. 101 ◽  
Author(s):  
Alison M Murray
Keyword(s):  
Northwest Territories ◽  
Neural Spine ◽  
Single Specimen ◽  
Western Interior Seaway ◽  
Incertae Sedis ◽  
Comprehensive Survey ◽  
The Subject ◽  
Future Work ◽  
A New Species ◽  
Cretaceous Deposits

A single specimen of a new acanthomorph fish is described from a Turonian locality sampling the northern part of the Cretaceous Western Interior Seaway. This brings to three the number of acanthomorphs from Lac des Bois, Northwest Territories, Canada. The previously named acanthomorph, Boreiohydrias dayi (Boriohydriidae), was placed in the Polymixiiformes. The second, represented by a poorly preserved fish, was left unnamed and incertae sedis in Acanthomorpha. The new one described here, Cumbaaichthys oxyrhynchus gen. et sp. nov. cannot be easily placed in any previously described families. This fish is placed in the Polymixiiformes based on the caudal skeleton having 18 principal rays (16 branched), and having a full neural spine on the second preural centrum. Polymixiiform relationships are not well established but they are the subject of several current studies; therefore, the new acanthomorph is placed incertae sedis within this order but with the understanding that this placement may be refined with future work. Previous studies have suggested that acanthomorphs may have flourished with warming climates of the Cenomanian–Turonian. A comprehensive survey of named acanthomorphs from mid-Cretaceous deposits shows there are more species known from the Cenomanian rather than the Turonian, although this may be biased by the age of known fossiliferous deposits.

Application of Satellite Based Augmentation Systems to Altitude Separation

1999 ◽  
Vol 52 (3) ◽  
pp. 313-317
Author(s):  
Jean Pierre Magny
Keyword(s):  
Design Principles ◽  
Preliminary Design ◽  
Vertical Separation ◽  
Safety Issues ◽  
The Subject ◽  
Future Work

This paper presents the application of GNSS1, or more precisely of Satellite Based Augmentation Systems (SBAS), to vertical separation for en-route, approach and landing operations. Potential improvements in terms of operational benefit and of safety are described for two main applications. First, vertical separation between en-route aircraft, which requires a system available across wide areas. SBAS (EGNOS, WAAS, and MSAS) are very well suited for this purpose before GNSS2 becomes available. And secondly, vertical separation from the ground during approach and landing, for which preliminary design principles of instrument approach procedures and safety issues are presented. Approach and landing phases are the subject of discussions within ICAO GNSS-P. En-route phases have been listed as GNSS-P future work and by RTCA for development of new equipments.

II. Bishop Wren and the Suppression of the Norwich Lecturers

1968 ◽  
Vol 11 (2) ◽  
pp. 237-254 ◽  
Author(s):  
Peter King
Keyword(s):  
Rapid Growth ◽  
Religious Organizations ◽  
The Subject ◽  
Future Work

One of the most serious problems facing Archbishop Laud was the rapid growth of the Lecturer Movement during the 1620s and 1630s. The increasing numbers of graduates available, and the increasing amount of money donated to support them meant that the weekly lectures had become one of the chief “religious … organizations of the opposition”, and were beginning to “undermine the hierarchical principle”. The gravity of the situation was marked by the increasingly stringent regulation of the lecturers. They had originally been allowed to preach with very little control, but from the Canons of 1604 onwards they were made the subject of several new regulations. These culminated in the Directions of March 16296 which, although issued by Archbishop Abbot, were based upon suggestions made by Laud to the king. Soon afterwards the lecturers in London Diocese were curtailed as a prelude to Laud's future work as archbishop. The Directions were reissued in January 1634, and a policy of deliberately reducing certain kinds of lecturer was initiated in several dioceses, pursued in the Metropolitical Visitation, and completed by Laud's supporters amongst the bishops.

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