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Isothermal ice crystallization kinetics in the gas-diffusion layer of a proton-exchange-membrane fuel cell.

Dursch, T J; Ciontea, M A; Radke, C J; Weber, A Z.

Langmuir ; 28(2): 1222-34, 2012 Jan 17.

Article in English | MEDLINE | ID: mdl-22133053

ABSTRACT

Nucleation and growth of ice in the fibrous gas-diffusion layer (GDL) of a proton-exchange membrane fuel cell (PEMFC) are investigated using isothermal differential scanning calorimetry (DSC). Isothermal crystallization rates and pseudo-steady-state nucleation rates are obtained as a function of subcooling from heat-flow and induction-time measurements. Kinetics of ice nucleation and growth are studied at two polytetrafluoroethylene (PTFE) loadings (0 and 10 wt %) in a commercial GDL for temperatures between 240 and 273 K. A nonlinear ice-crystallization rate expression is developed using Johnson-Mehl-Avrami-Kolmogorov (JMAK) theory, in which the heat-transfer-limited growth rate is determined from the moving-boundary Stefan problem. Induction times follow a Poisson distribution and increase upon addition of PTFE, indicating that nucleation occurs more slowly on a hydrophobic fiber than on a hydrophilic fiber. The determined nucleation rates and induction times follow expected trends from classical nucleation theory. A validated rate expression is now available for predicting ice-crystallization kinetics in GDLs.

[Importance of the study of risk factors in the chronic evolution of acute viral hepatitis]. / Studiul importantei factorilor de risc în cronicizarea hepatitelor acute virotice.

Buligescu, L; Ciontea, M; Boca, M.

Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Med Interna ; 35(1): 57-66, 1983.

Article in Romanian | MEDLINE | ID: mdl-6137047

Subject(s)

Hepatitis, Chronic , Adolescent , Adult , Aged , Child , Child, Preschool , Chronic Disease , Fatty Liver/etiology , Female , Hepatitis A/complications , Hepatitis B/complications , Humans , Liver Cirrhosis/etiology , Male , Middle Aged

[Evolutive characteristics of hepatic cirrhosis as a function of its etiology]. / Particularitati evolutive alc cirozei hepatice în functie de etiologie.

Buligescu, L; Ciontea, M; Boca, M.

Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Med Interna ; 33(4): 383-8, 1981.

Article in Romanian | MEDLINE | ID: mdl-6120555

Subject(s)

Liver Cirrhosis/etiology , Adult , Aged , Carcinoma, Hepatocellular/etiology , Chemical and Drug Induced Liver Injury/complications , Esophageal and Gastric Varices/etiology , Female , Gastrointestinal Hemorrhage/etiology , Hepatic Encephalopathy/etiology , Hepatitis, Viral, Human/complications , Humans , Liver Cirrhosis/chemically induced , Liver Cirrhosis/complications , Liver Cirrhosis, Alcoholic/complications , Liver Neoplasms , Male , Middle Aged

[Atypical clinical forms of gastroduodenal ulcer]. / Forme clinice antipice de ulcer gastroduodenal.

Buligescu, L; Ciontea, M.

Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Med Interna ; 30(5): 411-21, 1978.

Article in Romanian | MEDLINE | ID: mdl-32594

Subject(s)

Peptic Ulcer/diagnosis , Adult , Age Factors , Blood Group Antigens , Cardiovascular Diseases/complications , Female , Gastrointestinal Diseases/complications , Humans , Liver Diseases/etiology , Male , Middle Aged , Nervous System Diseases/complications , Occupations , Peptic Ulcer/complications , Peptic Ulcer/etiology , Rheumatic Diseases/complications , Sex Factors

[Immunosuppressive therapy in active chronic hepatopathies]. / Terapia imunodepresoare in hepatopatiile cronice active.

Buligescu, L; Ciontea, M.

Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Med Interna ; 30(3): 241-56, 1978.

Article in Romanian | MEDLINE | ID: mdl-30138

Subject(s)

Azathioprine/therapeutic use , Immunosuppressive Agents/therapeutic use , Liver Diseases/drug therapy , Prednisolone/therapeutic use , Adult , Chronic Disease , Drug Therapy, Combination , Female , Hepatitis A/drug therapy , Hepatitis B/drug therapy , Humans , Liver Cirrhosis/drug therapy , Male , Middle Aged

[Value of the secretin-pancreozymin (cerulein) test in the diagnosis of chronic pancreatitis]. / Valoarea testului la secretina-pancreozymina (ceruleina) in diagnosticul pancreatitei cronice.

Buligescu, L; Negrea, F; Tomescu, A; Ciontea, M.

Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Med Interna ; 30(1): 73-84, 1978.

Article in Romanian | MEDLINE | ID: mdl-25480

Subject(s)

Cholecystokinin , Pancreatic Juice/metabolism , Pancreatitis/diagnosis , Secretin , Chronic Disease , Humans , Pancreatic Juice/analysis , Pancreatitis/physiopathology , Secretory Rate

[Etiology and diagnosis of chronic pancreatitis]. / Contributii la etiologia si diagnosticul pancreatitei cronice.

Buligescu, L; Ciontea, M.

Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Med Interna ; 29(6): 537-41, 1977.

Article in Romanian | MEDLINE | ID: mdl-24250

Subject(s)

Pancreatitis , Chronic Disease , Humans , Pancreatitis/diagnosis , Pancreatitis/etiology

[Significance of anti-albumin antibodies in chronic liver disease]. / Semnificatia anticorpilor antialbumina în boala cronica de ficat.

Buligescu, L; Lenkei, R; Ciontea, M; Dan, E M.

Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Med Interna ; 29(4): 363-70, 1977.

Article in Romanian | MEDLINE | ID: mdl-22919

Subject(s)

Autoantibodies , Liver Diseases/immunology , Serum Albumin/immunology , Autoantibodies/analysis , Chronic Disease , Hepatitis/immunology , Hepatitis A/immunology , Hepatitis B/immunology , Humans , Liver Cirrhosis/immunology

[Arrhythmias and their treatment in chronic cor pulmonale]. / Consideratii privind tulburarile de ritm si tratamentul lor în cordul pulmonar cronic.

Nicolaescu, V; Carp, C; Câmpeanu, A; Nuta, M; Ciontea, M.

Rev Med Interna Neurol Psihiatr Neurochir Dermatovenerol Med Interna ; 29(3): 225-30, 1977.

Article in Romanian | MEDLINE | ID: mdl-18776

Subject(s)

Arrhythmias, Cardiac/etiology , Pulmonary Heart Disease/complications , Aged , Arrhythmias, Cardiac/therapy , Chronic Disease , Digitalis Glycosides/administration & dosage , Digitalis Glycosides/poisoning , Diuretics/administration & dosage , Female , Humans , Male , Middle Aged , Oxygen Inhalation Therapy , Pulmonary Embolism/complications , Respiratory Tract Infections/complications , Water-Electrolyte Imbalance/complications

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