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pH
pH
pH The negative logarithm of the hydrogen
ion concentration in a solution, pH = log
10 1/[H
+]. If the hydrogen ion concentration of a solution increases, as happens with increasing acidity, the pH will decrease, and vice versa. The pH is measured on a scale of 0–14; a neutral medium (such as pure water) has a pH of 7, numbers above 7 indicate relative alkalinity, numbers below 7 indicate relative acidity. Most pH values in natural systems lie in the range 4–9. Human blood has a pH of 7.4, ocean water 8.1–8.3, water in saline environments may have a pH around 9.0 or higher, while for water in acidic soils it may be as low as 4.0 or less.
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Testing pH of Concrete
Magazine article from: Concrete International; 4/1/2007; ; 700+ words
; ...concrete typically begins its life at a highly basic pH of about 13, the pH values at exposed surfaces soon fall as reactions occur...carbonation. Over time, fronts of carbonated concrete, with pH values of about 8.5, advance below exposed surfaces...
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Effects of pH and Ph fluctuations on microbial fermentation and nutrient flow from a dual-flow continuous culture system
Magazine article from: Journal of Dairy Science; 3/1/2002; ; 700+ words
; ...used in two consecutive periods to study the effects of pH and pH fluctuations on microbial fermentation and nutrient flow...17.6% acid detergent fiber). Treatments were high pH (constant at 6.4); low pH (constant at 5.7); cycles...
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Neutralizing pH.(ENVIRONMENTAL HEALTH & SAFETY CLINIC)
Magazine article from: Products Finishing; 3/1/2008; ; 700+ words
; ...wastewater mixes with the other waste streams for pH adjustment and metals removal. Our cyanide...bleach and caustic feed controlled by ORP and pH controllers, respectively. Periodically, we have very high-pH wastewaters that cause the pH within the...
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pH-dependent conformational change of gastric mucin leads to sol-gel transition
Magazine article from: Biophysical Journal; 3/1/1999; ; 700+ words
; ...ability of gastric mucin to form a gel at low pH, which is crucial to the barrier function...measured diffusion coefficient with decreasing pH, suggesting an apparent increase in size...depolarized scattering ratio with decreasing pH, these results suggest that gastric mucin...
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Diurnal Variation in Ruminal pH on the Digestibility of Highly Digestible Perennial Ryegrass During Continuous Culture Fermentation
Magazine article from: Journal of Dairy Science; 6/1/2004; ; 700+ words
; ...pastures exhibit pronounced diurnal variation in ruminal pH, with pH being below values considered optimal for digestion. Using...system, the hypothesis that minimizing diurnal variation in pH would improve digestion of pasture when pH was low, but...
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The Ph.D. degree: what it is and where it takes you.
Magazine article from: Occupational Outlook Quarterly; 6/22/1986; ; 700+ words
; The Ph.D. Degree: What It Is and Where It Takes...urging her to get a Doctor of Philosophy (Ph.D.) degree. Although the thought of continuing...she has many questions about what obtaining a Ph.D. entails. How does it differ from other...
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Maximize pH sensor performance.(ENVIRONMENTAL HEALTH & SAFETY CLINIC)
Magazine article from: Products Finishing; 1/1/2008; ; 700+ words
; ...the city. Over the last several months, we have had difficulty with calibration of our pH sensors, particularly the pH adjustment sensor that controls pH in the range of 9.19.5 for precipitation. Every week we remove both sensors, rinse...
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Extracellular pH regulates vascular endothelial growth factor activity.
Newspaper article from: Angiogenesis Weekly; 7/18/2003; 700+ words
; ...amp; NewsRx.net) -- Extracellular pH regulates vascular endothelial growth factor...to other extracellular parameters such as pH. Thus, the present study investigates the consequences of acidic pH on VEGF binding and activity in endothelial...
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Vaginal pH-lowering effect of locally applied vitamin C in subjects with high vaginal pH
Magazine article from: Gynecological Endocrinology; 4/1/2006; ; 700+ words
; ...controlled study was the assessment of the pH-lowering effect of three different formulations...vitamin C. Overall, 39 women with vaginal pH ≥5, without evidence of vaginal...The primary parameter assessed was vaginal pH, performed by the physician at the baseline...
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Ruminal pH-DG link explored.(Bottom Line)
Magazine article from: Feedstuffs; 7/21/2008; ; 700+ words
; ...he discussed the important role ruminal pH may play in DG utilization, and, perhaps...presentations that discussed the ruminal pH-DG relationship. Some of the conclusions relative to ruminal pH from these poster sessions were as follows...
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pH
Book article from: World of Microbiology and Immunology
pH The term pH refers to the concentration of hydrogen ions (H+) in a solution. An acidic...whereas a basic environment is relatively depleted of hydrogen ions. The pH of biological systems is an important factor that determines which microorganism...
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Mutants: Enhanced Tolerance or Sensitivity to Temperature and pH Ranges
Book article from: World of Microbiology and Immunology
...tolerance or sensitivity to temperature and pH ranges Microorganisms have optimal environmental...while most organisms grow well in neutral pH conditions, some organisms grow well under...Fungi are able to sense extracellular pH and alter the expression of genes. Some...
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pH scale
Book article from: A Dictionary of Biology
pH scale A logarithmic scale for expressing the...a solution. To a first approximation, the pH of a solution can be defined as –...7 mol dm –3 , so the pH is 7. A pH below 7 indicates an acid solution...
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PH
Book article from: Fly Fishing: The Lifetime Sport
PH The pH scale is a measure of the acid and base concentration of a solution. A pH of 7 is neutral; 0-7 is the acid range and 7-14 is the base or alkalinity range. The presence of dissolved carbonates, bicarbonates, and hydroxides in water...
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ph
Book article from: A Dictionary of the Internet
ph Abbreviation for phonebook. phs are found in many educational establishment sites containing directories of staff. Such listings are similar to those associated with FINGER and have often been the target of ADDRESS HARVESTERS in search of email addresses that can be SPAM med.
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