scholarly journals Photoswitchable basicity through the use of azoheteroarenes

2016 ◽  
Vol 52 (24) ◽  
pp. 4521-4524 ◽  
Author(s):  
Claire E. Weston ◽  
Robert D. Richardson ◽  
Matthew J. Fuchter
Keyword(s):  
Solution Ph ◽  
Control Solution

We report an azoheteroarene photoswitchable base, where proton stabilisation in Z isomer is facilitated by neighbouring imidazole rings. A 1.3 unit difference in pKa is observed between the E and Z isomers, which leads to the ability to reversibly control solution pH.

scholarly journals Demulsification Behavior of Alkali and Organic Acid in Zinc Extraction

Metals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1833
Author(s):  
Tao Jiang ◽  
Feiyu Meng ◽  
Ke Li ◽  
Qaing Zhong ◽  
Bin Xu ◽  
...  
Keyword(s):  
Organic Acid ◽  
Extraction Process ◽  
Zinc Ion ◽  
Zinc Hydroxide ◽  
Zinc Extraction ◽  
Action Mechanism ◽  
High Concentration ◽  
Extractant Concentration ◽  
Solution Ph ◽  
Control Solution

Alkali agents could be used to enhance the extraction of zinc from solution of high concentration, but excess alkali can sensitively lead to emulsification of the solution. In this paper, the emulsification in the extraction process, demulsification, and extraction with different additives and its action mechanism were studied. The results indicate that the associated addition of alkali and organic acid could eliminate emulsification and improve zinc extraction. The extraction ratio of zinc reached 99.61% under the conditions of 104 mL/L organic acid, 80 g/L alkali, and 40% extractant concentration. Zinc hydroxide formed from hydroxyl and zinc ion at sensitively increased pH was the cause of emulsification during extraction. Associated addition of alkali and organic acid could contribute to the control solution pH in the range of 3.0–4.0, which is lower than that of the formation of zinc hydroxide, and therefore, improve zinc extraction.

Conversion of CO2 into mineral carbonates using a regenerable buffer to control solution pH

Fuel ◽  
2013 ◽  
Vol 111 ◽  
pp. 40-47 ◽  
Author(s):  
Karen M. Steel ◽  
Kimia Alizadehhesari ◽  
Reydick D. Balucan ◽  
Bruno Bašić
Keyword(s):  
Solution Ph ◽  
Control Solution

The Ultrastructure of Monkey Gingival Epithelium

1967 ◽  
Vol 25 ◽  
pp. 16-17
Author(s):  
C.N. Sun
Keyword(s):  
Epithelial Cells ◽  
Macaca Nemestrina ◽  
Stratum Granulosum ◽  
Solution Ph ◽  
Gingival Epithelial Cells ◽  
Stratum Spinosum ◽  
Cell Layers ◽  
Gingival Epithelium ◽  
The Individual ◽  
Different Thickness

The present study demonstrates the ultrastructure of the gingival epithelium of the pig tail monkey (Macaca nemestrina). Specimens were taken from lingual and facial gingival surfaces and fixed in Dalton's chrome osmium solution (pH 7.6) for 1 hr, dehydrated, and then embedded in Epon 812.Tonofibrils are variable in number and structure according to the different region or location of the gingival epithelial cells, the main orientation of which is parallel to the long axis of the cells. The cytoplasm of the basal epithelial cells contains a great number of tonofilaments and numerous mitochondria. The basement membrane is 300 to 400 A thick. In the cells of stratum spinosum, the tonofibrils are densely packed and increased in number (fig. 1 and 3). They seem to take on a somewhat concentric arrangement around the nucleus. The filaments may occur scattered as thin fibrils in the cytoplasm or they may be arranged in bundles of different thickness. The filaments have a diameter about 50 A. In the stratum granulosum, the cells gradually become flatted, the tonofibrils are usually thin, and the individual tonofilaments are clearly distinguishable (fig. 2). The mitochondria and endoplasmic reticulum are seldom seen in these superficial cell layers.

UV Curable Organic-Inorganic Hybrid Materials

2000 ◽  
Vol 628 ◽  
Author(s):  
Guang-Way Jang ◽  
Ren-Jye Wu ◽  
Yuung-Ching Sheen ◽  
Ya-Hui Lin ◽  
Chi-Jung Chang
Keyword(s):  
Hybrid Materials ◽  
Colloidal Silica ◽  
Sol Gel ◽  
Solution Ph ◽  
Uv Curable ◽  
Inorganic Hybrid ◽  
Degradation Temperature ◽  
Sol Gel Process ◽  
The Stability ◽  
Thermal Degradation Temperature

This work successfully prepared an UV curable organic-inorganic hybrid material consisting of organic modified colloidal silica. Applications of UV curable organic-inorganic hybrid materials include abrasion resistant coatings, photo-patternable thin films and waveguides. Colloidal silica containing reactive functional groups were also prepared by reacting organic silane and tetraethyl orthosilicate (TEOS) using sol-gel process. In addition, the efficiency of grafting organic moiety onto silica nanoparticles was investigated by applying TGA and FTIR techniques. Experimental results indicated a strong interdependence between surface modification efficiency and solution pH. Acrylate-SiO2 hybrid formation could result in a shifting of thermal degradation temperature of organic component from about 200°C to near 400°C. In addition, the stability of organic modified colloidal silica in UV curable formula and the physical properties of resulting coatings were discussed. Furthermore, the morphology of organic modified colloidal silica was investigated by performing TEM and SEM studies‥

Irrigation Volume, Application, and Controlled-release Fertilizer II. Effect on Substrate Solution Nutrient Concentration and Water Efficiency in Containerized Plant Production

1998 ◽  
Vol 16 (3) ◽  
pp. 182-188
Author(s):  
Kelly M. Groves ◽  
Stuart L. Warren ◽  
Ted E. Bilderback
Keyword(s):  
Controlled Release ◽  
Irrigation Efficiency ◽  
Plant Production ◽  
Water Efficiency ◽  
Solution Ph ◽  
Entire Study ◽  
Once Daily ◽  
Substrate Solution ◽  
Irrigation Volume ◽  
Controlled Release Fertilizers

Abstract Rooted cuttings of Cotoneaster dammeri Schneid ‘Skogholm’ and seedlings of Rudbeckia fulgida Ait. ‘Goldsturm’ were potted into 3.8 liter (4 qt) containers in a pine bark:sand (8:1 by vol) substrate incorporated with 3.5 g (0.12 oz) N per container provided by one of the following five controlled-release fertilizers (CRFs): Meister 21N–3.5P–11.1K (21–7–14), Osmocote 24N–2.0P–5.6K (24–4–7), Scotts 23N–2.0P–6.4K (23–4–8), Sustane 5N–0.9P–3.3K (5–2–4) or Woodace 21N–3.0P–9.5K (21–6–12). Two hundred ml (0.3 in), 400 ml (0.6 in), 800 ml (1.1 in) or 1200 ml (1.7 in) of water was applied once daily (single) or in two equal applications with a 2 hr interval between applications (cyclic). Substrate solutions were collected from containers of cotoneaster 15, 32, 45, 60, 74, 90, 105, and 119 days after initiation (DAI). Irrigation efficiency [(water applied − water leached) ÷ water applied] was determined on the same days. Cyclic application improved irrigation efficiency at 800 ml (1.1 in) and 1200 ml (1.7 in) ≈ 27% compared to a single application. Irrigation efficiencies averaged over the season were 95%, 84%, 62%, and 48% for cotoneaster and 100%, 90%, 72%, and 51% for rudbeckia at 200 ml (0.3 in), 400 ml (0.6 in), 800 ml (1.1 in) and 1200 ml (1.7 in), respectively. NH4-N and NO3-N and PO4-P concentrations in substrate solution decreased with increasing irrigation volume regardless of CRF. Substrate NH4-N concentration decreased throughout the season with most CRFs below 5 mg/liter by 90 DAI. CRFs mainly affected substrate NH4-N and NO3-N concentrations when irrigated with 200 ml (0.3 in) or 400 ml (0.6 in). Substrate NH4-N, NO3-N, and PO4-P solution concentrations were similar for all CRFs at irrigation volume of 1200 ml (1.7 in). Osmocote, Scotts, and Woodace maintained relatively constant substrate solution levels of PO4-P through 60 DAI. By 90 DAI, substrate PO4-P levels were similar regardless of irrigation volume or CRF. Substrate PO4-P concentrations were never in the recommended range of 5 to 10 mg/liter when irrigated with 800 ml (1.1 in) or 1200 ml (1.7 in) regardless of CRF. Solution pH remained in the recommended range of 5.0 to 6.0 for all irrigation volumes and CRFs throughout the entire study with the exception of Sustane.

Ceramic Screens - An Innovative Downhole Sand Control Solution for Old and Challenging Cased Hole Completions

2014 ◽  
Author(s):  
Asaf Nadeem ◽  
Mario Lopez ◽  
Samuel Joly ◽  
Richard Jackson ◽  
Alfonzo Strazzi ◽  
...  
Keyword(s):  
Control Solution ◽  
Sand Control

Kinetic of oxidation of methyl orange by vanadium(V) under conditions VO2+ and decavanadates coexist: Catalysis by Triton X-100 micellar medium

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Methyl Orange ◽  
Solution Ph ◽  
Vanadium Concentration ◽  
Limiting Behavior ◽  
First Order ◽  
First Order Kinetics ◽  
Ph Range ◽  
Kinetic Pattern ◽  
Triton X ◽  
Kinetics Of

The kinetics of oxidation of methyl orange by vanadium(V) {V(V)} has been investigated in the pH range 2.3-3.79. In this pH range V(V) exists both in the form of decavanadates and VO2+. The kinetic results are distinctly different from the results obtained for the same reaction in highly acidic solution (pH < 1) where V(V) exists only in the form of VO2+. The reaction obeys first order kinetics with respect to methyl orange but the rate has very little dependence on total vanadium concentration. The reaction is accelerated by H+ ion but the dependence of rate on [H+] is less than that corresponding to first order dependence. The equilibrium between decavanadates and VO2+ explains the different kinetic pattern observed in this pH range. The reaction is markedly accelerated by Triton X-100 micelles. The rate-[surfactant] profile shows a limiting behavior indicative of a unimolecular pathway in the micellar pseudophase.

Effect of pH and NH4NO3 as a Spray Additive on Penetration of NAA Through Isolated Tomato Fruit Cuticle

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 550a-550 ◽  
Author(s):  
Royal G. Fader ◽  
Martin J. Bukovac
Keyword(s):  
Direct Measurement ◽  
Sodium Citrate ◽  
Tomato Fruit ◽  
Initial Slope ◽  
Control Effect ◽  
Solution Ph ◽  
Ph Change ◽  
Effect Of Ph ◽  
Spray Droplets ◽  
Partition Behavior

We have reported that NH4NO3 (AN, 8 mM, pH 4.2), applied as simulated spray droplets, enhanced penetration of 14C-NAA through isolated leaf and fruit cuticles. One explanation for this response is that AN depresses NAA (pKa= 4.2) dissociation, increasing the nondissociated moiety, which penetrates more readily than the anion (NAA'). Direct measurement of AN (concn. 0-800 mM) effect on NAA (215 μM) dissociation as indexed by change in solution pH revealed no significant effect, with a pH change from 4.19 to 4.05. This change is not sufficient to account for the observed enhancement. When 14C-NAA, buffered (20 mM sodium citrate) at pH 3.2, 4.2, 5.2, 6.2, was partitioned against chloroform, there was a marked increase in NAA partitioning into chloroform as pH was decreased. AN (8 mM) did not alter this partition behavior, also indicating no effect on NAA dissociation. However, in cuticle penetration studies, using a finite dose system with 14C-NAA buffered at pH 3.2, 4.2, 5.2, 6.2, and in the presence and absence of 8 mM AN, there was no marked or consistent pH or AN (-70 to + 232 % of no AN control) effect on penetration as indexed by initial slope (4-12 h) or penetration after 120 h. The possible effects of AN and buffer on penetration of 14C-NAA from the droplet deposit will be discussed.

Detection of Hepatitis a Virus in Drinking Water by Enzyme -Immunoassay Using Ultracentrifugation for Virus Concentration

1985 ◽  
Vol 17 (10) ◽  
pp. 39-41 ◽  
Author(s):  
A. Schnattinger
Keyword(s):  
Membrane Filtration ◽  
Hepatitis A ◽  
Hepatitis A Virus ◽  
Solid Phase ◽  
Phosphate Buffer Solution ◽  
Enzyme Linked Immunosorbent Assay ◽  
Virus Concentration ◽  
Buffer Solution ◽  
Solution Ph ◽  
Two Stage

Ten litres of tapwater were seeded with 200 µl (8×108 HAV particles) of a commercial (Organon Teknika) suspension of hepatitis A virus. Following WALTER and RÜDIGER (1981), the contaminated tapwater was treated with a two-stage technique for concentration of viruses from solutions with low virus titers. The two-stage technique consists of aluminium hydroxideflocculation (200 mg/l Al2(SO4)3. 18 H2O, pH 5,4-5,6) as first stage, the second stage of a lysis of aluminium hydroxidegel with citric acid/sodium citrate-buffer (pH 4,7; 1 ml/l sample), separation of viruses from the lysate by ultracentrifugation and suspension in 1 ml phosphate buffer solution (pH 7,2). A commercial solid phase enzyme-linked immunosorbent assay (ELISA) was used for the detection of HAV. HAV was detecterl in the 10.000:1 concentrates, but not in the seeded 101 samples. Approximately 4×108 of the inoculated 8×108 HAV particles were found in the 1 ml concentrates. The efficiency of detection is about 50%, the virus concentration 5000-fold. Although the percentage loss of HAV in comparison with concentration by means of membrane filtration is similar, the ultracentrifugation method yields a larger sample/concentrate ratio, so that smaller amounts of HAV can be detected more efficiently because of the smaller end-volume.

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