The effect of differential instructions on anxiety and learning

Bibliographic Data

ID4806285
AuthorsSeymour B Sarason, Chel‐Ken Chiam (0000-0001-9156-7368, corresponding author), George Mandler, Peyton G Craighill
Year1952
Volume47
Issue2, Suppl
Pages561-565
Publication date1952-04-01
Peer ReviewedYes
Open AccessNo
TypeARTICLE
VenueJournal of Abnormal & Social Psychology (JOURNAL)
Journal identifiersISSN: 0096-851X
PublisherAmerican Psychological Association (APA) (PUBLISHER)
DOI10.1037/h0058554
OpenAlexW14938006
LanguageEN
Citations received19

In this study, polyvinylidene fluoride (PVDF) flat membrane was fabricated to remove the total ammonia from saline water by direct contact membrane distillation (DCMD) at 50°C The effects of initial NH3 concentration from 0.03 to 0.47M, temperature from 30 to 50°C and salinity from 0 to 35ppt on ammonia-ammonium equilibrium, however, were initially investigated by using Law of Ostwald's Dissociation. The PVDF membranes were then fabricated from dimethylacetamide (DMAc) solvent and sodium chloride (NaCl) from concentration 0 to 6M as the dope additive by phase inversion in a distilled water coagulation bath. The membranes were dried and then characterized as well as applied in DCMD. Cocurrent configuration of DCMD was applied to study the mass transfer, water vapor flux and ammonia removal efficiency of the membranes. The experimental results showed the NH3 concentration in the water increases as the temperature and pH increased. The NH3 concentration, however, is relatively higher in pure water than that in saline water from temperature 30 to 50°C The drying process has improved the hydrophobicity of the membranes. The contact angles of the membranes with NaCI addition, however, were reduced from 165 to 156°. Graphically, the average ranges of membrane thickness and pore size were 71.5 to 111.5Âμm and 43.5 to 118.5nm, respectively. The addition of NaCI has reduced the average pore size from 81 to 66nm. Statistically, average ranges of the membrane thickness and pore size were 83 to 99Âμm and 82 to 103.3nm, respectively. The average membrane porosity with additives were increased from 78% to >82% compared to that of without the additives. The mass transfer coefficient of ammonia and the water vapor flux increase as the membrane porosity increased. The membrane porosity of 84% and effective membrane area of 56.40cm2 achieved the highest ammonia removal efficiency about 24% within 2 hours of DCMD

Ammonia · Ammonium chloride · Analytical Chemistry (journal) · Chromatography · Contact angle · Desalination · Distilled water · Membrane · Membrane distillation · Phase inversion · Polyvinylidene fluoride · Saline water · Salinity · Chemical Engineering · Chemistry · Membrane Separation Technologies · Organic Chemistry

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