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Sample records for naoh previa oxidacion

  1. Symbiodinium isolation by NaOH treatment.

    Science.gov (United States)

    Zamoum, Thamilla; Furla, Paola

    2012-11-15

    The presence of photosynthetic zooxanthellae (dinoflagellates) in the tissue of many cnidarians is the main reason for their ecological success (i.e. coral reefs). It could also be the main cause of their demise, as the worldwide bleaching of reef-building coral is nothing less than the breakdown of this symbiotic association. The stability of this relationship is the principal marker for the biomonitoring of cnidarian health. We have therefore developed a new, simple method to isolate zooxanthellae in a few steps using NaOH solution. The protocol was validated in three symbiotic cnidarian species: a sea anemone, a gorgonian and a coral. Our method allows the isolation of intact and viable zooxanthellae with better yields than classic methods, especially for species with a calcareous skeleton. Moreover, the isolated zooxanthellae were free of host nucleic contaminants, facilitating subsequent specific molecular analyses.

  2. Consulta previa y democracia en el Ecuador

    Directory of Open Access Journals (Sweden)

    Floresmilo Simbaña

    2012-11-01

    Full Text Available Este artículo aborda un tema clave respecto de la efectiva participación política de los pueblos indígenas: el derecho a la Consulta Previa. En el Ecuador, la Constitución establece que el Estado tiene que consultar a las comunidades antes de poner en marcha iniciativas de desarrollo que podrían afectarlas directamente. No obstante, esa obligación ha sido sistemáticamente eludida por diversos gobiernos y los pueblos indígenas se han visto obligados a acudir a las instancias internacionales de protección de los derechos humanos para hacer respetar sus derechos. Tal es el caso del pueblo kichwa de Sarayaku. El autor ofrece un panorama de esa lucha histórica.

  3. [Management of placenta previa and accreta].

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    Kayem, G; Keita, H

    2014-12-01

    Produce recommendations for the management of placenta previa and placenta accrete. A literature search was conducted using Medline and the Cochrane Library over a period from 1950 to 31/12/2013. Recommendations of the latest scientific societies have also been consulted. In cases of placenta previa, if bleeding episode before 34weeks gestation occurs, a short hospitalization and tocolysis may help stop bleeding (grade C). Vaginal delivery is preferable when the distance between the internal cervical os and the placental edge is greater than 20mm. When this distance is less than 20mm, vaginal delivery is possible (professional consensus). Caesarean section is recommended in cases of placenta overlapping the internal os (professional consensus). Antenatal screening placenta accreta could improve care (EL3). Upon discovery of a placenta accreta during childbirth, it is better to avoid a forced removal of the placenta (grade C). Conservative treatment or cesarean hysterectomy are possible (grade C). The management of placental abnormalities should be planned and managed with a multidisciplinary team (professional consensus). The use of blood-saving techniques such as "cell saver" is possible in situations where early intraoperative bleeding would be>1500mL (grade C). There are no studies that have sufficient methodological value to recommend an anesthetic technique [general anaesthesia (GA) or neuraxial anaesthesia] over another in the context of placental abnormalities (grade B). When a major bleeding risk is identified, GA can be chosen in order to avoid emergency conversions in difficult conditions (professional consensus). Placental insertion abnormalities require anesthetic and obstetric coordination. Delivery must be planned in a suitable structure. Copyright © 2014. Published by Elsevier Masson SAS.

  4. Optimization and kinetics decomposition of monazite using NaOH

    International Nuclear Information System (INIS)

    MV Purwani; Suyanti; Deddy Husnurrofiq

    2015-01-01

    Decomposition of monazite with NaOH has been done. Decomposition performed at high temperature on furnace. The parameters studied were the comparison NaOH / monazite, temperature and time decomposition. From the research decomposition for 100 grams of monazite with NaOH, it can be concluded that the greater the ratio of NaOH / monazite, the greater the conversion. In the temperature influences decomposition 400 - 700°C, the greater the reaction rate constant with increasing temperature greater decomposition. Comparison NaOH / monazite optimum was 1.5 and the optimum time of 3 hours. Relations ratio NaOH / monazite with conversion (x) following the polynomial equation y = 0.1579x 2 – 0.2855x + 0.8301 (y = conversion and x = ratio of NaOH/monazite). Decomposition reaction of monazite with NaOH was second orde reaction, the relationship between temperature (T) with a reaction rate constant (k), k = 6.106.e - 1006.8 /T or ln k = - 1006.8/T + 6.106, frequency factor A = 448.541, activation energy E = 8.371 kJ/mol. (author)

  5. Anesthesia for cesarean section in pregnancies complicated by placenta previa

    International Nuclear Information System (INIS)

    Imarengiaye, Charles O.; Osaigbovo, Etinosa P.; Tudjegbe, Sampson O.

    2008-01-01

    Objective was to evaluate the factors affecting the choice of anesthetic technique for cesarean section in women with placenta previa. In this retrospective study, the records of the labor Ward Theatre of the University of Benin Teaching Hospital, Benin City, Nigeria were examined from January 2000 to December 2004 to identify all the women who had cesarean section for placenta previa. The patient's socio-demographic characteristics, type of placenta previa, anesthesia technique, estimated blood loss, maternal and fetal outcomes were recorded. One hundred and twenty-six patients had cesarean section for placenta previa, however, only 81 patients 64.3% were available for analysis. General anesthesia was administered to 52/81 patients 64.2% and 29/81 patients 35.8% received spinal anesthesia. A history of antepartum bleeding was recorded in 61.7% n=50. Of 31 patients without antepartum hemorrhage APH, 15/31 had general anesthesia and 16/31 had spinal anesthesia. The patients who had APH, 37/50 had general anesthesia and 1/50 had spinal anesthesia. There was an increased chance of using general anesthesia and if APH were present p=0.03, odds ratio=3.1, 95% confidence interval=1.2-7.7. Spinal anesthesia may useful in patients with placenta previa. The presence of APH may encourage the use of general anesthesia for cesarean delivery. (author)

  6. Ion nitriding post-oxidation as an alternative technique to electrolytic chromium; Nitruracion post-oxidacion ionica como tecnica alternativa al cromado electrolitico

    Energy Technology Data Exchange (ETDEWEB)

    Diaz-Guillen, J. C.; Granda-Gutierrez, E.E.; Campa-Castilla, A.; Perez-Aguilar, S.I.; Garza-Gomez, A.; Candelas-Ramirez, J.; Mendez-Mendez, R. [COMIMSA. Corporacion Mexicana de Investigacion en Materiales S.A. de C.V., Saltillo, Coahuila (Mexico)]. E-mail: jcarlos@comimsa.com

    2010-11-15

    The effect of temperature and processing time during post-oxidation on hardness and corrosion resistance of AISI 1045 samples treated through nitriding and post-oxidation in a pulsed plasma discharge is evaluated in this paper. Also, a comparative analysis of the mechanical properties obtained with the dual nitriding - post oxidation process versus those properties of typical hard chrome coatings was performed with an aim to propose an alternative technique to the processes of galvanic coatings. The latter revealed that the process of ion nitriding and post-oxidation provides similar properties in hardness and improves the corrosion resistance compared to the hard chrome case. It is conclude that the technique of ion nitriding and post-oxidation is a non environmental harmful technology with strong potential to replace highly polluting electroplating techniques for application of hard chrome coatings. [Spanish] En el presente trabajo se evalua el efecto del tiempo y la temperatura de post-oxidacion sobre las propiedades de dureza y resistencia a la corrosion de muestras de acero AISI 1045 sometido al proceso de nitruracion post-oxidacion ionica en plasmas pulsados. Asi mismo, con el objetivo de fundamentar la propuesta de utilizacion de la nitruracion post-oxidacion ionica como una tecnica alternativa a los procesos galvanicos para aplicacion de recubrimientos de cromo duro, se realizo un analisis comparativo de propiedades, evidenciando que, mediante el proceso nitruracion postoxidacion ionica, es posible obtener caracteristicas similares en dureza y mejores en resistencia a la corrosion que las tipicas obtenidas para el cromo duro. Los resultados obtenidos permiten postular una tecnica que no dana al medio ambiente, como lo es la nitruracion post-oxidacion ionica, como candidata potencial para sustituir las tecnicas galvanicas altamente contaminantes para aplicacion de cromo duro.

  7. The cervix as a natural tamponade in postpartum hemorrhage caused by placenta previa and placenta previa accreta: a prospective study.

    Science.gov (United States)

    El Gelany, Saad A A; Abdelraheim, Ahmed R; Mohammed, Mo'men M; Gad El-Rab, Mohammed T; Yousef, Ayman M; Ibrahim, Emad M; Khalifa, Eissa M

    2015-11-11

    Placenta previa and placenta accreta carry significant maternal and fetal morbidity and mortality. Several techniques have been described in the literature for controlling massive bleeding associated with placenta previa cesarean sections. The objective of this study was to evaluate the efficacy and safety of the use of the cervix as a natural tamponade in controlling postpartum hemorrhage caused by placenta previa and placenta previa accreta. This prospective study was conducted on 40 pregnant women admitted to our hospital between June 2012 and November 2014. All participating women had one or more previous cesarean deliveries and were diagnosed with placenta previa and/or placenta previa accreta. Significant bleeding from the placental bed during cesarean section was managed by inverting the cervix into the uterine cavity and suturing the anterior and/or the posterior cervical lips into the anterior and/or posterior walls of the lower uterine segment. The technique of cervical inversion described above was successful in stopping the bleeding in 38 out of 40 patients; yielding a success rate of 95%. We resorted to hysterectomy in only two cases (5%). The mean intra-operative blood loss was 1572.5 mL, and the mean number of blood units transfused was 3.1. The mean time needed to perform the technique was 5.4 ± 0.6 min. The complications encountered were as follows: bladder injury in the two patients who underwent hysterectomy and wound infection in one patient. Postoperative fever that responded to antibiotics occurred in 1 patient. The mean duration of the postoperative hospital stay was 3.5 days This technique of using the cervix as a natural tamponade appears to be safe, simple, time-saving and potentially effective method for controlling the severe postpartum hemorrhage (PPH) caused by placenta previa/placenta previa accreta. This technique deserves to be one of the tools in the hands of obstetricians who face the life-threatening hemorrhage of placenta

  8. The role of shear wave elastography in the assessment of placenta previa-accreta.

    Science.gov (United States)

    Alıcı Davutoglu, Ebru; Ariöz Habibi, Hatice; Ozel, Ayşegül; Yuksel, Mehmet Aytac; Adaletli, Ibrahim; Madazlı, Riza

    2018-06-01

    To evaluate the value of shear wave elastography (SWE) in the prediction of morbidly adherent placenta. Forty-three women with normal placental location and 26 women with anteriorly localized placenta previa were recruited for this case-control study. Placental elasticity values in both the groups were determined by SWE imaging. SWE values were higher in the placenta previa group in all regions than in normal localized placentas (p  .05). Placental stiffness is significantly higher in placenta previa than normal localized placentas. However, we could not demonstrate any statistically significant difference in the elasticity values between the placenta previa with and without accreta.

  9. Zinc-zincate electrochemical behaviour in NaOH medium

    International Nuclear Information System (INIS)

    Pessine, E.J.

    1984-01-01

    The reaction mechanism of zinc/NaOH-zincate system was investigated with the rotating disk electrode technique, using both the surfaces of mercury film and zinc in 1M NaOH concentration and 25 0 C temperature. It was found that, at the mercury surface, the zincate ion deposition reaction occurs by two steps with one electron each, with comparable rates, with b sup(-) sub(K1) = (132+ -20)mV/decade and b sup(-) sub(K2) = (74 + - 9)mV/decade cathodic Tafel slopes. At the zinc surface the mechanism of the anodic and cathodic reactions is the same and is by two steps with one electron each. The rate-determining step is the first reaction in the cathodic direction. The exchange current density was found to be between 1.00 and 6.00mA/cm 2 , with b sup(-) sub(K) = (95+ -3)mV/decade cathodic and b sup(-) sub(a) = (61+ -5)mV/decade anodic Tafel slopes. The mechanism of passivation of zinc occurs as a result of the two reactions, the adsorption of the dissolved species of zinc II and the precipitation of the zincate ions over the electrode active sites. It has been verified that of all the chemical species studied namely the zincate, chloride, benzoate, silicate ions and the benzotriazole that affect the zinc anodic reaction the silicate ion is the one that change the reaction rate. However, for all the species studied we have the same anodic reaction mechanism (active dissolution). The deposition reaction mechanism of the zincate ion on zinc electrode is the same with NaOH plus benzoate or chloride. The diffusion coefficient found for the diffusion of the zincate ion in 1M NaOH with the mercury film RDE is D sup(-) = (4,90+ -0,20) x 10 -6 cm 2 s -1 . (Author) [pt

  10. Formation of titanate nanostructures under different NaOH concentration and their application in wastewater treatment

    International Nuclear Information System (INIS)

    Huang Jiquan; Cao Yongge; Deng Zhonghua; Tong Hao

    2011-01-01

    The effects of the concentration of NaOH on the formation and transformation of various titanate nanostructures were studied. With increasing NaOH concentration, three different formation mechanisms were proposed. Nanotubes can only be obtained under moderate NaOH conditions, and should transform into nanowires with prolonged hydrothermal treatment, and their formation rate is accelerated by increasing NaOH concentration. Low concentration of NaOH results in the direct formation of nanowires, while extra high concentration of NaOH leads to the formation of amorphous nanoparticles. Adsorption and photocatalysis studies show that titanate nanowires and nanotubes might be potential adsorbents for the removal of both heavy metal ions and dyes and photocatalysts for the removal of dyes from wastewater. -- Graphical abstract: The morphologies of the titanates depend deeply on the concentration of NaOH. With increasing NaOH concentration, three different formation mechanisms were proposed. The application of these titanate nanostructures in the wastewater treatment was studied. Display Omitted Research highlights: → Effect of NaOH concentration on the structures of various titanates was reported. → Three different formation mechanisms were presented with increasing NaOH concentration. → Various titanates were used as adsorbents/photocatalysts in wastewater treatment.

  11. Placenta previa; MRI as an adjunct to ultrasound in assessment of suspected placental invasion

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    Asmaa M. Abdel Magied

    2018-03-01

    Full Text Available Objective: Evaluate adding MRI to ultrasound in imaging of placenta previa with suspected placenta accreta. Patients and methods: evaluation of 23 pregnant females presenting with placenta previa was done. The age ranged from 20 to 39 years (mean = 30.9. All of the patients were subjected to ultrasonography (US and magnetic resonance imaging (MRI of the pelvis at gestational age of 25–37 weeks prior to elective delivery. Results: 11 out of 23 patients were proved placenta accreta based on surgical and pathological reports. US suggested diagnosis of placenta previa/accreta in 8 patients and placenta previa without accreta in 15 cases. 7/8 was true positive (87.5% & one was false positive (12.5% with sensitivity 63.64%, accuracy 78.26%, and specificity 91.67%. MRI has suggested diagnosis of placenta previa/accreta in 8/23 & placenta previa with no accreta in 15/23 patients. MRI was found to give true positive results in 8/8 patients proved to be accreta. MRI gave true negative in 12 patients (80% & false negative in 3 (20% with sensitivity 72.73%, accuracy 86.96%, and specificity 100%. Conclusion: Combining MRI and ultra sound provide more diagnostic information and may reduce unnecessary interventions with favorable outcome. Keywords: Ultra sound, MRI, Placenta previa, Placenta accreta

  12. Placenta previa and risk of major congenital malformations among singleton births in Finland.

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    Kancherla, Vijaya; Räisänen, Sari; Gissler, Mika; Kramer, Michael R; Heinonen, Seppo

    2015-06-01

    Placenta previa has been associated with adverse birth outcomes, but its association with congenital malformations is inconclusive. We examined the association between placenta previa and major congenital malformations among singleton births in Finland. We performed a retrospective population register-based study on all singletons born at or after 22+0 weeks of gestation in Finland during 2000 to 2010. We linked three national health registers: the Finnish Medical Birth Register, the Hospital Discharge Register, and the Register of Congenital Malformations, and examined several demographic and clinical characteristics among women with and without placenta previa, in association with major congenital malformations. We estimated adjusted odds ratios and 95% confidence intervals using multivariable logistic regression models. The prevalence of placenta previa was estimated as 2.65 per 1000 singleton births in Finland (95% confidence interval, 2.53-2.79). Overall, 6.2% of women with placenta previa delivered a singleton infant with a major congenital malformation, compared with 3.8% of unaffected women (p ≤ 0.001). Placenta previa was positively associated with almost 1.6-fold increased risk of major congenital malformations in the offspring, after controlling for maternal age, parity, fetal sex, smoking, socio-economic status, chorionic villus biopsy, In vitro fertilization, pre-existing diabetes, depression, preeclampsia, and prior caesarean section (adjusted odds ratio = 1.55; 95% confidence interval, 1.27-1.90). Using a large population-based study, we found that placenta previa was weakly, but significantly associated with an increased risk of major congenital malformations in singleton births. Future studies should examine the association between placenta previa and individual types of congenital malformations, specifically in high-risk pregnancies. © 2015 Wiley Periodicals, Inc.

  13. A comparison of morbidity associated with placenta previa with and without previous caesarean sections

    International Nuclear Information System (INIS)

    Baqai, S.; Siraj, A.; Noor, N.

    2018-01-01

    To compare the morbidity associated with placenta previa with and without previous caesarean sections. Study Design: Retrospective comparative study. Place and Duration of Study: From March 2014 till March 2016 in the department of Obstetrics and Gynaecology at PNS Shifa hospital Karachi. Material and Methods: After the approval from hospital ethical committee, antenatal patients with singleton pregnancy of gestational age >32 weeks, in the age group of 20-40 years diagnosed to have placenta previa included in the study. All patients with twin pregnancy less than 20 years and more than 40 years of age were excluded. The records of all patients fulfilling the inclusion criteria were reviewed. Data had been collected for demographic and maternal variables, placenta previa, history of previous lower segment caesarean section (LSCS), complications associated with placenta previa and techniques used to control blood loss were recorded. Results: During the study period, 6879 patients were delivered in PNS Shifa, out of these, 2060 (29.9%) had caesarean section out of these, 47.3% patients had previous history of LSCS. Thirty three (1.6%) patients were diagnosed to have placenta previa and frequency of placenta previa was significantly higher in patients with previous history of LSCS than previous normal delivery of LSCS i.e. 22 vs. 11 (p=0.023). It was observed that the frequency of morbidly adherent placenta (MAP) and Intensive care unit (ICU) stay were significantly higher in patients with previous history of LSCS than previous history of normal delivery. Conclusion: Frequency of placenta previa was significantly higher in patients with history of LSCS. Also placenta previa remains a major risk factor for various maternal complications. (author)

  14. Risk Factors and Consequent Outcomes of Placenta Previa: Report From a Referral Center

    Directory of Open Access Journals (Sweden)

    Soraya Saleh Gargari

    2016-12-01

    Full Text Available  Because of an unknown factor, the frequency of complicated pregnancy with placenta previa has been raised during past decade. This study was designed to deepen our understanding of risk factors and outcomes of placenta previa in our country. This study investigated 694 cases of placenta previa comparing with 600 healthy pregnant women with not overlie placenta in two referral and tertiary Obstetrics and Gynecological Hospital in Iran on the basis of the clinical and para-clinical analysis, in order to find the probable risk factors for occurrence of placenta previa and its effect on maternal and neonatal complications. The most important risk factor for the occurrence of placenta previa was advanced maternal age (P<0.001 and history of stillbirth (OR=117.2, CI=58.3-236.0. In the other hand, the most substantial outcome of this disorder was a reduction of gestational age (P<0.001 and low birth weight neonatally (P<0.001. The conservative follow-up should be programmed for women with placenta previa based on the type of risk factors which can provide the best possible management to decrease the morbidity and mortality of their related complications.

  15. Efficacy and Safety of Prophylactic Uterine Artery Embolization in Pregnancy Termination with Placenta Previa

    Energy Technology Data Exchange (ETDEWEB)

    Pei, Renguang, E-mail: mediprg@bjmu.edu.cn; Wang, Guoxiang; Wang, Heping; Huang, Xinyu; Yan, Xiaoxing; Yang, Xiaohua [Yijishan Hospital of Wannan Medical College, Department of Interventional Therapy (China)

    2017-03-15

    PurposeTo appraise the efficacy and safety of prophylactic uterine artery embolization in pregnancy termination with placenta previa.MethodsA cohort of 54 consecutive patients with placenta previa underwent prophylactic uterine artery embolization before vaginal delivery from February 2012 to March 2015. Vaginal delivery was attempted in all patients. Cesarean section or hysterectomy was introduced when vaginal delivery failed.ResultsVaginal delivery succeeded in 50 patients (93.6%) and failed in 4 patients (6.4%), thereupon converted to cesarean delivery. No patients resorted to hysterectomy. Six patients (11.1%) underwent blood transfusion. None of clinical characteristics, including maternal age, gestational age, history of abortion, history of cesarean delivery, and volume of vaginal bleeding, was significantly associated with complete placenta previa (P > 0.05). However, patients with complete placenta previa had a significantly lower successful rate of vaginal delivery than did patients without complete placenta previa (81 vs 100%, P = 0.038). The rate of complications was 3.7%. No major complications were observed.ConclusionUterine artery embolization is an effective and safe technique to assist pregnancy termination with placenta previa, which may lower the risk of cesarean section, hysterectomy, and blood transfusion.

  16. Efficacy and Safety of Prophylactic Uterine Artery Embolization in Pregnancy Termination with Placenta Previa

    International Nuclear Information System (INIS)

    Pei, Renguang; Wang, Guoxiang; Wang, Heping; Huang, Xinyu; Yan, Xiaoxing; Yang, Xiaohua

    2017-01-01

    PurposeTo appraise the efficacy and safety of prophylactic uterine artery embolization in pregnancy termination with placenta previa.MethodsA cohort of 54 consecutive patients with placenta previa underwent prophylactic uterine artery embolization before vaginal delivery from February 2012 to March 2015. Vaginal delivery was attempted in all patients. Cesarean section or hysterectomy was introduced when vaginal delivery failed.ResultsVaginal delivery succeeded in 50 patients (93.6%) and failed in 4 patients (6.4%), thereupon converted to cesarean delivery. No patients resorted to hysterectomy. Six patients (11.1%) underwent blood transfusion. None of clinical characteristics, including maternal age, gestational age, history of abortion, history of cesarean delivery, and volume of vaginal bleeding, was significantly associated with complete placenta previa (P > 0.05). However, patients with complete placenta previa had a significantly lower successful rate of vaginal delivery than did patients without complete placenta previa (81 vs 100%, P = 0.038). The rate of complications was 3.7%. No major complications were observed.ConclusionUterine artery embolization is an effective and safe technique to assist pregnancy termination with placenta previa, which may lower the risk of cesarean section, hysterectomy, and blood transfusion.

  17. Cane molasses and NaOH teated bagacillo diets for lambs | Chicco ...

    African Journals Online (AJOL)

    Cane molasses and NaOH teated bagacillo diets for lambs. C.F. Chicco, G Garcia, C Fernandez, C.R. Prays. Abstract. The eftect of alkali-treated bag acillo in diets varying in proportion of bagacillo and mollasses was studied in lambs. The bagacillo was treated with a concentration solution of NaOH in a horizontald rum-type ...

  18. Validation of the Preverbal Visual Assessment (PreViAs) questionnaire.

    Science.gov (United States)

    García-Ormaechea, Inés; González, Inmaculada; Duplá, María; Andres, Eva; Pueyo, Victoria

    2014-10-01

    Visual cognitive integrative functions need to be evaluated by a behavioral assessment, which requires an experienced evaluator. The Preverbal Visual Assessment (PreViAs) questionnaire was designed to evaluate these functions, both in general pediatric population or in children with high risk of visual cognitive problems, through primary caregivers' answers. We aimed to validate the PreViAs questionnaire by comparing caregiver reports with results from a comprehensive clinical protocol. A total of 220 infants (visual development, as determined by the clinical protocol. Their primary caregivers completed the PreViAs questionnaire, which consists of 30 questions related to one or more visual domains: visual attention, visual communication, visual-motor coordination, and visual processing. Questionnaire answers were compared with results of behavioral assessments performed by three pediatric ophthalmologists. Results of the clinical protocol classified 128 infants as having normal visual maturation, and 92 as having abnormal visual maturation. The specificity of PreViAs questionnaire was >80%, and sensitivity was 64%-79%. More than 80% of the infants were correctly classified, and test-retest reliability exceeded 0.9 for all domains. The PreViAs questionnaire is useful to detect abnormal visual maturation in infants from birth to 24months of age. It improves the anamnesis process in infants at risk of visual dysfunctions. Copyright © 2014. Published by Elsevier Ireland Ltd.

  19. Hydrogen production by sodium borohydride in NaOH aqueous solution

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    Wang, Q.; Zhang, L. F.; Zhao, Z. G.

    2018-01-01

    The kinetics of hydrolysis reaction of NaBH4 in NaOH aqueous solution is studied. The influence of pH of the NaOH aqueous solution on the rate of hydrogen production and the hydrogen production efficiency are studied for the hydrolysis reaction of NaBH4. The results show that the activation energy of hydrolysis reaction of NaBH4 increased with the increase of the initial pH of NaOH aqueous solution.With the increasing of the initial pH of NaOH aqueous solution, the rate of hydrogen production and hydrogen production efficiency of NaBH4 hydrolysis decrease.

  20. Raman spectra from very concentrated aqueous NaOH and from wet and dry, solid, and anhydrous molten, LiOH, NaOH, and KOH.

    Science.gov (United States)

    Walrafen, George E; Douglas, Rudolph T W

    2006-03-21

    High-temperature, high-pressure Raman spectra were obtained from aqueous NaOH solutions up to 2NaOHH2O, with X(NaOH)=0.667 at 480 K. The spectra corresponding to the highest compositions, X(NaOH)> or =0.5, are dominated by H3O2-. An IR xi-function dispersion curve for aqueous NaOH, at 473 K and 1 kbar, calculated from the data of Franck and Charuel indicates that the OH- ion forms H3O2- by preferential H bonding with nonhydrogen-bonded OH groups. Raman spectra from wet to anhydrous, solid LiOH, NaOH, and KOH yield sharp, symmetric OH- stretching peaks at 3664, 3633, and 3596 cm(-1), respectively, plus water-related, i.e., H3O2-, peaks near LiOH, 3562 cm(-1), NaOH, 3596 cm(-1), and, KOH, 3500 cm(-1). Absence of H3O2- peaks from the solid assures that the corresponding melt is anhydrous. Raman spectra from the anhydrous melts yield OH- stretching peak frequencies: LiOH, 3614+/-4 cm(-1), 873 K; NaOH, 3610+/-2 cm(-1), 975 K; and, KOH, 3607+/-2 cm(-1), 773 K, but low-frequency asymmetry due to ion-pair interactions is present which is centered near 3550 cm(-1). The ion-pair-related asymmetry corresponds to the sole IR maximum near 3550 cm(-1) from anhydrous molten NaOH, at 623 K. Bose-Einstein correction of published low-frequency Raman data from molten LiOH revealed an acoustic phonon, near 205 cm(-1), related to restricted translation of OH- versus Li+, and an optical phonon, at 625 cm(-1) and tau approximately 0.05 ps, due to protonic precession and/or pendular motion. Strong H bonding between water and the O atom of OH- forms H3O2-, but the proton of OH- does not bond with H significantly. Large Raman bandwidths (aqueous solutions) are explained in terms of inhomogeneous broadening due to proton transfer in a double well. Vibrational assignments are presented for H3O2-.

  1. Rising frequency of placenta previa and associated morbidity in women with previous casearean section

    International Nuclear Information System (INIS)

    Akhter, F.; Nawaz, Q.; Mushtaq, Q.U.A.

    2015-01-01

    To determine rising frequency of placenta previa and its associated morbidity in women with previous caesarean section. Study Design: Cross sectional study. Place and Duration of Study: This study was conducted in the Department of Obstetrics and Gynecology at CMH Kohat from Jul 2010 to Jun 2011. Patients and Methods: This study included all pregnant women undergoing repeat caesarean sections. Of these, total 74 patients were admitted with placenta previa. The frequency and associated morbidity were determined. Results: In our study 74 patients with placenta previa were included. 71.62% were less than 35 yrs of age, while 28.38% were equal to or more than 35 years. The gestational age at presentation was 24-36 weeks in 74.3% and 37 + weeks in 5.7% at presentation, 89% patients were symptomatic and 11% were asympyomatic. The morbidities observed were placenta accrete 47%, urinary tract trauma in 63.51%, caesarean hysterectomy in 62.16%, post operative febrile morbidity in 77.03%, maternal mortality was nil, paralytic ileus in 28.38%, PPH in 82.43%, surgical site infection in 16.21%. Conclusion: Frequency of placenta previa and its associated morbidity was raised due to repeated caesarean section rate which must be reduced to decrease maternal morbidity and mortality. (author)

  2. A danish national cohort study on neonatal outcome in singleton pregnancies with placenta previa

    DEFF Research Database (Denmark)

    Nørgaard, Lone N; Pinborg, Anja; Lidegaard, Ojvind

    2012-01-01

    . Main outcome measures. Gestational age, birthweight, Apgar score after 5min, stillbirth, neonatal mortality and admittance to neonatal intensive care unit. Results. The incidence of placenta previa in Denmark was 0.54% in 2006. Neonates born after pregnancies with placenta previa had a higher risk...... of being born at a gestational age below 37 weeks (OR 8.6; 95% CI 7.5-9.9), having Apgar score =7 at 5 min (OR 2.7; 95% CI 2.0-3.7), being transferred to neonatal intensive care unit (OR 4.3; 95% CI 3.8-4.9) and for stillbirth and neonatal mortality combined (OR 1.8; 95% CI 1.1-3.0), compared to neonates...... born in pregnancies without placenta previa. No increased risk of being small-for-gestational age was found (OR 1.0; 95% CI 1.0-1.2). Conclusion. When adjusting for confounders neonates born after pregnancies with placenta previa had a significantly higher risk of being born preterm, having a low Apgar...

  3. Efficacy of Intrauterine Bakri Balloon Tamponade in Cesarean Section for Placenta Previa Patients.

    Directory of Open Access Journals (Sweden)

    Hee Young Cho

    Full Text Available The aims of this study were to analyze the predictive factors for the use of intrauterine balloon insertion and to evaluate the efficacy and factors affecting failure of uterine tamponade with a Bakri balloon during cesarean section for abnormal placentation.We reviewed the medical records of 137 patients who underwent elective cesarean section for placenta previa between July 2009 and March 2014. Cesarean section and Bakri balloon insertion were performed by a single qualified surgeon. The Bakri balloon was applied when blood loss during cesarean delivery exceeded 1,000 mL.Sixty-four patients (46.7% required uterine balloon tamponade during cesarean section due to postpartum bleeding from the lower uterine segment, of whom 50 (78.1% had placenta previa totalis. The overall success rate was 75% (48/64 for placenta previa patients. Previous cesarean section history, anterior placenta, peripartum platelet count, and disseminated intravascular coagulopathy all significantly differed according to balloon success or failure (all p<0.05. The drainage amount over 1 hour was 500 mL (20-1200 mL in the balloon failure group and 60 mL (5-500 mL in the balloon success group (p<0.01.Intrauterine tamponade with a Bakri balloon is an adequate adjunct management for postpartum hemorrhage following cesarean section for placenta previa to preserve the uterus. This method is simple to apply, non-invasive, and inexpensive. However, possible factors related to failure of Bakri balloon tamponade for placenta previa patients such as prior cesarean section history, anterior placentation, thrombocytopenia, presence of DIC at the time of catheter insertion, and catheter drainage volume more than 500 mL within 1 hour of catheter placement should be recognized, and the next-line management should be prepared in advance.

  4. Antenatal Sonographic Diagnosis and Clinical Significance of Placenta Previa Accreta after Cesarean Section.

    Science.gov (United States)

    Liu, Zhen-Zhen; Wei, Yao; Wang, Ruo-Jiao; Xu, Wen; Shi, Zhi-Min; Dai, Qing

    2017-10-30

    Objective To investigate the clinical and antenatal sonographic characteristics of placenta previa accreta after cesarean section. Methods The data of 21 inpatients diagnosed as placenta previa accreta after cesarean section in PUMC Hospital from 2006 to 2016 were retrospectively reviewed. The clinical and ultrasound features were recorded and compared among three placental accreta groups,including placenta accrete group(n=5),increta group(n=12),and percreta group(n=4). The relationship between the placental thickness at the uterine anterior lower segment level and the blood loss of the following cesarean section was tested. Results Of 21 patients,placenta previa was diagnosed by ultrasound in 20 cases(95.2%) and placenta previa accreta was diagnosed in 9 cases(42.9%). Antenatal ultrasound findings included following signs:loss of "clear zone"(15/18,83.3%),myometrial thinning(12/18,66.7%),abnormal placental lacunae(12/19,63.2%),bladder wall interruption(2/18,11.1%),and uterovesical hypervascularity(4/9,44.4%). Myometrial thinning(J-T=64.000,P=0.036),abnormal placental lacunae(J-T=74.500,P=0.032) and the placental thickness at the uterine anterior lower segment level(U=83.000,P=0.010) showed significant difference among different placenta accreta groups. Placental thickness at the uterine anterior lower segment level showed linear correlation with the blood loss of the following cesarean section(r=0.669,P=0.002). The blood loss of the following cesarean section showed significant difference among different placenta accreta groups(U=118.500,P=0.000). Conclusions The clinical and sonographic manifestations of placenta previa accreta after cesarean section show a spectrum of demographic characteristics. The measurement of thickness of placenta at the anterior lower segment may help the evaluation of the clinical prognosis of this special pathology.

  5. Enhancement of Biogas Production from Rice Husk by NaOH and Enzyme Pretreatment

    Directory of Open Access Journals (Sweden)

    Syafrudin

    2018-01-01

    Full Text Available Biogas is a renewable energy source that can be used as an alternative fuel to replace fossil fuel such as oil and natural gas. This research aims to analyze the impact of NaOH (Sodium hydroxide and enzyme usage on the production of rice husk biogas using Solid State Anaerobic Digestion (SS-AD. Generally, SS-AD occurs at solid concentrations higher than 15%. The waste of rice husk are used as substrate with a C/N ratio of 25% and the total of solid that are used is 21%. Rice husk contains high lignin, therefore it is handled with chemical and biological treatment. The chemical preliminary treatment was using NaOH with various concentrations from 3%, 6% and 9% while the biological preliminary treatment was using enzyme with various concentration from 5%, 8%, and 11%. The biogas that is produced then measured every two days during 60 days of research with the biogas volume as a parameter observed. The result of the research shows that preliminary treatment with NaOH and enzyme can increase the production of biogas. The highest biogas production was obtained by the NaOH pretreatment using 6% NaOH which was 497 ml and by enzyme pretreatment using 11% enzyme which was 667,5 ml.

  6. Enhancement of Biogas Production from Rice Husk by NaOH and Enzyme Pretreatment

    Science.gov (United States)

    Syafrudin; Nugraha, Winardi Dwi; Agnesia, Shandy Sarima; Matin, Hashfi Hawali Abdul; Budiyono

    2018-02-01

    Biogas is a renewable energy source that can be used as an alternative fuel to replace fossil fuel such as oil and natural gas. This research aims to analyze the impact of NaOH (Sodium hydroxide) and enzyme usage on the production of rice husk biogas using Solid State Anaerobic Digestion (SS-AD). Generally, SS-AD occurs at solid concentrations higher than 15%. The waste of rice husk are used as substrate with a C/N ratio of 25% and the total of solid that are used is 21%. Rice husk contains high lignin, therefore it is handled with chemical and biological treatment. The chemical preliminary treatment was using NaOH with various concentrations from 3%, 6% and 9% while the biological preliminary treatment was using enzyme with various concentration from 5%, 8%, and 11%. The biogas that is produced then measured every two days during 60 days of research with the biogas volume as a parameter observed. The result of the research shows that preliminary treatment with NaOH and enzyme can increase the production of biogas. The highest biogas production was obtained by the NaOH pretreatment using 6% NaOH which was 497 ml and by enzyme pretreatment using 11% enzyme which was 667,5 ml.

  7. Formation of Lanthanum Hydroxide nano structures: Effect of NaOH and KOH solvents

    International Nuclear Information System (INIS)

    Mazloumi, M.; Zanganeh, S.; Kajbafvala, A.; Shayegh, M. R.; Sadrnezhaad, S. K.

    2008-01-01

    Lanthanum hydroxide (La(OH) 3 ) nano structures, including elliptical nanoparticles, octahedral rods and irregular nanoparticles were prepared chemically in NaOH and KOH solutions with 10 M concentration. The obtained powders were characterized with x-ray diffraction, scanning electron microscopy, transmission electron microscopy and differential thermal analysis. Crystallinities, morphologies and thermal behavior of the obtained nano structure powders were investigated under the influence of above mentioned solvents. The effect of chemical's temperature was also determined in one of the solvents (i.e. NaOH). The formation of growth in nano structure mechanism under the influence of alkali solutions (i.e., KOH and NaOH) have been discussed considerably in this paper

  8. Consulta previa en casos de minería para comunidades indígenas y tribales

    Directory of Open Access Journals (Sweden)

    Claudia Jimena Abello

    2012-12-01

    Full Text Available Este artículo hace un recorrido sobre la jurisprudencia de la Corte Constitucional sobre consulta previa y la minería. El objetivo es establecer las principales reglas, que ha creado la Corte al ponderar el derecho a la consulta previa versus el derecho del Estado a la explotación de recursos naturales. También, se intentará dar un esvoso de lo que entiende la Corte Constitucional como consulta previa y el procedimiento a seguir. Finalmente se hace una pequeña reflexión sobre el multiculturalismo y los derechos diferenciales.

  9. [Severe Adverse Pregnancy Outcomes in Placenta Previa and Prior Cesarean Delivery].

    Science.gov (United States)

    Zhou, Mi; Chen, Meng; Zhang, Li; He, Guo-Lin; He, Lei; Wei, Qiang; Li, Tao; Liu, Xing-Hui

    2017-09-01

    To investigate the severe adverse pregnancy outcomes in pregnancies with placenta previa and prior cesarean delivery and its risk factors. This retrospective casecontrol study reviewed all pregnancies with placenta previa and prior cesarean delivery delivered by repeat cesarean section in our institution between January 2005 and June 2015,and investigated the incidence of severe adverse pregnancy outcome. A composite of severe adverse pregnancy outcomes (including transfusion of 10 units or more red blood cells,maternal ICU admission,unanticipated injuries,repeat operation,hysterectomy,and maternal death) and other maternal and neonatal outcomes were described. Univariate and multivariable logistic regression analysis were used to quantify the effects of risk factors on severe adverse pregnancy outcomes. There were 478 women with placenta previa and prior cesarean delivery in our hospital over the last decade. The average age of them was 32.5±4.8 years old,most women were beyond 30 years old,the average gravidity and parity were 4 and 1,131 cases (27.4%) had severe adverse pregnancy outcomes. Transfusion of 10 units or more red blood cells happened in 75 cases (15.7%,75/478); 44 cases (9.2%,44/478) necessitated maternal ICU admission; unanticipated bladder injury occurred in 11 cases,but non ureter or bowel injury happened; All 4 repeat operations were due to delayed hemorrhage after conservative management during cesarean delivery,and an emergent hysterectomy was performed for all of the 4 cases. Hysterectomy (107 cases,22.4%) was the most common severe adverse pregnancy outcome. Among all 311 morbidly adherent placenta cases finally confirmed by pathological or surgical findings or both,only 172 (55.3%) were suspected before delivery. Multivariable logistic regression analysis showed that the risk of severe adverse pregnancy outcomes was significantly increased by pernicious placenta previa (i.e. anterior placenta overlying the prior cesarean scar),suspicion of

  10. Placenta Accreta and Total Placenta Previa in the 19th Week of Pregnancy

    Science.gov (United States)

    Findeklee, S.; Costa, S. D.

    2015-01-01

    Placentation disorders are the result of impaired embedding of the placenta in the endometrium. The prevalence of these disorders is estimated to be around 0.3 %. A history of previous prior uterine surgery (especially cesarean section and curettage) is the most common risk factor. Impaired placentation is differentiated into deep placental attachment; marginal, partial and total placenta previa; and placenta accreta, increta and percreta. Treatment depends on the severity of presentation and ranges from expectant management to emergency hysterectomy. In most cases, preterm termination of pregnancy is necessary. We report here on the case of a 39-year-old woman with placenta accreta and total placenta previa who underwent hysterectomy in the 19th week of pregnancy. PMID:26366004

  11. Penggunaan Katalis NaOH dalam Proses Transesterifikasi Minyak Kemiri menjadi Biodiesel

    Directory of Open Access Journals (Sweden)

    Farid Mulana

    2011-12-01

    Full Text Available Research on biodiesel production from hazelnut oil by transesterification process using NaOH catalyst was one of the efforts for renewable energy research. The purpose of this study was to determine the effect of NaOH catalyst and the ratio of hazelnut oil to methanol on the production of biodiesel via transesterification process. The transesterification process was carried out in a stirred reactor equipped by a condenser with speed of 200 rpm, temperature of 60°C and the operating time of 90 minutes. The results indicated that biodiesel could be produced from hazelnut oil through transesterification process with the highest yield of 81.7% that was obtained on the use of 2% wt. of NaOH catalyst and the mole ratio of oil to methanol of 1:9. Viscosity, density, and acid number of biodiesel obtained in this study met the Indonesia National Standard for biodiesel as SNI 04-7182-2006, therefore hazelnut oil produced biodiesel could potentially be an alternative diesel fuel. Keywords: hazelnut oil, biodiesel, transesterification, NaOH catalyst

  12. Comparative Analysis of the Use of Banana Peels and NaOH in Ph ...

    African Journals Online (AJOL)

    Ash produced from burnt banana peels were used as a substitutive for the industrial sodium hydroxide (NaOH) and potassium hydroxide, (KOH). The negative adverse effects of mud cuttings with inorganic additives on the environment have been demonstrated. The ash were observed to be environmentally more friendly ...

  13. Vasa previa screening strategies: a decision and cost-effectiveness analysis.

    Science.gov (United States)

    Sinkey, R G; Odibo, A O

    2018-05-22

    The aim of this study is to perform a decision and cost-effectiveness analysis comparing four screening strategies for the antenatal diagnosis of vasa previa among singleton pregnancies. A decision-analytic model was constructed comparing vasa previa screening strategies. Published probabilities and costs were applied to four transvaginal screening scenarios which occurred at the time of mid-trimester ultrasound: no screening, ultrasound-indicated screening, screening pregnancies conceived by in vitro fertilization (IVF), and universal screening. Ultrasound-indicated screening was defined as performing a transvaginal ultrasound at the time of routine anatomy ultrasound in response to one of the following sonographic findings associated with an increased risk of vasa previa: low-lying placenta, marginal or velamentous cord insertion, or bilobed or succenturiate lobed placenta. The primary outcome was cost per quality adjusted life years (QALY) in U.S. dollars. The analysis was from a healthcare system perspective with a willingness to pay (WTP) threshold of $100,000 per QALY selected. One-way and multivariate sensitivity analyses (Monte-Carlo simulation) were performed. This decision-analytic model demonstrated that screening pregnancies conceived by IVF was the most cost-effective strategy with an incremental cost effectiveness ratio (ICER) of $29,186.50 / QALY. Ultrasound-indicated screening was the second most cost-effective with an ICER of $56,096.77 / QALY. These data were robust to all one-way and multivariate sensitivity analyses performed. Within our baseline assumptions, transvaginal ultrasound screening for vasa previa appears to be most cost-effective when performed among IVF pregnancies. However, both IVF and ultrasound-indicated screening strategies fall within contemporary willingness-to-pay thresholds, suggesting that both strategies may be appropriate to apply in clinical practice. This article is protected by copyright. All rights reserved. This

  14. A Case Report and Literature Review of Midtrimester Termination of Pregnancy Complicated by Placenta Previa and Placenta Accreta

    OpenAIRE

    Matsuzaki, Satoko; Matsuzaki, Shinya; Ueda, Yutaka; Tanaka, Yusuke; Kakuda, Mamoru; Kanagawa, Takeshi; Kimura, Tadashi

    2014-01-01

    Objective - Concurrent placenta previa and placenta accreta increase the risk of massive obstetric hemorrhage. Despite extensive research on the management of placenta previa (including placenta accreta, increta, and percreta), the number and quality of previous studies are limited. We present a case of placenta accreta requiring an induced second-trimester abortion because of premature rupture of the membranes (PROM). Study Design - Case report and review of the literature. Results -...

  15. Symbol "&" suture to control atonic postpartum hemorrhage with placenta previa accreta.

    Science.gov (United States)

    Li, Guang Tai; Li, Xiao Fan; Liu, Ya Jing; Li, Wei; Xu, Hong Mei

    2015-02-01

    To evaluate the efficacy and safety of a symbol "&" compression suture technique in controlling severe atonic postpartum hemorrhage with placenta previa accreta during cesarean delivery. Nine women with heavy postpartum bleeding from uterine inertia and placenta previa percret, which did not react to conventional initial management protocols, were underwent the suture in the shape of symbol "&" in China Meitan General Hospital. The suture procedure was to staple the anterior and posterior walls (of the lower uterine segment as well as corpus uterus) together using number 1 chromic catgut, with a cross at about 2 cm above the upper boundary of lower uterine segment. Symbol "&" compression suture was capable of stanching the postpartum hemorrhage immediately in all nine women. None of these patients developed complications related to this method. Subsequent pregnancies after the suture were occurred in two women and delivered with repeat cesarean section. Symbol "&" compression suture is a simple, safe and highly effective technique to control the treatment-resistant uterine atonic bleeding, particularly in previous cesarean scar at lower segment and placenta previa accreta.

  16. Nursing care for patients with placenta previa undergoing interventional therapy in the second trimester of pregnancy

    International Nuclear Information System (INIS)

    Pan Suzhao; Lu Aijin; Wang Xuezhen

    2009-01-01

    Objective: To discuss the nursing care for patients with placenta previa,who receive uterine arterial catheterization and embolization in the second trimester of pregnancy. Methods: By using superselective catheterization with Seldinger technique, bilateral uterine artery angiography and embolization were performed in 16 patients with placenta previa in the second trimester of pregnancy. Two to four hours after the procedure, rivanol intra-amniotic injection was employed to induce the abortion. Close perioperative observation and careful nursing were carried out. Results: The fetus with its subsidiary tissue was delivered in a mean time of 4.5 hours after the operation in 15 cases. No postpartum hemorrhage occurred. Induced abortion failed in one case with 26 weeks pregnancy because of a scar uterus and cervical dystocia. Hysterotomy was performed 6 days later, blood loss during the operation was about 100 ml. No nursing care related complications occurred in all 16 patients. Conclusion: Uterine arterial embolization is very helpful in making the induced abortion for the treatment of bleeding placenta previa in the second trimester of pregnancy. Strengthening of perioperative care can improve successful rate of interventional therapy and prevent the occurrence of complication. (authors)

  17. Effect of grain size on corrosion of nanocrystalline copper in NaOH solution

    International Nuclear Information System (INIS)

    Luo Wei; Xu Yimin; Wang Qiming; Shi Peizhen; Yan Mi

    2010-01-01

    Research highlights: → Coppers display an active-passive-transpassive behaviour with duplex passive film. → Grain size variation has little effect on the overall corrosion behaviour of Cu. → Little effect on corrosion may be due to duplex passivation in NaOH solution. → Bulk nanocrystalline Cu show bamboo-like flake corrosion structure. - Abstract: Effect of grain size on corrosion of bulk nanocrystalline copper was investigated using potentiodynamic polarization measurements in 0.1 M NaOH solution. Bulk nanocrystalline copper was prepared by inert gas condensation and in situ warm compress (IGCWC) method. The grain sizes of all bulk nanocrystalline samples were determined to be 48, 68 and 92 nm using X-ray diffraction (XRD). Results showed that bulk coppers displayed an active-passive-transpassive behaviour with duplex passive films. From polycrystalline to nanocrystalline, grain size variation showed little effect on the overall corrosion resistance of copper samples.

  18. Cation incorporation into zirconium oxide in LiOH, NaOH, and KOH solutions

    International Nuclear Information System (INIS)

    Jeong, Y.H.; Kim, K.H.; Baek, J.H.

    1999-01-01

    To investigate the cation incorporation into zirconium oxide, SIMS analysis was performed on the specimens prepared to have an equal oxide thickness in LiOH, NaOH, and KOH solutions. Even though they have an equal oxide thickness in LiOH, NaOH, and KOH solutions, the penetration depth of cation into the oxide decreased with an increase in the ionic radius of cation. The cation is considered to control the corrosion in alkali hydroxide solutions and its effect is dependent on the concentration of alkali and the oxide thickness. The slight enhancement of the corrosion rate at a low concentration is thought to be caused by cation incorporation into oxide, while the significant acceleration at a high concentration is due to the transformation of oxide microstructures that would be also induced by cation incorporation into oxide. (orig.)

  19. Revisiting the Hydrogen Storage Behavior of the Na-O-H System

    Directory of Open Access Journals (Sweden)

    Jianfeng Mao

    2015-04-01

    Full Text Available Solid-state reactions between sodium hydride and sodium hydroxide are unusual among hydride-hydroxide systems since hydrogen can be stored reversibly. In order to understand the relationship between hydrogen uptake/release properties and phase/structure evolution, the dehydrogenation and hydrogenation behavior of the Na-O-H system has been investigated in detail both ex- and in-situ. Simultaneous thermogravimetric-differential thermal analysis coupled to mass spectrometry (TG-DTA-MS experiments of NaH-NaOH composites reveal two principal features: Firstly, an H2 desorption event occurring between 240 and 380 °C and secondly an additional endothermic process at around 170 °C with no associated weight change. In-situ high-resolution synchrotron powder X-ray diffraction showed that NaOH appears to form a solid solution with NaH yielding a new cubic complex hydride phase below 200 °C. The Na-H-OH phase persists up to the maximum temperature of the in-situ diffraction experiment shortly before dehydrogenation occurs. The present work suggests that not only is the inter-phase synergic interaction of protic hydrogen (in NaOH and hydridic hydrogen (in NaH important in the dehydrogenation mechanism, but that also an intra-phase Hδ+… Hδ– interaction may be a crucial step in the desorption process.

  20. Topical application of recombinant activated factor VII during cesarean delivery for placenta previa.

    Science.gov (United States)

    Schjoldager, Birgit T B G; Mikkelsen, Emmeli; Lykke, Malene R; Præst, Jørgen; Hvas, Anne-Mette; Heslet, Lars; Secher, Niels J; Salvig, Jannie D; Uldbjerg, Niels

    2017-06-01

    During cesarean delivery in patients with placenta previa, hemorrhaging after removal of the placenta is often challenging. In this condition, the extraordinarily high concentration of tissue factor at the placenta site may constitute a principle of treatment as it activates coagulation very effectively. The presumption, however, is that tissue factor is bound to activated factor VII. We hypothesized that topical application of recombinant activated factor VII at the placenta site reduces bleeding without affecting intravascular coagulation. We included 5 cases with planned cesarean delivery for placenta previa. After removal of the placenta, the surgeon applied a swab soaked in recombinant activated factor VII containing saline (1 mg in 246 mL) to the placenta site for 2 minutes; this treatment was repeated once if the bleeding did not decrease sufficiently. We documented the treatment on video recordings and measured blood loss. Furthermore, we determined hemoglobin concentration, platelet count, international normalized ratio, activated partial thrombin time, fibrinogen (functional), factor VII:clot, and thrombin generation in peripheral blood prior to and 15 minutes after removal of the placenta. We also tested these blood coagulation variables in 5 women with cesarean delivery planned for other reasons. Mann-Whitney test was used for unpaired data. In all 5 cases, the uterotomy was closed under practically dry conditions and the median blood loss was 490 (range 300-800) mL. There were no adverse effects of recombinant activated factor VII and we did not measure factor VII to enter the circulation. Neither did we observe changes in thrombin generation, fibrinogen, activated partial thrombin time, international normalized ratio, and platelet count in the peripheral circulation (all P values >.20). This study indicates that in patients with placenta previa, topical recombinant activated factor VII may diminish bleeding from the placenta site without initiation

  1. A Case Report and Literature Review of Midtrimester Termination of Pregnancy Complicated by Placenta Previa and Placenta Accreta

    Directory of Open Access Journals (Sweden)

    Satoko Matsuzaki

    2015-04-01

    Full Text Available Objective - Concurrent placenta previa and placenta accreta increase the risk of massive obstetric hemorrhage. Despite extensive research on the management of placenta previa (including placenta accreta, increta, and percreta, the number and quality of previous studies are limited. We present a case of placenta accreta requiring an induced second-trimester abortion because of premature rupture of the membranes (PROM. Study Design - Case report and review of the literature. Results - A 41-year-old female presented at 20 weeks of gestation with placenta previa and PROM. Ultrasonography revealed placenta accreta with multiple placental lacunae. She then developed massive hemorrhaging just prior to a planned termination of pregnancy. We performed a hysterectomy with the intent of preserving life because of the failure of the placenta to detach and blood loss totaling 4,500 mL. Conclusion - Previous studies suggest that second-trimester pregnancy terminations in cases of placenta previa which are not complicated with placenta accreta do not have a particularly high risk of hemorrhage. However, together with our case, the literature suggests that placenta previa complicated with placenta accreta presents a significant risk of hemorrhage both during delivery and intraoperatively. Further reports are needed to evaluate the most appropriate treatment options.

  2. A Case Report and Literature Review of Midtrimester Termination of Pregnancy Complicated by Placenta Previa and Placenta Accreta.

    Science.gov (United States)

    Matsuzaki, Satoko; Matsuzaki, Shinya; Ueda, Yutaka; Tanaka, Yusuke; Kakuda, Mamoru; Kanagawa, Takeshi; Kimura, Tadashi

    2015-04-01

    Objective Concurrent placenta previa and placenta accreta increase the risk of massive obstetric hemorrhage. Despite extensive research on the management of placenta previa (including placenta accreta, increta, and percreta), the number and quality of previous studies are limited. We present a case of placenta accreta requiring an induced second-trimester abortion because of premature rupture of the membranes (PROM). Study Design Case report and review of the literature. Results A 41-year-old female presented at 20 weeks of gestation with placenta previa and PROM. Ultrasonography revealed placenta accreta with multiple placental lacunae. She then developed massive hemorrhaging just prior to a planned termination of pregnancy. We performed a hysterectomy with the intent of preserving life because of the failure of the placenta to detach and blood loss totaling 4,500 mL. Conclusion Previous studies suggest that second-trimester pregnancy terminations in cases of placenta previa which are not complicated with placenta accreta do not have a particularly high risk of hemorrhage. However, together with our case, the literature suggests that placenta previa complicated with placenta accreta presents a significant risk of hemorrhage both during delivery and intraoperatively. Further reports are needed to evaluate the most appropriate treatment options.

  3. Placenta previa

    Science.gov (United States)

    ... cervix is the opening to the birth canal. Causes During pregnancy, the placenta moves as the womb stretches and ... care provider can diagnose this condition with a pregnancy ultrasound. ... or part of the cervix, a vaginal delivery can cause severe bleeding. This can be deadly to both ...

  4. A novel scoring system for predicting adherent placenta in women with placenta previa.

    Science.gov (United States)

    Tanimura, Kenji; Morizane, Mayumi; Deguchi, Masashi; Ebina, Yasuhiko; Tanaka, Utaru; Ueno, Yoshiko; Kitajima, Kazuhiro; Maeda, Tetsuo; Sugimura, Kazuro; Yamada, Hideto

    2018-04-01

    Placenta previa (PP) is one of the most significant risk factors for adherent placenta (AP). The aim of this study was to evaluate the diagnostic efficacy of a novel scoring system for predicting AP in pregnant women with PP. This prospective cohort study enrolled 175 women with PP. The placenta previa with adherent placenta score (PPAP score) is composed of 2 categories: (1) past history of cesarean section (CS), surgical abortion, and/or uterine surgery; and (2) ultrasonography and magnetic resonance imaging findings. Each category is graded as 0, 1, 2, or 4 points, yielding a total score between 0 and 24. When women with PP had PPAP score ≥8, they were considered to be at a high risk for AP and received placement of preoperative internal iliac artery occlusion balloon catheters. If they were found to have AP during CS, they underwent hysterectomy or placenta removal using advanced bipolar with balloon catheter occlusion. The predictive accuracy of PPAP score was evaluated. In total, 23 of the 175 women with PP were diagnosed as having AP, histopathologically or clinically. Twenty-one of 24 women with PPAP score ≥8 had AP, whereas two of 151 women with PPAP score PPAP scoring system may be useful for predicting AP in women with PP. Copyright © 2018 Elsevier Ltd. All rights reserved.

  5. Safe spinal anesthesia in a woman with chronic renal failure and placenta previa

    Directory of Open Access Journals (Sweden)

    Beyazit Zencirci

    2010-05-01

    Full Text Available Beyazit ZencirciKahramanmaras, TurkeyBackground: Chronic renal failure is strongly associated with poor pregnancy outcome. Women dependent on hemodialysis before conception rarely achieve a successful live birth.Case presentation: A 31-year-old multiparous Turkish woman was scheduled for cesarean section under spinal anesthesia at 37 weeks and five days’ gestation because of hemorrhage due to secondary placenta previa. Spinal anesthesia with 8 mg of hyperbaric bupivacaine was successfully performed. Invasive blood pressure, central venous pressure, and heart rate were stable during the surgery. The mother returned to regular hemodialysis on the first postoperative day.Conclusion: Pregnancy is uncommon in women with chronic renal failure requiring chronic dialysis. Rates of maternal hypertension, pre-eclampsia, anemia, and infection in the pregnant chronic dialysis patient are high. However, our findings suggest that with careful, close, and effective monitoring preoperatively and intraoperatively, spinal anesthesia can be safely performed for cesarean section in patients undergoing hemodialysis.Keywords: chronic renal failure, pregnancy, spinal anesthesia, hemodialysis, placenta previa

  6. Perinatal outcome and near-miss morbidity between placenta previa versus abruptio placentae

    International Nuclear Information System (INIS)

    Siddique, S.A.; Tariq, G.; Sheikh, A.; Hussain, F.S.U.; Memon, K.A.

    2010-01-01

    To compare perinatal outcome and near-miss morbidities between placenta previa versus abruptio placentae in patients of antepartum haemorrhage (APH). Patients with APH diagnosed as placenta previa and abruptio placentae who delivered after 24 weeks of regnancy were selected from labour room. Outcome measures were birth weight, neonatal intensive care admission, stillbirth, perinatal mortality rates, near-miss, surgical intensive care admission, postpartum haemorrhage, hysterectomy, massive transfusion, renal failure, coagulopathy and maternal death. Stillbirth was defined as a fetus weighing greater or equal to 500 gm showing no sign of life after birth. Near-miss was defined as severe organ dysfunction which if not treated appropriately, could result in death. Descriptive statistics were calculated and chi-square was applied with significance level < 0.05. Stillbirths and perinatal mortality rates were significantly higher in abruptio placentae, 52.97% versus 18.18% and 534/1000 versus 230/1000 (p < 0.01). Near-miss cases were also significantly higher in abruptio placentae, 22.27%. Verus 11.18% (p < 0.01). Hypovolemic shock and coagulation failure were also significantly higher in abruptio placentae (p < 0.05). (author)

  7. Frequency, Risk Factors, and Adverse Fetomaternal Outcomes of Placenta Previa in Northern Tanzania

    Directory of Open Access Journals (Sweden)

    Elizabeth Eliet Senkoro

    2017-01-01

    Full Text Available Background and Objective. Placenta previa (PP is a potential risk factor for obstetric hemorrhage, which is a major cause of fetomaternal morbidity and mortality in developing countries. This study aimed to determine frequency, risk factors, and adverse fetomaternal outcomes of placenta previa in Northern Tanzania. Methodology. A retrospective cohort study was conducted using maternally-linked data from Kilimanjaro Christian Medical Centre birth registry spanning 2000 to 2015. All women who gave birth to singleton infants were studied. Adjusted odds ratios (ORs with 95% confidence intervals for risk factors and adverse fetomaternal outcomes associated with PP were estimated in multivariable logistic regression models. Result. A total of 47,686 singleton deliveries were analyzed. Of these, the frequency of PP was 0.6%. Notable significant risk factors for PP included gynecological diseases, alcohol consumption during pregnancy, malpresentation, and gravidity ≥5. Adverse maternal outcomes were postpartum haemorrhage, antepartum haemorrhage, and Caesarean delivery. PP increased odds of fetal Malpresentation and early neonatal death. Conclusion. The prevalence of PP was comparable to that found in past research. Multiple independent risk factors were identified. PP was found to have associations with several adverse fetomaternal outcomes. Early identification of women at risk of PP may help clinicians prevent such complications.

  8. Placenta Previa Percreta: A Case Report of Successful Management via Conservative Surgery

    Directory of Open Access Journals (Sweden)

    Silvia Canonico

    2013-01-01

    Full Text Available Placenta percreta is one of the most serious complications of placenta previa and is frequently associated with severe obstetric hemorrhage usually necessitating hysterectomy. We present a case of placenta previa percreta diagnosed by ultrasound and magnetic resonance imaging techniques, in which we accomplished conservative management of postpartum hemorrhage. The management we propose includes the following steps: preventive catheterization of the descending aorta via transhumeral access; Stark cesarean delivery; uterotonics drugs; Affronti endouterine square hemostatic sutures; intrauterine application of Bakri balloon and partial filling with 100 mL of normal saline; B Lynch suture, hysterorrhaphy, and filling a Bakri balloon with up to 500 mL of normal saline; reversible radiological embolization; and/or surgical ligation of the uterine arteries. The bleeding stopped following placement of Affronti sutures combined with external (B-Lynch suture and internal (Bakri balloon uterine compression. Our experience indicates that this conservative method can be considered an option in the management of selected cases of pregnancy at high risk for intrapartum hemorrhage.

  9. Impact of targeted scanning protocols on perinatal outcomes in pregnancies at risk of placenta accreta spectrum or vasa previa.

    Science.gov (United States)

    Melcer, Yaakov; Jauniaux, Eric; Maymon, Shlomit; Tsviban, Anna; Pekar-Zlotin, Marina; Betser, Moshe; Maymon, Ron

    2018-04-01

    Placenta accreta spectrum and vasa previa (VP) are congenital disorders of placentation associated with high morbidity and mortality for both mothers and newborns when undiagnosed before delivery. Prenatal diagnosis of these conditions is essential to allow multidisciplinary management and thus improve perinatal outcomes. The objective of the study was to compare perinatal outcome in women with placenta accreta spectrum or vasa previa before and after implementation of targeted scanning protocols. This retrospective study included 2 nonconcurrent cohorts for each condition before and after implementation of the corresponding protocols (2004-1012 vs 2013-2016 for placenta accreta spectrum and 1988-2007 vs 2008-2016 for vasa previa). Clinical reports of women diagnosed with placenta accreta spectrum and vasa previa during the study periods were reviewed and outcomes were compared. In total, there were 97 cases of placenta accreta spectrum and 51 cases with vasa previa, all confirmed at delivery. In both cohorts, the prenatal detection rate increased after implementation of the scanning protocols (28 of 65 cases [43.1%] vs 31 of 32 cases [96.9%], P accreta spectrum and 9 of 18 cases [50%] vs 29 of 33 cases [87.9%], 87.9%, P accreta spectrum cohort, the estimated blood loss and the postoperative hospitalization stay decreased between periods (1520 ± 845 vs 1168 ± 707 mL, P accreta spectrum and vasa previa was associated with improved maternal and neonatal outcomes. The continuous increases in the rates of caesarean deliveries and use of assisted reproductive technology highlights the need to develop training programs and introduce targeted scanning protocols at the national and international levels. Copyright © 2018 Elsevier Inc. All rights reserved.

  10. SINTESIS DAN KARAKTERISASI BIODIESEL DARI MINYAK KEMIRI SUNAN (Reutealis trisperma DENGAN VARIASI KONSENTRASI KATALIS NAOH

    Directory of Open Access Journals (Sweden)

    Holilah -

    2014-06-01

    Full Text Available Sintesis biodiesel dari minyak Kemiri Sunan (Reutealis trisperma (RTO menggunakan NaOH sebagai katalis dengan variasi konsentrasi katalis yaitu 0,5; 1,0; 1,5 dan 2,0 wt% telah diteliti. Minyak kemiri sunan (Reutealis trisperma adalah bahan baku yang menarik untuk produksi biodiesel. Biodiesel disintesis dengan dua tahap reaksi yaitu esterifikasi menggunakan katalis H2SO4 dan transesterifikasi dengan menggunakan katalis NaOH. Dalam penelitian ini, diteliti pengaruh konsentrasi katalis terhadap produk biodisel serta dan karakteristiknya. Hasil penelitian menunjukkan bahwa yield biodiesel meningkat seiring dengan meningkatnya konsentrasi katalis dari 0,5-1,0 wt%, selanjutnya dengan meningkatnya konsentrasi katalis dari 1,5-2,0 wt% membuat yield menurun. Yield optimum dicapai pada 84,7%. FAME (fatty  acid  methyl  ester diperoleh dengan konsentrasi katalis 1 wt% pada kondisi reaksi 65°C, waktu reaksi 1 jam dan rasio metanol minyak 1:2 (wt/wt. Karakteristik biodiesel diamati dengan uji standart bahan bakar dan hasilnya dibandingkan dengan standart ASTM D6751-02. Karakteristik biodiesel yang disintesis dengan konsentrasi katalis NaOH 1% adalah angka asam (0,55 mg KOH/g, densitas (0,90 gr/cm3, viskositas pada 40°C (9,2 cSt, angka setana (54,5 dan residu karbon (0,24 wt%/wt. This research was investigated bio diesel synthesis of Reutealis trisperma oil (RTO by using NaOH as a catalist with variation of catalyst concentration as follow 0.5; 1.0; 1.5 and 2,0 wt% . Reutealis trisperma oil is an attractive raw material for  bio diesel production. It was produced by two steps of reactions, they are esterification by using H2SO4 catalyst and transesterification by using NaOH catalyst. This study examined the effect of catalyst concentration on the yield of biodiesel and their selected properties. The result showed, that the bio diesel yield  with catalyst concentration increasing from 0,5-1,0 wt%, increased, while increasing the concentration from 1

  11. PENGARUH KATALIS BASA (NaOH PADA TAHAP REAKSI TRANSESTERIFIKASI TERHADAP KUALITAS BIOFUEL DARI MINYAK TEPUNG IKAN SARDIN

    Directory of Open Access Journals (Sweden)

    Diah Probo Ningtyas

    2013-06-01

    The research purpose has studied the influence of NaOH concentration in transesterification process and examinate its effect on the quality of biofuels production, conversion, and physic quality. The variables that analysed was the effect of NaOH concentration as catalyst (0.5%, 1.0%, 1.5%, and 2.0% from amount of oil and methanol in the transesterification reaction step. The result showed that the increasing NaOH concentration (0.5 - 1.5%, enhanced the biofuel conversion (%. The highest conversion of biofuels was achieved by using 1.50% NaOH (w/w with 45.34% biofuels conversion. The major component in the biofuels was methyl palmitate (20.31%. ASTM analysis data also supported that the biofuel product was in agreement with automotive diesel fuel specification.

  12. Improvement of selective removal of heavy metals in cyanobacteria by NaOH treatment.

    Science.gov (United States)

    Nagase, Hiroyasu; Inthorn, Duangrat; Oda, Aiko; Nishimura, Jun; Kajiwara, Yumiko; Park, Myong-Oku; Hirata, Kazumasa; Miyamoto, Kazuhisa

    2005-04-01

    In the freshwater cyanobacterium, Tolypothrix tenuis, treatment with 0.1 M NaOH increased its Cd-selective adsorption ability in the presence of Ca(2+) or Mg(2+). The selective adsorption was also achieved by other alkaline treatments. Energy-distributed spectroscopy analysis revealed that Cd(2+) was found mainly on the surface of non-treated cells, whereas it was distributed throughout the cell after NaOH treatment. The alkaline treatment was effective in increasing the selective adsorption ability of the cyanobacterium for other bivalent heavy metals such as Cu(2+), Pb(2+) and Zn(2+). The treatment was also applicable to Anabaena variabilis and Microcystis aeruginosa, which are typical cyanobacteria causing algal blooms. The main binding site of Cd(2+) in NaOH-treated cells is assumed to be the carboxyl groups because the binding ability of the cells was diminished by the esterification of carboxyl groups. These results suggest that alkaline treatment of cyanobacteria is a useful technique for producing biosorbents having highly specific binding abilities for heavy metals.

  13. The Electrochemical Characteristics of Hybrid Capacitor Prepared by Chemical Activation of NaOH

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Jeong Eun; Bae, Ga Yeong; Yang, Jeong Min; Lee, Jong Dae [Chungbuk National Univ., Chungju (Korea, Republic of)

    2013-06-15

    Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481m{sup 2}/g) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using LiMn{sub 2}O{sub 4}, LiCoO{sub 2} as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes (LiPF{sub 6}, TEABF{sub 4}) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using LiMn{sub 2}O{sub 4}/AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg.

  14. The Electrochemical Characteristics of Hybrid Capacitor Prepared by Chemical Activation of NaOH

    International Nuclear Information System (INIS)

    Choi, Jeong Eun; Bae, Ga Yeong; Yang, Jeong Min; Lee, Jong Dae

    2013-01-01

    Active carbons with high specific surface area and micro pore structure were prepared from the coconut shell char using the chemical activation method of NaOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to char ratio and the flow rate of gas during carbonization. The active carbons with the surface area (2,481m 2 /g) and mean pore size (2.32 nm) were obtained by chemical activation with NaOH. The electrochemical performances of hybrid capacitor were investigated using LiMn 2 O 4 , LiCoO 2 as the positive electrode and prepared active carbon as the negative electrode. The electrochemical behaviors of hybrid capacitor using organic electrolytes (LiPF 6 , TEABF 4 ) were characterized by constant current charge/discharge, cyclic voltammetry, cycle and leakage tests. The hybrid capacitor using LiMn 2 O 4 /AC electrodes had better capacitance than other hybrid systems and was able to deliver a specific energy as high as 131 Wh/kg at a specific power of 1,448 W/kg

  15. Effect OF NaOH Treatment on Bending Strength Of The Polyester Composite Reinforce By Sugar Palm Fibers

    Science.gov (United States)

    Arif Irfai, Mochamad; Wulandari, Diah; Sutriyono; Marsyahyo, Eko

    2018-04-01

    The objective of this research is to investigate the effect of NaOH treatment on bending strength of lamina composite reinforced by sugar palm fiber. To know of mechanism fracture can be done with visual inspection of the fracture surface. The Materials used are random sugar palm fibers that have been in the treatment of NaOH, polyester resin and hardener. Sugar palm fibers after washed and dried then soaked NaOH with a long time soaking 0, 2, 4, 6 and 8 hours. The bending test specimens were produced according to ASTM D 790. All specimens were post cured at 62°C for 4 hours. The Bending test was carried out on a universal testing machine. The SEM analysis has conducted to provide the analysis on interface adhesion between the surfaces of fiber with the matrix. The result shows that polyester composite reinforced by sugar palm fiber has highest bending stress 176.77 N/mm2 for 2 hours of a long time soaking NaOH, the highest flexural strain 0.27 mm for 2 hours of a long time soaking NaOH, elongation 24.05% for 2 hours of a long time soaking NaOH and the highest bending modulus 1.267 GPa for 2 hours of a long time soaking NaOH. Based on the results, it can be concluded that the polyester composite reinforced by sugar palm fiber has the optimum bending properties for a long time soaking 2 hours. The fracture surface shows that the polyester composite reinforced by sugar palm fiber pull out that indicate weakens the bond between fiber and matrix.

  16. Solubility of flue gas components in NaOH based scrubber solutions

    Energy Technology Data Exchange (ETDEWEB)

    Sandelin, K; Backman, R

    1997-11-01

    The work reported here is a thermodynamic study on the solubility of flue gas components in aqueous solutions containing sodium salts. The result of the work is an equilibrium model. The model presented here includes sodium hydroxide and sodium salts that makes it possible to study simultaneous absorption of flue gas components in alkaline scrubber solutions. The model is applied on the absorption of a flue gas into a NaOH scrubber solution. The calculations show that it is possible to simultaneously absorb sulfur dioxide, sulfuric acid, and ammonia without carbon dioxide co-absorption. The calculations also show that gaseous NO and N{sub 2}O cannot be scrubbed unless they are oxidized to nitrate or reduced to ammonia. (author) SIHTI 2 Research Programme. 59 refs.

  17. Semiconducting properties of oxide films formed onto an Nb electrode in NaOH solutions

    Directory of Open Access Journals (Sweden)

    VLADIMIR D. JOVIC

    2008-03-01

    Full Text Available In this paper, the results of the potentiostatic formation of homogeneous and heterogeneous, nano-crystalline passive films of Nb2O5 onto an Nb electrode in NaOH solutions of different concentrations at potentials lower than 3.0 V vs. SCE are presented. The semiconducting properties of such films were investigated by EIS measurements. After fitting the EIS results by appropriate equivalent circuits, the space charge capacitance (Csc and space charge resistance (Rsc of these films were determined. The donor density (Nsc, flat band potential (Efb and thickness of the space charge layer (dsc for such oxide films were determined from the corresponding Mott–Schottky (M–S plots. It is shown that all oxide films were n-type semiconductors in a certain potential range.

  18. Dissolution of B-doped S1(100) layers in NaOH aqueous solutions

    International Nuclear Information System (INIS)

    Akhter, P.; Baig, A.; Mufti, A.

    1988-12-01

    NaOH solution has been used to study the dissolution rates of boron doped Sl(100) wafers as a function of solution normality (0.02 N to 15 N) and temperature in the range of 30 deg. C to boiling point. For a dissolution at boiling point, two distinctive ranges of solution normalities have been observed. For N ≤ 4.5, the dissolution rate increases logarithmically and is defect dependent. For higher values of N ≥ 4.5 normal, the dissolution rate becomes a linear function of normality and reaction is defect dependent. The reaction activation energy has been measured equal to 0.65 +- 0.03 eV. (author). 7 refs, 5 figs

  19. PENGARUH KATALIS BASA (NaOH PADA TAHAP REAKSI TRANSESTERIFIKASI TERHADAP KUALITAS BIOFUEL DARI MINYAK TEPUNG IKAN SARDIN

    Directory of Open Access Journals (Sweden)

    Diah Probo Ningtyas

    2013-06-01

    Full Text Available Biofuel is an alternative diesel engine fuel is produced from oils/fats of plants and animals (including the fisheries industry waste through the esterification and transesterifiksi reactions. A transesterification is reaction to form esters and glycerol from trigliserin (fat/oil and bioalcohol (methanol or ethanol. Transesterification is an equilibrium reaction so that the presence of a catalyst can accelerate the achievement of a state of equilibrium. Process of the transesterification reaction of sardine flour oil waste with NaOH as base catalyst in producing biofuels was conducted.The research purpose has studied the influence of NaOH concentration in transesterification process and examinate its effect on the quality of biofuels production, conversion, and physic quality. The variables that analysed was the effect of NaOH concentration as catalyst (0.5%, 1.0%, 1.5%, and 2.0% from amount of oil and methanol in the transesterification reaction step. The result showed that the increasing NaOH concentration (0.5 - 1.5%, enhanced the biofuel conversion (%. The highest conversion of biofuels was achieved by using 1.50% NaOH (w/w with 45.34% biofuels conversion. The major component in the biofuels was methyl palmitate (20.31%. ASTM analysis data also supported that the biofuel product was in agreement with automotive diesel fuel specification.

  20. Pembuatan Biodiesel Dari Minyak Kelapa Dengan Katalis NaOH Menggunakan Gelombang Mikro (Microwave Secara Kontinyu

    Directory of Open Access Journals (Sweden)

    Daru Satria Prayanto

    2016-04-01

    Full Text Available Biodiesel merupakan bioenergi atau bahan bakar nabati yang dibuat dari minyak nabati melalui proses transesterifikasi, esterifikasi, atau proses esterifikasi-transesterifikasi. Proses pembuatan biodiesel dapat dilakukan dengan metode pemanasan konvensional maupun dengan metode pemanasan microwave. Dengan radiasi microwave, maka waktu yang dibutuhkan saat proses transesterifikasi lebih singkat dibandingkan dengan konvensional. Disisi lain, minyak kelapa memiliki potensi yang besar untuk digunakan sebagai bahan baku dalam pembuatan biodiesel karena ketersediaannya yang melimpah. Penelitian ini bertujuan untuk membuat biodiesel dari minyak kelapa secara kontinyu melalui proses transesterifikasi metanol dengan menggunakan radiasi microwave dengan katalis NaOH dan mempelajari pengaruh konsentrasi tiap katalis, daya, dan laju umpan yang digunakan terhadap yield, densitas, dan viskositas biodiesel yang dihasilkan. Dalam penelitian ini di gunakan 3 variabel, yaitu laju umpan 0,73; 1,25; 1,72 ml/s, konsentrasi katalis 0,25; 0,5; 1 (% berat variabel daya microwave 100, 264, 400, 600, dan 800 Watt. Rasio umpan ditentukan pada 1:9. Pada tahap persiapan melarutkan metanol dan katalis sesuai dengan variabel hingga tercampur homogen. Selanjutnya tahap transesterifikasi dengan mencampurkan larutan metanol (metanol dan katalis dengan minyak kelapa dengan mol ratio yang telah ditentukan dan mengatur daya microwave untuk memulai proses transesterifikasi, proses berlangsung secara kontinyu menggunakan mix flow reaktor. Selanjutnya pemisahan hasil transesterifikasi dari gliserol, dilanjutkan dengan tahap pencucian dengan aquadest untuk memisahkan impurities dan katalis yang masih tersisa dalam biodiesel kemudian memanaskan pada oven untuk menguapkan kandungan air dalam biodiesel. Selajutnya menganalisisa hasil biodiesel terhadap yield, densitas, dan viskositasnya. Hasil terbaik dari variabel yang digunakan di atas adalah pada katalis NaOH dengan konsentrasi 1

  1. Effects of Etching Time and NaOH Concentration on the Production of Alumina Nanowires Using Porous Anodic Alumina Template

    Science.gov (United States)

    Sadeghpour-Motlagh, M.; Mokhtari-Zonouzi, K.; Aghajani, H.; Kakroudi, M. Ghassemi

    2014-06-01

    In this work, two-step anodizing of commercial aluminum foil in acid oxalic solution was applied for producing alumina film. Then the anodic alumina film was etched in sodium hydroxide (NaOH) solution resulting dense and aligned alumina nanowires. This procedure leads to splitting of alumina nanotubes. Subsequently nanowires are produced. The effects of NaOH solution concentration (0.2-1 mol/L) and etching time (60-300 s) at constant temperature on characteristic of nanotubes and produced nanowires were investigated using scanning electron microscopy. The results show that an increase in NaOH solution concentration increases the rate of nanowires production and in turn the manipulation process will be more specific.

  2. A novel rate of the reaction between NaOH with CO2 at low temperature in spray dryer

    Directory of Open Access Journals (Sweden)

    Yadollah Tavan

    2017-03-01

    Full Text Available Carbon dioxide (CO2 is an influential greenhouse gas that has a significant impact on global warming partly. Nowadays, many techniques are available to control and remove CO2 in different chemical processes. Since the spray dryer has high removal efficiency rate, a laboratory-scale spray dryer is used to absorb carbon dioxide from air in aqueous solution of NaOH. In the present study, the impact of NaOH concentration, operating temperature and nozzle diameter on removal efficiency of CO2 is explored through experimental study. Moreover, the reaction kinetic of NaOH with CO2 is studied over the temperature range of 50–100 °C in a laboratory-scale spray dryer absorber. In the present contribution, a simple reaction rate equation is proposed that shows the lowest deviation from the experimental data with error less than 2%.

  3. PENGARUH PERENDAMAN TULANG IKAN TUNA (Thunnus albacares DALAM LARUTAN NaOH TERHADAP KUALITAS GELATIN HASIL OLAHANNYA

    Directory of Open Access Journals (Sweden)

    Tazwir Tazwir

    2009-06-01

    Full Text Available Gelatin tulang ikan tuna (Thunnus albaceres dengan kualitas baik seringkali sulit diperoleh, karena kebanyakan produk ini mengandung lemak dan protein non kolagen yang cukup tinggi. Dalam memproduksi gelatin tulang tuna, lemak, dan protein non kolagen tersebut harus direduksi hingga batas minimum. Dalam penelitian ini dipelajari pengaruh perendaman tulang ikan tuna dalam larutan NaOH sebelum ekstraksi terhadap kualitas gelatin yang dihasilkan. Tahapan yang dilakukan adalah degreasing, pencucian, perendaman dalam NaOH dengan variasi konsentrasi 0; 0,4; dan 0,8%, kemudian perendaman dalam HCl, ekstraksi, filtrasi, evaporasi, dan pengeringan. Hasil penelitian menunjukkan bahwa karakteristik gelatin yang terbaik diperoleh dari perendaman tulang dalam NaOH 0,4%, yaitu dengan nilai rendemen 8,37%; viskositas 3,27-3,37 cPs; pH 5,03; dan kekuatan gel 157,8 g Bloom gel strength.

  4. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

    Directory of Open Access Journals (Sweden)

    Rafiza Abdul Razak

    2015-05-01

    Full Text Available This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA using LUSI (Sidoarjo mud and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced.

  5. Optimization of NaOH Molarity, LUSI Mud/Alkaline Activator, and Na2SiO3/NaOH Ratio to Produce Lightweight Aggregate-Based Geopolymer

    Science.gov (United States)

    Abdul Razak, Rafiza; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Ismail, Khairul Nizar; Hardjito, Djwantoro; Yahya, Zarina

    2015-01-01

    This paper presents the mechanical function and characterization of an artificial lightweight geopolymer aggregate (ALGA) using LUSI (Sidoarjo mud) and alkaline activator as source materials. LUSI stands for LU-Lumpur and SI-Sidoarjo, meaning mud from Sidoarjo which erupted near the Banjarpanji-1 exploration well in Sidoarjo, East Java, Indonesia on 27 May 2006. The effect of NaOH molarity, LUSI mud/Alkaline activator (LM/AA) ratio, and Na2SiO3/NaOH ratio to the ALGA are investigated at a sintering temperature of 950 °C. The results show that the optimum NaOH molarity found in this study is 12 M due to the highest strength (lowest AIV value) of 15.79% with lower water absorption and specific gravity. The optimum LUSI mud/Alkaline activator (LM/AA) ratio of 1.7 and the Na2SiO3/NaOH ratio of 0.4 gives the highest strength with AIV value of 15.42% with specific gravity of 1.10 g/cm3 and water absorption of 4.7%. The major synthesized crystalline phases were identified as sodalite, quartz and albite. Scanning Electron Microscope (SEM) image showed more complete geopolymer matrix which contributes to highest strength of ALGA produced. PMID:26006238

  6. Feasibility study of NaOH regeneration in acid gas removal unit using membrane electrolysis

    Science.gov (United States)

    Taufany, Fadlilatul; Pratama, Alvian; Romzuddin, Muhammad

    2017-05-01

    The world's energy demand is increasing with the development of human civilization. Due to limited energy resource, after 2020 fossil fuels thus is predicted will be replaced by renewable resources. Taking an example, one of the potential renewable energy to be considered is biogas, as its high content of methane, which can be produced via the fermentation process of the organic compounds under controlled anaerobic environment by utilizing the methanogen bacteria. However, prior the further use, this biogas must be purified from its impurities contents, i.e. acid gas of CO2 and H2S, up to 4% and 16 ppmv, respectively, in the acid gas removal unit. This such of purification efforts, will significantly increase the higher heating value of biogas, approximately from 600 to 900 Btu/Scf. During the purification process in this acid gas removal unit, NaOH solution is used as a liquid absorbent to reduce those acid gases content, in which the by-product of alkali salt (brine) was produced as waste. Here we report the feasibility study of the NaOH regeneration process in acid gas removal unit via membrane electrolysis technology, in which both the technical and economic aspects are taken account. To be precise in procedure, the anode semi-cell was filled with the brine solution, while the cathode semi-cell was filled with demineralized water, and those electrodes were separated by the cation exchange membrane. Furthermore, the applied potential was varied ranging from 5, 10, 15 and to 20 V, while the concentration of KCl electrolyte solutions were varied ranging from 0.01, 0.05, 0.1, and to 0.03 M. This study was conducted under controlled temperatures of 30 and 50 °C. Here we found that the % sodium recovery was increased along with the applied potential, temperature, and the decrease in KCl electrolyte concentration. We found that the best results, by means of the highest % sodium recovery, i.e. 97.26 %, was achieved under the experimental condition of temperature at 30

  7. Valorisation of Jatropha curcas: Solubilisation of proteins and sugars from the NaOH extracted de-oiled press cake

    NARCIS (Netherlands)

    Kootstra, A.M.J.; Beeftink, H.H.; Sanders, J.P.M.

    2011-01-01

    In this study, we investigated the possibilities for increasing the valorisation of de-oiled Jatropha press cake (DO-JPC). The studied raw material is the by-product of the alkaline protein extraction of the DO-JPC: NaOH Extracted DO-JPC (NEDO-JPC). Protein solubilisation of NEDO-JPC was performed

  8. Function of NaOH hydrolysis in electrospinning ZnO nanofibers via using polylactide as templates

    International Nuclear Information System (INIS)

    Liu, Mengzhu; Wang, Yongpeng; Cheng, Zhiqiang; Song, Lihua; Zhang, Mingyue; Hu, Meijuan; Li, Junfeng

    2014-01-01

    Graphical abstract: - Highlights: • PLA was used as templates to electrospin ZnO nanofibers for the first time. • Without NaOH hydrolysis, only ZnO film was prepared. • Under function of NaOH, ZnO nanofibers were obtained. • The function of NaOH was discussed. • ZnO nanofibers showed much higher photocatalytical efficiency than ZnO film. - Abstract: Mixture of polylactide (8 wt%), zinc acetate (6 wt%) and hexafluoroisopropanol was first used as electrospinning solution to fabricate ZnO nanofibers. Unfortunately, after direct calcination of the precursor polylactide/zinc acetate nanofibers, only ZnO film was prepared. Surprisingly, when the precursor fibers were pre-hydrolyzed with NaOH, ZnO nanofibers with diameter of 678 nm were obtained. The mechanism analysis showed that the preserve of fiber structure was attributed to the formation of zinc polylactic acid in the process of hydrolyzation. After characterized by scanning electron microscope and transmission electron microscope, the ZnO film was found to be an aggregation of irregular nanoparticles and the ZnO nanofiber was a necklace-like arrangement of cylindrical grains. X-ray diffraction and photoluminescence measurements indicated that the crystalline quality of the ZnO nanofibers was higher than the film. Furthermore, photocatalytic performance of the ZnO samples was investigated. Comparing with ZnO film, ZnO nanofibers exhibited much higher activity

  9. The Effect of NaOH Concentration on pH, Egg White Protein Content and Yolk Colour Pidan Egg

    Directory of Open Access Journals (Sweden)

    Herly Evanuarini

    2017-11-01

    Full Text Available The purpose of this research was to determine the best treatment NaOH addition on pidan eggs. The materials used for this research was pidan made from duck egg, NaOH, salt, black tea and water. The method was used experiment laboratory and Completely Randomized Design (CRD using 4 treatments and 4 replications. The treatments were T0 (control, T1 (1.4%, T2 (2.8% and T3 (4.2%. The data were analyzed by Analysis of Variance (ANOVA if there was significantly continued by Duncan’s Multiple Range Test (DMRT. The result showed that NaOH concentration on pidan eggs gave significant effect (P<0.05 on albumen protein content, gave highly significant (P<0.01 on pH value and yolk colour. The conclusion of this research was 4.2% NaOH addition on pidan egg was the best treatment with gave result yolk and albumen pH: 10.69; 10.25, albumen protein content 26.89%, egg yolk colour L* (lightness, a* (redness, b* (yellowness:  26.89; 11.33, and 26.77. The suggestion of this research was ussed different immersion time on pidan egg production.

  10. Reliability of trans-abdominal ultrasonography in determining exact location of placenta in patients of placenta previa major

    International Nuclear Information System (INIS)

    Zafar, M.; Hayat, N; Gul, U.

    2017-01-01

    Objective: To determine the reliability of trans-abdominal ultrasonographical localization of placenta in cases of placenta previa major, by taking peroperative finding as gold standard. Study Design: Validation study. Place and Duration of Study: Maternity ward, Obstetrics and Gynecology department, Military Hospital Rawalpindi from 2007 to 2008. Patients and Methods: A total of 100 patients fulfilling the inclusion and exclusion criteria were recruited for the study. These patients were admitted to the maternity ward, where trans-abdominal ultrasound was performed, site of the placenta and its relation to the internal os was documented. These patients under went elective cesarean section, during which the site and relation of the placenta to the internal os was confirmed. Results: The mean age of patients was 34.23 +- 6.76 years. Transabdominal ultrasound had a sensitivity of 93.4 percent in localizing major placenta previa while the specificity was 83 percent. Positive predictive value was 94.7 percent, negative predictive value was 80 percent and accuracy 91 percent. Conclusion: Trans-abdominal ultrasound was found highly effective in diagnosing and localizing placenta previa. (author)

  11. Resistivity and Passivity Characterization of Ni-Base Glassy Alloys in NaOH Media

    Directory of Open Access Journals (Sweden)

    Khadijah M. Emran

    2018-01-01

    Full Text Available Resistivity and passivation behavior of two Ni-base bulk metallic glasses, with the nominal composition of Ni70Cr21Si0.5B0.5P8C ≤ 0.1Co ≤ 1Fe ≤ 1 (VZ1 and Ni72.65Cr7.3-Si6.7B2.15C ≤ 0.06Fe8.2Mo3 (VZ2, in various concentrations of NaOH solutions were studied. The investigations involved cyclic polarization (CP, electrochemical impedance spectroscopy (EIS, and electrochemical frequency modulation (EFM methods. Cyclic polarization measurements showed spontaneous passivation for both Ni-base glassy alloys at all alkaline concentrations, due to the presence of chromium as an alloying element that formed an oxide film on the alloy surface. The EIS analysis showed that the passive layers grown on the two Ni-base glassy alloy surfaces are formed by a double oxide layer structure. Scanning electron microscope (SEM examinations of the electrode surface showed Cr, Ni, Fe, and O rich corrosion products that reduced the extent of corrosion damage. Atomic force microscopy (AFM imaging technique was used to evaluate the topographic and morphologic features of surface layers formed on the surface of the alloys.

  12. Effect of Different Concentration of Sodium Hydroxide [NaOH] on Kenaf Sandwich Structures

    Science.gov (United States)

    Aziz, M.; Halim, Z.; Othman, M.

    2018-01-01

    Sandwich panels are structures that made of three layers, low-density core inserted in between thin skin layers. This structures allow the achievement of excellent mechanical performance with low weight, thus this characteristic fulfil requirement to be use in aircraft application. In recent time, sandwich structures have been studied due to it has multifunction properties and lightweight. The aim of this study is to fabricate a composite sandwich structures with biodegradable material for face sheet [skin] where the fibre being treat with different concentration of sodium hydroxide [NaOH] with 10 and 20 hours of soaking time. Kenaf fibre [treated] reinforced epoxy will be used as skins and Nomex honeycomb is chosen to perform as core for this sandwich composite structure. The mechanical properties that are evaluated such as flexural strength and impact energy of kenaf fibre-reinforced epoxy sandwich structures. For flexural test, the optimum flexural strength is 13.4 MPa and impact strength is 18.3 J.

  13. Enhanced hydrogen entry into iron from 0.1 M NaOH at definite potentials

    International Nuclear Information System (INIS)

    Flis-Kabulska, I.; Flis, J.; Zakroczymski, T.

    2008-01-01

    This work aimed at explaining the enhancement of hydrogen entry into iron from alkaline solution occurring at definite potentials. Hydrogen permeation rate (HPR) through a 35-μm thick iron membrane was measured with the electrochemical technique in 0.1 M NaOH at 25 deg. C during cathodic and anodic polarizations. Enhanced HPR was observed at potentials of oxide reduction or iron oxidation, and potentials more cathodic than about -1.65 V NHE during prolonged galvanostatic polarization. XPS analysis showed that after the polarization, surface layers contained hydrated iron oxides and that amount of these products increased with the polarization time. It is suggested that the enhanced hydrogen entry can be explained by acidification of the near-metal solution due to iron oxidation and/or oxide reduction, and probably by a promoting effect of some Fe-O species. It is proposed that these effects are associated with surface layers. They can affect hydrogen entry as a source of protons in the oxide reduction, as a diffusion barrier making the near-metal acidification possible, and as a resistance causing an IR drop. Strong enhancement of HPR after prolonged galvanostatic polarizations can be associated with the formation of thick surface layers with IR drop enabling anodic oxidation of iron under these layers

  14. Promotion of hydrogen entry into iron from NaOH solution by iron-oxygen species

    International Nuclear Information System (INIS)

    Flis-Kabulska, I.; Flis, J.; Zakroczymski, T.

    2007-01-01

    This study was carried out to explain reasons of the enhanced hydrogen entry into iron at low polarisations. Hydrogen permeation rate (HPR) through a 35-μm thick iron membrane was studied with the electrochemical technique in 0.1 M NaOH at 25 o C. A rotating split-ring disk electrode was used to detect soluble Fe(II) species. Enhanced hydrogen entry (HPR peaks) was observed at low cathodic and low anodic polarisations during voltammetric cycling, and also during galvanostatic anodic polarisation applied after cathodic charging. HPR peaks occurred at potentials from about -1.2 to -0.9 V (NHE) which were more cathodic than the potentials of thermodynamic stability of Fe(OH) 2 or Fe 3 O 4 , and of the formation of soluble Fe(II) species. It has been suggested that the enhanced hydrogen entry is associated with the presence of FeOH ad . In this species oxygen is bound with hydrogen (oxo-hydride), hence it can be supposed that the mechanism of its promoting effect can be similar to that of hydrides of other elements of the VIb group

  15. The effects of H2SO4 and NaOH solutions on irradiated sawdust for ethanol production

    International Nuclear Information System (INIS)

    Lina, M.R.; Susiana; Siagian, E.G.

    1988-01-01

    The research of gamma irradiated sawdust, which were added H2SO4 and NaOH solutions on fermentation process for ethanol production was investigated. Irradiation doses used were : 0 and 200 kGy, while H2SO4 and NaOH solutions had concentrations of 0,1 and 2% (v/v) and (b/v), with a ratio of sawdust weight and solution volume = 1:3. Fine powder of sawdust with a mesh of 60, was hydrolysed by enzyme (cellulase), S.cerevisiae was a yeast used for fermentation process and fermentation time was 4 hours. From the experimental results showed that irradiation doses up to 200 kGy, could increase the ethanol concentration from sawdust fermentation signivicantly (P= . Irradiation treatment, addition of the solutions and its interaction could not influence the total carbohydrate before and after fermentation. (author). 9 refs, 2 figs, 6 tabs

  16. Production of hydrogen in the reaction between aluminum and water in the presence of NaOH and KOH

    Directory of Open Access Journals (Sweden)

    C. B. Porciúncula

    2012-06-01

    Full Text Available The objective of this work is to investigate the production of hydrogen as an energy source by means of the reaction of aluminum with water. This reaction only occurs in the presence of NaOH and KOH, which behave as catalysts. The main advantages of using aluminum for indirect energy storage are: recyclability, non-toxicity and easiness to shape. Alkali concentrations varying from 1 to 3 mol.L-1 were applied to different metallic samples, either foil (0.02 mm thick or plates (0.5 and 1 mm thick, and reaction temperatures between 295 and 345 K were tested. The results show that the reaction is strongly influenced by temperature, alkali concentration and metal shape. NaOH commonly promotes faster reactions and higher real yields than KOH.

  17. A quick method for maintaining the molarity of NaOH solution during continuous etching of CR-39

    International Nuclear Information System (INIS)

    Khan, E.U.; Husaini, S.N.; Malik, F.; Sajid, M.; Karim, S.; Qureshi, I.E.

    2002-01-01

    A series of experiments have been performed to investigate the physio-chemical changes that occurred in the 6 M NaOH solution after etching CR-39 (Pershore and Homalite) detectors, each for 3, 6, 9, 12 and 15 h. Various physical parameters like concentration, electrical conductivity (EC) and density of the solutions have been measured after each etching interval. Results have been discussed in the light of stoichiometrical equation for the interaction of CR-39 with NaOH. It is found that the concentration, EC and the density of the solution, in which CR-39 has been etched, increase linearly with respect to the etching time. The inter-relationship of EC-concentration and density-concentration suggest that the concentration of the etchant can be maintained at certain desired value by adjusting the corresponding value of EC or density, measured through non-destructive and quick methods

  18. Enhanced ethanol and glucosamine production from rice husk by NAOH pretreatment and fermentation by fungus Mucor hiemalis

    Directory of Open Access Journals (Sweden)

    Maryam Omidvar

    2016-09-01

    Full Text Available Ethanol production from rice husk by simultaneous saccharification and fermentation using Mucor hiemalis was investigated. To reach the maximum ethanol production yield, the most important influencing factors in the pretreatment process, including temperature (0-100°C, NaOH concentration (1-3 M, and the pretreatment time (30-180 min, were optimized using an experimental design by a response surface methodology (RSM. The maximum ethanol production yield of 86.7 % was obtained after fungal cultivation on the husk pretreated with 2.6 M NaOH at 67°C for 150 min. This was higher than the yield of 57.7% obtained using Saccharomyces cerevisiae as control. Furthermore, fermentation using M. hiemalis under the optimum conditions led to the production of a highly valuable fungal biomass, containing 60 g glucosamine (GlcN, 410 g protein, and 160 g fungal oil per each kg of the fungal biomass.

  19. Penentuan Jumlah NaOH yang Dibutuhkan pada Unit Gliserin Destilasi dan Pemutihan dengan Parameter Bilangan Penyabunan

    OpenAIRE

    Damanik, Maria E.P

    2015-01-01

    Ecogreen Oleochemicals Co., is one of oleochemical industry manufacturing raw material of palm oil to be fatty acid, glycerine and alcohol. Before processing, characteristic treatment is necessary to do earlier is saponification value. Determination of saponification value can do by using titration method. Given the large number of NaOH, the low number of high influence saponification value. This data according to standart methode of Ecogreen Oleochemicals Co. 102401060

  20. Pseudo-ternary phase diagram in the Na2O-Na2O2-NaOH system

    International Nuclear Information System (INIS)

    Saito, Jun-ichi; Tendo, Masayuki; Aoto, Kazumi

    1997-10-01

    Generally, the phase diagrams are always used to understand the present state of compounds at certain temperature. In order to understand the corrosion behavior of structural material for FBR by main sodium compounds (Na 2 O, Na 2 O 2 and NaOH), it is very important to comprehend the phase diagrams of their compounds. However, only Na 2 O-NaOH pseudo-binary phase diagram had been investigated previously in this system. There is no study of other pseudo-binary or ternary phase diagrams in the Na 2 O-Na 2 O 2 -NaOH system. In this study, in order to clarify the present states of their compounds at certain temperatures, the pseudo-binary and ternary phase diagrams in the Na 2 O-Na 2 O 2 -NaOH system were prepared. A series of thermal analyses with binary and ternary component system has been carried out using the differential scanning calorimetry (DSC). The liquidus temperature and ternary eutectic temperatures were confirmed by these measurements. The beneficial indications for constructing phase diagrams were obtained from these experiments. On the basis of these results, the interaction parameters between compounds which were utilized for the Thermo-Calc calculation were optimized. Thermo-Calc is one of thermodynamic calculation software. Consequently the accurate pseudo-binary and ternary phase diagrams were indicated using the optimized parameters. (author)

  1. Activity of NaOH buffered by silicate solids in molten sodium acetate-water at 3170C

    International Nuclear Information System (INIS)

    Weres, O.; Tsao, L.

    1988-01-01

    Silica and sodium acetate are present in the steam generator tube sheet crevices of many nuclear power plants. Trace solutes in the condensate are tremendously concentrated in the crevices by boiling. Sparingly soluble sodium silicates and other solids precipitate from the crevice liquid leaving an extremely concentrated molten mixture of water, sodium acetate and other salts. The precipitates buffer the activity of sodium hydroxide in the superheated liquid that remains. The activity of NaOH corresponding to the buffers quartz/sodium disilicate and sodium disilicate/sodium metasilicate at 317 0 C has been determined experimentally. The sodium hydroxide content of a sodium acetate-water melt buffered by these reactions was determined by chemical analysis, and the corresponding activity of NaOH at temperature was calculated using the recently published Pitzer-Simonson Model of molten salt-water mixtures. The molten mixture of sodium acetate and water plays the role solvent in these experiments and calculations. The free energies of formation of solid sodium silicates at 317 0 C were also determined. The activity of NaOH corresponding to other silicate and phosphate buffers was calculated using published thermodynamic data and estimated from phase diagrams

  2. ACCRETA COMPLICATING COMPLETE PLACENTA PREVIA IS CHARACTERIZED BY REDUCED SYSTEMIC LEVELS OF VASCULAR ENDOTHELIAL GROWTH FACTOR AND EPITHELIAL-TO-MESENCHYMAL TRANSITION OF THE INVASIVE TROPHOBLAST

    Science.gov (United States)

    Wehrum, Mark J.; Buhimschi, Irina A.; Salafia, Carolyn; Thung, Stephen; Bahtiyar, Mert O.; Werner, Erica F.; Campbell, Katherine H.; Laky, Christine; Sfakianaki, Anna K.; Zhao, Guomao; Funai, Edmund F.; Buhimschi, Catalin S.

    2011-01-01

    OBJECTIVE To characterize serum angiogenic factor profile of women with complete placenta previa and determine if invasive trophoblast differentiation characteristic of accreta, increta or percreta shares features of epitehelial-mesenchymal-transition (EMT). STUDY DESIGN We analyzed gestational age matched serum samples from 90 pregnant women with either complete placenta previa (n=45) or uncomplicated pregnancies (n=45). Vascular-endothelial-growth-factor (VEGF), placental-growth-factor (PlGF) and soluble fms-like-tyrosine-kinase-1 (sFlt-1) were immunoassayed. VEGF and phosphotyrosine (P-Tyr) immunoreactivity was surveyed in histological specimens relative to expression of vimentin and cytokeratin-7. RESULTS Women with previa and invasive placentation [accreta (n=5); increta (n=6); percreta (n=2)] had lower systemic VEGF (invasive previa: median [IQR]: 0.8[0.02–3.4] vs. control: 6.5[2.7–10.5] pg/mL, P=0.02). VEGF and P-Tyr immunostaining predominated in the invasive extravillous trophoblasts (EVT) which co-expressed vimentin and cytokeratin-7, a EMT feature and tumor-like cell phenotype. CONCLUSIONS Lower systemic free VEGF and a switch of the interstitial EVT to a metastable cell phenotype characterize placenta previa with excessive myometrial invasion. PMID:21316642

  3. Expectativas previas y satisfacción del usuario en un programa de tratamiento de mantenimiento con metadona

    OpenAIRE

    Forcada Chapa, Rafael; Santos Díez, F. J.; González Monte, Carmen

    2006-01-01

    Los indicadores de satisfacción miden el grado de conformidad con la atención recibida y se construyen en base a las apreciaciones subjetivas de los pacientes. Los factores que influyen en la percepción de los tratamientos con metadona son: la utilización del fármaco, las listas de espera y la influencia sobre aspectos laborales. Se plantea este estudio con los objetivos de conocer las expectativas de los pacientes, previas al inicio de un programa de tratamiento con metadona y estudiar el gr...

  4. CATEGORIZACIÓN DE LAS IDEAS PREVIAS DE LOS ESTUDIANTES DE GRADO SÉPTIMO SOBRE EL CONCEPTO DE RESPIRACIÓN ANIMAL

    Directory of Open Access Journals (Sweden)

    Bayron Gil Bohórquez

    2015-12-01

    Full Text Available La escuela es un escenario de transición desde las ideas previas de los estudiantes hacia formas de comprensión más cercanas a las del conocimiento científico, por ello las ideas previas constituyen el punto de partida más importante en el diseño y la implementación de toda Unidad Didáctica basada en el enfoque de aprendizaje significativo. Se analizaron las ideas previas de 40 estudiantes del grado séptimo (11-15 años de la Institución Educativa Departamental San Gabriel, ubicado en el municipio de Cajicá, Cundinamarca; a través de la aplicación de un instrumento fundamentado en una pregunta abierta ¿Cómo respiramos?, la creación de un mapa conceptual acerca de la respiración en los animales, y un cuestionario con preguntas de selección múltiple y de tipo Falso o Verdadero que permiten conocer lo que el estudiante sabe acerca del concepto de respiración animal. Por último, se realiza la sistematización de datos para un posterior análisis cualitativo de las ideas previas utilizando el programa NVivo 10. Las ideas previas de los estudiantes acerca del concepto de Respiración Animal se asocian principalmente al proceso de intercambio gaseoso. Se observan dificultades para explicar procesos a nivel celular y de tipo estructura-función; aunque los estudiantes evidencian la importancia de la respiración para los animales y su relación con el sistema circulatorio. Es posible categorizar las ideas previas en los modelos explicativos: Intercambio gaseoso, vitalismo, pseudomolecular, y órganos-estructuras.

  5. Extraction of gelatin from catfish bone using NaOH and its utilization as a template on mesoporous silica alumina

    Science.gov (United States)

    Nuryanto, R.; Trisunaryanti, W.; Falah, I. I.; Triyono

    2018-04-01

    Gelatin extraction from catfish bone using NaOH and its utilization as a template on a synthesis of mesoporous silica-alumina had been investigated. The extraction was prepared by immersing 25 g catfish bone in 125 mL of NaOH in concentration of 0.0; 0.05; 0.10; 0.15 and 0.20 M for 24 h, then washing with demineralized water until pH 7, followed by immersed the bone into 125 mL of 1 M HCl for 1 h, then washed using demineralized water into pH 5. To produce gelatin the bone was refluxed with 100 mL demineralized water at 70°C for 5 h then evaporated at 50°C. The dry gelatin was characterized using FTIR and electrophoresis (SDS-PAGE). The best performance of gelatin was produced by NaOH 0.10 M. The gelatin consists of amide A, B, I, II, III and molecular weight of 25-200kDa. Silica and Alumina material prepared from Lapindo mud extraction. Dry Lapindo mud crushed and filtered until pass 100 mesh, then reflux using 6 M HCl (1:4 w/V) at 90°C for 5h then filtered. The filtrate was consisting alumina solution adding with 6 M NaOH (2/3 V/V) them filtered. The filtrate then injected by CO2 gas for 30 minutes and filtered, the residue was calcined at 500°C for 5h. The residual of Lapindo mud dried and refluxed with 6 M NaOH (1:4 w/v) at 90 °C. After 5h filtered and the filtrate added by HCl to pH 8 and filtered, the residual then dried. The Si and Al were then analyzed by XRF and consist of silica and alumina for 99.1 and 87.73%, respectively. Silica-alumina was prepared using silica and alumina extracted from Lapindo mud. 6 g of SiO2 and 2 g of NaOH was immersed in 62 mL of demineralized water then added with alumina solution (0.204 g alumina in 30 mL demineralized water). The gelatin solution (5 g gelatin in 70 mL demineralized water) was dropped into the silica-alumina while stirring at 50°C for 4 h and aging for 24 h. The synthesized silica alumina was analysed using FTIR and surface area analyser. The FT-IR spectra indicated the TO4 (T=Si, Al) vibration at wave

  6. Carbon dioxide sequestration using NaHSO4 and NaOH: A dissolution and carbonation optimisation study.

    Science.gov (United States)

    Sanna, Aimaro; Steel, Luc; Maroto-Valer, M Mercedes

    2017-03-15

    The use of NaHSO 4 to leach out Mg fromlizardite-rich serpentinite (in form of MgSO 4 ) and the carbonation of CO 2 (captured in form of Na 2 CO 3 using NaOH) to form MgCO 3 and Na 2 SO 4 was investigated. Unlike ammonium sulphate, sodium sulphate can be separated via precipitation during the recycling step avoiding energy intensive evaporation process required in NH 4 -based processes. To determine the effectiveness of the NaHSO 4 /NaOH process when applied to lizardite, the optimisation of the dissolution and carbonation steps were performed using a UK lizardite-rich serpentine. Temperature, solid/liquid ratio, particle size, concentration and molar ratio were evaluated. An optimal dissolution efficiency of 69.6% was achieved over 3 h at 100 °C using 1.4 M sodium bisulphate and 50 g/l serpentine with particle size 75-150 μm. An optimal carbonation efficiency of 95.4% was achieved over 30 min at 90 °C and 1:1 magnesium:sodium carbonate molar ratio using non-synthesised solution. The CO 2 sequestration capacity was 223.6 g carbon dioxide/kg serpentine (66.4% in terms of Mg bonded to hydromagnesite), which is comparable with those obtained using ammonium based processes. Therefore, lizardite-rich serpentinites represent a valuable resource for the NaHSO 4 /NaOH based pH swing mineralisation process. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Production Biodiesel from Coconut Oil Using Microwave: Effect of Some Parameters on Transesterification Reaction by NaOH Catalyst

    Directory of Open Access Journals (Sweden)

    A. Suryanto

    2015-07-01

    Full Text Available The purpose of this research was to study the effect of reaction time and NaOH catalyst in transesterification of coconut oil enhanced by microwave and to obtain a biodiesel. Reaction was conducted in batch reactor which equipped by microwave. Coconut oil contains saturated fatty acids about 70% with medium chain (C8-C14, especially lauric acid and myristic acid. The reaction was initiated by mixing oil and methanol with oil to methanol mole ratios of 1:3, 1:6, 1:9 and 1:12, catalyst concentration of 0.1, 0.15, 0.2, 0.25 and 0.3 wt.%, as well as setting electrical power at 100, 264 and 400 W. The reaction times were of  0.5, 1, 1.5, 2, 2.5, 3 and 3.5 min. The result showed that microwave could be employed as an energy source and was able to accelerate the transesterification process to produce biodiesel using NaOH catalyst. The biodiesel yields increase with increasing microwave power. The highest yield of biodiesel obtained  was of  97.37%  with reaction conditions set at 0.2 wt.% catalyst, a reaction time of 2 min, molar ratio of methanol to oil 1:9 and microwave power of 400 watt. © 2015 BCREC UNDIP. All rights reservedReceived: 15th January 2015; Revised: 10th March 2015; Accepted: 15th March 2015How to Cite: Suryanto, A., Suprapto, S., Mahfud, M. (2015. Production Biodiesel from Coconut Oil Using Microwave: Effect of Reaction Time on Transesterification Reaction by NaOH Catalyst. Bulletin of Chemical Reaction Engineering & Catalysis, 10 (2: 162-168. (doi:10.9767/bcrec.10.2.8080.162-168 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.10.2.8080.162-168 

  8. Characterization of hydroxyapatite coatings deposited by hydrothermal electrochemical method on NaOH immersed Ti6Al4V

    International Nuclear Information System (INIS)

    He, Daihua; Liu, Ping; Liu, Xinkuan; Ma, Fengcang; Chen, Xiaohong; Li, Wei; Du, Jiandi; Wang, Pu; Zhao, Jun

    2016-01-01

    The hydrothermal electrochemical method was used to deposit hydroxyapatite coating on Ti6Al4V. In order to improve the bonding strength between the coating and substrate, the substrates were modified by 8 M NaOH solution before the deposition. The effects of immersing time on the substrate, on the hydroxyapatite coating, and on the bonding strength were studied. X-Ray Diffraction, Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy and Drop Shape Analysis Method were applied. And the crystallinity of hydroxyapatite coating was calculated. The results show that immersing treatment effects the phase compositions, the microstructure and the wettability of the substrate surface. A porous, three-dimensional network structure is formed on the Ti6Al4V surface through the NaOH immersion. The pore size and depth increase with the increase of immersing time from 12 to 48 h. The surface microstructure of Ti6Al4V with 60 h′ immersion time was different from the others. The modification treatment can improve the bonding strength between hydroxyapatite coating and the substrate obviously. The value of the bonding strength with the substrate immersed for 48 h is larger than those of the others. A bone-like apatite layer forms on the coating after 3 days of soaking in SBF, implying with good bioactivity of the hydroxyapatite coatings deposited by the method. The surface characteristics of the sample immersed with 48 h are more conductive to the deposition of hydroxyapatite and to the improvement of the bonding strength. The formation mechanism of hydroxyapatite coating deposited by hydrothermal electrochemical method was discussed. - Highlights: • Immerse Ti6Al4V alloy with NaOH solution for different immersing time. • We deposit hydroxyapatite coating by hydrothermal electrochemical method. • We examine changes of composition, microstructure, bonding strength and bioactivity of the hydroxyapatite coating. • 48 h is the optimal immersing time. • We

  9. Correlation of the Na2SiO3 to NaOH Ratios and Solid to Liquid Ratios to the Kedah’s Soil Strength

    Directory of Open Access Journals (Sweden)

    Nur Hamzah Hazamaah

    2016-01-01

    Full Text Available Geopolymer was used for the soil stabilization of Kedah’s soil at different ratios of solid to liquid and Na2SiO3 to NaOH in order to achieve the desired compressive strength. The geopolymerization process which produces an aluminosilicate gel was occurred due to the mixing of Kedah’s soil and fly ash with Na2SiO3 and NaOH. Soil stabilization by geopolymer was synthesized by the activation of fly ash and Kedah’s soil with Na2SiO3 and NaOH at different ratios of solid to liquid (1.5, 2.0, 2.5 and 3.0 and Na2SiO3 to NaOH (0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 at a specific constant concentration of NaOH solution of 6M. The compressive strength up to 5.12 MPa was obtained at 3.0 of solid to liquid ratio and 2.5 of Na2SiO3 to NaOH ratio in 7 days curing at room temperature.

  10. Placenta Prévia: Fatores de risco para o Acretismo Placenta Previa: Risk Factors for Accretion

    Directory of Open Access Journals (Sweden)

    Maria Regina Torloni

    2001-08-01

    Full Text Available Objetivo: investigação dos fatores de risco associados ao acretismo em pacientes com placenta prévia (PP. Métodos: foi realizada uma análise retrospectiva caso-controle de todos os prontuários de pacientes com diagnóstico de PP que tiveram seus partos na Maternidade Escola Vila Nova Cachoeirinha (São Paulo entre 1986 e 1998. O grupo com acretismo foi comparado ao grupo sem acretismo quanto à idade, paridade, antecedentes de abortamentos, curetagens e cesarianas, o tipo de PP e a área predominante de inserção placentária. Para avaliar a associação entre a variável dependente (acretismo placentário e as variáveis independentes (características maternas e placentária foram utilizados o teste do chi², análise univariada e multivariada, considerando-se significantes os valores de p Purpose: to investigate risk factors associated with accretion in placenta previa (PP patients. Methods: this was a retrospective case-control study of all the records of patients who delivered between 1986-1998 at Maternidade Escola de Vila Nova Cachoeirinha (São Paulo with a diagnosis of placenta previa. The groups with and without accretion were compared regarding age, parity, previous history of miscarriage, curettage and cesarean section, type of PP and predominant area of placental attachment. Possible associations between the dependent (accretion and independent (maternal and placental characteristics variables were evaluated using the chi² test, univariate and multivariate analyses. Results: reviewing 245 cases of PP, two risk factors were significantly associated with accretion: central placenta previa (odds ratio (OR: 2.93 and two or more previous cesarean sections(OR: 2.54. Based on these data, a predictive model was constructed, according to which a patient with central PP and two more previous cesarean sections has a 44.4% risk for accretion. Conclusions: results of the current study may help obstetricians in the classification of their

  11. Enhanced Enzymatic Hydrolysis and Structural Features of Corn Stover by NaOH and Ozone Combined Pretreatment

    Directory of Open Access Journals (Sweden)

    Wenhui Wang

    2018-05-01

    Full Text Available A two-step pretreatment using NaOH and ozone was performed to improve the enzymatic hydrolysis, compositions and structural characteristics of corn stover. Comparison between the unpretreated and pretreated corn stover was also made to illustrate the mechanism of the combined pretreatment. A pretreatment with 2% (w/w NaOH at 80 °C for 2 h followed by ozone treatment for 25 min with an initial pH 9 was found to be the optimal procedure and the maximum efficiency (91.73% of cellulose enzymatic hydrolysis was achieved. Furthermore, microscopic observation of changes in the surface structure of the samples showed that holes were formed and lignin and hemicellulose were partially dissolved and removed. X-ray Diffraction (XRD, Fourier Transform Infrared Spectroscopy (FTIR and Cross-Polarization Magic Angle Spinning Carbon-13 Nuclear Magnetic Resonance (CP/MAS 13C-NMR were also used to characterize the chemical structural changes after the combined pretreatment. The results were as follows: part of the cellulose I structure was destroyed and then reformed into cellulose III, the cellulose crystal indices were also changed; a wider space between the crystal layer was observed; disruption of hydrogen bonds in cellulose and disruption of ester bonds in hemicellulose; cleavage of bonds linkage in lignin-carbohydrate complexes; removal of methoxy in lignin and hemicellulose. As a result, all these changes effectively reduced recalcitrance of corn stover and promoted subsequent enzymatic hydrolysis of cellulose.

  12. Bio diesel Production via Transesterification of Palm Oil Using NaOH/ Al2O3 Catalysts

    International Nuclear Information System (INIS)

    Taufiq Yap Yun Hin; Nurul Fitriyah Abdullah; Mahiran Basri; Taufiq Yap Yun Hin; Nurul Fitriyah Abdullah

    2011-01-01

    Due to the increase in price of petroleum and environmental concerns, the search for alternative fuels has gained importance. In this work, bio diesel production by transesterification of palm oil with methanol has been studied in a heterogeneous system using sodium hydroxide loaded on alumina (NaOH/ Al 2 O 3 ). NaOH/ Al 2 O 3 catalyst was prepared by impregnation of alumina with different amount of an aqueous solution of sodium hydroxide followed by calcination in air for 3 h. The prepared catalysts were then characterized by using x-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR), Brunner-Emmett-Teller surface area measurement (BET), scanning electron microscopy (SEM) and temperature-programmed desorption of CO 2 (CO 2 -TPD). Moreover, the dependence of the conversion of palm oil on the reactions variables such as the molar ratio of methanol/oil, the amount of catalysts used, reaction temperatures and reaction times were performed. The conversion of 99 % was achieved under the optimum reaction conditions. The bio diesel obtained was characterized by FT-IR and the pour point was measured. (author)

  13. Electrochemical impedance spectroscopy investigation on indium tin oxide films under cathodic polarization in NaOH solution

    International Nuclear Information System (INIS)

    Gao, Wenjiao; Cao, Si; Yang, Yanze; Wang, Hao; Li, Jin; Jiang, Yiming

    2012-01-01

    The electrochemical corrosion behaviors of indium tin oxide (ITO) films under the cathodic polarization in 0.1 M NaOH solution were investigated by electrochemical impedance spectroscopy. The as-received and the cathodically polarized ITO films were characterized by scanning electron microscopy, energy dispersive X-ray spectroscopy and X-ray diffraction for morphological, compositional and structural studies. The results showed that ITO films underwent a corrosion process during the cathodic polarization and the main component of the corrosion products was body-centered cubic indium. The electrochemical impedance parameters were related to the effect of the cathodic polarization on the ITO specimens. The capacitance of ITO specimens increased, while the charge transfer resistance and the inductance decreased with the increase of the polarization time. The proposed mechanism indicated that the corrosion products (metallic indium) were firstly formed during the cathodic polarization and then absorbed on the surface of the ITO film. As the surface was gradually covered by indium particles, the corrosion process was suppressed. - Highlights: ► Cathodic polarization of indium tin oxide (ITO) in 0.1 M NaOH. ► Cathodic polarization studied with electrochemical impedance spectroscopy. ► ITO underwent a corrosion attack during cathodic polarization, indium was observed. ► Electrochemical parameters of ITO were obtained using equivalent electrical circuit. ► A corrosion mechanism is proposed.

  14. Simultaneous absorption of SO2 and NO from flue gas with KMnO4/NaOH solutions

    International Nuclear Information System (INIS)

    Chu, H.; Chien, T.W.; Li, S.Y.

    2001-01-01

    The wet scrubbing combined SO x /NO x removal system is an advanced air pollution control device. This study attempts to understand the absorption kinetics in the system. The absorption of diluted SO 2 and simultaneous absorption of diluted SO 2 and NO, as occurs in flue gases, in a stirred tank reactor with KMnO 4 /NaOH solutions were carried out at 50C. The liquid-side and gas-side mass transfer coefficients of the system were determined. The results indicate that the absorption of SO 2 is close to completely gas-film controlled where the NaOH concentration is greater than 0.1 M or the KMnO 4 concentration is greater than 0.05 M. The increasing gas flow rate has a positive effect on the absorption rate of SO 2 . The existence of O 2 has no significant effect on the absorption rate of SO 2 . Adding SO 2 would decrease the absorption rate of NO; however, the addition of NO has no effect on the absorption rate of SO 2

  15. Bioconversion of different sizes of microcrystalline cellulose pretreated by microwave irradiation with/without NaOH

    International Nuclear Information System (INIS)

    Peng, Huadong; Chen, Hongzhang; Qu, Yongshui; Li, Hongqiang; Xu, Jian

    2014-01-01

    Highlights: • High concentration of alkali or temperature was necessary in cellulose degradation. • Effects of alkali pretreatment could be enhanced with the addition of microwave irradiation. • The structures diversities of microcrystalline cellulose were eliminated in the fermentation. • The significance of particle size and treat condition varied with reaction time. - Abstract: The process of microwave irradiation (MWI) pretreatment on microcrystalline cellulose (MCC) with different sizes with/without NaOH was investigated on the variation of the ratio of degradated solid residue (R DS ), particle size, crystallinity index (CrI), crystallite size (Sc) and specific surface area (SSA). High concentration of alkali or high temperature was necessary in dissolving or decomposing the cellulose. Appropriate pretreatment severity eliminated the effects of structural diversities in feedstocks, which led to convergence in the ethanol fermentation. After the reaction proceeded to 120 h, the samples could be converted to glucose completely and the highest ethanol yield of the theoretical was 58.91% for all the samples pretreated by the combined treatment of MWI and NaOH. In addition, the statistical analysis implied that when reaction time got to 24 h, particle size and pretreatment condition affected much more significant than other factors

  16. Investigation into the role of NaOH and calcium ions in the synthesis of calcium phosphate nanoshells

    Directory of Open Access Journals (Sweden)

    C. H. Yeo

    2012-03-01

    Full Text Available Calcium phosphate (CaP nanoshells were prepared using negatively charged liposomes (1,2-dioleoyl-sn-glycero-3-phosphate sodium salt (DOPA as a template by base titration synthesis at various concentrations of NaOH and calcium ions. The elemental composition, morphology, particle size, particle size distribution and zeta potential of the products were determined via various characterisation techniques, such as energy-dispersive X-ray spectrometry (EDX, transmission electron microscopy (TEM, dynamic light scattering (DLS, laser Doppler velocimetry (LDV and Fourier transform infrared spectroscopy (FTIR. The best results showed that stable spherical CaP nanoshells with a mean particle size of 197.5 ± 5.8 nm and a zeta potential of -34.5 ± 0.6 mV were successfully formed when 0.100 M sodium hydroxide (NaOH and 0.100 M calcium ions were used. Moreover, an optimal pH of 10.52 and a final Ca/P molar ratio of 0.97 were achieved under these conditions.

  17. Maintenance nifedipine therapy for preterm symptomatic placenta previa: A randomized, multicenter, double-blind, placebo-controlled trial.

    Directory of Open Access Journals (Sweden)

    Eric Verspyck

    Full Text Available To assess the impact of maintenance nifedipine therapy on pregnancy duration in women with preterm placenta previa bleeding.PPADAL was a randomized, double-blind, placebo-controlled trial conducted between 05/2008 and 05/2012 in five French hospitals. The trial included 109 women, aged ≥ 18 years, with at least one episode of placenta previa bleeding, intact membranes and no other pregnancy complication, at gestational age 24 to 34 weeks and after 48 hours of complete acute tocolysis. Women were randomly allocated to receive either 20 mg of slow-release nifedipine three times daily (n = 54 or placebo (n = 55 until 36 + 6 weeks of gestation. The primary outcome for the trial was length of pregnancy measured in days after enrolment. Main secondary outcomes were rates of recurrent bleeding, cesarean delivery due to hemorrhage, blood transfusion, maternal side effects, gestational age at delivery and adverse perinatal outcomes (perinatal death, chronic lung disease, neonatal sepsis, intraventricular hemorrhage > grade 2, perventricular leukomalacia > grade 1, or necrotizing enterocolitis. Analysis was by intention to treat.Mean (SD prolongation of pregnancy was not different between the nifedipine (n = 54 and the placebo (n = 55 group; 42.5 days ± 23.8 versus 44.2 days ± 24.5, p = 0.70. Cesarean due to hemorrhage performed before 37 weeks occurred more frequently in the nifedipine group in comparison with the placebo group (RR, 1.66; 95% confidence interval, 1.05-2.72. Adverse perinatal outcomes were comparable between groups; 3.8% for nifedipine versus 5.5% for placebo (relative risk, 0.52; 95% confidence interval 0.10-2.61. No maternal mortality or perinatal death occurred.Maintenance oral nifedipine neither prolongs duration of pregnancy nor improves maternal or perinatal outcomes.ClinicalTrials.gov NCT00620724.

  18. Caracteristicas de las personas que acuden a las consultas de demanda del centro de salud sin citación previa

    Directory of Open Access Journals (Sweden)

    Pomar Carlos Isanta

    2000-01-01

    Full Text Available FUNDAMENTO: El tiempo de espera para acceder a la consulta está considerado un indicador de satisfacción. Las visitas no urgentes, realizadas sin cita previa, provocan un incremento del tiempo de espera de los pacientes citados, con la consiguiente insatisfacción de los mismos. El objetivo del estudio persigue la valoración cuantitativa de este tipo de visitas y conocer las características de las mismas, para introducir las medidas destinadas a su corrección y racionalización. MÉTODOS: Estudio descriptivo. Se realizó un registro que recogiera las características de los pacientes que originan las consultas sin cita previa, como la edad y el sexo y las relativas a la consulta: motivo, modalidad, jornada laboral y si era realizada de forma directa o indirecta. RESULTADOS: El 14,19% de consultas a demanda no urgentes son sin citación previa. Con el análisis factorial de correspondencias múltiple se identifican dos perfiles de consultas: las directas, solicitadas por pacientes jóvenes, por enfermedad o tareas burocráticas, al final de la consulta de la mañana, estando ellos presentes, y las consultas indirectas, ocasionadas durante las consultas con cita previa por pacientes que solicitan recetas. CONCLUSIONES: Hay un elevado número de visitas sin cita previa. Son precisas medidas que puedan conducir a la utilización del sistema de organización de las consultas y a la mejora de aquellas situaciones que impliquen una falta de accesibilidad, con la finalidad última de mejorar la satisfacción de los usuarios de los servicios sanitarios públicos.

  19. Hydrogen evolution reaction at Ru-modified nickel-coated carbon fibre in 0.1 M NaOH

    Directory of Open Access Journals (Sweden)

    Pierożyński Bogusław

    2015-03-01

    Full Text Available The electrochemical activity towards hydrogen evolution reaction (HER was studied on commercially available (Toho-Tenax and Ru-modified nickel-coated carbon fibre (NiCCF materials. Quality and extent of Ru electrodeposition on NiCCF tows were examined by means of scanning electron microscopy (SEM. Kinetics of the hydrogen evolution reaction were investigated at room temperature, as well as over the temperature range: 20-50°C in 0.1 M NaOH solution for the cathodic overpotential range: -100 to -300 mV vs. RHE. Corresponding values of charge-transfer resistance, exchange current-density for the HER and other electrochemical parameters for the examined fibre tow composites were recorded.

  20. Corrosion Inhibition of Aluminium using 3-Hydroxy flavone in the Presence of Quarternary Ammonium Salts in NaOH Medium

    International Nuclear Information System (INIS)

    Princey, J. Morris; Nagarajan, Prabavathi

    2012-01-01

    The anticorrosive effect of 3-Hydroxyflavone (3HF) in combination with quarternary ammonium bromide and iodide salts (QAB and QAI) for aluminium corrosion in NaOH medium was studied at the temperature range of 303K-323K using weight loss study, potentiodynamic polarization study and impedance spectroscopic measurements. The results revealed that the inhibition efficiency increases with the inhibitor concentration and it further increases on the addition of quarternary ammonium bromide and iodide salts. The enhanced inhibition efficiency of the inhibitor in the presence of quarternary ammonium salts may be due to synergistic effect. The adsorption process of 3HF on the aluminium surface obeys Langmuir's adsorption isotherm. The mechanism of adsorption is further supported by Scanning Electron Microscopic study (SEM)

  1. Improved diffusivity of NaOH solution in autohydrolyzed poplar sapwood chips for chemi-mechanical pulp production.

    Science.gov (United States)

    Zhang, Honglei; Hou, Qingxi; Liu, Wei; Yue, Zhen; Jiang, Xiaoya; Ma, Xixi

    2018-07-01

    This work investigated the changes in the physical structure of autohydrolyzed poplar sapwood chips and the effect on the subsequent alkali liquor diffusion properties for chemi-mechanical pulping (CMP). An alkali impregnation process was conducted by using the autohydrolyzed poplar sapwood with different levels of autohydrolysis intensity. The results showed that the volume porosity, water constraint capacity, and saturated water absorption of the autohydrolyzed poplar sapwood chips increased. Also, the effective capillary cross-sectional area (ECCSA) in the radial direction and the diffusion coefficients of NaOH solution in both the radial and axial directions all increased. Autohydrolysis pretreatment enhanced the alkali liquor diffusion properties in poplar sapwood chips, and the diffusion coefficient was increased more greatly in the radial direction than that in the axial direction. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Prenatal ultrasound diagnosis and outcome of placenta previa accreta after cesarean delivery: a systematic review and meta-analysis.

    Science.gov (United States)

    Jauniaux, Eric; Bhide, Amar

    2017-07-01

    Women with a history of previous cesarean delivery, presenting with a placenta previa, have become the largest group with the highest risk for placenta previa accreta. The objective of the study was to evaluate the accuracy of ultrasound imaging in the prenatal diagnosis of placenta accreta and the impact of the depth of villous invasion on management in women presenting with placenta previa or low-lying placenta and with 1 or more prior cesarean deliveries. We searched PubMed, Google Scholar, clinicalTrials.gov, and MEDLINE for studies published between 1982 and November 2016. Criteria for the study were cohort studies that provided data on previous mode of delivery, placenta previa, or low-lying placenta on prenatal ultrasound imaging and pregnancy outcome. The initial search identified 171 records, of which 5 retrospective and 9 prospective cohort studies were eligible for inclusion in the quantitative analysis. The studies were scored on methodological quality using the Quality Assessment of Diagnostic Accuracy Studies tool. The 14 cohort studies included 3889 pregnancies presenting with placenta previa or low-lying placenta and 1 or more prior cesarean deliveries screened for placenta accreta. There were 328 cases of placenta previa accreta (8.4%), of which 298 (90.9%) were diagnosed prenatally by ultrasound. The incidence of placenta previa accreta was 4.1% in women with 1 prior cesarean and 13.3% in women with ≥2 previous cesarean deliveries. The pooled performance of ultrasound for the antenatal detection of placenta previa accreta was higher in prospective than retrospective studies, with a diagnostic odds ratios of 228.5 (95% confidence interval, 67.2-776.9) and 80.8 (95% confidence interval, 13.0-501.4), respectively. Only 2 studies provided detailed data on the relationship between the depth of villous invasion and the number of previous cesarean deliveries, independently of the depth of the villous invasion. A cesarean hysterectomy was performed in

  3. The effect of NaOH and KOH on the characterization of meso porous AlOOH nano structures in the hydrothermal route

    International Nuclear Information System (INIS)

    Haghnazari, N.; Abdollahifar, M.; Jahani, F.

    2014-01-01

    Meso porous AlOOH was synthesized by hydrothermal treatment from aluminium nitrate and NaOH or KOH. The effect of NaOH and KOH as precipitating agents on the characterization of samples were investigated. XRD, Ftir, FESEM and N 2 adsorption-desorption analytical techniques were used to characterize the products. Our results showed that using KOH as precipitating agent was favour-able for the formation of meso porous and crystalline AlOOH with high Bet-specific surface area of 98 m 2 /g. (Author)

  4. The effect of NaOH and KOH on the characterization of meso porous AlOOH nano structures in the hydrothermal route

    Energy Technology Data Exchange (ETDEWEB)

    Haghnazari, N.; Abdollahifar, M.; Jahani, F., E-mail: abdollahifar@gmail.com [Islamic Azad University, Kermanshah Branch, Department of Chemical Engineering, 67131 Kermanshah (Iran, Islamic Republic of)

    2014-10-01

    Meso porous AlOOH was synthesized by hydrothermal treatment from aluminium nitrate and NaOH or KOH. The effect of NaOH and KOH as precipitating agents on the characterization of samples were investigated. XRD, Ftir, FESEM and N{sub 2} adsorption-desorption analytical techniques were used to characterize the products. Our results showed that using KOH as precipitating agent was favour-able for the formation of meso porous and crystalline AlOOH with high Bet-specific surface area of 98 m{sup 2}/g. (Author)

  5. Comparación del nivel de condiciones previas de rendimiento de tenistas de élite (estudio de caso

    Directory of Open Access Journals (Sweden)

    Jiří Zháněl

    2015-04-01

    Full Text Available En el mundo del tenis de hoy en día, hay una clara tendencia hacia un juego físicamente exigente, en el que las condiciones previas motrices más importantes son la velocidad (acción y reacción, la fuerza (sobre todo la inicial y la explosiva, la fuerza resistencia y las habilidades específicas de coordinación. El presente estudio se basa en la teoría retrospectiva. El objetivo de la investigación fue el análisis longitudinal del nivel de condiciones previas somáticas y motrices de tenistas checos de élite (el tenista Tomas Berdych –TB– y la tenista Petra Kvitova –PK–. Con fecha 1 de junio de 2014, Tomas Berdych es el tenista número 1 de República Checa y el número 6 del mundo en el Ranking ATP (4330 puntos, habiendo logrado su mejor ranking hasta la fecha en 2013 (número 5 del mundo; con la misma fecha la tenista Petra Kvitova también es la tenista número 1 de República Checa y la número 6 del mundo en el Ranking WTA (4600 puntos, habiendo logrado su mejor ranking hasta la fecha en 2011 (número 2 del mundo. Los dos tenistas fueron evaluados longitudinalmente mediante la batería de test TENDIAG1, la cual contiene tres ítems somáticos y seis ítems motores. Los resultados de ambos tenistas claramente mostraron que, a lo largo de todo el periodo de monitorización, su puntuación total en la batería de test se encontraba por encima de la media de la población de tenistas. La evaluación de las diferencias entre sexos mostró un nivel significativamente más alto en la mayoría de ítems en el tenista TB, excepto en los ítems de flexibilidad del torso y de velocidad de reacción de brazos y piernas. La tenista PK obtuvo un mejor nivel en el índice de movilidad del hombro. Los resultados proporcionan interesantes conocimientos y sugerencias para el entrenamiento del tenis.

  6. Effect of low B-Lynch suture on menstrual cycle recovery and sex hormone levels in patients after cesarean section for placenta previa

    Directory of Open Access Journals (Sweden)

    Su-Lan Zhang

    2016-03-01

    Full Text Available Objective: To explore the effect of low B-Lynch suture on the menstrual cycle recovery and sex hormone levels in patients after cesarean section for placenta previa. Methods: A total of 40 patients who were admitted in our hospital from August, 2013 to August, 2015 for cesarean section due to placenta previa were included in the study and randomized into the observation group and the control group. The patients in the observation group were given low B-lynch suture, while in the control group, yarns were plugged in the uterus. The bleeding during operation and 24 h after operation, the postpartum lochia duration, and menstrual cycle recovery in the two groups were observed. The postpartum FSH, E2, and LH levels in the two groups were determined. Results: The amount of bleeding during operation and 24 h after operation in the observation group was significantly less than that in the control group (P0.05. The comparison of FSH, E2, and LH levels between the two groups was not statistically significant (P>0.05. Conclusions: Low B-Lynch suture can effectively reduce the amount of bleeding after cesarean section for placenta previa, and has no effect on the menstrual recovery and ovarian function with a simple operation and less postoperative complications; therefore, it deserves to be widely recommended in the clinic.

  7. Assessment of total placenta previa by magnetic resonance imaging and ultrasonography to detect placenta accreta and its variants.

    Science.gov (United States)

    Peker, Nuri; Turan, Volkan; Ergenoglu, Mete; Yeniel, Ozgur; Sever, Ahmet; Kazandi, Mert; Zekioglu, Osman

    2013-03-01

    To evaluate the importance of ultrasonography (US) and magnetic resonance imaging (MRI) in detecting placental adherence defects. Patients diagnozed with total placenta previa (n = 40) in whom hysterectomy was performed due to placental adherence defects (n = 20) or in whom the placenta detached spontaneously after a Cesarean delivery (n = 20) were included into the study between June 2008 and January 2011, at the Department of Obstetrics and Gynecology Ege University (lzmir Turkey). Gray-scale US was used to check for any placental lacunae, sub-placental sonolucent spaces or a placental mass invading the vesicouterine plane and bladder Intra-placental lacunar turbulent blood flow and an increase in vascularization in the vesicouterine plane were evaluated with color Doppler mode. Subsequently all patients had MRI and the results were compared with the histopathologic examinations. The sensitivity of MRI for diagnosis of placental adherence defects before the operation was 95%, with a specificity of 95%. In the presence of at least one diagnostic criterion, the sensitivity and specificity of US were 87.5% and 100% respectively, while the sensitivity of color Doppler US was 62.5% with a specificity of 100%. Currently MRI appears to be the gold standard for the diagnosis of placenta accreta. None of the ultrasonographic criteria is solely sufficient to diagnose placental adherence defects, however they assist in the diagnostic process.

  8. Enhancing anaerobic digestion of waste activated sludge by the combined use of NaOH and Mg(OH)2: Performance evaluation and mechanism study.

    Science.gov (United States)

    Huang, Cheng; Lai, Jia; Sun, Xiuyun; Li, Jiansheng; Shen, Jinyou; Han, Weiqing; Wang, Lianjun

    2016-11-01

    In this study, the combination treatment of NaOH and Mg(OH)2 was applied to anaerobic digestion of waste activated sludge (WAS) for simultaneously enhancement of volatile fatty acids (VFAs) production, nutrients removal and sludge dewaterability. The maximum VFAs production (461mg COD/g VSS) was obtained at the NaOH/Mg(OH)2 ratio of 75:25, which was much higher than that of the blank or sole NaOH. Moreover, nutrients removal and sludge dewaterability were improved by the combined using of NaOH and Mg(OH)2. Mechanism investigations revealed that the presence of Mg(OH)2 could maintain alkaline environment, which contributed to inhibit the activity of methanogens. Also, the bridging between Mg(2+) and extracellular polymeric substances (EPS) plays an important role in the solubilization and dewatering of sludge. High-throughput sequencing analysis demonstrated that the abundance of bacteria involved in sludge hydrolysis and VFAs accumulation was greatly enriched with the mixtures of NaOH and Mg(OH)2. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. The use of CH3OH additive to NaOH for etching alpha particle tracks in a CR-39 plastic nuclear track detector

    International Nuclear Information System (INIS)

    Ashry, A.H.; Abdalla, A.M.; Rammah, Y.S.; Eisa, M.; Ashraf, O.

    2014-01-01

    Fast detection of alpha particles in CR-39 detectors was investigated using a new chemical etchant. 252 Cf and 241 Am sources were used for irradiating samples of CR-39 SSNTDs with fission fragments and alpha particles in air at normal temperature and pressure. A series of experimental chemical etching are carried out using new etching solution (8 ml of 10N NaOH+1 ml CH 3 OH) at 60 °C to detect alpha particle in short time in CR-39 detectors. Suitable analyzing software has been used to analyze experimental data. From fission and alpha track diameters, the value of bulk etching rate is equal to 2.73 μm/h. Both the sensitivity and etching efficiency were found to vary with the amount of methanol in the etching solution. Pure NaOH was used as a control to compare with the result from etching in NaOH with different concentrations of CH 3 OH. The etching efficiency is determined and compared with conventional aqueous solution of 6.25N NaOH at 70 °C for etching time equals 5 h. In this study, the obtained etching efficiency shows a considerable agreement with the previous work. - Highlights: • The value of bulk etching rate is equal to 2.73 μm/h. • Fast detection of alpha particles in CR-39 detectors. • Samples of CR-39 have been irradiated with fission fragments. • Etching efficiency was determined

  10. Combining Experiments and Simulation of Gas Absorption for Teaching Mass Transfer Fundamentals: Removing CO2 from Air Using Water and NaOH

    Science.gov (United States)

    Clark, William M.; Jackson, Yaminah Z.; Morin, Michael T.; Ferraro, Giacomo P.

    2011-01-01

    Laboratory experiments and computer models for studying the mass transfer process of removing CO2 from air using water or dilute NaOH solution as absorbent are presented. Models tie experiment to theory and give a visual representation of concentration profiles and also illustrate the two-film theory and the relative importance of various…

  11. Effect of NaOH on large-volume sample stacking of haloacetic acids in capillary zone electrophoresis with a low-pH buffer.

    Science.gov (United States)

    Tu, Chuanhong; Zhu, Lingyan; Ang, Chay Hoon; Lee, Hian Kee

    2003-06-01

    Large-volume sample stacking (LVSS) is an effective on-capillary sample concentration method in capillary zone electrophoresis, which can be applied to the sample in a low-conductivity matrix. NaOH solution is commonly used to back-extract acidic compounds from organic solvent in sample pretreatment. The effect of NaOH as sample matrix on LVSS of haloacetic acids was investigated in this study. It was found that the presence of NaOH in sample did not compromise, but rather help the sample stacking performance if a low pH background electrolyte (BGE) was used. The sensitivity enhancement factor was higher than the case when sample was dissolved in pure water or diluted BGE. Compared with conventional injection (0.4% capillary volume), 97-120-fold sensitivity enhancement in terms of peak height was obtained without deterioration of separation with an injection amount equal to 20% of the capillary volume. This method was applied to determine haloacetic acids in tap water by combination with liquid-liquid extraction and back-extraction into NaOH solution. Limits of detection at sub-ppb levels were obtained for real samples with direct UV detection.

  12. Facile preparation of hierarchically porous diatomite/MFI-type zeolite composites and their performance of benzene adsorption: the effects of NaOH etching pretreatment.

    Science.gov (United States)

    Yu, Wenbin; Yuan, Peng; Liu, Dong; Deng, Liangliang; Yuan, Weiwei; Tao, Bo; Cheng, Hefa; Chen, Fanrong

    2015-03-21

    Hierarchically porous diatomite/MFI-type zeolite (Dt/Z) composites with excellent benzene adsorption performance were prepared. The hierarchical porosity was generated from the microporous zeolite coated at the surface of diatom frustules and from the macroporous diatomite support. A facile NaOH etching method was employed for the first time to treat the frustule support, followed by hydrothermal growth of MFI-type zeolite at the surface of frustules previously seeded with nanocrystalline silicalite-1 (Sil-1). NaOH etching enlarged the pores on diatom frustules and further increased the coated zeolite contents (W(z)). The central macropore size of the diatom frustules increased from approximately 200-500 nm to 400-1000 nm after NaOH etching. The W(z) could reach 61.2%, while the macroporosity of the composites was largely preserved due to more voids for zeolite coating being formed by NaOH etching. The Dt/Z composites exhibited higher benzene adsorption capacity per unit mass of zeolite and less mass transfer resistance than Sil-1, evaluated via a method of breakthrough curves. These results demonstrate that etching of a diatomite support is a facile but crucial process for the preparation of Dt/Z composites, enabling the resulting composites to become promising candidates for uses in volatile organic compounds emission control. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Effect of small addition of Mn on the passivation of Zn in 0.1 M NaOH solution

    International Nuclear Information System (INIS)

    Shang Xiuling; Zhang Bo; Han Enhou; Ke Wei

    2011-01-01

    The passivation of pure Zn (99.995 wt%) and Zn-0.4Mn (0.4 wt% Mn) alloy in a deaerated 0.1 M NaOH solution (pH 12.9) was investigated by electrochemical measurements, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The potentiodynamic polarization and electrochemical impedance measurements show that addition of 0.4 wt% Mn can decrease the passive current density of Zn in the passive region. XPS surface analysis indicates that there is approximately 1.0-2.0 at% Mn 2+ being incorporated into the passive film on Zn-0.4Mn alloy with Mn content being higher in the outer layers. Mott-Schottky analysis shows that the incorporated Mn can decrease concentration of defects in the film. AFM observations disclose that Mn can decrease the grain size of the film. The mechanism by which Mn additions improve the passivity of Zn is that the incorporated Mn can inhibit ions transportation in the film and inhibit its growth. Meanwhile, Mn can also promote the nucleation of Zn oxides and decrease film porosity.

  14. Using GC-FID to Quantify the Removal of 4-sec-Butylphenol from NGS Solvent by NaOH

    Energy Technology Data Exchange (ETDEWEB)

    Sloop, Jr., Frederick V. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moyer, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-12-01

    A caustic wash of the solvent used in the Next-Generation Caustic-Side Solvent Extraction (NG-CSSX) process was found to remove the modifier breakdown product 4-sec-butylphenol (SBP) with varying efficiency depending on the aqueous NaOH concentration. Recent efforts at ORNL have aimed at characterizing the flowsheet chemistry and reducing the technical uncertainties of the NG-CSSX process. One technical uncertainty has been the efficacy of caustic washing of the solvent for the removal of lipophilic anions, in particular, the efficient removal of SBP, an important degradation product of the solvent modifier, Cs-7SB. In order to make this determination, it was necessary to develop a sensitive and reliable analytical technique for the detection and quantitation of SBP. This report recounts the development of a GC-FID-based (Gas Chromatography Flame Ionization Detection) technique for analyzing SBP and the utilization of the technique to subsequently confirm the ability of the caustic wash to efficiently remove SBP from the Next Generation Solvent (NGS) used in NG-CSSX. In particular, the developed technique was used to monitor the amount of SBP removed from a simple solvent and the full NGS by contact with sodium hydroxide wash solutions over a range of concentrations. The results show that caustic washing removes SBP with effectively the same efficiency as it did in the original Caustic-Side Solvent Extraction (CSSX) process.

  15. Passivation kinetics of Mg-Nd-Gd-Zn-Zr (EV31A and Mg-Y-Nd-Gd-Zr (WE43C in NaOH solutions

    Directory of Open Access Journals (Sweden)

    Jakraphan Ninlachart

    2017-09-01

    Full Text Available Passivation kinetics of two Mg-RE alloys, such as Mg-Nd-Gd-Zn-Zr (EV31A, and Mg-Y-Nd-Gd-Zr (WE43C were investigated in two different heat treated conditions (solution treated and overaged in 0.01 - 1.0 M NaOH solutions under potentiostatic conditions. Negative reaction order was observed in dilute NaOH which transitioned to positive values as the passivation time increased and in the 1 M NaOH as well. The passive layers showed platelet morphology and the size of the platelets decreased with increase in the NaOH concentration. The hydrogen evolution reaction (HER kinetics was not improved on the passive layer covered surface of the Mg-RE alloys in contrast to the improvements reported on the hydroxide covered pure magnesium. The electrochemical impedance increased with increase in the NaOH concentration in the solution treated condition of both Mg-RE alloys, whereas the overaged EV31A alloy showed a reverse trend. The passive layer of EV31A showed almost 100% higher charge carrier density than the film formed on the WE43C in the overaged condition. A better passivation behavior was observed in the solution treated condition than that in the overaged condition which could be attributed to the uniform distribution of the RE elements in the solution treated specimens. The WE43C alloy revealed better corrosion resistance in the alkaline solution than the EV31A alloy.

  16. Back to basics: an evaluation of NaOH and alternative rapid DNA extraction protocols for DNA barcoding, genotyping, and disease diagnostics from fungal and oomycete samples.

    Science.gov (United States)

    Osmundson, Todd W; Eyre, Catherine A; Hayden, Katherine M; Dhillon, Jaskirn; Garbelotto, Matteo M

    2013-01-01

    The ubiquity, high diversity and often-cryptic manifestations of fungi and oomycetes frequently necessitate molecular tools for detecting and identifying them in the environment. In applications including DNA barcoding, pathogen detection from plant samples, and genotyping for population genetics and epidemiology, rapid and dependable DNA extraction methods scalable from one to hundreds of samples are desirable. We evaluated several rapid extraction methods (NaOH, Rapid one-step extraction (ROSE), Chelex 100, proteinase K) for their ability to obtain DNA of quantity and quality suitable for the following applications: PCR amplification of the multicopy barcoding locus ITS1/5.8S/ITS2 from various fungal cultures and sporocarps; single-copy microsatellite amplification from cultures of the phytopathogenic oomycete Phytophthora ramorum; probe-based P. ramorum detection from leaves. Several methods were effective for most of the applications, with NaOH extraction favored in terms of success rate, cost, speed and simplicity. Frozen dilutions of ROSE and NaOH extracts maintained PCR viability for over 32 months. DNA from rapid extractions performed poorly compared to CTAB/phenol-chloroform extracts for TaqMan diagnostics from tanoak leaves, suggesting that incomplete removal of PCR inhibitors is an issue for sensitive diagnostic procedures, especially from plants with recalcitrant leaf chemistry. NaOH extracts exhibited lower yield and size than CTAB/phenol-chloroform extracts; however, NaOH extraction facilitated obtaining clean sequence data from sporocarps contaminated by other fungi, perhaps due to dilution resulting from low DNA yield. We conclude that conventional extractions are often unnecessary for routine DNA sequencing or genotyping of fungi and oomycetes, and recommend simpler strategies where source materials and intended applications warrant such use. © 2012 Blackwell Publishing Ltd.

  17. Effect of LiOH, NaOH and KOH on corrosion and oxide microstructure of Zr-based alloys

    International Nuclear Information System (INIS)

    Jeong, Y.H.; Kim, H.G.; Jung, Y.H.; Ruhmann, H.

    1999-01-01

    Long-term corrosion test, SIMS analysis, and TEM microstructural study were carried out to investigate the corrosion characteristics and mechanism of Zr alloys in alkali hydroxides. The corrosion tests were performed in solutions of LiOH, NaOH, KOH, RbOH, and CsOH at 350 deg. C for 500 days. SIMS analysis was performed for the specimens prepared to have an equal oxide thickness. TEM studies on the specimens with an equal oxide thickness in various solutions in both pre- and post-transition regimes were also conducted. The corrosion rate in alkali hydroxide solutions was observed to decrease as the ionic radius of alkali cation was increased. The penetration depth of cation into the oxide decreases with increasing the ionic radius of cation. Even though the oxide thickness was equal, the different oxide morphologies were observed in specimens. Namely, in LiOH solution the oxide morphology was transformed early from columnar to equiaxed structure. However, in KOH solution the columnar structure was maintained up to post-transition regime. Based on the corrosion test, SIMS analysis, and microstructural study, the cation is considered to control the corrosion in a alkali hydroxide solution and its effect is dependent on the concentration of alkali and the oxide thickness. The slight acceleration of the corrosion rate at a low concentration is thought to be caused by cation incorporation into oxide while the significant acceleration at a high concentration is due to the transformation of oxide microstructure that would be induced by cation incorporation. KOH was shown not to affect significantly the corrosion and the hydrogen pickup of Zircaloy. Therefore, it has a potential for PWR application only from the point of view of Zircaloy corrosion. (author)

  18. Thermal and mechanical properties of NaOH treated hemp fabric and calcined nanoclay-reinforced cement nanocomposites

    International Nuclear Information System (INIS)

    Hakamy, A.; Shaikh, F.U.A.; Low, I.M.

    2015-01-01

    Highlights: • Fabrication of nanoclay and hemp fabric-reinforced cement composites. • The optimum nanoclay and hemp fabric content is 1.0 and 6.9 wt.% respectively. • Surface-treated hemp fabric-reinforced cement composites demonstrated better mechanical properties. • Surface modification of hemp fabric was effective in improving the hemp fabric-cement matrix adhesion. - Abstract: Cement nanocomposites reinforced with hemp fabrics and calcined nanoclay (CNC) have been fabricated and investigated. CNC is prepared by heating nanoclay (Cloisite 30B) at 900 °C for 2 h. The influences of CNC dispersion on the mechanical properties and thermal properties of these composites have been characterized in terms of porosity, density, water absorption, flexural strength, fracture toughness, impact strength and thermal stability. The microstructure is investigated using Quantitative X-ray Diffraction Analysis (QXDA) and High Resolution Transmission Electron Microscopy (HRTEM). The effects of alkali (NaOH) treatment of hemp fabric on the mechanical properties of hemp fabric-reinforced cement composites with different fabric contents of 4.5, 5.7, 6.9 and 8.1 wt% are also investigated. Results show that the optimum hemp fabric content is 6.9 wt% (i.e. 6 fabric layers). Results also indicated that physical, mechanical and thermal properties were enhanced due to the addition of CNC into the cement matrix and the optimum content of CNC was 1 wt%. The treated hemp fabric-reinforced nanocomposites containing 1 wt% CNC exhibited the highest flexural strength, fracture toughness, impact strength and thermal stability by virtue of good fibre–matrix interface. This environmentally friendly nanocomposite can be used for various construction applications such as ceilings and roofs

  19. Fast preparation of Na0.44MnO2 nanorods via a high NaOH concentration hydrothermal soft chemical reaction and their lithium storage properties

    International Nuclear Information System (INIS)

    Liu, Cai; Li, Jiangang; Zhao, Pengxiang; Guo, Wenli; Yang, Xiaoping

    2015-01-01

    This paper describes a high NaOH concentration hydrothermal soft chemical reaction to prepare Na 0.44 MnO 2 nanorods. In this process, Na-birnessite precursors and concentrated NaOH solution are introduced into the hydrothermal reaction. As a result, the hydrothermal time can be significantly shortened from 96 to 24 h, the hydrothermal temperature can be reduced from 205 to 180 °C and the yield of Na 0.44 MnO 2 can be increased from about 0.6 to about 2.4 g/(mL . day), respectively. Furthermore, the obtained Na 0.44 MnO 2 nanorods with one-dimensional tunnel structures exhibit favorable electrochemical lithium storage properties, which make them promising for the cathode materials of lithium-ion batteries

  20. Performance and Meat Quality of Thin Tailed Sheep in Supplementary Feeding Lemuru Fish Oil Protected By Saponification with Different NaOH Concentration

    Directory of Open Access Journals (Sweden)

    Agustinah Setyaningrum

    2015-09-01

    Full Text Available This study was aimed to obtain oil and the exact saponification with different NaOH concentration to protect unsaturated fats, which does can result in good production performance and lamb meat quality with low saturated fatty acid. Stage one studied the performance of sheep production on supplementing lemuru fish oil (LFO protected with different saponification optimization. Twenty lambs aged 5-6 months early weighing 8-14 kg were divided into 4 treatments, namely P0 basal feed (50% elephant grass + 50% concentrate, P1 (basal feed + soap LFO NaOH 10%, P2 (basal feed + soap LFO NaOH 20% and P3 (basal feed + soap LFO NaOH 30% with completely randomized design and 5 replication for performance and 3 replication for meat quality. The results showed that the treatment effect was not significant (P>0.05 on the consumption of dry matter (DM, crude protein (CP, ether extract (EE, total digestible nutrien (TDN, daily gain and blood cholesterol. P2 yield the highest daily gain 130.95 ± 19.29 g/head/day of cholesterol at the same time low of 58.67 mg/dl. Stage two studied the criteria of lamb carcass and meat quality in supplementary feeding LFO protected with different saponification optimization. Twelve sheeps were slaughtered for P0, P1, P2 and P3. The results showed that the treatment effect was not significant (P> 0.05 to slaughter weight, carcass weight and carcass percentage, the physical quality of meat (pH, water holding capacity, cooking losses and tenderness, and chemical quality of the meat (DM levels, CP , EE, saturated fatty acids and unsaturated fatty acids except in EPA and DHA increased very significantly (P<0.01. Conclusively, giving soap LFO with different optimization did not significantly affect the appearance and quality of sheep meat production, except in EPA and DHA which were significantly increased

  1. Pengolahan Internal Air Boiler Dengan Penambahan Asam Sulfat (H2SO4) 98% dan Kaustik Soda (NaOH) Di PTPN III Pabrik Kelapa Sawit Rambutan Tebing Tinggi

    OpenAIRE

    Simanjuntak, Depi Fitri

    2010-01-01

    Have been do observation to treatment of water domestic boiler with additional material of chemistry that is: H2SO4 98 % in tank cation and NaOH in tank anion. From result of observation, so geted, pH value, Total Dissolved Solid (TDS), Phenolphtalein Alkalinity, Methyl Alkalinity, Total Alkalinity, Sulfite, Chloride, Total Hardness, Hardness, has appropriate with prerequirement water of boiler wich used in PTPN III RAMBUTAN TEBING TINGGI. 072409006

  2. Increased Levels of Cell-Free Human Placental Lactogen mRNA at 28-32 Gestational Weeks in Plasma of Pregnant Women With Placenta Previa and Invasive Placenta

    Science.gov (United States)

    Sekizawa, Akihiko; Ventura, Walter; Koide, Keiko; Hori, Kyouko; Okai, Takashi; Masashi, Yoshida; Furuya, Kenichi; Mizumoto, Yoshifumi

    2014-01-01

    We compared the levels of cell-free human placental lactogen (hPL) messenger RNA (mRNA) in maternal plasma at 28 to 32 weeks of gestation between women with diagnosis of placenta previa or invasive placenta and women with an uneventful pregnancy. Sensitivity and specificity of hPL mRNA for the prediction of invasive placenta were further explored. Plasma hPL mRNA were quantified by real-time reverse-transcriptase polymerase chain reaction in women with placenta previa (n = 13), invasive placenta (n = 5), and normal pregnancies (n = 92). Median (range) hPL mRNA was significantly higher in women with placenta previa, 782 (10-2301) copies/mL of plasma, and in those with invasive placenta, 615 (522-2102) copies/mL of plasma, when compared to normal pregnancies, 90 (4-4407) copies/mL of plasma, P < .01 and P < .05, respectively. We found a sensitivity of 100% and a specificity of 61.5% for the prediction of invasive placenta among women with placenta previa. In conclusion, expression of hPL mRNA is increased in plasma of women with placenta previa and invasive placenta at 28 to 32 weeks of gestation. PMID:23744883

  3. PENGARUH PERLAKUAN DELIGNIFIKASI DENGAN LARUTAN NAOH DAN KONSENTRASI SUBSTRAT JERAMI PADI TERHADAP PRODUKSI ENZIM SELULASE DARI ASPERGILLUS NIGER NRRL A-II, 264

    Directory of Open Access Journals (Sweden)

    IDA BAGUS WAYAN GUNAM

    2010-12-01

    Full Text Available his research was done in order to utilize agricultural waste (rice straw as substrate to produce crude cellulase enzyme from Aspergillus niger. This research was conducted in two stages; the first stage was determination of the initial pH and fermentation time by pH treatment (5, 6 and 7 and fermentation time (7, 9 and 11 days. The second stage was determination of concentration of NaOH treatment and concentration of substrate, namely: concentrations of NaOH (2, 4 and 6% and concentrations of substrate (1, 2 and 3% (w/v. The results showed that the fermentation time of 9 days with the initial pH 6.0 was the optimal condition for production of crude cellulase enzyme from A. niger with rice straw as a substrate. The highest enzyme activity derived from interaction of delignification treatment with NaOH concentration of 6% and 2% rice straw substrate which produces endoglukanase enzyme activity (0.037 units/ml, filter paperase activity (0.033 units/ml, soluble protein (0.362 mg/ml, and specific activity of filter paperase (0.123 units/mg.

  4. Investigation on the Effect of Green Inhibitors for Corrosion Protection of Mild Steel in 1 M NaOH Solution

    Directory of Open Access Journals (Sweden)

    Premjith Jayakumar Ramakrishnan

    2014-01-01

    Full Text Available Alkaline corrosion is one of the main issues faced by the industries. The main chemicals abundantly used in industries are NaOH, H3PO4, HCl, and H2SO4. Corrosion control of metals has technical, economical, environmental, and aesthetical importance. The use of inhibitors is one of the best options to protect metals and alloys against corrosion. The corrosion protection of mild steel in 1 M NaOH solution by mix of Henna/Zeolite powder was studied at different temperatures by weight loss technique. Adsorption, activation, and statistical studies were addressed in this work. Adsorption studies showed that inhibitor adsorbed on metal surface according to Langmuir isotherm. Surface studies were performed by using UV-spectra and SEM. The adsorption of inhibitor on the steel surface was found to obey Langmuir’s adsorption isotherm. The inhibition efficiency increased with increasing concentration of the inhibitor in NaOH medium. Inhibition mechanism is deduced from the concentration and temperature dependence of the inhibition efficiency, Langmuir’s adsorption isotherm, SEM, and UV spectroscopic results.

  5. Preparative treatment with NaOH to selectively concentrate iron oxides of a Chilean volcanic soil material to produce effective heterogeneous Fenton catalyst

    International Nuclear Information System (INIS)

    Manzo, Valentina; Pizarro, Carmen; Rubio, María Angélica; Cavalcante, Luis Carlos Duarte; Garg, Vijayendra Kumar; Fabris, José Domingos

    2011-01-01

    A Chilean volcanic Ultisol material was first size-fractionated so as to obtain the fraction with mean particle sizes φ   − 1 NaOH, in an attempt to evaluate the effectiveness of the selective chemical dissolution to concentrate iron oxides, as a preparation procedure before using the materials as heterogeneous Fenton catalysts. The effects of those treatments on the iron oxides mineralogy were monitored with Mössbauer spectroscopy. The NaOH-treated samples were tested as catalysts towards the H 2 O 2 decomposition. Three or five sequential NaOH treatments were found to be comparably effective, by concentrating nearly the same proportion of iron oxides in the remaining solid phase (25.1 ± 0.4 and 23.3 ± 0.2 mass%, respectively). 298 K-Mössbauer patterns were similar for both samples, with a central (super)paramagnetic Fe 3 +  doublet and a broad sextet, assignable to several closely coexisting magnetically ordered forms of iron oxides. Despite of this nearly similar effect of the two treatments, the Ultisol material treated three times with NaOH presents higher heterogeneous catalytic efficiency and is more suitable to decompose H 2 O 2 than that with five treatments.

  6. La relevancia de la deliberación del consumidor en el ecosistema digital previa a la decisión de compra

    OpenAIRE

    Zevallos Miranda, Fernando R.

    2014-01-01

    Este estudio analiza el rol y la importancia que ha adquirido la búsqueda de información, conversación en foros y redes sociales y deliberación previa a la toma decisiones en el proceso de compra. Partiendo de la hipótesis de que el fácil acceso de los usuarios de Internet a reseñas y prescripciones sobre productos y marcas es uno de los principales detonantes de este fenómeno, se presentan los antecedentes y las opiniones de expertos en relación a la relevancia que ha cobrado la información ...

  7. La práctica de los deportes de lucha. Un estudio preliminar sobre la experiencia previa de los estudiantes de la Licenciatura en Ciencias del Deporte

    OpenAIRE

    Villamón Herrera, Miguel; Gutiérrez García, Carlos; Espartero Casado, Julián; Molina Alventosa, J. Pere

    2005-01-01

    En este trabajo se presenta un primer estudio sobre la experiencia previa en la práctica de deportes de lucha que tienen los estudiantes de la Licenciatura en Ciencias de la Actividad Física y el Deporte. El estudio se basó en la recogida y análisis de datos procedente de un cuestionario administrado a los estudiantes de primer ciclo de dicha licenciatura, de las universidades de Valencia y León, al inicio de los cursos académicos 2001-2002 y 2002-2003. Los resultados muestran que cerca del 5...

  8. Pregnancy Complications: Placenta Previa

    Science.gov (United States)

    ... Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & ... Report Cards Careers Archives Pregnancy Before or between pregnancies Nutrition, weight & fitness Prenatal care Is it safe? Labor & ...

  9. Invasive placenta previa. Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Xin; Zhang, Xinjuan; Wang, Shanshan; Shi, Honglu; Gao, Fei; Wang, Guangbin [Shandong University, Department of MR, Shandong Medical Imaging Research Institute, Jinan, Shandong (China); Shan, Ruiqin [Jinan Maternity and Child Care Hospital, Department of Obstetrics, Jinan (China); Zhao, Lianxin [Qilu Hospital of Shandong University, Department of Radiology, Jinan, Shandong (China); Song, Qingxu [Qilu Hospital of Shandong University, Department of Radiation Oncology, Jinan, Shandong (China); Zuo, Changting [Shandong Provincial Hospital Affiliated to Shandong University, Department of Obstetrics and Gynaecology, Jinan, Shandong (China); Qian, Tianyi [MR Collaborations NE Asia, Siemens Healthcare, Beijing (China); Limperopoulos, Catherine [Children' s National Health System, Division of Diagnostic Imaging and Radiology, Washington, DC (United States); George Washington University School of Medicine, Department of Radiology, Washington, DC (United States)

    2018-02-15

    To characterise MRI features of invasive placenta previa and to identify specific features for differentiating placenta percreta (PP) from placenta accreta (PA). Forty-five women with PP and 93 women with PA who underwent 1.5T placental MRI were included. Two radiologists independently evaluated the MRI features of invasive placenta previa, including our novel type of placental bulge (i.e. placental bulge type-II, characterized by placental bulge with distorted uterine outline). Pearson's chi-squared or Fisher's two-sided exact test was performed to compare the MRI features between PP and PA. Logistic stepwise regression analysis and the area under the receiver operating characteristic curve (AUC) were performed to select the optimal features for differentiating PP from PA. Significant differences were found in nine MRI features between women with PP and those with PA (P <0.05). Placental bulge type-II and uterine serosal hypervascularity were independently associated with PP (odds ratio = 48.618, P < 0.001; odds ratio = 4.165, P = 0.018 respectively), and the combination of the two MRI features to distinguish PP from PA yielded an AUC of 0.92 for its predictive performance. Placental bulge type-II and uterine serosal hypervascularity are useful MRI features for differentiating PP from PA. (orig.)

  10. Invasive placenta previa: Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta.

    Science.gov (United States)

    Chen, Xin; Shan, Ruiqin; Zhao, Lianxin; Song, Qingxu; Zuo, Changting; Zhang, Xinjuan; Wang, Shanshan; Shi, Honglu; Gao, Fei; Qian, Tianyi; Wang, Guangbin; Limperopoulos, Catherine

    2018-02-01

    To characterise MRI features of invasive placenta previa and to identify specific features for differentiating placenta percreta (PP) from placenta accreta (PA). Forty-five women with PP and 93 women with PA who underwent 1.5T placental MRI were included. Two radiologists independently evaluated the MRI features of invasive placenta previa, including our novel type of placental bulge (i.e. placental bulge type-II, characterized by placental bulge with distorted uterine outline). Pearson's chi-squared or Fisher's two-sided exact test was performed to compare the MRI features between PP and PA. Logistic stepwise regression analysis and the area under the receiver operating characteristic curve (AUC) were performed to select the optimal features for differentiating PP from PA. Significant differences were found in nine MRI features between women with PP and those with PA (P Placental bulge type-II and uterine serosal hypervascularity were independently associated with PP (odds ratio = 48.618, P Placental bulge type-II and uterine serosal hypervascularity are useful MRI features for differentiating PP from PA. • Placental bulge type-II demonstrated the strongest independent association with PP. • Uterine serosal hypervascularity is a useful feature for differentiating PP from PA. • MRI features associated with abnormal vessels increase the risk of massive haemorrhage.

  11. Invasive placenta previa. Placental bulge with distorted uterine outline and uterine serosal hypervascularity at 1.5T MRI - useful features for differentiating placenta percreta from placenta accreta

    International Nuclear Information System (INIS)

    Chen, Xin; Zhang, Xinjuan; Wang, Shanshan; Shi, Honglu; Gao, Fei; Wang, Guangbin; Shan, Ruiqin; Zhao, Lianxin; Song, Qingxu; Zuo, Changting; Qian, Tianyi; Limperopoulos, Catherine

    2018-01-01

    To characterise MRI features of invasive placenta previa and to identify specific features for differentiating placenta percreta (PP) from placenta accreta (PA). Forty-five women with PP and 93 women with PA who underwent 1.5T placental MRI were included. Two radiologists independently evaluated the MRI features of invasive placenta previa, including our novel type of placental bulge (i.e. placental bulge type-II, characterized by placental bulge with distorted uterine outline). Pearson's chi-squared or Fisher's two-sided exact test was performed to compare the MRI features between PP and PA. Logistic stepwise regression analysis and the area under the receiver operating characteristic curve (AUC) were performed to select the optimal features for differentiating PP from PA. Significant differences were found in nine MRI features between women with PP and those with PA (P <0.05). Placental bulge type-II and uterine serosal hypervascularity were independently associated with PP (odds ratio = 48.618, P < 0.001; odds ratio = 4.165, P = 0.018 respectively), and the combination of the two MRI features to distinguish PP from PA yielded an AUC of 0.92 for its predictive performance. Placental bulge type-II and uterine serosal hypervascularity are useful MRI features for differentiating PP from PA. (orig.)

  12. Reseña: Abal Oliú, Alejandro: C.G.P. y conciliación previa en materia laboral, Editorial Universidad Ltda. Montevideo, 1992, 64 págs.

    Directory of Open Access Journals (Sweden)

    o. C. R.

    2015-10-01

    Full Text Available Abal Oliú, Alejandro: C.G.P. y conciliación previa en materia laboral, Editorial Universidad Ltda. Montevideo, 1992, 64 págs. Editorial Universidad Ltda. Montevideo, 1992, 64 págs.El autor, profesor de Derecho Procesal y de Técnica Forense en nuestra Facultad, analiza en la presente obra las distintas fórmulas que es posible estab~ecer en cuanto a la tentativa de conciliación previa a la iniciación de los procesos laborales, luego de la entrada en vigencia del Código General del Proceso. (...

  13. Improved Oxidation Resistance of Zirconium Resulting from Addition of Small Amounts of Copper; Amelioration de la Resistance a l'Oxydation du Zirconium par de Faibles Additions de Cuivre; Povyshenie soprotivlyaemosti k okisleniyu tsirkoniya posle dobavlenij nebol'shikh kolichestv medi; Aumento de la Resistencia del Circonio a la Oxidacion por Agregado de Pequenas Cantidades de Cobre

    Energy Technology Data Exchange (ETDEWEB)

    Loriers, H.; Darras, R.; Baque, P. [Centre d' Etudes Nucleaires de Saclay (France)

    1966-02-15

    600 et 700 Degree-Sign C. En effet, les alliages correspondants, notamment celui a 2,5% de cuivre, semblent offrir des possibilites interessantes comme materiaux de gainage ou de structure pour les elements combustibles des reacteurs de la filiere eau lourde-gaz carbonique. La corrosion du zirconium par le gaz carbonique se ramene essentiellement a une oxydation, au cours de laquelle deux processus interferent: 1. l'edification d'une couche de zircone monoclinique, a travers laquelle l'oxygene diffuse par migration des lacunes anioniques, 2. la dissolution et la diffusion de l'oxygene, qui passe en insertion dans le metal. La combinaison des donnees gravimetriques et des mesures d'epaisseur des couches d'oxyde permet d'evaluer les deux coefficients de diffusiqn correspondants. Ce calcul a ete etendu par analogie au cas des alliages binaires zirconium-cuivre, de concentration en cuivre inferieure ou egale a 4% en poids. La comparaison des resultats obtenus montre que le coefficient de diffusion apparent de l'oxygene dans la couche d'oxyde formee decroit lorsque la teneur en cuivre de l'alliage envisage augmente; d'autre part, le coefficient de diffusion apparent de l'oxygene dans l'alliage, s'il est peu modifie a 600 Degree-Sign C, decroit a 700 Degree-Sign C lorsque la teneur en cuivre augmente jusqu'a 2,5%. L'amelioration de la resistance a l'oxydation, liee au ralentissement des processus de diffusion, se traduit en particulier par le maintien prolonge d'une cinetique du type parabolique, alors que, dans le cas du zirconium non allie ou d'autres alliages, la fissuration de la couche d'oxyde conduit rapidement a une cinetique d'oxydation lineaire, a la suite du phenomene de desquamation. (author) [Spanish] Los autores procuraron interpretar el efecto favorable que pequenas cantidades de cobre ejercen sobre la resistencia del circonio a la oxidacion por accion del anhidrido carbonico a presion, entre 600 y 700 Degree-Sign C. Las aleaciones correspondientes y, en

  14. A Contribution to the Study of the Oxidation of Uranium Monocarbide in Carbonic Anhydride at High Temperatures; Contribution a l'etude de l'oxydation du monocarbure d'uranium dans l'anhydride carbonique aux temperatures elevees; Vklad v izuchenie voprosa okisleniya monokarbida urana v ugol'nom angidride pri povyshennykh temperaturakh; Contribucion al estudio de la oxidacion del monocarburo de uranio en anhidrido carbonico a temperaturas elevadas

    Energy Technology Data Exchange (ETDEWEB)

    Desrues, R; Paidassi, J.; Darras, R. [Centre d' Etudes Nucleaires, Saclay (France)

    1963-11-15

    fragmentation progressive des echantillons. Les augmentations de poids trouvees sont d'ailleurs nettement plus faibles que celles publiees jusqu'a ce jour, ce qu'il faut tres vraisemblablement attribuer a une purete plus grande de l'anhydride carbonique mis en oeuvre et a une porosite particulierement faible du monocarbure d'uranium utilise. 2. La presence d'inclusions dans le monocarbure, qu'elles correspondent a de l'uranium ou a du dicarbure, diminue la resistance a.l'oxydation de ce materiau, ce qu'il faut surtout imputer au fait que celles-ci subissent une oxydation catastrophique, notamment par suite des contraintes mecaniques qu' elles introduisent. 3. Dans tous les cas, le processus d'oxydation peut etre caracterise par une energie d'activation egale a 29 000 cal/mole, valeur tres voisine de celle qui correspond a l'oxydation de l'uranium metallique dans le meme gaz, et a la diffusion de l'oxygene dans l'oxyde d'uranium (UO{sub 2}) forme. (author) [Spanish] Los autores tomaron muestras de monocarburo de uranio, obtenidas por dos procedimientos distintos, y de un cermet compuesto de 96,7% de U y 3,3% de C (en peso), las sometieron a la accion del anhidrido carbonico practicamente exento de oxigeno y vapor de agua, en un intervalo de temperaturas de 350 a 600 deg. C; observaron el progreso de la oxidacion por gravimetria (con una termobalanza de Eyraud) y por micrografia a la vez. Llegaron a las siguientes conclusiones: 1. Al principio, las graficas que representan los aumentos de peso en funcion del tiempo son sensiblemente rectilineas, pero luego su pendiente se acentua, lo que se explica sobre todo por la fragmentacion progresiva de las muestras. Por otra parte, los aumentos de peso verificados son netamente inferiores a los datos publicados hasta el presente, lo que cabe atribuir muy probablemente a la mayor pureza del anhidrido carbonico utilizado y a la porosidad particularmente baja del monocarburo de uranio empleado. 2. La presencia de inclusiones en el

  15. Hemicelluloses negatively affect lignocellulose crystallinity for high biomass digestibility under NaOH and H2SO4 pretreatments in Miscanthus

    Directory of Open Access Journals (Sweden)

    Xu Ning

    2012-08-01

    Full Text Available Abstract Background Lignocellulose is the most abundant biomass on earth. However, biomass recalcitrance has become a major factor affecting biofuel production. Although cellulose crystallinity significantly influences biomass saccharification, little is known about the impact of three major wall polymers on cellulose crystallization. In this study, we selected six typical pairs of Miscanthus samples that presented different cell wall compositions, and then compared their cellulose crystallinity and biomass digestibility after various chemical pretreatments. Results A Miscanthus sample with a high hemicelluloses level was determined to have a relatively low cellulose crystallinity index (CrI and enhanced biomass digestibility at similar rates after pretreatments of NaOH and H2SO4 with three concentrations. By contrast, a Miscanthus sample with a high cellulose or lignin level showed increased CrI and low biomass saccharification, particularly after H2SO4 pretreatment. Correlation analysis revealed that the cellulose CrI negatively affected biomass digestion. Increased hemicelluloses level by 25% or decreased cellulose and lignin contents by 31% and 37% were also found to result in increased hexose yields by 1.3-times to 2.2-times released from enzymatic hydrolysis after NaOH or H2SO4 pretreatments. The findings indicated that hemicelluloses were the dominant and positive factor, whereas cellulose and lignin had synergistic and negative effects on biomass digestibility. Conclusions Using six pairs of Miscanthus samples with different cell wall compositions, hemicelluloses were revealed to be the dominant factor that positively determined biomass digestibility after pretreatments with NaOH or H2SO4 by negatively affecting cellulose crystallinity. The results suggested potential approaches to the genetic modifications of bioenergy crops.

  16. The effect of NaOH catalyst concentration and extraction time on the yield and properties of Citrullus vulgaris seed oil as a potential biodiesel feed stock

    Directory of Open Access Journals (Sweden)

    J.K. Efavi

    2018-06-01

    Full Text Available In this work, oil was extracted from Citrullus vulgaris (watermelon seeds for potential feedstock in biodiesel production. The results showed that, the oil content from Citrullus vulgaris seeds oil during extraction reached an average yield of 50%. Biodiesel was produced via transesterification using NaOH as catalyst. The effect of NaOH on the yield of the biodiesel was investigated at three different concentrations; 0.13, 0.15 and 0.18 g and oil to methanol ratio of 5:1 under different reaction times; 90, 120 and 150 min at 60 °C. The yield of biodiesel from NaOH concentration of 0.13 g was found to be 70% as compared to those of concentrations, 0.15 g and 0.18 g which were 53% and 49% respectively.Gas chromatography was used to identify the methyl ester groups present in the biodiesel and the results revealed both concentration and time-dependent increase in oil yield. The physicochemical properties of the watermelon seed oil such as flash point (141.3 ± 0.4–143.4 ± 0.2, density (0.86 ± 0.04–0.91 ± 0.01 g/cm3, kinematic viscosity (30.50 ± 0.1–31.20 ± 0.04 mm2/s and acid value (mg KOH/g are similar to conventional vegetable oils. This work therefore, highlights the potential utility of water melon seeds for biodiesel production. Keywords: Citrullus vulgaris, Gas chromatography, Catalyst

  17. Pengaruh Simultan Parameter Suhu dan Konsentrasi Larutan NaOH Terhadap Kuantitas dan Kualitas Hasil Cellulose Powder pada Proses Delignifikasi Tongkol Jagung

    Directory of Open Access Journals (Sweden)

    Suprianto Suprianto

    2015-08-01

    Full Text Available Jagung merupakan sumber karbohidrat ketiga di Indonesia setelah padi dan ketela. Produksi jagung Indonesia meningkat terus menerus selama 10 tahun terakhir, yang diikuti dengan konsekuensi meningkatnya tongkol jagung sebagai produk ikutan pertanian jagung. Jumlah tongkol jagung dapat mencapai 40% dari produksi jagung. Fakta ini menunjukkan semakin tinggi potensi tongkol jagung untuk dapat dimanfaatkan bagi penunjang kehidupan manusia. Pemanfaatan tongkol jagung secara langsung sebagai bahan bakar maupun tidak langsung, yaitu melalui tahapan proses fisika dan kimia, sebelum dimanfaatkan langsung, telah mulai banyak menarik perhatian. Penelitian ini dimaksudkan untuk menambah informasi pengolahan tongkol jagung menghasilkan selulosa powder yang dapat digunakan sebagai cellulose gel, selulose membrane filter penjernihan air maupun sebagai bahan baku turunan senyawa selulosa, seperti selulosa asetat, carboxy methyl cellulose dan nitro selulosa.Proses pengolahan tongkol jagung menjadi cellulose prowder dilakukan dalam tiga tahapan proses, masing-masing untuk menghilangkan komponen hemiseluola, lignin dan warna dalam tongkol jagung. Proses tahap pertama menggunakan larutan asam nitrat 7,5% pada suhu 80 o C selama 2 jam, dilanjutkan dengan proses tahap kedua menggunakan larutan NaOH selama 2 jam dengan variasi suhu 80 sampai 100 o C dan variasi konsentrasi NaOH dari 1 N sampai 3 N dan selanjutnya proses tahap ketiga menggunakan hydrogen peroksida dengan konsentrasi 4%, suhu 80 o C dan waktu 2 Jam. Keberhasilan proses diidentifikasi dengan kuantitas dan kualitas hasil cellulose powder.Hasil penelitian menunjukkan bahwa kondisi proses yang baik dalam tahap proses delignifikasi adalah suhu antara 85 sampai 95 o C dan konsentrasi NaOH antara 1,25 N sampai 2 N. Produk pengolahan dari tongkol jagung, dengan proses tiga tahap ini diperoleh hasil cellulose powder warna putih dengan kadar   selulosa sekitar 88 sampai 90%, dengan yield investor sekitar 30

  18. [Determination of calcium, magnesium and potassium in nurtured cell by AAS with quick-pulsed nebulization technique and NaOH base digestion].

    Science.gov (United States)

    Shi, C; Gao, S; Gun, S

    1997-06-01

    The sample is digested with 6% NaOH solution and an amount of 50 microl is used for protein content analysis by the method of Comassie Brilliant Blue G250, the residual is diluted with equal 0.4% Lathanurm-EDTA solution. Its Calcium magensium and potassium content are determined by AAS. With quick-pulsed nebulization technique. When a self-made micro-sampling device is used, 20microl of sample volume is needed and it is only the 1/10 approximately 1/20 of the sample volume required for conventional determination. Sensitivity, precision and rate of recovery agree well with those using regular wet ashing method.

  19. Absorption of CO2 from modified flue gases of power generation Tarahan chemically using NaOH and Na2CO3 and biologically using microalgae

    Science.gov (United States)

    Purba, Elida; Agustina, Dewi; Putri Pertama, Finka; Senja, Fita

    2018-03-01

    This research was carried out on the absorption of CO2 from the modified flue gases of power generation Tarahan using NaOH (sodium hydroxide) and Na2CO3 (sodium carbonate). The operation was conducted in a packed column absorber and then the output gases from the packed column was fed into photo-bioreactor for biological absorption. In the photo-bioreactor, two species of microalgae, N. occulata and T. chuii, were cultivated to both absorb CO2 gas and to produce biomass for algal oil. The aims of this research were, first, to determine the effect of absorbent flow rate on the reduction of CO2 and on the decrease of output gas temperature, second, to determine the characteristics of methyl ester obtained from biological absorption process. Flow rates of the absorbent were varied as 1, 2, and 3 l/min. The concentrations of NaOH and Na2CO3 were 1 M at a constant gas flow rate of 6 l/min. The output concentrations of CO2 from the absorber was analyzed using Gas Chromatography 2014-AT SHIMADZU Corp 08128. The results show that both of the absorbents give different trends. From the absorption using NaOH, it can be concluded that the higher the flow rate, the higher the absorption rate obtained. The highest flow rate achieved maximum absorption of 100%. On the other hand, absorption with Na2CO3 revealed the opposite trend where the higher the flow rates the lower the absorption rate. The highest absorption using Na2CO3 was obtained with the lowest flow rate, 1 l/min, that was 45,5%. As the effect of flow rate on output gas temperature, the temperature decreased with increasing flow rates for both absorbents. The output gas temperature for NaOH and Na2CO3 were consecutively 35 °C and 31 °C with inlet gas temperature of 50°C. Absorption of CO2 biologically resulted a reduction of CO2 up to 60% from the input gas concentration. Algal oil was extracted with mixed hexane and chloroform to obtain algal oil. Extracted oil was transesterified to methyl ester using sodium

  20. Participación del consejo comunitario de la comunidad negra de Bellavista en la consulta previa para la formulación del plan de manejo ambiental de la central hidroeléctrica del bajo Anchicayá

    Directory of Open Access Journals (Sweden)

    Nixon Arboleda Montaño

    2016-01-01

    Full Text Available El presente trabajo analiza el proceso de participación que se llevó a cabo en el marco de la consulta previa entre el Consejo Comunitario de la Comunidad Negra de Bellavista (CCCNB, situado en el distrito de Buenaventura y la Empresa de Energía del Pacífico (EPSA con motivo de la formulación del Plan de Manejo Ambiental para la actual operación y mantenimiento la Central Hidroeléctrica del Bajo Anchicayá (Colombia. Se presentan los antecedentes de la evaluación de impacto ambiental en el ámbito internacional y en Colombia, y se explica en qué consiste el proceso de la consulta previa en los proyectos que requieren licencia ambiental. Posteriormente se analizan las etapas del proceso (etapa previa; estudios ambientales y socioeconómicos; identificación y evaluación de impactos ambientales; y construcción de medidas de manejo ambiental y finalmente se analiza el proceso de consulta previa, identificando los valores agregados que pudo generar el proceso.

  1. Estabilidade da sílica biogênica extraída de capim Jaraguá (Hyparrhenia rufa em solução de NaOH Stability of biogenic silica extract of Jaraguá grass (Hyparrhenia rufa in NaOH solution

    Directory of Open Access Journals (Sweden)

    Liovando M. Costa

    2010-01-01

    Full Text Available Biogenic silica is used to describe compounds of hydrated silica (SiO2.nH2O, with specific shapes and sizes, deposited in plants. The chemical composition of biogenic silica and its stability in Jaraguá grass was studied in increasing concentration of NaOH. The analytical results demonstrated high concentration of Si, Al, Fe, Mg, P and low of Cu, Cd and Zn in the phytoliths composition. The silica bodies stability in NaOH solution with increasing concentration was different among the shapes and sizes. Silicified stomata and silicified plant tissues were dissolved along with the dumbbells because they are the less stable forms of biogenic silica.

  2. Silicon content design of CrSiN films for good anti-corrosion and anti-wear performances in NaOH solution

    Science.gov (United States)

    Wang, Haixin; Ye, Yuwei; Wang, Chunting; Zhang, Guangan; Liu, Wei

    2018-06-01

    The CrSiN films with different silicon contents were fabricated by medium frequency magnetron sputtering. The 304L stainless steel and Si (1 0 0) wafer were used for substrate specimens. Film plasticity, corrosion and tribological behaviors in 0.1 M NaOH solution were systematically investigated. Results show that the plasticity of CrN film could be improved by the addition of silicon. During the corrosion test, with the increase of silicon content, the corrosion current density exhibited a descending trend and impedance presented a rising trend. The COF and wear rate of as-prepared CrSiN film initially decreased and then increased as the silicon content increased. The CrSiN film with 12.7 at.% Si exhibited the lowest COF of 0.04 and a wear rate of 6.746  ×  10‑8 mm3 Nm‑1 in 0.1 M NaOH solution.

  3. Response of CR-39 to 0.9–2.5 MeV protons for KOH and NaOH etching solutions

    Energy Technology Data Exchange (ETDEWEB)

    Bahrami, F. [Department of Medical Radiation Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Mianji, F., E-mail: fmianji@aeoi.org.ir [Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of); Iran Nuclear Regulatory Authority, Tehran (Iran, Islamic Republic of); Faghihi, R. [Department of Medical Radiation Engineering, Shiraz University, Shiraz (Iran, Islamic Republic of); Taheri, M. [Iran Nuclear Regulatory Authority, Tehran (Iran, Islamic Republic of); Ansarinejad, A. [Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2016-03-21

    In some circumstances passive detecting methods are the only or preferable measuring approaches. For instance, defining particles' energy profile inside the objects being irradiated with heavy ions and measuring fluence of neutrons or heavy particles in space missions are the cases covered by these methods. In this paper the ability of polyallyl diglycol carbonate (PADC) track detector (commercially known as CR-39) for passive spectrometry of proton particles is studied. Furthermore, the effect of KOH and NaOH as commonly used chemical etching solutions on the response of the detector is investigated. The experiments were carried out with protons in the energy range of 0.94–2.5 MeV generated by a Van de Graaff accelerator. Then, the exposed track dosimeters were etched in the two aforementioned etchants through similar procedure with the same normality of 6.25 N and the same temperature of 85 °C. Formation of the tracks was precisely investigated and the track diameters were recorded following every etching step for each solution using a multistage etching process. The results showed that the proposed method can be efficiently used for the spectrometry of protons over a wider dynamic range and with a reasonable accuracy. Moreover, NaOH and KOH outperformed each other over different regions of the proton energy range. The detection efficiency of both etchants was approximately 100%.

  4. Response of CR-39 to 0.9-2.5 MeV protons for KOH and NaOH etching solutions

    Science.gov (United States)

    Bahrami, F.; Mianji, F.; Faghihi, R.; Taheri, M.; Ansarinejad, A.

    2016-03-01

    In some circumstances passive detecting methods are the only or preferable measuring approaches. For instance, defining particles' energy profile inside the objects being irradiated with heavy ions and measuring fluence of neutrons or heavy particles in space missions are the cases covered by these methods. In this paper the ability of polyallyl diglycol carbonate (PADC) track detector (commercially known as CR-39) for passive spectrometry of proton particles is studied. Furthermore, the effect of KOH and NaOH as commonly used chemical etching solutions on the response of the detector is investigated. The experiments were carried out with protons in the energy range of 0.94-2.5 MeV generated by a Van de Graaff accelerator. Then, the exposed track dosimeters were etched in the two aforementioned etchants through similar procedure with the same normality of 6.25 N and the same temperature of 85 °C. Formation of the tracks was precisely investigated and the track diameters were recorded following every etching step for each solution using a multistage etching process. The results showed that the proposed method can be efficiently used for the spectrometry of protons over a wider dynamic range and with a reasonable accuracy. Moreover, NaOH and KOH outperformed each other over different regions of the proton energy range. The detection efficiency of both etchants was approximately 100%.

  5. Kinetic model of the thermal pyrolysis of chrome tanned leather treated with NaOH under different conditions using thermogravimetric analysis.

    Science.gov (United States)

    Bañón, E; Marcilla, A; García, A N; Martínez, P; León, M

    2016-02-01

    The thermal decomposition of chrome tanned leather before and after a soaking treatment with NaOH was studied using thermogravimetric analysis (TGA). The effect of the solution concentration (0.2M and 0.5M) and the soaking time (5min and 15min) was evaluated. TGA experiments at four heating rates (5, 10, 15 and 20°Cmin(-1)) were run in a nitrogen atmosphere for every treatment condition. A kinetic model was developed considering the effect of the three variables studied, i.e.: the NaOH solution concentration, the soaking time and the heating rate. The proposed model for chrome tanned leather pyrolysis involves a set of four reactions, i.e.: three independent nth order reactions, yielding the corresponding products and one of them undergoing a successive cero order reaction. The model was successfully applied simultaneously to all the experimental data obtained. The evaluation of the kinetic parameters obtained (activation energy, pre-exponential factor and reaction order) allowed a better understanding of the effect of the alkali treatment on these wastes. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Ideas previas sobre carga, fuerza y campo eléctrico en estudiantes universitarios. Consideraciones para su superación

    Directory of Open Access Journals (Sweden)

    Marianela Nava

    2008-05-01

    Full Text Available El presente trabajo trata sobre el valor didáctico de las ideas previas de los estudiantes para la construcción de nuevos saberes, que lo posibiliten para dar explicaciones acordes con el conocimiento científico. Luego del análisis de los datos, se plantea el diseño de situaciones didácticas, fundamentadas en Posner et al, Ausubel, Amestoy, Alonso et al, que permitan promover la construcción de conceptos, aplicable a diversos campos. El estudio se encuentra enmarcado en un paradigma cuali-cuantitativo, a nivel descriptivo. Una conclusión importante es que las nociones sobre campo eléctrico, resultaron más deficientes que las de carga, pero menos que las de fuerza eléctrica, siendo necesario fomentar la construcción de conceptos científicos en los estudiantes universitarios.

  7. A novel process for recovery of iron, titanium, and vanadium from titanomagnetite concentrates: NaOH molten salt roasting and water leaching processes

    International Nuclear Information System (INIS)

    Chen, Desheng; Zhao, Longsheng; Liu, Yahui; Qi, Tao; Wang, Jianchong; Wang, Lina

    2013-01-01

    Highlights: ► The conversion of titanium is 96.6% in the rich titanium–vanadium slag. ► MgTi 2 O 5 and M 3 O 5 (M = Ti, Mg, Fe) were converted to Na 2 TiO 3 and NaMO 2 , respectively. ► Na 2 TiO 3 is converted to undefined structure of H 2 TiO 3 . ► NaMO 2 is converted to α-NaFeO 2 -type structure of HMO 2 . ► 87.3% of sodium, 42.3% of silicon, 43.2% of aluminum, 22.8% of manganese and 96.6% of vanadium were leached out. -- Abstract: A novel process for recovering iron, titanium, and vanadium from titanomagnetite concentrates has been developed. In the present paper, the treatment of rich titanium–vanadium slag by NaOH molten salt roasting and water leaching processes is investigated. In the NaOH molten salt roasting process, the metallic iron is oxidized into ferriferous oxide, MgTi 2 O 5 is converted to NaCl-type structure of Na 2 TiO 3 , and M 3 O 5 (M = Ti, Mg, Fe) is converted to α-NaFeO 2 -type structure of NaMO 2 , respectively. Roasting temperature and NaOH–slag mass ratio played a considerable role in the conversion of titanium in the rich titanium–vanadium slag during the NaOH molten salt roasting process. Roasting at 500 °C for 60 min and a 1:1 NaOH–slag mass ratio produces 96.3% titanium conversion. In the water leaching process, the Na + was exchanged with H + , Na 2 TiO 3 is converted to undefined structure of H 2 TiO 3 , and NaMO 2 is converted to α-NaFeO 2 -type structure of HMO 2 . Under the optimal conditions, 87.3% of the sodium, 42.3% of the silicon, 43.2% of the aluminum, 22.8% of the manganese, and 96.6% of the vanadium are leached out

  8. Microstructural and optical properties of Co doped NiO nanoparticles synthesized by auto combustion using NaOH as fuel

    Science.gov (United States)

    Parveen, Azra; Agrawal, Shraddha; Azam, Ameer

    2018-05-01

    The nanoparticles of 5% Co doped NiO were synthesized by auto-combustion method in aqueous medium using NaOH as a fuel. The obtained particles were characterized using X-ray diffraction studies XRD. The results of structural characterization shows the formation of Co doped Nickel oxide nanoparticles in single phase without any impurity. The optical absorption spectra of Co doped NiO sample recorded by UV-VIS spectrophotometer in the range of 200 to 800 nm have been presented. The variation of dielectric constant and dielectric loss has been studied as function of frequency. Co doping affects the optical properties and band gap. NiO can potentially be used in optical, electronic, catalytic materials, antimicrobial agent and super-paramagnetic devices.

  9. Improvement of corrosion resistance in NaOH solution and glass forming ability of as-cast Mg-based bulk metallic glasses by microalloying

    Directory of Open Access Journals (Sweden)

    Peng Hao

    2011-02-01

    Full Text Available The influences of the addition of Ag on the glass forming ability (GFA and corrosion behavior were investigated in the Mg-Ni-based alloy system by X-ray diffraction (XRD and electrochemical polarization in 0.1 mol/L NaOH solution. Results shows that the GFA of the Mg-Ni-based BMGs can be improved dramatically by the addition of an appropriate amount of Ag; and the addition element Ag can improve the corrosion resistance of Mg-Ni-based bulk metallic glass. The large difference in atomic size and large negative mixing enthalpy in alloy system can contribute to the high GFA. The addition element Ag improves the forming speed and the stability of the passive film, which is helpful to decrease the passivation current density and to improve the corrosion resistance of Mg-Ni-based bulk metallic glass.

  10. Characterization of Ti6Al7Nb alloy foams surface treated in aqueous NaOH and CaCl2 solutions.

    Science.gov (United States)

    Bütev, Ezgi; Esen, Ziya; Bor, Şakir

    2016-07-01

    Ti6Al7Nb alloy foams having 53-73% porosity were manufactured via evaporation of magnesium space holders. A bioactive 1µm thick sodium hydrogel titanate layer, NaxH2-xTiyO2y+1, formed after 5M NaOH treatment, was converted to crystalline sodium titanate, Na2TiyO2y+1, as a result of post-heat treatment. On the other hand, subsequent CaCl2 treatment of NaOH treated specimens induced calcium titanate formation. However, heat treatment of NaOH-CaCl2 treated specimens led to the loss of calcium and disappearance of the titanate phase. All of the aforementioned surface treatments reduced yield strengths due to the oxidation of the cell walls of the foams, while elastic moduli remained mostly unchanged. Accordingly, equiaxed dimples seen on the fracture surfaces of as-manufactured foams turned into relatively flat and featureless fracture surfaces after surface treatments. On the other hand, Ca- and Na-rich coating preserved their mechanical stabilities and did not spall during fracture. The relation between mechanical properties of foams and macro-porosity fraction were found to obey a power law. The foams with 63 and 73% porosity met the desired biocompatibility requirements with fully open pore structures and elastic moduli similar to that of bone. In vitro tests conducted in simulated body fluid (SBF) showed that NaOH-heat treated surfaces exhibit the highest bioactivity and allow the formation of Ca-P rich phases having Ca/P ratio of 1.3 to form within 5 days. Although Ca-P rich phases formed only after 15 days on NaOH-CaCl2 treated specimens, the Ca/P ratio was closer to that of apatite found in bone. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Inhibition of stress corrosion cracking of alloy 600 in 10% NaOH solutions with and with lead oxide at 315 C

    International Nuclear Information System (INIS)

    Hur, D.H.; Kim, J.S.; Baek, J.S.; Kim, J.G.

    2002-01-01

    Alloy 600 steam generator tube materials have experienced various degradations by corrosion such as stress corrosion cracking (SCC) on the inner and outer diameter surface of tube, intergranular attack and pitting, and by mechanical damage such as fretting-wear and fatigue. These tube degradations not only increase the costs for tube inspection, maintenance and repair but also reduce the operation safety and the efficiency of plants. Therefore, the methodologies have been extensively developed to mitigate them. The addition of inhibitors to the coolant is a feasible method to mitigate tube degradations in operating plants. In this paper, a new inhibitor is proposed to mitigate the secondary side stress corrosion cracking of alloy 600 tubes. The effect of inhibitors on the electrochemical behavior and the stress corrosion cracking resistance of alloy 600 was evaluated in 10% sodium hydroxide solution with and without lead oxide at 315 C. The specimens of a C-ring type for stress corrosion cracking test were polarized at 150 mV above the corrosion potential for 120 hours without and with inhibitors such as titanium oxide, titanium boride, cerium boride. The chemical compositions of the films formed on the crack tip in the C-ring specimens were analyzed using a scanning Auger electron spectroscopy. The cerium boride, the most effective inhibitors, was observed to decrease the crack propagation rate more than a factor of three compared with that obtained in pure 10% NaOH solution. Furthermore, no SCC was observed in lead contaminated 10% NaOH solution by the addition of the cerium boride. (authors)

  12. Determination of the solubility of Np(IV), Pu(III) - (VI),Am(III) - (VI), and Te(IV), (V) hydroxo compounds in 0.5 - 14 M NaOH solutions

    Energy Technology Data Exchange (ETDEWEB)

    Delegard, C.H.

    1996-09-24

    The solubilities of Am(III), Np(IV), Pu(IV), Tc(IV), Np(V), Pu(V), Am(V), and Tc(V) hydroxo compounds were studied in 0.5 to 14 M NaOH solutions at 25{+-}2 {degrees}C. The effects of fluoride, phosphate, carbonate, oxalate, and some other organic complexing agents on the solubilities of Np(IV), Pu(IV), and TC(IV) hydroxides were investigated at 1.0 and 4.0 M NAOH. Some predictions were made on the dissolved (I.V) and (V) species present in alkali solutions.

  13. The effect of diets containing pistachio by products treated with electron irradiation, NaOH, and PEG on nutrients digestibility and performance of finishing Zandi lambs

    Directory of Open Access Journals (Sweden)

    Masoud Moradi

    2016-04-01

    Full Text Available Introduction It has been estimated that PBP production based on fresh weight in Iran is over 400,000 MT annually. Pistachio by-products consist of 53.50% external hull (epicarp with the remaining composed of leaves, mesocarp and kernel. The results of few studies showed feeding of low levels of PBP had no effects on sheep, dairy cow and goat performance. Ensiled of PBP with PEG, NaOH and urea then treated by electron irradiation could be caused to better nutrition value via deactivation of tannins. The aim of this study was to survey the effect of diets containing pistachio by products treated by electron irradiation, NaOH, and PEG on nutrients digestibility and performance of finishing Zandi lambs. Materials and methods Twenty male Zandi lambs with the initial average body weight of 21±1.52 kg were housed in individual pens and were allocated to four dietary treatments in a completely randomized design for 70 days. The basal diet consisted of 220 g/kg DM PBP, 130 g/kg DM wheat straw and 650 g/kg DM barley based concentrate. The four dietary treatments included control diet (Treatment 1; basal diet containing 22% PB, ER-PBP (Treatment 2; containing 22% electron irradiated PBP, NaOH-PBP (Treatment 3; containing 22% NaOH treated PBP and PEG-PBP (Treatment 4; PEG added to basal diet as 15 g/kg of diets DM. Throughout the 70 d experiment, body weight was measured weekly. Feed intake and ort of lambs were recorded and sampled daily for determination of nutrient intake of DM, CP (N × 6.25, EE and NDF as describes before. Apparent total digestibility of nutrients was estimated by the marker ratio technique using acid insoluble ash (AIA as an internal marker. Blood samples (10 ml were taken from jugular vein of lambs before morning feeding on d 70 of experiment. The serum concentrations of total protein (TP, albumin, creatinine, glucose and urea were determined using commercial laboratory kits (Pars Azmun Laboratory, Tehran, Iran and an auto analyzer

  14. Evaluación Médica Previa a La Práctica Deportiva Para Deportistas Aficionados y de Nivel Competitivo

    Directory of Open Access Journals (Sweden)

    Dr. D. Fernando yáñez

    2012-05-01

    Full Text Available La actividad física y el deporte reducen la mortalidad general y cardiovascular, pero durante la práctica de ejercicio aumenta el riesgo de muerte súbita que puede ser la primera manifestación de una enfermedad cardiovascular no diagnosticada en deportistas previamente asintomáticos. Las causas de muerte súbita difieren según la edad, en los menores de 35 años se debe a patologías congénitas o hereditarias y en los mayores de esta edad a enfermedad coronaria. En el presente artículo se analizan las causas más frecuentes de muerte súbita, así como los protocolos de evaluación médica previa a la práctica de actividad física o deporte propuestos en la literatura para su prevención en deportistas de diferentes edades y nivel de actividad, desde el competitivo de alto rendimiento hasta el recreativo por salud, y utilización del tiempo libre.

  15. Influence of 8-hydroxyquinoline addition on the corrosion behavior of commercial Al and Al-HO411 alloys in NaOH aqueous media

    International Nuclear Information System (INIS)

    Soliman, H.N.

    2011-01-01

    Highlights: → The corrosion of commercial Al alloy is higher than that of Al-HO411 alloy. → The inhibition efficiency increases with the increasing of 8-hydroxyquinoline (8HQ) concentration. → The inhibition efficiencies of Al-HO411 samples are higher than those of commercial Al. → The 8HQ is promising candidate to be added to the coating systems as active anti-corrosive component for corrosion protection of both alloys. - Abstract: The effect of 8-hydroxyquinoline (8HQ) on the corrosion inhibition of commercial Al and Al-HO411 alloys has been investigated in NaOH solutions. Results showed that the inhibition efficiency was increased with increasing concentration of 8HQ. Al-HO411 alloy exhibited higher corrosion resistance and inhibition efficiency than the commercial Al. Examination of both samples was studied by means of optical microscope as well as energy-dispersive X-ray spectrometer. The crystallographic structure of both samples was analyzed by means of X-ray diffractometry. It was observed that protective films are formed on the surfaces that play an essential role in the corrosion inhibition of the alloys under investigation.

  16. The Recovery of Uranium From The Rejected Fuel Plate Dispersion Type of U3O8-Al and U3Si2Al by NaOH

    International Nuclear Information System (INIS)

    Widodo, G; Aji, D

    1998-01-01

    The recovery of uranium from the rejected fuel plate dispersion type of U 3 O 8 -AI And U 3 Si 2 -AI with a dissolution has been performed.Each of 5 fragment of fuel plate dispersion of U 3 O 8 -AI or U 3 Si 2 Al of 1x4 cm size was put in the distilled glass content of 250 ml NaOH solution whit The concentration variation 10,15,20,25,and 30%,and than was heated at temperature of 102 o C and was stirred constantly by magnetic stirred.Uranium in the form of U 3 O 8 or U 3 Si 2 was separated by filtration and Either residu and filtrate was analyzed by potentiometry using modified Devies Gray method. From the experiment data it was found in the residu that presentation of uranium was 83.99-84.05% and 84.67-86.556% while in filtrate it was found 53.90 ppm and 69.3 ppm

  17. Raman scattering investigation of Bi2Te3 hexagonal nanoplates prepared by a solvothermal process in the absence of NaOH

    International Nuclear Information System (INIS)

    Liang Yujie; Wang Wenzhong; Zeng Baoqing; Zhang Guling; Huang Jing; Li Jin; Li Te; Song Yangyang; Zhang Xiuyu

    2011-01-01

    Research highlights: → Hexagonal Bi 2 Te 3 thin nanoplates were synthesized by a simple solvothermal method. → Optical properties of the nanoplates were investigated by micro-Raman spectroscopy. → Infrared (IR) active mode (A 1u ) is greatly activated in Raman scattering spectrum. → Infrared (IR) active mode (A 1u ) shows up in Raman spectrum of hexagonal nanoplates. → Raman spectrum clearly shows crystal symmetry breaking of hexagonal nanoplates. - Abstract: Hexagonal Bi 2 Te 3 nanoplates were synthesized by a simple solvothermal process in the absence of NaOH. The composition, morphology and size of the as-prepared products were characterized by powder X-ray diffraction (XRD) and transmission electron microscopy (TEM). Raman scattering optical properties of the as-prepared Bi 2 Te 3 nanoplates were investigated by micro-Raman spectroscopy. The Raman spectrum shows that infrared (IR) active mode (A 1u ), which must be odd parity and is Raman forbidden for bulk crystal due to its inversion symmetry, is greatly activated and shown up clearly in Raman scattering spectrum. We attribute the appearance of infrared active (A 1u ) in Raman spectrum to crystal symmetry breaking of Bi 2 Te 3 hexagonal nanoplates. The as-grown Bi 2 Te 3 hexagonal nanoplates, exhibiting novel Raman optical properties compared with bulk crystals, may find potential applications in thermoelectric devices.

  18. Flotation separation of PET from a PET, PVC and PS mixture by the hydrofilization of the PET surface in NaOH solutions

    Directory of Open Access Journals (Sweden)

    Ľubica Kozáková

    2005-11-01

    Full Text Available Recycling is the most effective method of waste minimization created by the human activity. The idea of waste re-use as a result of environmental, social and economical factors is becoming very relevant in the last decades. The portion of plastics in the municipal waste is growing year by year as also is its use in the wrapping industry. A condition for recycling technologies is the input of highly pure plastics (without undesirable admixtures suitable for recycling. Various separation technologies can be used which provide separation of particular components of plastic waste and contaminants. Flotation is one of the separation methods used especially for the ore beneficiation but recently is widely also used for the separation of various types of waste. Plastics, which are not possible to be separated by gravitational methods (because they have almost the same density, PET from beverage bottles, PVC from bottles and foils and PS from beverage beakers, were studied. By changing the surface properties of PET from naturally hydrophobic to hydrophilic by the adjustment in a NaOH solution, PET with the recovery of up to 99 % in the non-foamy product and with the product purity of up to 98 % was acquired by the flotation.

  19. Effect of potential on the corrosion fatigue crack propagation of inconel 600 in 50% NaOH solution at 850C

    International Nuclear Information System (INIS)

    Misawa, Toshihei; Sugawara, Hideo; Harada, Tadashi

    1979-01-01

    A study has been made of corrosion fatigue crack growth for Inconel 600 solution-annealed at 1100 0 C for 0.5 h in 85 0 C 50% NaOH solution with a frequency of 1.1 cycle per minute. The effect of potential on the corrosion fatigue crack growth rate (da/dN) as a function of ΔK was examined and the fracture surfaces were observed. The results obtained are as follows: (1) The crack growth rate and the cracking mode were affected by the applied potentials in the anodic polarization curve. The value of da/dN was arranged in the following order of the observed potentials: secondary passive region > corrosion potential > primary active region > primary passive region. (2) Intergranular cracking took place at a secondary passive potential (-0.04 V vs SCE) which gave a maximum crack growth rate. Transgranular cracking with fatigue striations occurred at the other potentials. (3) The variation in current with the alternating loading was observed at the potentials where transgranular cracking occurred, whereas no appreciable correlation between current and cyclic loading was shown at a potential of -0.04 V where the intergranular mode cracking occurred. (4) It is pointed out to be helpful in studying the influence of applied potential on the accelerated rate of cracking at the crack tip by the ''crack-tip opening displacement'' estimated from the stress intensity, as the major mechanical condition. (author)

  20. The effectiveness of sodium hydroxide (NaOH) and sodium carbonate (Na2CO3) on the impurities removal of saturated salt solution

    Science.gov (United States)

    Pujiastuti, C.; Ngatilah, Y.; Sumada, K.; Muljani, S.

    2018-01-01

    Increasing the quality of salt can be done through various methods such as washing (hydro-extraction), re-crystallization, ion exchange methods and others. In the process of salt quality improvement by re-crystallization method where salt product diluted with water to form saturated solution and re-crystallized through heating process. The quality of the salt produced is influenced by the quality of the dissolved salt and the crystallization mechanism applied. In this research is proposed a concept that before the saturated salt solution is recrystallized added a chemical for removal of the impurities such as magnesium ion (Mg), calcium (Ca), potassium (K) and sulfate (SO4) is contained in a saturated salt solution. The chemical reagents that used are sodium hydroxide (NaOH) 2 N and sodium carbonate (Na2CO3) 2 N. This research aims to study effectiveness of sodium hydroxide and sodium carbonate on the impurities removal of magnesium (Mg), calcium (Ca), potassium (K) and sulfate (SO4). The results showed that the addition of sodium hydroxide solution can be decreased the impurity ions of magnesium (Mg) 95.2%, calcium ion (Ca) 45%, while the addition of sodium carbonate solution can decreased magnesium ion (Mg) 66.67% and calcium ion (Ca) 77.5%, but both types of materials are not degradable sulfate ions (SO4). The sodium hydroxide solution more effective to decrease magnesium ion than sodium carbonate solution, and the sodium carbonate solution more effective to decrease calcium ion than sodium hydroxide solution.

  1. Stress corrosion cracking in 17-4PH and 17-7PH stainless steels in NaCl and NaOH (20%) a 90 deg C

    International Nuclear Information System (INIS)

    Gaona-Tiburcio, C.; Almeraya-Calderon, F.; Martinez-Villafane, A.

    2000-01-01

    One of the problems that affects to the electric industry is the not programmed stoppages in the power plants, due to the failure of any main component: boiler, turbine and generator. In the turbine, the combined action of a corrosive agent (humid polluted vapor) and a mechanical effort, generally will result in Stress Corrosion Cracking (SCC). In this work the SCC susceptibility of the precipitation hardening stainless steels 17-4PH and 17-17PH, thoroughly used in steam turbine blades of power stations is analyzed. The specimens were tested in the presence of NaCl and NaOH(20%) to 90 deg C and different pH. The CERT test (Constant Extension Rate Test) was used, at 10''-6 s''-1, supplementing it with electrochemical noise, the aim was to identify the conditions of maximum susceptibility and the performance of the studied materials. The fractographic analysis revealed ductile and brittle fracture. Intergranular cracking, characteristic of the anodic dissolution mechanisms of the materials was observed. Nevertheless, the main mechanism responsible the failure was hydrogen embrittlement. (Author) 6 refs

  2. Dissolution of targets for the production of Mo-99: Part 1. Influence of NaOH concentration and the addition of NaNO3 and NaNO2 on the dissolution time

    International Nuclear Information System (INIS)

    Camilo, Ruth L.; Araujo, Izilda da C.; Mindrisz, Ana C.; Forbicini, Christina A.L.G. de O.

    2011-01-01

    Faced with global crisis in the production of radioisotope 99 Mo, which product of decay, 99 mTc, is the tracer element most often used in nuclear medicine and accounts for about 80% of all diagnostic procedures in vivo, since September 2008 Brazil is developing the project called Brazilian Multipurpose Reactor (RMB). Within the Brazilian Nuclear Program (PNB) the construction of the RMB, is seen as a long term solution to meet all domestic demand relative to the supply of radioisotopes and radiopharmaceuticals. In the process to be studied to obtain 99 Mo from irradiated UA1 x -A1 LEU targets employing alkaline dissolution, processing time should be minimized, considering the short half life of 99 Mo and 99 mTc, about 66 h and 6 h, respectively. That makes dissolution time a significant factor in the development of the process. This paper presents the results of alkaline dissolution of scraps of Al, used to simulate the dissolution process of UA1 x -A1 targets. Al corresponds to about 79% of the total weight of the UA1 x -A1 target. The effect of NaOH concentration on dissolution time for the interval of 1 to 3.5 mol.L-1 was studied, keeping the molar ratio in 1Al:2.16NaOH and the initial temperature of 88 degree C. The influence of reagent composition over dissolution time was studied using three different solutions: a) 3 mol.L -1 NaOH, b) 3 mol.L -1 NaOH/NaNO 3 and c) 3 mol.L -1 NaOH/NaNO 2 , keeping the same molar ratio and temperature. The results showed that the dissolution time decreases with increasing NaOH concentration and the addition of NaNO 3 or NaNO 2 in the NaOH solution reduces both dissolution time and volume of gases released. (author)

  3. Isotopic data to study the mechanism of the oxidation of mercaptoacetic acid; Donnees isotopiques pour l'etude du mecanisme d'oxydation de l'acide mercaptoacetique; Izotopnyj metod issledovaniya mekhanizma okisleniya merkapgouksusnoj kisloty; Estudio del mecanismo de oxidacion del acido mercaptoacetico por medio de datos obtenidos con radioisotopos

    Energy Technology Data Exchange (ETDEWEB)

    Gal, D [Central Isotope Laboratory, University of Szeged (Hungary); Guczi, L [Department of Radiology, Elelmiszeripari Kutato Intezet, Budapest (Hungary)

    1962-03-15

    }S augmentait considerablement le taux d'absorption d'oxygene, tant dans le processus de catalysation par le fer qu'en l'absence de fer. Au cours de la reaction, on a mesure la concentration du sulfure, son activite specifique et son activite totale. En. partant de ces donnees, et en utilisant la methode d'etude cinetique au moyen d'isotopes, mise au point par Neiman et ses collaborateurs, on a pu calculer le taux de formation de sulfure et le taux de son oxydation ulterieure. La comparison de ces donnees avec d'autres donnees cinetiques revele que l'oxydation de l'acide mercaptoacetique en phase liquide est une reaction en chaine ramifiee, l'un des principaux elements de cette chaine etant la formation de Na{sub 2}S et son oxydation ulterieure. On a constate en outre qu'il se forme du sulfate, lors de la reaction, mais seulement a partir du sulfure mineral. Le fer catalyse la formation de disulfure organique et, de ce fait, influe aussi sur la formation de sulfure. (author) [Spanish] Numerosos investigadores han estudiado la autooxidacion en fase liquida, por oxigeno molecular, de compuestos que contienen un grupo mercaptano; si bien han llegado a la conclusion de que se forman sulfuros en el curso de la reaccion, el mecanismo exacto del proceso no se conoce. Los autores estudiaron la autooxidacion del acido mercaptoacetico a 50{sup o} C y pH 8 en presencia de complexon IV y de hierro. Anadieron al sistema Na{sub 2}S marcado con {sup 35}S y comprobaron que este compuesto aumenta notablemente la velocidad de absorcion de oxigeno tanto en las reacciones catalizadas por hierro como en las que transcurren en ausencia de iones de este metal. En el curso de la reaccion, los autores midieron la concentracion del sulfuro, su actividad especifica y su actividad total. Gracias a estos datos y empleando el metodo isotopico cinetico establecido por Neiman y colaboradores, pudieron calcular la velocidad de formacion del sulfuro y la velocidad de su oxidacion subsiguiente. Por

  4. Isolation and characterization of α-cellulose from blank bunches of palm oil and dry jackfruit leaves with alkaline process NaOH continued with bleaching process H2O2

    Science.gov (United States)

    Tristantini, Dewi; Dewanti, Dian Purwitasari; Sandra, Cindy

    2017-11-01

    Alpha cellulose is a pure form of cellulose. Cellulose is a natural polymer in the form of carbohydrates (polysaccharides) that has fiber which is white, insoluble in water, renewable, easily decomposes, and non-toxic. Cellulosic sources are abundant in nature even in untapped biomass wastes. In this study, cellulose was isolated from Empty Palm Oil Bunches (EPOB) of 45% and Dry Jackfruit Leaves (DJL) of 21.45%. This study aims to obtain optimum yield of cellulose at NaOH concentration and cellulose characterization with water content, FTIR, and SEM analysis. The optimum α-cellulose yield was determined by alkali process with 8, 10, 12 and 14% (w/v) NaOH variations at 90-100 °C for 3 hours to remove hemicellulose and lignin followed by bleaching process with H2O2 10% (w/v) at 80-90 °C for 1.5 h to obtain pure α-cellulose. The optimum yield of EPOB cellulose was 38,562% in 12% NaOH and DJL was 7.27% in 10% NaOH. The water content in OPB cellulose was 4.38% and DJL was 6.37%. A typical cellulose-forming functional group seen in FTIR (Fourier Transform Infra-Red) and morphological results appears in SEM (Scanning Electron Microscopy) analysis. From FTIR analysis result shows cellulose from EPOB and DJL contains O-H, C-H, and C-O. SEM analysis shows fibers from EPOB and DJL are uniform and have pores. However, DJL fibers have white patches, which suspected to be impurities.

  5. Catalytic hydrodechlorination of trichloroethylene in a novel NaOH/2-propanol/methanol/water system on ceria-supported Pd and Rh catalysts.

    Science.gov (United States)

    Cobo, Martha; Becerra, Jorge; Castelblanco, Miguel; Cifuentes, Bernay; Conesa, Juan A

    2015-08-01

    The catalytic hydrodechlorination (HDC) of high concentrations of trichloroethylene (TCE) (4.9 mol%, 11.6 vol%) was studied over 1%Pd, 1%Rh and 0.5%Pd-0.5%Rh catalysts supported on CeO2 under conditions of room temperature and pressure. For this, a one-phase system of NaOH/2-propanol/methanol/water was designed with molar percentages of 13.2/17.5/36.9/27.6, respectively. In this system, the alcohols delivered the hydrogen required for the reaction through in-situ dehydrogenation reactions. PdRh/CeO2 was the most active catalyst for the degradation of TCE among the evaluated materials, degrading 85% of the trichloroethylene, with alcohol dehydrogenation rates of 89% for 2-propanol and 83% for methanol after 1 h of reaction. Fresh and used catalysts were characterized by Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS), and Thermogravimetric analysis (TGA). These results showed important differences of the active phase in each catalyst sample. Rh/CeO2 had particle sizes smaller than 1 nm and the active metal was partially oxidized (Rh(0)/Rh(+δ) ratio of 0.43). This configuration showed to be suitable for alcohols dehydrogenation. On the contrary, Pd/CeO2 showed a Pd completed oxidized and with a mean particle size of 1.7 nm, which seemed to be unfavorable for both, alcohols dehydrogenation and TCE HDC. On PdRh/CeO2, active metals presented a mean particle size of 2.7 nm and more reduced metallic species, with ratios of Rh(0)/Rh(+δ) = 0.67 and Pd(0)/Pd(+δ) = 0.28, which showed to be suitable features for the TCE HDC. On the other hand, TGA results suggested some deposition of NaCl residues over the catalyst surfaces. Thus, the new reaction system using PdRh/CeO2 allowed for the degradation of high concentrations of the chlorinated compound by using in situ hydrogen liquid donors in a reaction at room temperature and pressure. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Novedoso método para preparar materiales nanoporosos compuestos MFI/MCM-41 a partir de caolín venezolano. Efecto de la concentración de NaOH

    Directory of Open Access Journals (Sweden)

    Freddy Imbert

    2012-05-01

    Full Text Available A MFI/MCM-41 composite material, a zeolite type MFI and Al-MCM-41 were synthesized from kaolin, using TPA and CTAB as structure directing agents. The MFI/MCM-41 composite material was synthesized in two steps. In the first, MFI was obtained and then treated with solutions of different NaOH concentrations (1 – 4M, in the second step the reaction mixture was treated under MCM-41 synthesis conditions. The solids obtained were characterized by scanning electron microscopy (SEM, chemical analysis by energy dispersive X-ray spectroscopy (EDX, transmission electron microscopy (TEM, adsorption of N2 at 77K, X-ray diffraction (XRD. In the absence of alkaline treatment two phases were observed – zeolite and mesoporous, whereas the zeolite crystals were larger than mesoporous particles. The alkaline treatment dissolved the zeolite structure creating mesoporosity, modifying the characteristic zeolite morphology and reducing its crystal domains. The treatment with 2 or 3M NaOH eases zeolite dissolution and leads to assemble of the zeolite building units around the surfactant and into the mesoporous walls. The incorporation of the zeolite building units into the mesoporous walls is governed by the relative quantities of crystalline and amorphous materials in the synthesis gel. The treatment with 4M NaOH led exclusively to the formation of Al-MCM-41.

  7. CONSIDERACIONES PREVIAS A LA ANTIBIOTICOTERAPIA

    Directory of Open Access Journals (Sweden)

    Moisés Morejón García

    2004-01-01

    Full Text Available Exponemos y valoramos los aspectos más sobresalientes a tener en cuenta antes de la aplicación de una terapia con fármacos antimicrobianos. La violación de estos aspectos puede, en muchas ocasiones, provocar el uso inadecuado de los mismos, lo que puede conllevar a un fallo de la farmacoterapia esperada, al surgimiento o incremento de resistencia bacteriana, así como a la aparición de efectos adversos evitables.

  8. Dissolution of targets for the production of Mo-99: Part 1. Influence of NaOH concentration and the addition of NaNO{sub 3} and NaNO{sub 2} on the dissolution time

    Energy Technology Data Exchange (ETDEWEB)

    Camilo, Ruth L.; Araujo, Izilda da C.; Mindrisz, Ana C.; Forbicini, Christina A.L.G. de O., E-mail: rcamilo@ipen.br, E-mail: icaraujo@ipen.br, E-mail: acmindri@ipen.br, E-mail: cforbici@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN/SP), Sao Paulo, SP (Brazil)

    2011-07-01

    Faced with global crisis in the production of radioisotope {sup 99}Mo, which product of decay, {sup 99}mTc, is the tracer element most often used in nuclear medicine and accounts for about 80% of all diagnostic procedures in vivo, since September 2008 Brazil is developing the project called Brazilian Multipurpose Reactor (RMB). Within the Brazilian Nuclear Program (PNB) the construction of the RMB, is seen as a long term solution to meet all domestic demand relative to the supply of radioisotopes and radiopharmaceuticals. In the process to be studied to obtain {sup 99}Mo from irradiated UA1{sub x}-A1 LEU targets employing alkaline dissolution, processing time should be minimized, considering the short half life of {sup 99}Mo and {sup 99}mTc, about 66 h and 6 h, respectively. That makes dissolution time a significant factor in the development of the process. This paper presents the results of alkaline dissolution of scraps of Al, used to simulate the dissolution process of UA1{sub x}-A1 targets. Al corresponds to about 79% of the total weight of the UA1{sub x}-A1 target. The effect of NaOH concentration on dissolution time for the interval of 1 to 3.5 mol.L-1 was studied, keeping the molar ratio in 1Al:2.16NaOH and the initial temperature of 88 degree C. The influence of reagent composition over dissolution time was studied using three different solutions: a) 3 mol.L{sup -1} NaOH, b) 3 mol.L{sup -1} NaOH/NaNO{sub 3} and c) 3 mol.L{sup -1} NaOH/NaNO{sub 2}, keeping the same molar ratio and temperature. The results showed that the dissolution time decreases with increasing NaOH concentration and the addition of NaNO{sub 3} or NaNO{sub 2} in the NaOH solution reduces both dissolution time and volume of gases released. (author)

  9. Penurunan Kromium (Cr dalam Limbah Cair Proses Penyamakan Kulit Menggunakan Senyawa Alkali Ca(OH2, NaOH, dan NaHCO3 (Studi Kasus di Pt Trimulyo Kencana Mas Semarang

    Directory of Open Access Journals (Sweden)

    Tri Joko

    2015-12-01

    Full Text Available ABTRACT Background : One of the industrial type which use hazardous materials in its production process is leather tanning industry, by using chromium compound (Cr. Chromium is a heavy metal compound which recognized has a high poison energy. Result of analysis of sampel industrial liquid waste of leather tanning of PT Trimulyo Kencana Mas (TKM Semarang showed that total chromium concervation was 49,575 m/l. This total Chromium rate was still above the standard quality of which enabled maximal 2,0 mg/l, according to Kep51/MENLH/110/1995. Alkali compound of Ca(OH2, NaOH and NaHC03 is chemicals able to be used for the processing of industrial liquid waste of pregnant leather tanning of chromium, functioning to boost up condensation pH andprecipitated chromium so that obtained chrome in theform of hydroxide chromium (Cr(OH3. Methods : which used in this research is (quasi experimental, with experiment variable repeated or referred as one group pretest ‑ posttest design. Results : of this research showed that optimum pH for the compound of each alkali at condition of pH 8, with the efficiency dissociation of chromium was equal to 99,28 % by using alkali compound of Ca(OH2 and of NaOH, while usage of NaHC03 equal to 98,50 %. Conclusions: Alkali compound of Ca(OH2, NaOH and NaHCO3 can degrade chromium concentration (Cr in liquid waste with high efficiency, that is reaching under standard quality. The most effective Compound of Alkali, evaluated from the technical aspect for the degradation of chromium concentration in liquid waste is NaOH, because with only small dose can dissociate chromium in liquid waste with high efficiency (99,28 %, For economic reason and recommendation for application in the field is Ca(OH2. Keyword : Efficiency Ca(OH2,, hydroxide chromium, NaHCO3, NaOH, pH, Chromium Compound

  10. Ideas previas sobre el reino vegetal en niños entre los 7 y 10 años de tercero de primaria de la Escuela Normal Superior Distrital María Montessori (E.N.S.D.M.M.)

    OpenAIRE

    Daniela Gomez; Daniela Velasco

    2015-01-01

    La presente investigación busca reconocer las ideas previas sobre el reino vegetal en niños entre los 7 y 10 años. Se eligió un grupo de 37 estudiantes de tercero de primaria perteneciente a la E.N.S.D.M.M., con los cuales se implementó un instrumento de caracterización tipo cuestionario conformado por 3 preguntas referentes al reino vegetal. A partir de las respuestas dadas por los niños, se clasificaron sus ideas previas generando categorías de estas, posterior a ello, con la referencia de ...

  11. RUMINAL DEGRADATION KINETIC PARAMETERS OF COFFEE HULLS (Coffea arabica, L. TREATED WITH SODIUM HYDROXIDE (NAOH PARÂMETROS CINÉTICOS DA DEGRADAÇÃO RUMINAL DA CASCA DE CAFÉ (Coffea arabica, L. TRATADA COM HIDRÓXIDO DE SÓDIO (NAOH

    Directory of Open Access Journals (Sweden)

    Luciano Fernandes de Sousa

    2008-04-01

    Full Text Available The objective of this work was to evaluate dry matter ruminal degradation kinetics of coffee hulls treated with increasing sodium hydroxide quantities. Two rumen fistulated cows were used to incubate samples in nylon bags for 12. 24, 36. 48 and 72 hours. Four ruminal incubation periods were used, in a complete randomized block design. Coffee hulls were treated with 0%, 3%, 6% and 9% of sodium hydroxide (dry matter basis, corresponding to treatments T1 to t4 respectively. Experimental results were compared using Tukey test, at 5% probability level, as follows for treatments 1 to 4 respectively: soluble fraction (9.35d; 17.65c; 31.93b; 32.28a, de (34.40d; 40.50c; 43.28b; 50.35a, potential degradability (44.33d; 50.33c; 52.35b; 57.70a and lag time in hours (4.03a; 3.93a; 4.33a; 2.55a. The results indicate that increasing the levels of NaOH in the coffee hulls treatments increased significantly their ruminal solubility, as well as their effective and potential degradabilities. However that increase had no effect upon coffee hulls lag time in the rumen.KEY WORDS: by-product feedstuffs, rumen degradability, ruminant.

    O objetivo deste trabalho foi o de determinar a cinética de degradação ruminal da matéria seca da casca de café, tratada com diferentes quantidades de hidróxido de sódio. Utilizaram-se duas vacas fistuladas no rúmen, incubando-se as amostras em sacolas de náilon por 12, 24, 36, 48 e 72 horas, por quatro rodadas seqüenciais, sendo que cada uma destas representou um bloco, dentro de um delineamento de blocos inteiramente casualizados. Tratou-se a casca de café com 0%, 3%, 6% e 9 % de hidróxido de sódio (base seca constituindo assim os tratamentos t1

  12. Relación entre la autonomía y las experiencias educativas previas de los actores curriculares encontradas en un contexto de educación superior de Bogotá, Colombia

    Directory of Open Access Journals (Sweden)

    Hélder Barahona Urbano

    2011-01-01

    universitarios sobre la autonomía en los procesos de aprendizaje y enseñanza, en el programa académico de Administración de Empresas, de la jornada diurna? La metodología que utilizó fue cualitativa, con enfoque etnográfico crítico; corresponde a la línea de investigación que se denomina ¿Pedagogía y Didáctica¿. Los resultados describen las relaciones que existen entre las creencias y las experiencias educativas previas, de los actores curriculares sobre la autonomía en los procesos de enseñanza y aprendizaje. Se concluye que relaciones pedagógicas establecidas en los procesos educativos afectan directamente la autonomía.

  13. La educación y la salud como coberturas previas a aplicación de la tabla de pensiones alimenticias básicas para niños, niñas y adolescentes

    Directory of Open Access Journals (Sweden)

    Juan Martínez Yntriago

    2015-11-01

    Full Text Available En Ecuador se usa lo coercitivo de la ley para hacer cumplir el derecho de niños, niñas y adolescentes a la manutención por parte de sus padres y familiares cercanos; con este objetivo, se creó la Tabla de Pensiones Alimenticias Básicas para ser aplicada obligatoriamente en los juicios de alimentos respecto al ingreso del alimentante, sin considerar necesidades que previamente son cubiertas y que no deben ser parte del reclamo; por lo cual, esta investigación hace una revisión a la teoría del derecho de alimentos y un análisis de la cobertura previa de educación y salud que no son apreciadas al momento de imponer la pensión alimenticia, así como una crítica a la aplicación de la referida tabla por la variación de los aspectos que motivaron su creación y un trabajo de campo que permitió concluir que estas coberturas anticipadas continúan siendo reclamadas por quienes demandan alimentos para sus hijos.

  14. Estudio de corrosión bajo tensión en los aceros inoxidables 17-4PH y 17-7PH en presencia de NaCl y NaOH (20 % a 90 °C

    Directory of Open Access Journals (Sweden)

    Gaona-Tiburcio, Citlalli

    2000-04-01

    Full Text Available One of the problems that affects to the electric industry is the not programmed stoppages in the power plants, due to the failure of any main component: boiler, turbine and generator. In the turbine, the combined action of a corrosive agent (humid polluted vapor and a mechanical effort generally will result in Stress Corrosion Cracking (SCC. In this work the SCC susceptibility of the precipitation hardening stainless steels 17-4PH and 17- 7PH, thoroughly used in steam turbine blades of power stations is analyzed. The specimens were tested in the presence of NaCl and NaOH (20 % to 90 °C and different pH. The CERT test (Constant Extension Rate Test was used, at 10-6 s-1 supplementing it with electrochemical noise; the aim was to identify the conditions of maximum susceptibility and the performance of the studied materials. The fractographic analysis revealed ductile and brittle fracture. Intergranular crackings, characteristic of the anodic dissolution mechanism of the material was observed. Nevertheless, the main mechanism responsible the failure was hydrogen embrittlement.

    Uno de los problemas que afecta a la industria eléctrica es el de los paros no programados en las plantas generadoras de electricidad, debidos al fallo de algún componente principal: caldera, turbina y generador. En la turbina, la acción combinada de un agente corrosivo (vapor húmedo contaminado y un esfuerzo mecánico, generalmente provocará corrosión bajo tensión (CBT. En este trabajo se analiza la susceptibilidad a la CBT de los aceros inoxidables, endurecibles por precipitación, 17-4PH y 17-7PH, ampliamente usados en alabes de turbina de vapor de centrales termoeléctricas. Las muestras se ensayaron en presencia de NaCl y NaOH (20 % a 90 °C, y distintos valores de pH. Se empleó el ensayo CERT (Constant Extensión Rate Test, a velocidades de 10-6 s-1, complementándolo con ruido electroquímico, buscando

  15. Measurement of bulk etch rates for poly-allyl-diglycol carbonate (PADC) and cellulose nitrate in a broad range of concentration and temperature of NaOH etching solution

    International Nuclear Information System (INIS)

    Hermsdorf, D.; Hunger, M.; Starke, S.; Weickert, F.

    2007-01-01

    In the present work the dependence of the bulk etch rate v B for solid state nuclear track detectors (SSNTD) on the concentration c and the temperature T of the NaOH etching solution has been studied for material types PADC and cellulose nitrate. As commonly applied exponents of PADC and cellulose nitrate material, the commercial products CR-39 and LR-115 were investigated. The concentration and temperature have been varied in the ranges 0.5moll -1 -1 and 313 -1 and T between 313 and 333K for cellulose nitrate, respectively. The application of a simple Arrhenius-law of chemical reactions fails in the interpretation of the dependence on the concentration. A constant activation energy cannot describe the behaviour of v B (c,T) over the whole range of concentration. To understand the deviation, more qualified models treating the superposition of chemical and physical processes including reaction kinetics and material transport phenomena by diffusion have to be developed and tested

  16. Digestibilidade do bagaço de cana-de-açúcar tratado com hidróxido de sódio em dietas para coelhos em crescimento Digestibility of sugar cane bagasse after a NaOH treatment in growing rabbit diets

    Directory of Open Access Journals (Sweden)

    Renata Apocalypse Nogueira Pereira

    2008-04-01

    Full Text Available Avaliou-se o bagaço de cana-de-açúcar não tratado (BN e tratado (BT com 2, 4 e 6% de hidróxido de sódio (NaOH na dieta para coelhos em crescimento. Os coeficientes de digestibilidade (CD dos nutrientes do BN e BT foram determinados em delineamento inteiramente casualizado, com cinco tratamentos (ração básica e rações com 40% de bagaço com 0, 2, 4 e 6% de NaOH e quatro repetições. Para obtenção dos valores de CD apenas do bagaço, e não da dieta total, adotou-se o método de substituição isométrica da dieta basal proposto por Matterson et al. (1965. A adição de NaOH ao bagaço não melhorou significativamente (P>0,05 os CD da matéria seca, proteína bruta, fibra em detergente neutro, fibra bruta e energia bruta e piorou significativamente (P=0,0023 o CD da fibra em detergente ácido (y = 20,042 - 2,7615x, r² = 0,984. Concluiu-se que o tratamento do bagaço de cana-de-açúcar com NaOH não trouxe vantagens práticas sobre os valores de CD que justificassem o seu uso, já que a adoção dessa técnica demanda aumento de mão-de-obra e do custo da alimentação.The NaOH treated sugar cane bagasse (BT (2, 4 e 6% and untreated cane bagasse (BN was evaluated as rabbit diet ingredients. The digestion coefficients (CD were determined in a completely randomized design, with five treatments (basic diet and 40% bagasse diets (0, 2, 4 e 6% NaOH and four replications, using substitution methodology (Matterson et al., 1965. The nutritive values of bagasse (DM, CP, NDF, CF and GE were not significantly (P>0,05 affected by NaOH treatment, whereas AFD was significantly (P = 0,0023 linearly decreased by the chemical treatment (y = 20,042 - 2,7615x , r² = 0,984. It was concluded that the treatment was not effective to improving the CD of sugar cane bagasse, being the practice not justifiable.

  17. Ideas Previas Acerca de “Evolución y Su Relación con la Genética” en Estudiantes de Grado Noveno del Colegio Nicolás Esquerra

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    Sergio Alejandro Peláez Plazas

    2015-12-01

    Full Text Available Como primera experiencia didáctica, en este trabajo se muestran las ideas previas que construyen 10  estudiantes de noveno grado del colegio Nacional Nicolás Esguerra acerca del proceso de evolución, las cuales se encuentran relacionadas con algunos conceptos que aborda la genética. Los datos fueron recogidos por medio de una encuesta de pregunta abierta y un dibujo en base al método cualitativo, con el fin de conocer la comprensión que los estudiantes tienen acerca de la evolución y  los conceptos mencionados en sus explicaciones, entre los cuales se encontraron: adaptación, ADN y código genético,  relacionando en estos el tiempo como factor de cambio. Estas ideas se organizaron en tres categorías  (Comprensión de Procesos evolutivos basados en variabilidad y selección natural e Ideas relacionadas al catastrofismo como factor promotor de especiación. Entre estas, la mayoría de los alumnos hace alusión a cambios en el ciclo de vida y desarrollo, y no como un proceso a nivel histórico y constante en las poblaciones. En cuanto a la comprensión del ADN, el gen y su relación con las especies, no hay claridad con respecto a la expresión de caracteres desde  la información que se expresa en las proteínas. Por consiguiente, se infiere que las ideas encontradas están poco articuladas  ya que ellos no las logran conectar de forma apropiada en sus respuestas.

  18. Preparation and surface characterization of activated carbons from Euphorbia rigida by chemical activation with ZnCl2, K2CO3, NaOH and H3PO4

    International Nuclear Information System (INIS)

    Kılıç, Murat; Apaydın-Varol, Esin; Pütün, Ayşe Eren

    2012-01-01

    Highlights: ► An arid land plant evaluated as low cost activated carbon precursor. ► Four types of different chemical activation agents are used. ► Higher surface area (2600 m 2 /g) obtained by chemical activation. ► Obtained activated carbon can be effectively used as an adsorbent for the removal of toxic pollutants from aqueous solutions. - Abstract: Preparation of activated carbons from Euphorbia rigida by chemical activation with different impregnation agents and ratios was studied. ZnCl 2 , K 2 CO 3 , NaOH and H 3 PO 4 were used as chemical activation agents and four impregnation ratios (25–50–75–100%) by mass were applied on biomass. Activation is applied to impregnated biomass samples at 700 °C under sweeping gas in a fixed bed reactor. For determination of chemical and physical properties of the obtained activated carbons; elemental analysis was applied to determine the elemental composition (C, H, N, O) and FT-IR spectra was used to analyze the functional groups. BET equation was used to calculate the surface areas of activated carbons. For understanding the changes in the surface structure, activated carbons were conducted to Scanning Electron Microscopy (SEM). Maximum BET surface area (2613 m 2 /g) was reached with 75% K 2 CO 3 impregnated biomass sample. Experimental results showed that impregnation types and ratios have a significant effect on the pore structure of activated carbon and E. rigida seems to be an alternative precursor for commercial activated carbon production.

  19. Hematometra following caesarean section for placenta previa

    African Journals Online (AJOL)

    2017-12-08

    Dec 8, 2017 ... to surgical procedures such as cone biopsy. Hematometra following ... Subharti Medical College, Meerut, India, with abdominal pain for the previous 3 ... spinal anaesthesia, the vagina was visualised with the help of two.

  20. territorial previa a la toma de decisiones

    Directory of Open Access Journals (Sweden)

    Ángel Raúl Ruiz Pulpón

    2006-01-01

    Full Text Available La expansión de la agricultura de regadío ha ocasionado una signifi cativa confl ictividad ecológica, económica y social concerniente al uso del agua en la cuenca del Guadiana. Ante la ausencia, en estos últimos treinta años, de enfoques territoriales y sistémicos para la resolución de la problemática, se propone una metodología que permite la clasifi cación territorial de los municipios de la cuenca hidrográfi ca del Guadiana que presenten unas características similares de sus regadíos, con el objeto de plantear un modelo espacial previo a la toma de decisiones sobre la gestión de los recursos hídricos, agrarios y ambientales en Castilla-La Mancha, en consonancia con los preceptos estipulados por la Directiva Marco de Aguas y la Estrategia Territorial Europea

  1. La censura previa sobre medios digitales y contenidos personales en internet: un análisis sobre la calidad de la democracia en el Ecuador a partir de la entrada en vigencia de la Ley Orgánica de Comunicación 2013-2016

    OpenAIRE

    Rosas Lanas, Diana Gabriela

    2016-01-01

    La Ley Orgánica de Comunicación (LOC) es un instrumento de regulación que modificó el panorama mediático en el Ecuador con la entrada en vigencia en el 2013 -- El presente estudio ofrece un análisis de censura previa en el Ecuador en el período 2013 – 2016, sobre los principales medios digitales y cuentas personales en internet, artículo 18 y 4 de la LOC, respectivamente -- Con base en lo anterior y a partir del análisis de caso, el estudio reconoce la fase de implementación de la política pú...

  2. Ideas previas sobre el reino vegetal en niños entre los 7 y 10 años de tercero de primaria de la Escuela Normal Superior Distrital María Montessori (E.N.S.D.M.M.

    Directory of Open Access Journals (Sweden)

    Daniela Gomez

    2015-12-01

    Full Text Available La presente investigación busca reconocer las ideas previas sobre el reino vegetal en niños entre los 7 y 10 años. Se eligió un grupo de 37 estudiantes de tercero de primaria perteneciente a la E.N.S.D.M.M., con los cuales se implementó un instrumento de caracterización tipo cuestionario conformado por 3 preguntas referentes al reino vegetal. A partir de las respuestas dadas por los niños, se clasificaron sus ideas previas generando categorías de estas, posterior a ello, con la referencia de las 3 fuentes de origen (sensorial, social y analógica siendo la social en la cual se basa este trabajo; se generaron dos sub-categorias (experiencia cotidiana y  experiencia académica y, en esta última  se tuvieron en cuenta los modelos explicativos de nutrición vegetal para lo cual fue necesario analizar conceptos claves como respiración, morfología, metabolismo e interacciones con el medio. Como resultado de la caracterización se determinó que las construcciones mentales sobre el reino vegetal en estos estudiantes son mediadas por la experiencia cotidiana y son frecuentemente nutridas, modificadas o adecuadas por este a pesar de lo adquirido en la escuela, además se estableció que los modelos de nutrición vegetal más comunes en las representaciones de los niños a esta edad son el edáfico y el de transmutación

  3. Cinetica de oxidacion de polimeros conductores: poli-3,4- etilendioxitiofeno

    Science.gov (United States)

    Caballero Romero, Maria

    Films of poly-3,4-ethylenedioxythiophene (PEDOT) perchlorate used as electrodes in liquid electrolytes incorporate anions and solvent during oxidation for charge and osmotic balance: the film swells. During reduction the film shrinks, closes its structure trapping counterions getting then rising conformational packed states by expulsion of counterions and solvent. Here by potential step from the same reduced initial state to the same oxidized final state the rate coefficient, the activation energy and reaction orders related to the counterion concentration in solution and to the concentration of active centers in the polymer film, were attained following the usual methodology used for chemical and electrochemical kinetics. Now the full methodology was repeated using different reduced-shrunk or reduced-conformational compacted initial states every time. Those initial states were attained by reduction of the oxidized film at rising cathodic potentials for the same reduction time each. Rising reduced and conformational compacted states give slower subsequent oxidation rates by potential step to the same anodic potential every time. The activation energy, the reaction coefficient and reaction orders change for rising conformational compacted initial states. Decreasing rate constants and increasing activation energies are obtained for the PEDOT oxidation from increasing conformational compacted initial states. The experimental activation energy presents two linear ranges as a function of the initial reduced-compacted state. Using as initial states for the oxidation open structures attained by reduction at low cathodic potentials, activation energies attained were constant: namely the chemical activation energy. Using as initial states for the oxidation deeper reduced, closed and packed conformational structures, the activation energy includes two components: the constant chemical energy plus the conformational energy required to relax the conformational structure generating free volume which allows the entrance of the balancing counterions required for the reaction. The conformational energy increases linearly as a function of the reduction-compaction potential. The kinetic magnitudes include conformational and structural information. The Chemical Kinetics becomes Structural (or conformational) Chemical Kinetics.

  4. Oxidation of vanadium carbide in air; Oxidacion de carburo de vanadio en aire

    Energy Technology Data Exchange (ETDEWEB)

    Ruiz, A.; Troiani, L.; Materan, E. [Universidad Simon Bolivar, Depto. de la Ciencia de los Materiales, Grupo de Ingenieria de Superficies e Interfaces, Caracas, Venezuela, (Venezuela)

    1998-12-31

    It was studied the samples oxidation of vanadium carbide (V{sub 8}C{sub 7}), synterized and in powder, in order to know the temperature influence and the aggregation state in the kinetics and the oxidation products. The assays were realized in static air, at temperature between 600 y 750 Centigrade, between 6 and 24 hours periods. The gaseous products were analyzed through gas chromatography while the condensates ones were analyzed through optical microscopy and scanning electron microscopy, X-ray diffraction and chemical analysis by X-ray fluorescence analysis. It was found that in the V{sub 8}C{sub 7} oxidation occurs two basic processes: the gaseous oxides production which results of the carbon oxidation, fundamentally CO{sub 2}, and the vanadium condensate oxides production, fundamentally V{sub 2}O{sub 5}. In the synterized samples assayed under 650 Centigrade, the kinetics is lineal with loss of mass, suggesting a control by the formation of gaseous products in the sample surface, while in the synterized samples assayed over 650 Centigrade, it occurs a neat gain of mass, which is attributed to vanadium pentoxide fusion. These processes produce stratified layers of V{sub 2}O{sub 5} although at higher temperatures also it was detected V{sub 2}O{sub 4}. The superficial area effect is revealed in what the powder samples always experiment a mass neat increase in all essay temperatures, being the condensate oxidation products, fundamentally V{sub 2}O{sub 5} and V{sub 6}O{sub 13}. (Author)

  5. Advanced oxidation in waste water treatment; Oxidacion avanzada en el tratamiento de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Baraza, J.; Esplugas, S. [Universitat de Barcelona (Spain)

    2000-07-01

    The treatment of waste waters and, sometimes, drinking water, using advanced oxidation processes is reviewed on the basis of the studies carried out in which the hydroxyl radical plays an important part, with different techniques and reagents offering a broad range of possibilities. A distinction is made between photochemical an non-photochemical processes. A simple presentation of the fundamentals of each method is made together with a wide-ranging review of the literature and the results obtained in the degradation of certain contaminants resistant to conventional chemical treatments. (Author) 43 refs.

  6. EFFECTS OF NaOH MODIFICATION ON THE MECHANICAL ...

    African Journals Online (AJOL)

    user

    characterized for the following tensile strength (TS), modulus of elasticity (MOE), ... showed desirable properties at 10 wt%, where fiber content was in the range of 5 wt% to 30 wt% at interval of 5 wt%. ... baobab fiber chemically is a novel technique that will ..... Hinrichsen G., A Review on Pineapple Leaf Fibers, Sisal.

  7. Reforma Tributaria en Argentina: Algunas necesarias definiciones previas

    Directory of Open Access Journals (Sweden)

    Ricardo Bara

    2015-09-01

    Full Text Available Hay aceptación general que nuestro actual “sistema” tributario tiene inconvenientes graves. Pero también hay diferencias notorias respecto cuáles son las reformas aconsejables. Para ordenar el tratamiento del tema se exponen los criterios normativos básicos en los que se apoya cualquier propuesta de un sistema tributario aconsejable, derivados de la literatura académica sobre Hacienda Pública y la experiencia práctica de otras naciones. Las relaciones fiscales son una parte de las normas, derechos y facultades de cada uno de los sectores, establecidas en el sistema institucional que define la Constitución Nacional. Los recientes avances de la economía política y de la economía institucional han producido resultados importantes para la comprensión de las interrelaciones en los sistemas económicos e institucionales y ellos son aplicables a los sistemas tributarios. El trabajo procura incorporar estos nuevos aportes para derivar los criterios normativos. Por otra parte, una reforma tributaria es un fenómeno complejo. Se trata de un cambio sobre un sistema ya existente que debe “seguir funcionando” con importantes efectos en la transición. Una reforma tributaria es un cambio institucional significativamente importante. Esto aconseja definir cuestiones como el sistema económico-político donde se va aplicar la reforma y el orden institucional que va reglar las relaciones entre el ciudadano-contribuyente y el fisco, el alcance del uso del poder, la relación entre reglas y discrecionalidad.

  8. Effectiveness of disinfection with alcohol 70% (w/v of contaminated surfaces not previously cleaned Eficacia de la desinfección con alcohol al 70% (p/v de superficies contaminadas sin limpieza previa Eficácia da desinfecção com álcool 70% (p/v de superfícies contaminadas sem limpeza prévia

    Directory of Open Access Journals (Sweden)

    Maurício Uchikawa Graziano

    2013-04-01

    Full Text Available OBJECTIVE: To evaluate the disinfectant effectiveness of alcohol 70% (w/v using friction, without previous cleaning, on work surfaces, as a concurrent disinfecting procedure in Health Services. METHOD: An experimental, randomized and single-blinded laboratory study was undertaken. The samples were enamelled surfaces, intentionally contaminated with Serratia marcescens microorganisms ATCC 14756 106 CFU/mL with 10% of human saliva added, and were submitted to the procedure of disinfection WITHOUT previous cleaning. The results were compared to disinfection preceded by cleaning. RESULTS: There was a reduction of six logarithms of the initial microbial population, equal in the groups WITH and WITHOUT previous cleaning (p=0.440 and a residual microbial load ≤ 102 CFU. CONCLUSION: The research demonstrated the acceptability of the practice evaluated, bringing an important response to the area of health, in particular to Nursing, which most undertakes procedures of concurrent cleaning /disinfecting of these work surfaces. OBJETIVO: Evaluar la eficacia desinfectante de alcohol al 70% (p/v por fricción, sin limpieza previa, en las superficies de trabajo, como procedimiento de desinfección cotidiana o de rutina en Servicios de Salud. MÉTODO: Fue desarrollado un estudio experimental de laboratorio, aleatorio y uni-ciego. Las muestras fueron obtenidas de superficies esmaltadas, intencionalmente contaminadas con microorganismos Serratia marcescens ATCC 14756 106 UFC/mL acrecido con 10% de saliva humana, sometidas al procedimiento de desinfección SIN limpieza previa. Los resultados fueron comparados a la desinfección después de limpieza. RESULTADOS: Hubo una reducción de seis logaritmos de la población microbiana inicial, igualmente en los grupos COM y SIN limpieza previa (p=0,440 y una carga microbiana residual ≤ 102 UFC. CONCLUSIÓN: La investigación demostró que es aceptable la práctica evaluada ofreciendo así una importante respuesta para

  9. SINTESIS, CARACTERIZACION Y ELECTRO-OXIDACION DE 2,2- DITIENIL DERIVADOS, EFECTO DE LA FUNCIONALIZACION SOBRE LAS PROPIEDADES ELECTRICAS

    OpenAIRE

    BROVELLI SEPULVEDA, FRANCISCO ANTONIO

    2002-01-01

    Desde el descubrimiento de la conducción eléctrica en sistemas poliméricos, se han realizado muchos esfuerzos con el propósito de mejorar tanto la conductividad como la resistencia mecánica de estos materiales, sin embargo, en la última década, se ha manifestado un gran interés por los sistemas semiconductores para el desarrollo de nuevos dispositivos, como por ejemplo, diodos emisores de luz (OLED). Debido a la versatilidad estructural que presentan los polímeras, se ha propuesto la sí...

  10. Desulfurization of fuel oils using an advanced oxidation method; Desulfuracion de combustibles usando un metodo de oxidacion avanzada

    Energy Technology Data Exchange (ETDEWEB)

    Flores Velazquez, Roberto; Rodas Grapain, Arturo [Instituto de Investigaciones Electricas, Cuernavaca, Morelos (Mexico)

    2008-07-01

    In the present work, the oxidative desulfurization of fuel oils assisted by ultrasound was analyzed. It was studied the effect of hydrogen peroxide concentration, the fuel oil to aqueous solution volumetric ratio, and type of catalyst. The Fenton-like catalysts studied were ferric chloride and copper sulfate. [Spanish] En esta investigacion se analiza la desulfuracion oxidativa de combustoleo asistida con ultrasonido. Tambien se estudia el efecto de la concentracion de peroxido de hidrogeno (H{sub 2}O{sub 2}), la relacion volumetrica combustoleo/solucion acuosa y el tipo de catalizador. Los catalizadores tipo Fenton que se estudiaron fueron el cloruro ferrico (FeCl{sub 3}) y el sulfato de cobre (CuSO{sub 4}).

  11. Industrial waste water treatment by advanced oxidation processes; Tratamiento de aguas residuales industriales mediante procesos de oxidacion avanzada

    Energy Technology Data Exchange (ETDEWEB)

    Gasso, S.; Baldasano, J.M.

    1996-06-01

    Advanced Oxidation Technologies have been defined as processes which involve the generation of highly reactive oxy radicals. These systems show promise for the destruction of non biodegradable and hazardous organic substances in industrial wastewater. Two types of advanced oxidation processes are considered in this paper: (1) systems that use high energy oxidants (O{sub 3}, H{sub 2}O{sub 2}, UV, etc) at ambient temperature to initiate the oxidation reaction, and (2) processes that use molecular oxygen and high temperature and pressure to initiate the reaction (wet oxidation at subcritical and supercritical conditions). The fundamental aspects of these oxidation technologies are discussed, the application framework is defined and the technology development is indicated. (Author) 33 refs.

  12. Synthesis and anodic oxidation of a Di and tri substituted anthracenes; Sintesis y oxidacion anodica de antracenos Di y trisustituidos

    Energy Technology Data Exchange (ETDEWEB)

    Farina, F.; Paredes, M.C.; Puebla, L. [Instituto de Quimica Organica General, CSIC, Madrid (Spain)

    1995-08-01

    A variety of anthracene type 1, 4-7,11,12 and 18, were prepared from substituted anthraquinones. The anodic oxidation of a wide range of anthracene have been studied. The hydrosis of bisketals 19 and 20 afforded the monoketal 23 and 1,4-anthraquinone 24. 10 refs.

  13. Ter anemia falciforme: nota prévia sobre seu significado para a criança expresso através da brincadeira Tener anemia falciforme: nota previa sobre el significado para el niño expresado a través del juego Having sickle-cell disease: short communication on the meaning for children as expressed through games what it means for them to have the disease

    Directory of Open Access Journals (Sweden)

    Ana Augusta Maciel de Souza

    2011-03-01

    Full Text Available Nota prévia de uma pesquisa que tem como objetivo compreender o significado de ter anemia falciforme para crianças de 3 a 12 anos de idade, a partir de uma investigação qualitativa ancorada no Interacionismo Simbólico como referencial teórico, e na Teoria Fundamentada nos Dados como referencial metodológico. Os dados são coletados por meio de entrevista com as crianças, mediada por uma sessão de Brinquedo Terapêutico. A análise preliminar dos dados permitiu compreender que ter anemia falciforme é uma vivência triste para a criança, porque, além de ser permeada pela dor, ela se percebe impotente frente ao sofrimento, reconhece seus sintomas, compreende a necessidade do tratamento, considerando-o apenas paliativo; que a família é um importante suporte, e o hospital, uma referência.Nota previa de una investigación que tiene como objetivo comprender el significado de tener anemia falciforme para niños de 3 a 12 años. Investigación cualitativa anclada en el Interaccionismo Simbólico como referencia teórica y en la Teoría Fundamentada en los datos como referencia metodológica. Los datos son recolectados por medio de entrevista con los niños, mediada por una sesión de Juguete Terapéutico. El análisis preliminar de los datos permitió comprender que tener anemia falciforme es una vivencia triste para el niño, porque además de ser atravesada por el dolor, ella se percibe impotente frente al sufrimiento, reconoce los síntomas, comprende la necesidad de tratamiento, considerándolo solamente paliativo, que la familia es un importante soporte y el hospital una referencia.Advance notice of a study aimed at understanding the significance of having sickle cell anemia for children 3 to 12 years old. It is a qualitative research grounded in Symbolic Interactionism as a theoretical perspective, and in Grounded Theory as a research method. The data have been collected through interview with the children by using therapeutic play

  14. Densities and apparent molar volumes of atmospherically important electrolyte solutions. 1. The solutes H2SO4, HNO3, HCl, Na2SO4, NaNO3, NaCl, (NH4)2SO4, NH4NO3, and NH4Cl from 0 to 50 °C, including extrapolations to very low temperature and to the pure liquid state, and NaHSO4, NaOH, and NH3 at 25 °C.

    Science.gov (United States)

    Clegg, S L; Wexler, A S

    2011-04-21

    Calculations of the size and density of atmospheric aerosols are complicated by the fact that they can exist at concentrations highly supersaturated with respect to dissolved salts and supercooled with respect to ice. Densities and apparent molar volumes of solutes in aqueous solutions containing the solutes H(2)SO(4), HNO(3), HCl, Na(2)SO(4), NaNO(3), NaCl, (NH(4))(2)SO(4), NH(4)NO(3), and NH(4)Cl have been critically evaluated and represented using fitted equations from 0 to 50 °C or greater and from infinite dilution to concentrations saturated or supersaturated with respect to the dissolved salts. Using extrapolated densities of high-temperature solutions and melts, the relationship between density and concentration is extended to the hypothetical pure liquid solutes. Above a given reference concentration of a few mol kg(-1), it is observed that density increases almost linearly with decreasing temperature, and comparisons with available data below 0 °C suggest that the fitted equations for density can be extrapolated to very low temperatures. As concentration is decreased below the reference concentration, the variation of density with temperature tends to that of water (which decreases as temperature is reduced below 3.98 °C). In this region below the reference concentration, and below 0 °C, densities are calculated using extrapolated apparent molar volumes which are constrained to agree at the reference concentrations with an equation for the directly fitted density. Calculated volume properties agree well with available data at low temperatures, for both concentrated and dilute solutions. Comparisons are made with literature data for temperatures of maximum density. Apparent molar volumes at infinite dilution are consistent, on a single ion basis, to better than ±0.1 cm(3) mol(-1) from 0 to 50 °C. Volume properties of aqueous NaHSO(4), NaOH, and NH(3) have also been evaluated, at 25 °C only. In part 2 of this work (ref 1 ) an ion interaction (Pitzer

  15. Gold recovery from refractory ores. The role of pressure oxidation. Recuperacion de oro de minerales refractarios. El papel de la oxidacion a presion

    Energy Technology Data Exchange (ETDEWEB)

    Alguacil, F.J.; Cobo, A.; Caravaca, C. (Consejo Superior de Investigaciones Cientificas. Centro Nacional de Investigaciones Metalurgicas. Madrid (Spain))

    1993-01-01

    Pressure oxidation is a hydrometallurgical technique that renders auriferous refractory materials, specially sulphides, amenable to cyanidation process. The effectiveness of the operation as a pretreatment to the recovery of refractory gold, is reflected by the succesful startup over the last ten years of seven commercial plants. Some factors affecting the selection of pressure oxidation as pretreatment for gold recovery are discussed. (Author)

  16. ESTUDIO DE LA PARTICIPACION DE PROTEINAS CODIFICADAS EN LOS GRUPOS GENETICOS DE DOXDA Y TETH EN LA OXIDACION DEL TIOSULFATO EN ACIDITHIOBACILLUS FERROOXIDANS ATCC 23270

    OpenAIRE

    BEARD BORQUEZ, SIMON RODRIGO; BEARD BORQUEZ, SIMON RODRIGO

    2010-01-01

    El azufre es un macronutriente esencial para todos los seres vivos que forma parte de aminoácidos, cofactores y vitaminas. Algunos microorganismos son capaces de obtener su energía de la oxidación disasimilatoria del sulfuro, azufre elemental o tiosulfato, entre otros compuestos inorgánicos de azufre reducidos. En bacterias Gram-negativas se han descrito tres vías para la oxidación de compuestos de azufre: la vía del Paracoccus (PSO), la vía PSO ramificada y la vía del intermediar...

  17. Mecanismos de oxidaciones fotosensibilizadas de nucleótidos púricos y pirimidínicos por pterinas de interés biomédico

    OpenAIRE

    Serrano, Mariana Paula

    2014-01-01

    La radiación UV es la porción más energética del espectro solar que alcanza la superficie terrestre. Este tipo de radiación y, en mucha menor proporción, la luz visible, son capaces de modificar la estructura química de ciertas macromoléculas y metabolitos presentes en los tejidos. En particular, los cambios químicos sufridos por las proteínas y por el ADN producen graves consecuencias a nivel celular. Dichos efectos van desde disfunciones en el metabolismo celular hasta la muerte, pasando po...

  18. Simulation with GOTHIC of experiments Oxidation of fuel in Air; Simulacion con GOTHIC de Experimentos de Oxidacion de Combustible en Aire

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Murillo Mendez, J. C.

    2012-07-01

    In the present work has been addressed for the first time la simulation with the GOTHIC code, experiments oxidation and ignition of SFP in phase 1. This work represents a solid starting point for analysis of specific degradation of fuel in the pools of our facilities.

  19. Spectroscopy study of electron spin resonance of coal oxidation of different rank; Estudio por espectroscopia de resonancia espin electron de la oxidacion de carbones de diferente rango

    Energy Technology Data Exchange (ETDEWEB)

    Enciso Prieto, Hector Manuel

    1992-07-01

    The present work constitutes an initial step for the knowledge of the coal oxidation, with the purpose of preventing the adverse influences caused by this phenomenon in the physical-chemical characteristics and in the tendency to the spontaneous combustion. Since the knowledge the influence of the free radicals in this process, their relative concentration was measured by means of the use of the technique of resonance spin electron. This technique measures the absorption of electromagnetic radiation, generally in the microwaves region, for the materials that not have electrons matched up in a strong magnetic field. In the essays of oxidation three coal of different range and different characteristics of mass were used and it was studied the influence of the temperature, particle size and the range. The results showed that the coal of Guacheta (bituminous low in volatile) it presents bigger concentration of free radicals, after the reaction with the atmospheric oxygen, with regard to the coal of the Cerrejon (bituminous high in volatile B) and Amaga (bituminous high in volatile C). Although this doesn't indicate that the coal of Guacheta is that more easily is oxidized, but rather it possibly presents stabilization of radicals for resonance. It concluded that there are differences in the oxidation mechanism between coal of different rank and different agglomeration properties.

  20. Analytical evaluation and optimization of advanced oxidation process in a solar pilot power plant; Evaluacion analitica y optimizacion de procesos de oxidacion avanzada en planta piloto solar

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Vazquez, J.; Malato Rodriguez, S.; Rodriguez Fernandez-Alba, A.

    2003-07-01

    The technical feasibility mechanisms and performance of degradation of several pesticides (imidacloprid, methomyl and diuron) dissolved in water have been studies at pilot scale in two well-defined photocatalytic systems of special interest because natural UV light can be used: heterogeneous photocatalysis with titanium dioxide and homogeneous photocatalysis by photo-Fenton.Equivalent pilot-scale (made up of Compound Parabolic Collectors (CPCs) specially designed for solar photocatalytic applications) and field conditions used for both systems and the three pesticides allowed adequate comparison of the degree of mineralization and toxicity achieved as well as the transformation products generated en route to mineralization. Total disappearance of the parent compounds and 90% mineralisation have been attained with all pesticides tested, methomyl being the most difficult to be degraded with both treatments. First order rate constants, initial rate,time necessary for mineralizing 90% of the initial TOC and hydrogen peroxide consumption were calculated in all cases, enabling comparison both of treatments and of the selected pesticide reactivity. Complete mineralisation of TOC is not achieved even after quite a long time (more than 300 minutes). Three different bioassays (Vibrio fischeri, Daphnia magna and a Microalga) have been used for testing the progress of toxicity during treatments. All remained toxic down to very low pesticide disappearance of the pesticide. Only if treatment is maintained throughout enough mineralisation (i. e. TOC disappearance), the toxicity is reduced to below the threshold (EC 50%). Transformation products evaluated by GC-MS/AED (after two SPE procedures), LC-IT-MS and LC-IC were the same in both phototreatments. The main differences between the two processes are in the amount of transformation products (TPs) generated, not in the TPs detected which were always the same. (Author)

  1. Removal of surfactants from water by adsorption on activated carbon and advanced oxidation process; Eliminacion de surfactantes de las aguas mediante adsorcion sobre carbon activado y oxidacion avanzada

    Energy Technology Data Exchange (ETDEWEB)

    Mendez Diaz, J. D.; Sanchez Polo, M.; Rivera Utrilla, J.; Bautista, M. I.

    2007-07-01

    The objective of this study was to analyze the elimination process of surfactants from water, using sodium dode-cilbencenesulfonate (SDBS) as model compound, by means of adsorption on activated carbons as well as different processes of advanced oxidation (O{sub 3}, O{sub 3}/H{sub 2}O{sub 2} and O{sub 3}/activated carbon). Results obtained have shown that the activated carbons used have a high efficiency to eliminate SDBS from waters which was enhanced when the adsorption process was carried out in the presence of bacteria. With regard to the oxidation processes studied, the results have indicated that the efficiency in the elimination of SDBS from water of the system based on the simultaneous use of O{sub 3} and powder activated carbon (PAC) is much higher than those of the other systems studied (O{sub 3},O{sub 3}/H{sub 2}O{sub 2}). (Author) 15 refs.

  2. Treating leachate with advanced oxidation: applying Fenton's reagent; Oxidaciones avanzadas para el tratamiento de lixiviado: aplicacion del Reactivo de Fenton

    Energy Technology Data Exchange (ETDEWEB)

    Maranonn Ruiz, I.; Sancho Seuma, L.

    2003-07-01

    The present study investigates the removal of refractory organics by Advanced Oxidation Process: Fenton's Reaction. A batch test protocol was designed to study the oxidation and coagulation in Fenton Reaction. The batch tests were conducted to determine the optimum conditions for the plant operation such as pH, H{sub 2}O{sub 2} dosage, FeSO{sub 4} dosage and contact time. It was found that the highest removal efficiencies of COD were with the oxidation at acid pH around 3 and the coagulation at basic pH around 8, few minutes of treatment time, the initial concentrations of H{sub 2}O{sub 2} were in the range 68-1550 mg/l and the different dosages of FeSO{sub 4} were in the range 487-3038 mg/l. They were added in determinate proportions to get the highest efficiency of producing OH, DBO{sub 5}/DQO ratio was decreased from 0,3 to 0,1. Therefore Fenton's reaction process is a very effective means for a pretreatment or tertiary treatment of biological methods. (Author) 20 refs.

  3. Oxidaciones en biología y farmacología. Integración de conocimientos sobre inmunidad, dieta y medicamentos

    Directory of Open Access Journals (Sweden)

    Cristina Pérez

    2013-01-01

    Full Text Available Se relata una experiencia didáctica innovadora en el área de las ciencias naturales. La misma fue llevada a cabo con alumnos de séptimo grado (12- 13 años de edad en una escuela primaria dependiente del Ministerio de Educación de Buenos Aires (Argentina. En varios trabajos prácticos de laboratorio, se difundieron e ilustraron conocimientos científicos impartidos o generados por la Universidad de Buenos Aires y otras instituciones extranjeras. Se relacionó información diversa proveniente de distintas disciplinas escolares y universitarias; por ende, se brindaron las nociones necesarias para comprenderla, en forma adecuada a las características de los alumnos. De esta forma, el currículo escolar se enriqueció en contenidos y enfoques. La actividad, perteneciente a la serie pedagógica De la Universidad a la Escuela, aplica tres funciones universitarias esenciales: docencia, investigación y extensión universitaria.

  4. Catalytic oxidation of albendazole using molybdenum supported on carbon nanotubes as catalyst; Oxidacion catalitica de albendazol empleando como catalizador molibdeno soportado en nanotubos de carbono

    Energy Technology Data Exchange (ETDEWEB)

    Sun-Kou, Maria del Rosario; Vega Carrasco, Edgar R., E-mail: msun@pucp.edu.pe [Departamento de Ciencias, Seccion Quimica. Pontificia Universidad Catolica del Peru, Avenida Universitaria 1801, Lima (Peru); Picasso Escobar, Gino I. [Laboratorio de Investigacion de Fisicoquimica, Facultad de Ciencias, Universidad Nacional de Ingenieria, Avenida Tupac Amaru 210, Lima (Peru)

    2013-10-15

    The catalytic oxidation reaction of the thioether group (-S-) in the structure to the drug albendazole (C{sub 12}H{sub 15}N{sub 3}O{sub 2}S) was studied in order to obtain a pharmacologically active molecule known as albendazole sulfoxide. With this purpose, three heterogeneous catalysts were prepared using molybdenum (Mo) as active phase and carbon nanotubes as a multiple-layer catalyst support. The incorporation of the active phase was performed by wet impregnation, with subsequent calcination for 4 hours at 400 {sup o}C. For the catalytic oxidation reaction was employed hydrogen peroxide-urea (H{sub 2}NCONH{sub 2}·H{sub 2}O{sub 2}) as oxidizing agent and methanol (CH{sub 3}OH) as reaction medium. The textural and morphology characterization of carbon nanoparticles and catalysts was carried out by adsorption-desorption of N{sub 2} (BET) and scanning electron microscopy (SEM). The identification and quantification of the reaction products were followed by Fourier transform infrared spectroscopy (FTIR) and high performance liquid chromatography (HPLC), respectively. With the yield, selectivity and conversion higher than 90% after 60 minutes of reaction, albendazole sulphoxide was obtained as major product of oxidation reaction. (author)

  5. Activated carbon derived from rice husk by NaOH activation and its application in supercapacitor

    Directory of Open Access Journals (Sweden)

    Khu Le Van

    2014-06-01

    Full Text Available Four activated carbon (AC samples prepared from rice husk under different activation temperatures have been characterized by N2 adsorption–desorption isotherms, thermogravimetric analysis (TGA–DTA, Fourier transform infrared spectroscopy (FTIR and scanning electron microscopy (SEM. The specific surface area of AC sample reached 2681 m2 g−1 under activation temperature of 800 °C. The AC samples were then tested as electrode material; the specific capacitance of the as-prepared activated carbon electrode was found to be 172.3 F g−1 using cyclic voltammetry at a scan rate of 5 mV s−1 and 198.4 F g−1 at current density 1000 mA g−1 in the charge/discharge mode.

  6. Highly porous activated carbons prepared from carbon rich Mongolian anthracite by direct NaOH activation

    Energy Technology Data Exchange (ETDEWEB)

    Byamba-Ochir, Narandalai [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of); Shim, Wang Geun [Department of Polymer Science and Engineering, Sunchon National University, 255 Jungang-Ro, Suncheon, Jeollanam-Do 57922 (Korea, Republic of); Balathanigaimani, M.S., E-mail: msbala@rgipt.ac.in [Department of Chemical Engineering, Rajiv Gandhi Institute of Petroleum Technology, Ratapur Chowk, Rae Bareli, 229316 Uttar Pradesh (India); Moon, Hee, E-mail: hmoon@jnu.ac.kr [School of Chemical Engineering, Chonnam National University, 77 Yongbong-Ro, Gwangju 61186 (Korea, Republic of)

    2016-08-30

    Highlights: • Highly porous carbon materials from Mongolian anthracite by chemical activation. • Cheaper and eco-friendly activation process has been employed. • Activated carbons with graphitic structure and energetically heterogeneous surface. • Surface hydrophobicity and porosity of the activated carbons can be controlled. - Abstract: Highly porous activated carbons (ACs) were prepared from Mongolian raw anthracite (MRA) using sodium hydroxide as an activation agent by varying the mass ratio (powdered MRA/NaOH) as well as the mixing method of chemical agent and powdered MRA. The specific BET surface area and total pore volume of the prepared MRA-based activated carbons (MACs) are in the range of 816–2063 m{sup 2}/g and of 0.55–1.61 cm{sup 3}/g, respectively. The pore size distribution of MACs show that most of the pores are in the range from large micropores to small mesopores and their distribution can be controlled by the mass ratio and mixing method of the activating agent. As expected from the intrinsic property of the MRA, the highly graphitic surface morphology of prepared carbons was confirmed from Raman spectra and transmission electron microscopy (TEM) studies. Furthermore the FTIR and XPS results reveal that the preparation of MACs with hydrophobic in nature is highly possible by controlling the mixing conditions of activating agent and powdered MRA. Based on all the results, it is suggested that the prepared MACs could be used for many specific applications, requiring high surface area, optimal pore size distribution, proper surface hydrophobicity as well as strong physical strength.

  7. Effect of soaking time and concentration of NaOH solution on ...

    Indian Academy of Sciences (India)

    The increase of treated fibre content resulted in a sig- nificant increase in ... Cellulose/lignin content (%). 43/45. 6. Specific ..... Engineering and Technology, Karaikudi and G Kannan,. Government College of Engineering, Tirunelveli, for their.

  8. Efectos de la cobertura vacunal previa en la dinamica de un brote de sarampion

    OpenAIRE

    Luna Sánchez Antonio

    1997-01-01

    FUNDAMENTO: La eficacia de una vacuna debería medirse mediante ensayos clínicos controlados, no obstante, aspectos éticos lo impiden. Orenstein sugiere que se estime la eficacia de una vacuna mediante, entre otros métodos, el estudio de los brotes epidémicos de la enfermedad caso de ser posible. El presente estudio plantea el cálculo de la eficacia vacunal en el terreno y de los efectos protectores de un programa de vacunación mediante el análisis de un brote epidémico de sarampión. MATERIAL ...

  9. Mecanismos fisiológicos implicados en la ansiedad previa a exámenes

    Directory of Open Access Journals (Sweden)

    Annia Yolanda del Toro Añel

    2014-10-01

    Full Text Available En el campo de la salud mental, llama la atención de clínicos e investigadores la situación de los estudiantes universitarios en cuanto al estrés académico, puesto que las exigencias en este sentido, particularmente la presión ante los exámenes, es reconocida por los propios jóvenes como uno de los factores más estresantes que genera estados de ansiedad en ellos y, por ende, afecta su rendimiento académico. En este artículo se destacan las interacciones entre el sistema nervioso y endocrino, así como las influencias del estrés psicológico sobre el rendimiento académico

  10. Profilaxis antimicrobiana previa a procedimientos dentales. Situación actual y nuevas perspectivas

    OpenAIRE

    Rodríguez-Campos, LF; Ceballos-Hernández, H; Bobadilla-Aguirre, A

    2017-01-01

    Resumen La bacteremia secundaria a los procedimientos dentales puede dar origen a episodios de endocarditis infecciosa. La implementación de la profilaxis antimicrobiana tiene como finalidad aminorar la bacteremia transitoria reduciendo la posibilidad de desarrollar endocarditis infecciosa, por lo que es indispensable conocer qué antibióticos son de elección y en qué casos o situaciones administrarlos u omitirlos. Existen múltiples guías para aplicar profilaxis antimicrobiana, éstas difieren ...

  11. Profilaxis antimicrobiana previa a procedimientos dentales. Situación actual y nuevas perspectivas

    Directory of Open Access Journals (Sweden)

    Luis Fernando Rodríguez-Campos

    2017-08-01

    Full Text Available La bacteremia secundaria a los procedimientos dentales puede dar origen a episodios de endocarditis infecciosa. La implementación de la profilaxis antimicrobiana tiene como finalidad aminorar la bacteremia transitoria reduciendo la posibilidad de desarrollar endocarditis infecciosa, por lo que es indispensable conocer qué antibióticos son de elección y en qué casos o situaciones administrarlos u omitirlos. Existen múltiples guías para aplicar profilaxis antimicrobiana, éstas difieren en sus recomendaciones, a tal grado que pueden confundir al facultativo al momento de determinar si el paciente requiere antibiótico profiláctico y a elegir el antimicrobiano adecuado.   OBJETIVO: comparar las diferentes guías de profilaxis antimicrobiana y recomendaciones para converger en una recopilación única con las aportaciones destacadas de cada guía revisada; de la misma manera, exponer el régimen utilizado en nuestra institución por el servicio de estomatología.   CONCLUSIÓN: el estomatólogo se puede basar principalmente en las guías de la American Heart Association (AHA y el Centro Nacional de Excelencia Tecnológica en Salud (CENETEC para condiciones cardiacas que ameriten profilaxis antimicrobiana, y para pacientes con enfermedades sistémicas sobre la guía de la American Academy of Pediatric Dentistry (AAPD y las recomendaciones de nuestra institución. La administración de profilaxis antimicrobiana se da por razones científicas consolidadas y por carácter de tipo médico-legal, en un futuro se espera establecer criterios para aumentar los métodos no antibióticos preventivos de endocarditis infecciosa y aminorar el uso de antimicrobianos, reduciendo el uso de antibiótico profiláctico, sin exponer al paciente a infecciones diseminadas y con mínimos efectos secundarios posibles.

  12. Profilaxis antimicrobiana previa a procedimientos dentales. Situación actual y nuevas perspectivas

    OpenAIRE

    Luis Fernando Rodríguez-Campos; Hilda Ceballos-Hernández; Alfredo Bobadilla-Aguirre

    2017-01-01

    La bacteremia secundaria a los procedimientos dentales puede dar origen a episodios de endocarditis infecciosa. La implementación de la profilaxis antimicrobiana tiene como finalidad aminorar la bacteremia transitoria reduciendo la posibilidad de desarrollar endocarditis infecciosa, por lo que es indispensable conocer qué antibióticos son de elección y en qué casos o situaciones administrarlos u omitirlos. Existen múltiples guías para aplicar profilaxis antimicrobiana, éstas difieren en sus r...

  13. Efectos de la cobertura vacunal previa en la dinamica de un brote de sarampion

    Directory of Open Access Journals (Sweden)

    Luna Sánchez Antonio

    1997-01-01

    Full Text Available FUNDAMENTO: La eficacia de una vacuna debería medirse mediante ensayos clínicos controlados, no obstante, aspectos éticos lo impiden. Orenstein sugiere que se estime la eficacia de una vacuna mediante, entre otros métodos, el estudio de los brotes epidémicos de la enfermedad caso de ser posible. El presente estudio plantea el cálculo de la eficacia vacunal en el terreno y de los efectos protectores de un programa de vacunación mediante el análisis de un brote epidémico de sarampión. MATERIAL Y MÉTODOS: Estudio de cohortes retrospectivo. La población de estudio la constituyó el grupo de niños nacidos en el municipio de Aznalcollar (localidad de 5.571 habitantes perteneciente al Distrito Sanitario Aljarafe-Sevilla entre dos brotes epidémicos de sarampión ocurridos en dicha localidad en los años 1986 y 1994. Se excluyeron de la cohorte a aquellos niños que a comienzos del brote de 1994 no habían cumplido la edad de vacunación y también a quienes tuvieron exposición anterior al virus, es decir los nacidos antes y durante la epidemia de 1986. El estudio incluyó a vacunados y no vacunados. Todos los casos cumplían los criterios diagnósticos establecidos. A todos los niños en seguimiento se les revisó sus antecedentes vacunales. Tras el cálculo de las tasas de ataque en vacunados y no vacunados, se determinaron la eficacia vacunal y los efectos indirectos totales y medios del programa de vacunación. RESULTADOS: La vacuna resultó eficaz en el 91'5 % de los vacunados. El programa de vacunación produjo una reducción del número de casos en los no vacunados del 78'9%, del 98% en los vacunados y del 92% en el conjunto de la cohorte estudiada, siendo la cobertura vacunal de la misma del 66'4%. CONCLUSIONES: Los efectos de la vacunación y la eficacia vacunal pueden y deben ser calculados aprovechando la aparición de brotes epidémicos caso de ser posible. Se recomienda incrementar las coberturas de vacunación de la población y mejorar así los efectos protectores del programa.

  14. Hidroxiapatita en defectos óseos craneales: Comunicación previa

    Directory of Open Access Journals (Sweden)

    Susana A Fernández Benítez

    1997-12-01

    Full Text Available Se exponen los resultados iniciales de un ensayo experimental y clínico, con gránulos de hidroxiapatita como implante en defectos óseos craneales aun radiológicos y microscópicos (BAAF el tiempo de los pasos de osificación craneal. Hubo crecimiento de fibroblasto en 7 días; en 2 meses y medio, crecimiento de osteoblastos y de hueso intramembranoso. En 3 meses la plastia presentaba consistencia ósea palpableThe initial results of an experimental and clinical assay using hydroxyapatite granules as implants in skull defects over 3 cm are exposed. An attempt is made to verify by clinical, radiological and microscopic examinations (BAAF the time of the cranial ossification steps. It was observed a growth of fibroblasts in 7 days, and of osteoblasts and intramembranous bone in 2 months and a half. 3 months later the plastic presented a palpable osteal consistency

  15. Embarazo deseado y planificado, lactancia previa, aptitud para lactar y conocimientos de las madres sobre lactancia

    Directory of Open Access Journals (Sweden)

    Remigio Rafael Gorrita Pérez

    Full Text Available Introducción: la OMS y la Unicef recomiendan lactancia materna exclusiva durante los primeros 6 meses de vida, y complementada, al menos, hasta los 2 años; sin embargo, los resultados no son los esperados. Objetivo: evaluar la relación entre la planificación del embarazo, la lactancia en hijos anteriores, la aptitud referida para lactar y los conocimientos sobre lactancia materna de las gestantes en su tercer trimestre, de los Policlínicos "Luis Augusto Turcios Lima" y "Mártires del 9 de Abril", del municipio San José de las Lajas. Métodos: se realizó un estudio analítico y transversal, entre marzo de 2010 y marzo de 2011. De 192 gestantes en su tercer trimestre, y que cumplieron los criterios de inclusión, se estudiaron: hijos previos y si recibieron lactancia materna, planificación, deseos del embarazo, aptitudes referidas, así como conocimientos sobre la lactancia. Se aplicaron 22 preguntas y se estableció un sistema de puntaje. Resultados: algo más de la mitad de las madres se consideraron aptas para la lactancia, y asumieron que poseían los conocimientos necesarios para lograrlo, pero menos de la quinta parte mostró poseerlos. Las gestantes que obtuvieron valores superiores en el cuestionario fueron: las que tenían un hijo previo, las que ya habían ofrecido lactancia materna exclusiva de 4 a 6 meses, y las que deseaban y habían planificado su embarazo. Conclusiones: aunque la mayoría de las gestantes consideraron que estaban aptas para la lactancia materna, no demostraron tener los conocimientos necesarios para asumirla exitosamente.

  16. Optimización y validación metodológica de la cuantificación de arsénico por inyección en flujo-generación de hidruros- espectrometría de absorción atómicas (IF-GH-EAA previa derivatizacíon con L-Cisteína Optimización and validation method for arsenic quantification by flow injection-hydride generation - atomic absorption spectrometry (fi-hg-aas after L-Cysteine derivatization

    Directory of Open Access Journals (Sweden)

    Julio A Navoni

    2009-12-01

    Full Text Available El arsénico (As es un contaminante natural que afecta una amplia zona de Argentina. El nivel de As en agua de consumo es utilizado para evaluar la fuente de exposición y en orina para evaluar exposición a este tóxico. El presente trabajo tuvo como objetivo la optimización y validación metodológica de una técnica para la cuantificación de As [As suma = As inorgánico (AsI + especies metiladas: ácido monometilarsónico (MMA y ácido dimetilarsínico (DMA], producto del metabolismo del AsI, por inyección en flujo- generación de hidruros- espectrometría de absorción atómica (IF-GH-EAA, previa derivatización con L-cisteína. La recuperación de las especies estudiadas: AsI (AsIII y AsV, MMA y DMA fue cercana al 100% en todos los casos. Los límites de detección y cuantificación encontrados fueron para agua y orina: 2 y 3 μg/L; 5 y 8 μg/L respectivamente y el rango dinámico de trabajo establecido fue desde 5 a 75 μg/L, permitiendo cuantificar As en muestras de agua cercanos a los estándares internacionales vigentes para valores máximos de As en agua de consumo y en orina en niveles comparables con los establecidos en población laboralmente no expuesta. Esta propuesta metodológica es una alternativa para evaluar la exposición al As en muestras de agua y orina, sin necesidad de utilizar prolongados pre-tratamientos de muestra, de forma más rápida y económica.Arsenic (As is a natural contaminant that affects a large area of Argentina. Quantification of As in drinking water has been used to evaluate the source of exposure and As in urine to assess exposure to this toxic. This study aimed to optimize and validate a methodological technique for the quantification of As [As sum = inorganic As (AsI + methylated species: monometilarsonic acid (MMA and dimetilarsinic acid (DMA], product of AsI metabolism by flow injectionhydride generation-atomic absorption spectrometry (FI-GH-AAS, after derivatization with L-cysteine. The recovery

  17. Preparation and Characterization of TiO2 Nanostructure by TiCl4 Hydrolysis with Additive NaOH

    Directory of Open Access Journals (Sweden)

    Rashed Taleb Rasheed

    2018-04-01

    Full Text Available Titanium dioxide (TiO2 nanostructures were synthesized via the hydrolysis of TiCl4 in alcohol / water solution/with sodium hydroxide solution in the ice-bath (0-5 ◦C. The particles were char-acterized by using X-ray diffraction technique (XRD, spectroscopy of Ultra Violet-Visible (UV / Visible and infrared (FT-IR, atomic force microscope (AFM and scanning electron micro-scope (SEM analysis were used in order to gain information about the material, morphology, size and the shape of the particles

  18. Derechos colectivos y consulta previa: territorio cucapá y recursos pesqueros en Baja California, México

    Directory of Open Access Journals (Sweden)

    Alejandra Navarro Smith

    2014-07-01

    Full Text Available Las demandas de reconocimiento de derechos territoriales y de uso de los recursos naturales que los pescadores cucapás le hacen al Estado mexicano, desde 1993, después de la creación de la Reserva del Alto Golfo de California y Delta del Río Colorado (en adelante, la Reserva, son unas más en el panorama de los problemas socioambientales y de despojo territorial, que afectan a los pueblos originarios en México. La característica particular en este caso es que el Estado mismo es quien construye los marcos legales en materia de protección a las especies —sin consultar debidamente a dichos pueblos—, volviendo ilegal la presencia cucapá en esa zona y vulnerando sus derechos como población indígena del delta. En consecuencia, las autoridades medioambientales y de pesca mexicanas han constituido la zona del delta del río Colorado como un territorio en disputa, al implementar esquemas de protección ambiental y de pesca, sustentados en modelos disciplinarios, que únicamente se alimentan de información biológica y pesquera. El conflicto se genera cuando se deja al elemento humano fuera de los análisis, como si las comunidades asentadas en los territorios protegidos y usuarias de los recursos no formaran parte de los ecosistemas. Al crear el núcleo de la Reserva en el mismo lugar donde se encontraban los campamentos de pesca del pueblo cucapá se volvió ilegal el aprovechamiento de los recursos pesqueros en la zona. En este contexto se han criminalizado las acciones de resistencia con las que los cucapás responden ante la regulación medioambiental del delta del río Colorado. Al ver imposibilitada la continuidad de su práctica pesquera, los habitantes se organizan para defender su acceso al territorio y, en un sentido más amplio, sus formas de vida y de trabajo. Este caso, en particular, visibiliza maneras contemporáneas por las que el Estado despoja el territorio y desaparece prácticas culturales propias de los pueblos naturales, a través de ciertos discursos y prácticas legales —en este caso los de conservación—.

  19. Ideas previas en el aprendizaje del efecto invernadero y el calentamiento global en estudiantes universitarios de ciencias exactas y naturales

    OpenAIRE

    Gulizia, Carla; Zazulie, Natalia

    2012-01-01

    El calentamiento global es un tema presente en la mayoría de los cursos iniciales de Ciencias de la Atmósfera y representa una problemática a nivel social que es ampliamente discutida tanto por científicos expertos, tomadores de decisiones, comunidades educativas y de protección ambiental. Es por esto que adquiere real importancia que este tema sea correctamente entendido por los estudiantes de niveles medio y superior que podrían eventualmente cumplir diversos roles en la sociedad. En este t...

  20. La erosión de las certezas previas: significados, percepciones e impactos del desempleo en la experiencia argentina

    Directory of Open Access Journals (Sweden)

    María Cristina Bayón

    2003-06-01

    Full Text Available In Argentina, the disruptive effects of unemployment acquire particularly serious dimensions because of the context of disintegration of what was previously a relatively well established social and employment structure.This article examines the experience, meanings and perceptions of work and unemployment, with particular emphasis on their dynamic and heterogeneous nature. The article offers a critical review of the literature on unemployment and an analysis of the major transformations of the employment market from the 1980s on, before proceeding to demonstrate, through in–depth interviews, the concrete repercussions of these processes on “ordinary people”. It thus aims to provide an appreciation of unemployment from a broad perspective, and contribute to a reformulation of welfare politics with a comprehensive, overall vision.

  1. Electrochemical advanced oxidation processes applied to the degradation of organic compounds in aqueous effluents; Aplicacion de procesos electroquimicos de oxidacion avanzada para la degradacion de compuestos organicos en efluentes acuosos

    Energy Technology Data Exchange (ETDEWEB)

    Peralta-Hernandez, J. M.; Maldonado, M. I.; Meas-Vong, Y.; Rodriguez, F.; Godinez, L. A.; Malato, S.

    2007-07-01

    Dyeing and finishing operations produce large quantities of wastewater that contains organic dyestuff, surfactants and other contaminants that can be characterized as high levels of total organic and color. Electro-Fenton (in situ electrochemical generation of the Fenton reagent) has been studied in order to exploit the fact that the reduction of dissolved oxygen to peroxide can be carried out selectively in acidic medium on the surface of a carbonaceous cathode. In this work, we report a study in which two approaches to water treatment are combined, photo catalysis and Fenton reaction, which involves the homogeneous conversion of peroxide to hydroxyl radical (OH). (Author) 140 refs.

  2. Study of the oxidation of the matrix of irradiated fuel under conditions of dry storage; Estudio de la oxidacion de la matriz del combustible irradiado en condiciones de almacenamiento en seco

    Energy Technology Data Exchange (ETDEWEB)

    Elorrieta, J. M.; Bonales, L. J.; Rodriguez, N.; Gutierrez, L.; Cobos, J.; Baonza, V. G.

    2014-07-01

    Spain holds the open cycle for the management of spent fuel of nuclear power stations. The solution adopted, given the urgent need for greater storage capacity, has been the construction of a centralized temporary storage, with an expected 100-year life, which will be stored from 2017 both spent fuel from nuclear power plants and other waste high activity of NPPs. (Author)

  3. Degradation of non-biodegradable pesticides in water by coupling photo catalysis and bio treatment; Eliminacion de plaguicidas no biodegrabables en aguas mediante acoplamiento de fotocatalisis solar y oxidacion biologica

    Energy Technology Data Exchange (ETDEWEB)

    Ballesteros Martin, M. M.; Sanchez Perez, J. A.; Malato Rodriguez, S.

    2008-07-01

    The influence of pesticide concentration, expressed as dissolved organic carbon (DOC), on combined solar photo-Fenton and biological oxidation treatment was studied using wastewater containing different pure and commercial pesticides (dimethoate, oxydemeton-methyl, carbaryl, oxamyl, methomyl, imidacloprid, dimethoate and pyrimethanil). Different initial concentrations were assayed. Variation in biodegradability with photo catalytic treatment intensity was tested using Pseudomonas putida. Biodegradation efficiencies after the photoreaction were found to be lower for the pesticide solution with the higher concentration, showing that to achieve sufficient biodegradability, the photo-Fenton treatment time must be increased with pesticide concentration. Bio treatment was carried out in different reactor including sequencing batch reactor (SBR) mode. As revealed by the biodegradation kinetics, intermediates generated at the higher pesticide concentration caused lower carbon removal rates in spite of the longer photo-Fenton treatment time applied. One strategy for treating water with high concentrations of pesticides and overcoming the low biodegradability of photo-Fenton intermediates is to mix it with a biodegradable carbon source (wastewater containing an easily biodegradable substrate, such as urban wastewater) before biological oxidation. This combination of photo-Fenton and acclimatized activated sludge in several SBR cycles led to complete biodegradation of a pesticide solutions up to of 500 mg/L of DOC. (Author)

  4. By-products of the oxidation of 2,4-dichlorophenol formed during the treatment of waste waters; Subproductos de oxidacion del 2,4-diclorofenol formados durante el tratamiento de aguas residuales

    Energy Technology Data Exchange (ETDEWEB)

    Pardos, M.; Alfonso, M. A.; Ormad, P.; Ovelleiro, J. L. [Universidad de Zaragoza (Spain)

    2000-07-01

    Nowadays, new technologies for the elimination of toxic and persistent substances present in industrial processes wastewater are being developed. One of these technologies uses the Fenton's reactive (iron salts and hydrogen peroxide) and UV light. In this work, it has been made an study about by-products generated and their formation mechanism, when an oxidation treatment is apply to a synthetic sample of 2,4-dichlorophenol (2,4-DCP) in aquatic medium. During the treatment it is detected the aromatic ring dehalogenation, the formation of low molecular weight oxygenated organic compounds (aldehydes, alcohols, and acids) and an important decreasing of the toxicity. (Author) 15 refs.

  5. Cyclic and isothermal oxidation behavior of 2.25Cr-1Mo steel; Estudio del comportamiento del acero 2.25Cr-1Mo frente a los fenomenos de oxidacion ciclica e isoterma

    Energy Technology Data Exchange (ETDEWEB)

    Proy, M.; Utrilla, M. v.; Otero, E.

    2014-04-01

    Cyclic and isothermal oxidation of chromium-molybdenum steel 2.25Cr-1Mo were analyzed at 550 degree centigrade and 650 degree centigrade during 360 hours in air atmospheres. The cycles were performed with two stages; one of heating in furnace during 90 minutes and then the sample were cooled to 50 degree centigrade by air flow. Thermogravimetric analyses were performed to obtain high temperature corrosion kinetics. Several characterization techniques have been used to identify the corrosion mechanism, as X-Ray Diffraction (XRD), Optical Microscopy (OM) and Scanning Electron Microscopy (SEM). Thermal cycling tests can changes the corrosion mechanism, due cracks propagation in oxide scale, that witch can favors the access of oxidant agent to the substrate. (Author)

  6. Study of cyclic oxidation for stainless steels AISI 309 T 253 M A, with low additions of cerium; Estudio de la oxidacion ciclica de los aceros inoxidables AISI 309 T 253 MA, con pequenas adiciones de Cerio

    Energy Technology Data Exchange (ETDEWEB)

    Velazquez F, G.L.; Martinez, M.; Ruiz, A. [Universidad Nacional Experimental Politecnica (UNEXPO) - Vicerrectorado de Puerto Ordaz, Centro de Estudios de Corrosion. Puerto Ordaz. venezuela (Venezuela)

    1998-12-31

    It has been detected that the addition of small amounts (<1%) of the so called `reactive elements` such as Cerium to Fe-Cr alloys that was utilized in oxidating environment at high temperatures improving its resistance to oxidation under isothermal and cyclic conditions. In this work, it was evaluated the behavior under cyclic oxidation conditions for an austenitic stainless steel at chromium-nickel (253MA) with cerium addition, and comparing it with the AISI 310S austenitic stainless steel. The cyclic oxidation essays consist of five cycles by 24 hours each one, following of a cooling in air until ambient temperature from the temperatures of 850, 900 and 950 Centigrade, registering the gain mass of the specimen at end of each cycle. In order to this were prepared samples with dimensions of 20 mm. x 10 mm. x 1 mm. Later to the oxidation essays was evaluated the morphology of the corrosion products layer by scanning electron microscopy. The present phases were identified by X-ray diffraction and by chemical microanalysis by Dispersive energy (EDAX). The results obtained show that the steel with cerium addition, presents a higher adherence and resistance to the spalling noting that the cerium promotes the casting anchor of the oxides layer to matrix and by reducing the grain size of the layer improving its plasticity. Additionally the cerium promotes the preferential oxidation of the forming elements of protective layers like the chromium. (Author)

  7. Degradation of Remazol Red in batik dye waste water by contact glow discharge electrolysis method using NaOH and NaCl electrolytes

    Science.gov (United States)

    Saksono, Nelson; Putri, Dita Amelia; Suminar, Dian Ratna

    2017-03-01

    Contact Glow Discharge Electrolysis (CGDE) method is one of Plasma Electrolysis technology which has been approved to degrade organic waste water because it is very productive in producing hydroxyl radical. This study aims to degrade Remazol Red by CGDE method and evaluate important parameters that have influent in degradation process of Remazol Red in Batik dye waste water in batch system. The kind of electrolyte (acid and base) and the addition of metal ion such as Fe2+ have affected Remazol Red degradation percentage. Ultraviolet-Visible (UV-Vis) absorption spectra were used to monitor the degradation process. The result of study showed that percentage degradation was 99.97% which obtained by using NaCl 0.02 M with addition Fe2+ 20 ppm, applied voltage 700 volt, anode depth 0.5 cm, initial concentration of Remazol Red 250 ppm and the temperature of solutions was maintained 50-60 ˚C.

  8. Influence of density on radiation-chemical yield of molecular hydrogen formed at radiolysis of aqueous solution of NaOH

    International Nuclear Information System (INIS)

    Jafarov, Y.D.; Hajiyeva, S.R.; Ramazanova, N.K.; Aliyev, S.M.; Alasgarov, A.M.

    2014-01-01

    Full text : In atom and nuclear energy the specialists knowledge about radiation-chemical yield of the initial products formed under the influence of ionizing rays on water is of great importance from the point of security. The radiation-chemical yields of molecular hydrogen have been defined according to the graph and the obtained results

  9. Induction and stability of oxidative stress adaptation in Listeria monocytogenes EGD (Bug600) and F1057 in sublethal concentrations of H2O2 and NaOH

    Science.gov (United States)

    Food processing and food handling environments may contain residual levels of sanitizers or cleaners which may trigger oxidative stress adaptation in Listeria monocytogenes. The aim of this study was to determine the induction and stability of oxidative stress adaptation in L. monocytogenes EGD (Bug...

  10. Mass transfer in a bubble column discrete bubble modeling of CO2 absorption in a NaOH solution in a micro-Structured Bubble Column

    NARCIS (Netherlands)

    Jain, D.; Kuipers, J.A.M.; Deen, N.G.

    2015-01-01

    Gas-liquid-solid reactive flows are encountered in many industrial processes. While the transport of reactants and chemical reaction is between gas and liquid phase, solid particles are introduced as catalysts to facilitate the reaction. Major industrial processes where such flows are encountered

  11. Voltammetric and impedance study of the influence of the anode composition on the electrochemical ferrate(VI) production in molten NaOH

    International Nuclear Information System (INIS)

    Hrnčiariková, Lucia; Gál, Miroslav; Kerekeš, Kamil; Híveš, Ján

    2013-01-01

    Three typical anode materials: pure iron (Fe), silicon-rich steel (FeSi) and white cast iron (FeC) electrodes were used in the process of electrochemical ferrate(VI) synthesis in the molten sodium hydroxide. The voltammetric peak current densities corresponding to the first and second step of the anode dissolution in the case of FeC as well as FeSi electrode are higher compared to the pure iron electrode. After passivity region subsequently the transpassive iron dissolution, including ferrate(VI) formation together with an oxygen evolution occurs and the current shoulder is visible for all electrodes used. Measured electrochemical impedance spectra confirm the physical model of the polarized surface based on the concept of two macrohomogeneous surface layers. In all cases the resistance of both inner and outer layer decrease with increasing applied potential. With increasing temperature the resistance of inner and outer layer decreases. The capacity of inner and outer layer increases with increasing potential. This is in agreement with decrease of the resistances of both layers: layers are getting thinner or more disintegrated by oxygen evolution or strong anodic dissolution. The number of exchanged electrons calculated from a static polarization curve at the potentials in ferrate(VI) formation region is z = 3 for all electrode materials used

  12. Morphology evaluation of ZrO2 dip coating on mild steel and its corrosion performance in NaOH solution

    Science.gov (United States)

    Anwar, M. A.; Kurniawan, T.; Asmara, Y. P.; Harun, W. S. W.; Oumar, A. N.; Nandyanto, A. B. D.

    2017-10-01

    In this work, the morphology of ZrO2 thin film from dip coating process on mild steel has been investigated. Mild steel was dip-coated on solution made of zirconium butoxide as a precursor, ethanol as solvent, acetylacetone as chelating agent and water for hydrolysis. Number of dipping was adjusted at 3, 5 and 7 times. The dipped sample then annealed at 350°C for two hours by adjusting the heating rate at 1°C/min respectively. The optical microscope showed that micro-cracks were observed on the surface of the coating with its concentration reduced as dipping sequence increased. The XRD result showed that annealing process can produce polycrystalline tetragonal-ZrO2. Meanwhile, SEM image showed that the thicknesses of the ZrO2 coatings were in between 400-600 nm. The corrosion resistance of uncoated and coated substrates was studied by polarization test through potentio-dynamic polarization curve at 1mV/s immersed in with 3.5% NaCl. The coating efficiency was improved as the number of layer dip coated increased, which showed improvement in corrosion protection.

  13. ISO 14006. Experiencias previas de estudios de arquitectura que han adoptado el estándar de ecodiseño UNE 150301:2003

    Directory of Open Access Journals (Sweden)

    Arana-Landín, G.

    2012-09-01

    Full Text Available This paper aims to analyze the pioneer UNE 150301 standard, as well as its adoption process and its practical results in the sector of architecture studios. First, the structure, the aim and the scope of norm UNE 150301 have been analysed. Second, the standard's implementation has been examined, concluding that 73% of the companies that have obtained the certificate are architecture studios. A case study has therefore been carried out with the participation of five architecture studios pioneers. These experiences have let us know the main aspects and difficulties of the process. In conclusion, the adoption of the standard UNE 150301 can be a helpful tool in order to reduce the environmental impact of the products and obtain some competitive advantages such as cost reduction, improvement in energy efficiency of the product and a better adaptation to acts and regulations.

    En este artículo se analiza la experiencia de implantación de la norma UNE 150301 de ecodiseño en el sector de los estudios de arquitectura. Tras el examen de la estructura de norma UNE 150301, de sus objetivos y de su alcance, se analiza su difusión, destacándose que el 73% de las empresas certificadas en España son estudios de arquitectura. A continuación se estudia el proceso de implantación real, mediante el estudio de caso que lo analiza en cinco estudios de arquitectura. El estudio realizado permite conocer de primera mano las principales claves y dificultades del proceso de implantación del estándar, así como los resultados obtenidos, entre los que destaca una reducción del impacto ambiental. Se constata, en suma, que la norma UNE 150301 es una herramienta que puede proporcionar ventajas competitivas interesantes a las empresas del sector de los estudios de arquitectura.

  14. La necesaria comprensión previa de la realidad constructiva del monumento: el caso singular de la Cripta de la Colonia Güell

    Directory of Open Access Journals (Sweden)

    Casals Balagué, Albert

    1993-10-01

    Full Text Available The Crypt of the Güell Colony is a building of a unique importance in the history of architecture although it is only a part of the church which Antoni Gaudí designed for Eusebio Güell. It owes its fame to the perfect conjunction of the expressive will of the author and the demands of statics it represents. This conjunction was achieved by using the design method based on the properties of funicular lines. This is where the great paradox of the Crypt lies: it is arable in spite of being a part of a whole which, logically thinking, should have reached the balance only after being completed, which, consequentially, casts doubt on whether the building would have been stable had it been finished. This article presents the conclusions of a study which was carried out by the authors who allow this paradox to be understood. The study is a part of another complete physical-constructive analysis which compiles the necessary information for the restoration of the monument ordered by the Servei de Patrimoni Arquitectonic Local de la Diputación de Barcelona under the direction of the architec Antoni González. The methods for building modelling used in the study range from graphic statics, which does not explain the paradox, to the finite element method, which contributes a sufficient number of facts for such on explanation. The finally developed model is a powerful and reliable tool which allows us to forsee the effects of any modification of the present state of the monument, including those produced by its hypothetical completion.

    La Cripta de la Colonia Güell es un edificio de similar relevancia en la historia de la arquitectura, a pesar de tratarse sólo de una parte de la iglesia que proyectó Antoni Gaudí para don Eusebio Güell. Debe su notoriedad a la conjunción perfecta que en ella se dan entre la voluntad expresiva de su autor y los requerimientos de la estática, conjunción que se consiguió gracias al método de proyecto basado en las propiedades de las líneas funiculares. Y en ello reside la gran paradoja que envuelve a la cripta: ser estable a pesar de ser una parte de un conjunto que, en buena lógica, debería haber alcanzado el equilibrio al haberse completado, lo que, en consecuencia, pone en duda la estabilidad de éste si se hubiera finalizado. El estudio realizado por los autores que permite entender esta paradoja ha utilizado como métodos para modelizar el edificio desde la estática gráfica, que no la explica hasta el método de los elementos finitos, que aporta suficientes datos para comprenderla. El modelo desarrollado finalmente es una herramienta potente y fiable que permite prever los efectos de cualquier modificación del estado actual del monumento, incluidos los producidos por su hipotética finalización.

  15. Limpieza del vidrio por erosión iónica, previa a la deposición del recubrimiento decorativo

    Directory of Open Access Journals (Sweden)

    Vershinin, N.

    2000-10-01

    Full Text Available Sputter cleaning is the most reliable way for the pre-treatment of substrates before the deposition of coatings with the aid of magnetron sputtering or vacuum arc deposition. In this work, a large-aperture Hall current accelerator was developed for the sputter cleaning of large-area glasses, metals and plastics sheets. The main advantage of the Hall current accelerator is the possibility to use reactive gases. The Hall accelerator developed is able to work with argon, oxygen, nitrogen and carbon dioxide. The accelerator has the form of a very elongated loop with a large aperture (1400 mm in the vertical direction. The maximum power of the Hall current accelerator is 10 kW. The current-voltage characteristic measured for argon is presented. It allows one to optimise the regime of sputter cleaning by finding the maximum power value at a stable discharge.

    La erosión iónica es el método más eficaz para la eliminación de la capa superficial de los substratos en su fase de preparación para la deposición de recubrimientos en vacío. En el presente trabajo se describe la construcción y características de un acelerador Hall de la corriente eléctrica de abertura larga, diseñado para la limpieza, mediante erosión iónica, de superficies de substratos de vidrio, metal y plástico en forma de láminas con área extensa. Una de las ventajas del acelerador Hall es la posibilidad de uso de gases reactivos. El acelerador aquí descrito es capaz de trabajar con argón, oxígeno, nitrógeno y dióxido de carbono. Este acelerador tiene una forma de bucle muy alargado y, por tanto, dispone de una abertura larga (1400 mm en vertical. La potencia máxima del acelerador es de 10 kW. Se presenta la característica corriente-tensión del acelerador en atmósfera de argón que permite optimizar el régimen de limpieza por erosión, encontrando el máximo de potencia para la descarga estable.

  16. EL AGOTAMIENTO DE LA VIA ADMINISTRATIVA PREVIA EN EL DERECHO CHILENO. EL ARTICULO 54 DE LA LEY N°19.880, Y EL REGIMEN EN LOS PROCEDIMIENTOS ESPECIALES

    OpenAIRE

    BETANCOURT SOLAR, RICARDO ALONSO; BETANCOURT SOLAR, RICARDO ALONSO

    2012-01-01

    El presente trabajo pretende determinar si existe en Chile una regla general sobre la obligatoriedad o no de agotar la vía administrativa, previo a intentar la acción contenciosa administrativa, lo que nos llevará a analizar las reglas contenidas en el artículo 54 de la ley N° 19.880, y luego revisar lo que ocurre en algunos de los innumerables procedimientos especiales. Antes de ello, ciertamente, es necesario efectuar ciertas precisiones a la institución del agotamiento de la vía prev...

  17. Glaucoma maligno en paciente con cirugía previa de catarata traumática e implante valvular: reporte de caso

    Directory of Open Access Journals (Sweden)

    Juan Carlos Serna-Ojeda

    2015-07-01

    Full Text Available El glaucoma maligno es un glaucoma secundario asociado con un bloqueo ciliar y dirección equivocada del flujo del humor acuoso. Se presenta el caso de un paciente masculino de 19 años con antecedente de explosión de filtro metálico en ojo derecho. Se encuentra con una presión intraocular de 52 mmHg y cristalino luxado a cámara anterior. Se inicia terapia máxima para glaucoma y se realiza facoemulsificación con posterior colocación de válvula de Ahmed, y 3 semanas después de la cirugía presenta hallazgos clínicos compatibles con glaucoma maligno. Se presenta el seguimiento del paciente y los estudios de imagen indicados

  18. EFECTO ANALGESICO DEL LASER EN PUNTOS ASHI, EN PACIENTES GERIATRICOS CON GONOARTROSIS, EVALUANDO EL DOLOR CON ESCALA VISUAL ANALOGA. PREVIA APERTURA DE CANALES TENDINOMUSCULARES

    OpenAIRE

    LUENGAS CRUCES, SARA ELIZABETH

    2010-01-01

    LA GONOARTROSIS, ES EL PADECIMIENTO MAS FRECUENTE EN LA PRACTICA CLINICA REUMATOLOGICA. TIENE UNA PREVALENCIA ALTA EN PERSONAS MAYORES DE 30 ANOS, POR LO QUE YA CONSTITUYE UN PROBLEMA DE SALUD Y FORMA PARTE DE UNA PANDEMIA DE ENFERMEDADES CRONICO-DEGENERATIVAS (VAZQUEZ MARTINEZ F Y ORTIZ ALVAREZ O. LA INVESTIGACION LATINOAMERICANA SOBRE OSTEOARTROSIS. GAC.MED. VOL. IV,1990 PG. 131)EN LOS REPORTES ESTADISTICOS DEL INEGI Y EN LOS SERVICIOS DE CONSULTA EXTERNA DE ESPECIALIDADES DEL IMSS LA PREVA...

  19. ¿Se están alcanzando las metas en el perfil lipídico de personas con enfermedad coronaria previa?

    Directory of Open Access Journals (Sweden)

    Alonso Merchán, MD

    2011-08-01

    Conclusiones: después de nueve años de la publicación de las guías del NCEP-ATPIII y de las recomendaciones posteriores sobre las metas del perfil lipídico en pacientes con enfermedad coronaria y a pesar de la divulgación de las mismas a través de conferencias, congresos y publicaciones, estas metas las cumple un porcentaje bajo de pacientes, tal como lo demuestra este estudio observacional en sujetos hospitalizados por causas diferentes a la enfermedad coronaria pero con este antecedente. Una de las explicaciones para este pobre resultado es el uso de lovastatina, estatina de baja efectividad para reducir el cLDL. Se analizan otras posibles causas y se hacen propuestas para lograr los objetivos.

  20. Introducción a los Materiales de Construcción: Revisión de experiencia previa y nuevas propuestas metodológicas

    OpenAIRE

    Chinchón Yepes, Servando; Prado Govea, Raúl Hugo; Chinchón Payá, Servando; Piedecausa García, Beatriz

    2015-01-01

    El Curso Académico 2010-2011 comenzaron los estudios de Grado de Ingeniería de la Edificación en la Universidad de Alicante. Cuatro años después, la Titulación ha retomado de nuevo el nombre de Grado en Arquitectura Técnica sin que haya habido modificación en las enseñanzas. Después de solo cuatro años, la asignatura de Introducción a los Materiales de Construcción no presenta un recorrido tan extenso como para hacer una evaluación exhaustiva. Pero sí lo suficiente como para revisar algunos t...

  1. The Uterine Sandwich Method for Placenta Previa Accreta in Mullerian Anomaly: Combining the B-Lynch Compression Suture and an Intrauterine Gauze Tampon

    Directory of Open Access Journals (Sweden)

    Mustafa Kaplanoğlu

    2013-01-01

    Full Text Available Mullerian duct anomalies may cause obstetric complications, such as postpartum hemorrhage (PPH and placental adhesion anomalies. Uterine compression suture may be useful for controlling PPH (especially atony. In recent studies, uterine compression sutures have been used in placenta accreta. We report a case of PPH, a placenta accreta accompanying a large septae, treated with B-Lynch suture and intrauterine gauze tampon.

  2. Resistencia transmitida del virus de la inmunodeficiencia humana en pacientes sin exposición previa a tratamiento antirretroviral, Cali, Colombia, 2010

    Directory of Open Access Journals (Sweden)

    Pablo Galindo-Orrego

    Full Text Available Introducción: En Colombia, existe poca información publicada sobre farmacorresistencia transmitida en el virus de inmunodeficiencia humana (VIH, y actualmente, las pruebas genotípicas de resistencia no son recomendadas por las guías colombianas para pacientes nunca expuestos ( naïve a terapia antirretroviral (TAR. Se condujo un estudio para determinar la frecuencia de resistencias transmitidas en pacientes naïve a TAR, quienes fueron atendidos en una clínica especializada en VIH/síndrome de inmunodeficiencia adquirida en Cali, Colombia. Metodología: Se realizó un estudio transversal en 152 pacientes adultos elegibles, con infección confirmada por VIH, naïve a TAR, con pruebas genotípicas de resistencia disponibles, y que accedieron a participar. El período de reclutamiento fue de 2008 a 2010. Las mutaciones de resistencias incluidas en el análisis fueron las definidas por la Organización Mundial de la Salud 2009 e International AIDS Society-USA 2010. Adicionalmente, se recolectó información sociodemográfica y condiciones relacionadas con el VIH. Resultados: La edad promedio fue 32 ± 10,2 años, 76% fueron hombres. La frecuencia de resistencia primaria fue de 6,6% (según la lista de Bennett-Organización Mundial de la Salud 2009, pero se encontró algún nivel de resistencia hasta en un 11,8% de los casos (al considerar mutaciones de la lista International AIDS Society-USA 2010. Las mutaciones más comunes fueron K103N/S (2%, F77L (2% y M46L (2%. Mutaciones a los inhibidores no nucleosídicos de transcriptasa reversa fueron encontradas en 5,3%, mutaciones a los inhibidores no nucleosídicos de transcriptasa reversa en 3,9% y mutaciones a inhibidor de proteasa en 2% de las secuencias. El único factor relacionado con la resistencia primaria fue la duración de la infección por VIH. Conclusiones: La frecuencia de resistencia transmitida es similar a la encontrada en estudios previos en Colombia y en otros países con amplio uso de antirretrovirales, y está por encima del umbral sobre el cual sería costo-efectivo incluir el estudio genotípico de resistencias como test de rutina antes de la iniciación de la TAR, especialmente en pacientes con infección por VIH de menos de un año de duración.

  3. La cultura de la información como institución previa a la sociedad de la información

    Directory of Open Access Journals (Sweden)

    Alfons Cornella Solans

    2015-02-01

    Las economías occidentales se están convirtiendo en economías de la información. Quizás sea el caso norteamericano el más claro exponente del proceso de informacionalización de las economías. El discurso tradicional señala a la inversión en tecnologías de la información como principal causa de este proceso. Sin embargo, puede que existan factores culturales, como por ejemplo la existencia de una cultura de la información desarrollada, que expliquen porque la evolución hacia la sociedad de la información se produce más aceleradamente en algunos países. Conseguir una economía de la información sería, pues, distinto de alcanzar la sociedad de la información. La cultura informacional de los ciudadanos sería un requisito necesario para conseguir este último objetivo. Y la cultura de la información no puede alcanzarse simplemente mediante el establecimiento de políticas y acciones, sino que requiere de una evolución del orden espontáneo. La cultura de la información se constituiría, pues, como una institución necesaria en las sociedades modernas.

  4. Eficiencia de la implantación del cultivo de maíz (Zea mays l.) en secuencias de siembra directa y labranza previa

    OpenAIRE

    Soza, Eduardo Leonardo; Tourn, Mario César; Agnes, Diego Wilfredo; Botta, Guido Fernando

    2008-01-01

    p.11-17 El cultivo de maíz requiere una correcta implantación para la obtención de un buen rendimiento y la siembra directa es una técnica que no siempre está unida al cumplimiento de este objetivo, siendo la sembradora, su alistamiento y regulación, una herramienta clave para ese propósito. En siembra directa la cuchilla labrasurco y surcador doble disco generan mínima remoción de suelo, obteniéndose emergencias inferiores a la siembra convencional. Utilizando una misma máquina sembradora...

  5. El Derecho a la Consulta Previa de los Pueblos Indígenas y Ciudadanía Multicultural en Brasil

    Directory of Open Access Journals (Sweden)

    Germana Aguiar Ribeiro do Nascimento

    2016-06-01

    Full Text Available Desde finales del siglo XX, las reclamaciones de los pueblos indígenas se tornaran frequentes, lo que contribuyó para los cambios legislativos. En efecto, derechos indígenas son ahora garantizados, es el caso del derecho a consulta. El objetivo de este artículo es analizar el acceso de este derecho, observando en qué medida está protegido y su relación con la construcción de una ciudadanía multicultural. La investigación es de carácter cualitativo: son analizados la legislación y jurisprudencia. Se puede observar que a pesar de la legislación, él no es respectado, lo que impide la realización de una ciudadanía multicultural en Brasil.

  6. Spectrophotometric Determination of Microamounts of Uranium previous Extraction with TBP-MIC; Determinacion Espectrofotometrica de Microcantidades de Uranio previa extraccin con Metilisobutilcetona-Fosfato de Tributilo

    Energy Technology Data Exchange (ETDEWEB)

    Vera Palomino, J; Palomares Delgado, F; Petrement, J; Fernandez Cellini, R

    1962-07-01

    Selective extraction of uranium in nitric acid medium with a mixture of Tbp-MIC (1:10) has been achieved. Aluminium nitrate was used as salting agent. Complexing agents were added in order to avoid extraction of impurities. Extraction conditions have been studied so that extraction is almost practically complete in a single run. (Author) 19 refs.

  7. Desarrollo de un nuevo modelo de Aspergilosis Pulmonar en rata consideraciones previas, estudio comparativo y aplicaciones al diagnóstico de la enfermedad

    OpenAIRE

    Caballero de Toro, Jesús

    2005-01-01

    Aspergilosis incluye una gran cantidad de enfermedades, incluida la Aspergilosis Invasora. El objetivo de esta tesis es el estudio de la Aspergilosis invasora en humanos. En primer lugar se evalúan los perfiles proteicos de A. fumigatus crecidos en diferentes medios y su capacidad antigénica. Posteriormente se realiza una evaluación de la capacidad de infección de A. fumigatus en modelos animales en ratones y ratas. Se desarrolla un nuevo modelo de infección transtorácia con hifas. Finalmente...

  8. Plan de mejoramiento financiero previa realización de auditoría de estados financieros de la empresa Tobamac S.A., ejercicio fiscal 2010

    OpenAIRE

    León Llanos, Andrés Paúl

    2012-01-01

    El presente trabajo de investigación en la empresa Tobamac S.A., tiene por objetivo sugerir recomendaciones respecto 4 temas influyentes en la situación financiera de la compañía consideradas críticas por la administración: Liquidez, impacto de los gastos no deducibles en el cálculo del Impuesto a la renta causado, apreciación de los estados financieros y evaluaciones de centros de costos. Previo a realizar el análisis, se ejecuta un trabajo de Auditoría a Estados Financieros del año 2010 con...

  9. Modification of Colombian clays with pillars mixed Al-Fe and their evaluation in the catalytic oxidation of phenol in diluted watery solution; Modificacion de arcillas colombianas con pilares mixtos Al-Fe y su evaluacion en la oxidacion catalitica de Fenol en solucion acuosa diluida

    Energy Technology Data Exchange (ETDEWEB)

    Galeano, Luis A; Moreno G, Sonia

    2002-07-01

    The environmental legislation has become in the last time particularly restrictive with the bio-recalcitrant pollutants manage in the wastewaters. The pillared clays show great versatility to adjust at demands of the environmental reactions. Present study show that is achieve the modification of starting Colombian clays with precursor solutions of Al-Fe mixed pillars, and is found an excellent performance of them in the catalytic oxidation of aqueous solutions with middle contents of Total Organic Carbon TOC (36 mg C/L). The materials prepared in this way reached quantitative conversion of phenol, as model pollutant, in 2 hours of reaction at 20 Celsius degrade and atmospheric pressure; in 4 hours of reaction, the removal reached 62% of TOC in the solution yielding light carboxylic acids as main byproducts, although that CO{sub 2}. The materials are stable under strongly oxidation media of reaction, and the iron leached in the effluent is close to 0,2 mg/L for the material of better catalytic performance.

  10. Characterization of the surface oxidation reaction and its influence on the radiation absorption during the surface laser hardening process of the 42CrMo4 steel; Caracterizacion de la reaccion de oxidacion superficial y su influencia sobre la absorcion de radiacion durante el proceso de temple superficial con laser para el acero 42CrMo4

    Energy Technology Data Exchange (ETDEWEB)

    Cordovilla, F.; Dominguez, J.; Sancho, P.; Garcia-Beltran, A.; Ocana, J. L.

    2016-10-01

    Surface laser hardening of steel is a process that produces an enormous interest due to its uncountable advantages in terms of quality and productivity against induction hardening The effective implantation of this process, nevertheless, is been hampered because of the lack of reliable and flexible predictive tools. There are different models focused on the temperature calculation, thought, few make a thorough analysis of the surface oxidation associated with the process and its important implications over the absorption coefficient. This work proposes and explains a coupled model temperature/ oxidation available in literature, applied, for the first time, for the simulation of simple processes carried out with different conditions of power and speed, for the 42CrMo4 steel. These conditions have been reproduced experimentally, tracking the maximum surface temperature and the oxide thickness. Both results have shown a high degree of coincidence whit theoretical predictions, confirming the capabilities and utility of the model. (Author)

  11. Evaluation of the behavior of PtPd/MWCNT electrocatalysts as ethylene glycol-tolerant electrodes for oxygen oxidation reaction (ORR); Evaluacion del comportamiento de electrocatalizadores tipo PtPd/MWCNT como electrodos para la reaccion de oxidacion del oxigeno (ORR) tolerantes al etilenglicol

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, D.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Pedro Escobedo, Queretaro (Mexico)]. E-mail: dmorales@cideteq.mx; Alvarez-Contreras, L. [Centro de Investigacion en Materiales Avanzados S. C., Chihuahua, Chihuahua (Mexico); Fraire Luna, S.; Rodriguez Varela, F.J. [Cinvestav, Unidad Saltillo, Ramos Arizpe, Coahuila, (Mexico)

    2009-09-15

    Pt-Pd/MWCNTs (atomic ratio Pt:Pd 43:57) and Pt/MWCNTs electrocatalysts were synthesized and evaluated as cathodes for oxygen reduction reaction (ORR) with the application of direct ethylene glycol fuel cells (DEGFC). A commercial PtC material was also evaluated as a reference. It was found that Pt-Pd/MWCNT has a capability for high tolerance to ethylene glycol (EG) and higher selectivity for ORR compared to a single Pt- cathode. As a result, the change in onset potential of the ORR, Eonset, in Pt-Pd/MWCNTs was considerably less than the change in Pt/MWCNTs or Pt/C. The average particle size (XRD) was 3.5nm and 4nm for Pt/MWCNTs and Pt-Pd/MWCNTs, respectively. A moderate degree of alloying was determined for the material. The application of Pt-Pd electrocatalysts in DEGFCs should be advantageous. [Spanish] Electrocatalizadores Pt-Pd/MWCNTs (relacion atomic Pt:Pd 43:57) y Pt/MWCNTs fueron sintetizados y evaluados como catodos para la reaccion de reduccion del oxigeno (ORR) con aplicacion del celdas de consumo directo de etilenglicol (Direct Ethylene Glycol Fuel Cells, o DEGFC). Como referencia, un material comercial tipo Pt/C fue tambien evaluado. Se encontro que Pt-Pd/MWCNTs tiene una alta capacidad de tolerancia al etilenglicol (EG) y una selectividad mayor hacia la ORR comparado con el catodo basado en Pt-solo. Como resultado, el cambio en potencial de inicio de la ORR, Eonset, en Pt-Pd/MWCNTs fue considerablemente menor que el cambio en Pt/MWCNTs o Pt/C. La talla de particula promedio (de XRD) fue 3.5 nm y 4 nm para Pt/MWCNTs y Pt-Pd/MWCNTs, respectivamente. Un moderado grado de aleacion fue determinado para el material. Una aplicacion ventajosa para electrocatalizadores tipo Pt-Pd debe ser en DEGFCs.

  12. Synthesis and characterization of palladium nanoparticles, deposited on a modified support of TiO{sub 2} and its study in the oxidation reaction of CO to CO{sub 2}; Sintesis y caracterizacion de nanoparticulas de paladio, depositadas sobre un soporte modificado de TiO{sub 2} y su estudio en la reaccion de oxidacion de CO a CO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Arreola S, R.; Fierro M, S. I.; Garcia M, J. A., E-mail: arreola@fisica.unam.mx [UNAM, Instituto de Fisica, Departameto de Estado Solido, Circuito Exterior, Ciudad Universitaria, 04510 Ciudad de Mexico (Mexico)

    2017-11-01

    In this article, we report the synthesis of heterogeneous catalysts with low palladium loading (Pd/TiO{sub 2}) by deposition-precipitation using urea (DPU) and the catalyst activity that was evaluated by means of the CO-CO{sub 2} oxidation reaction, showing CO conversion at room temperature. The results indicate that Pd/TiO{sub 2} catalyst with 2% Pd exhibits excellent activity for CO oxidation and high stability during forty-nine days. The characterization was carried out by X-ray diffraction and transmission electron microscopy. (Author)

  13. Comparison of high-titer lactic acid fermentation from NaOH- and NH3-H2O2-pretreated corncob by Bacillus coagulans using simultaneous saccharification and fermentation

    Science.gov (United States)

    Zhang, Zhenting; Xie, Yuejiao; He, Xiaolan; Li, Xinli; Hu, Jinlong; Ruan, Zhiyong; Zhao, Shumiao; Peng, Nan; Liang, Yunxiang

    2016-01-01

    Lignocellulose is one of the most abundant renewable feedstocks that has attracted considerable attention as a substrate for biofuel and biochemical production. One such biochemical product, lactic acid, is an important fermentation product because of its great potential for the production of biodegradable and biocompatible polylactic acid. High-titer lactic acid production from lignocellulosic materials has been achieved recently; however, it requires biodetoxification or results in large amounts of waste washing water. In this study, we employed two alkaline pretreatment methods and compared their effects on lactic acid fermentation of pretreated corncob by Bacillus coagulans LA204 using fed-batch simultaneous saccharification and fermentation under non-sterile conditions. The lactic acid titer, yield, and productivity from 16% (w/w) NaOH-pretreated and washed corncob were 122.99 g/L, 0.77 g/g corncob, and 1.37 g/L/h, respectively, and from 16% NH3-H2O2-pretreated and washed corncob were 118.60 g/L, 0.74 g/g corncob, and 1.32 g/L/h, respectively. Importantly, the lactic acid titer, yield, and productivity from 18.4% NH3-H2O2-pretreated and unwashed corncob by using fed-batch simultaneous saccharification and fermentation reached 79.47 g/L, 0.43 g/g corncob, and 1.10 g/L/h, respectively, demonstrating that this method is possible for industrial applications and saves washing water. PMID:27853308

  14. Detailed modelling of hydrodynamics, mass transfer and chemical reactions in a bubble column using a discrete bubble model: Chemisorption of CO2 into NaOH solution, numerical and experimental study

    NARCIS (Netherlands)

    Darmana, D.; Henket, R.L.B.; Deen, N.G.; Kuipers, J.A.M.

    2007-01-01

    This paper describes simulations that were performed with an Euler–Lagrange model that takes into account mass transfer and chemical reaction reported by Darmana et al. (2005. Detailed modelling of hydrodynamics, mass transfer and chemical reactions in a bubble column using a discrete bubble model.

  15. Effect of SiO2/Al2O3 Ratio on Micro-Mesopore Formation for Pt/Beta-MCM-41 via NaOH Treatment and the Catalytic Performance in N-heptane Hydro isomerization

    Science.gov (United States)

    Gao, Li; Shi, Zhiyuan; Liu, Yingming; Zhao, Yuanshou; Liu, Qinghua; Xu, Chengguo; Bai, Peng; Yan, Zifeng

    2018-01-01

    Micro-mesoporous composite material Beta-MCM-41(BM) were hydrothermally synthesized by treating parent beta with molar SiO2/Al2O3 ratios of 12.5, 20 and 30 as precursors. The influence of SiO2/Al2O3 ratio of zeolite beta on effective micro-mesoporous composite formation was studied by investigating the crystallinity, morphology, chemical composition, acidity and textural property of Beta-MCM-41 through XRD, nitrogen adsorption, SEM, TEM, NH3-TPD, FTIR and Pyridine-FTIR. The catalytic performance was evaluated in terms of n-heptane hydro isomerization. The results demonstrated that Beta-MCM-41 supported Pt catalysts showed higher selectivity to isoheptanes than Pt/Beta. It was attributed to the superiorities of the pore structure and mesoporous accelerated the diffusion of larger molecules of isoheptanes.

  16. Comparison of high-titer lactic acid fermentation from NaOH- and NH3-H2O2-pretreated corncob by Bacillus coagulans using simultaneous saccharification and fermentation.

    Science.gov (United States)

    Zhang, Zhenting; Xie, Yuejiao; He, Xiaolan; Li, Xinli; Hu, Jinlong; Ruan, Zhiyong; Zhao, Shumiao; Peng, Nan; Liang, Yunxiang

    2016-11-17

    Lignocellulose is one of the most abundant renewable feedstocks that has attracted considerable attention as a substrate for biofuel and biochemical production. One such biochemical product, lactic acid, is an important fermentation product because of its great potential for the production of biodegradable and biocompatible polylactic acid. High-titer lactic acid production from lignocellulosic materials has been achieved recently; however, it requires biodetoxification or results in large amounts of waste washing water. In this study, we employed two alkaline pretreatment methods and compared their effects on lactic acid fermentation of pretreated corncob by Bacillus coagulans LA204 using fed-batch simultaneous saccharification and fermentation under non-sterile conditions. The lactic acid titer, yield, and productivity from 16% (w/w) NaOH-pretreated and washed corncob were 122.99 g/L, 0.77 g/g corncob, and 1.37 g/L/h, respectively, and from 16% NH 3 -H 2 O 2 -pretreated and washed corncob were 118.60 g/L, 0.74 g/g corncob, and 1.32 g/L/h, respectively. Importantly, the lactic acid titer, yield, and productivity from 18.4% NH 3 -H 2 O 2 -pretreated and unwashed corncob by using fed-batch simultaneous saccharification and fermentation reached 79.47 g/L, 0.43 g/g corncob, and 1.10 g/L/h, respectively, demonstrating that this method is possible for industrial applications and saves washing water.

  17. Spectrophotometric determination of uranium with arsenazo previous liquid-liquid extraction and colour development in organic medium; Determinacion espectrofotometrica de uranio con arsenazo, previa extraccion y desarrollo del color en medio organico

    Energy Technology Data Exchange (ETDEWEB)

    Palomares Delgado, F; Vera Palomino, J; Petrement Eguiluz, J C

    1964-07-01

    The determination of uranium with arsenazo is hindered by a great number of cation which form stable complexes with the reactive and may given rise to serious interferences. By studying the optimum conditions of uranium the extraction be means of tributylphosphate solutions dissolved in methylisobuthylketone, under conditions for previous masking of the interfering cations, an organic extract was obtained containing all the uranium together with small amounts of iron. The possible interference derived from the latter element is avoided by reduction with hydroxylammoniumchlorid followed by complex formation of the Fe(II)-ortophenantroline compound in alcoholic medium. (Author) 17 refs.

  18. Suporte articulado para o tratamento cirúrgico da escoliose: nota prévia Soporte articulado para el tratamiento quirúrgico de la escoliosis: nota previa Support for surgical treatment of scoliosis: foreword

    Directory of Open Access Journals (Sweden)

    Francisco Limeira dos Santos Neto

    2009-03-01

    Full Text Available Foi desenvolvido um suporte para ser utilizado nas cirurgias de correção da escoliose que permite a realização de manobras para a correção da deformidade. O objetivo deste relato inicial é a apresentação do conceito do suporte desenvolvido e os resultados iniciais com a sua utilização.Fue desarrollado un soporte para ser utilizado en las cirugías de corrección de la escoliosis. El soporte desarrollado permite la realización de maniobras para la corrección de la deformidad y el objetivo de este relato inicial es la presentación del concepto del soporte desarrollado y los resultados iniciales con su utilización.One support was developed for use in surgery for correction of scoliosis. This support allows the execution of surgery for the correction of the deformity, and the initial purpose of this report is the presentation of the concept support development and the initial results with its use.

  19. Persistencia de las ideas previas sobre potencial eléctrico, intensidad de corriente y ley de Ohm en los estudiantes de segundo curso de Ingeniería

    OpenAIRE

    Periago Oliver, María Cristina; Bohigas Janoher, Xavier

    2005-01-01

    El objetivo del trabajo que se presenta es la evaluación y el análisis de los conocimientos previos sobre los contenidos conceptuales de Teoría de circuitos que tienen los alumnos de segundo curso de Ingeniería Industrial e Ingeniería Química, con la finalidad de detectar la persistencia de estos conocimientos desde niveles educativos anteriores. Concretamente, nos hemos centrado en los conceptos básicos de potencial eléctrico e intensidad de la corriente, así como la relación fundamental ent...

  20. Territorialidad y autonomía, proyectos minero-energéticos y consulta previa: el caso de los pueblos indígenas de la Amazonía ecuatoriana

    Directory of Open Access Journals (Sweden)

    Fernando García Serrano

    2014-07-01

    Full Text Available From the review of two areas of relative state / indigenous peoples, territoriality, mining and energy projects and consultation, is to analyze the progress, setbacks and dissections lived in this relationshipduring the period 1990-2013, to contribute to the discussion of this problem in other countries experiencing similar circumstancesin Latin America. Of particular importance is the case of Ecuador to the constitutions of 1998 and 2008, in which the multiethnic and multicultural nature of the Ecuadorian State acknowledged at the first, and the plurinational and intercultural character in the second. Likewise, the indigenous movement since its emergence as an actor in national politics since 1990, has not only been a pioneer and leader in the region, but has been challenger extractivismo process carried outby the state.

  1. La Investigación Básica. La Investigación en Ciencias Fisiológicas: Bioquímica, Biología Molecular y Fisiología. Cuestiones Previas

    Directory of Open Access Journals (Sweden)

    Constancio González Martínez

    Full Text Available La conferencia impartida los últimos días de enero de 2004 en las Dependencias del Instituto Carlos III (Madrid ante un grupo de colegas latinoamericanos, y que transcribo en el escrito que sigue, ha tenido como objetivo fundamental tratar de conjugar algunas ideas sobre investigación con la realidad socioeconómica de los países de Latinoamérica. En la primera parte de la conferencia he dado un concepto de Investigación y he enfatizado el valor que la consideración de la teleología de los fenómenos biológicos tiene en el avance de las propias ciencias biológicas. A continuación, he pasado revista de forma muy rápida a las Normas del Bien Hacer en le Laboratorio o Good Laboratory Practices, y he presentado unos pocos datos objetivos sobre la realidad económica de los países latinoamericanos. En una segunda parte, he tratado de promover en nuestros colegas latinoamericanos una actitud reivindicativa que les ayude a pedir a sus gobernantes y a defender frente a sus conciudadanos, la necesidad de implementar una política científica clara como una prioridad nacional. Tal reivindicación estaría apoyada en el reconocimiento de que la investigación es una herramienta para aprovechar la capacidad intelectual de los ciudadanos de cada país, de que la investigación es un medio para aprovechar recursos de organismos internacionales, de que la investigación es una fuente de cultura que contribuye a la creación de una identidad nacional y, finalmente, de que la investigación es una actividad generadora de riqueza y bienestar. Concluyo la conferencia señalando que la investigación básica, y por tanto la investigación en Ciencias Fisiológicas, está ensamblada tan estrechamente con la investigación aplicada que constituyen una realidad única.

  2. Efecto de la presión ambiental en la efectividad del lanzamiento al aro y la ansiedad previa a la ejecución en basquetbolistas principiantes y avanzados

    Directory of Open Access Journals (Sweden)

    Guadalupe Delgado Socatelli

    2003-01-01

    Full Text Available Con el objetivo de determinar si las condiciones de presión ambiental dadas por: el tiempo de ejecución, y la ausencia o presencia de público afectaban el rendimiento de 10 jugadores de baloncesto principiantes y 10 jugadores avanzados al ejecutar 10 tiros libres al aro lo cual permitiría conocer los cambios en la ansiedad grupal e individual de los participantes mediante la aplicación de los instrumentos POMS de McNair, Loor y Droppleman (1971 y el CSAI-2 de Martens y Vealey (1990. El análisis estadístico se efectuó mediante la aplicación de un ANOVA de medidas repetidas para buscar diferencias entre los intentos según el tipo de presión. La determinación de las diferencias entre grupos, entre las mediciones, según el nivel de presión ambiental, y la interacción de la presión de los grupos, se hizo mediante la aplicación de un ANOVA Factorial Mixto. Los resultados de la investigación permitieron corroborar la individualidad de las respuestas de la ansiedad ante distintas situaciones y la importancia de la personalización del afrontamiento para el manejo de la ansiedad competitiva

  3. Evaluación higiénica previa de acrilamida en aire durante la preparación de gel de poliacrilamida (PAA en un laboratorio de genética

    Directory of Open Access Journals (Sweden)

    Antonio Blein Sánchez de León

    2007-06-01

    Full Text Available Objetivos: Conocer el nivel aproximado de concentración en aire de Acrilamida, cancerígeno y mutagénico tipo 2, durante la preparación del gel de Poliacrilamida en el Laboratorio, para verificar si la situación higiénica es tolerable, o si no lo es, para tomar medidas preventivas inmediatamente, antes de llevar a cabo una evaluación detallada con arreglo a UNE-EN 689, con un coste notablemente mayor. Metodología: Una vez seleccionadas las etapas de preparación del gel donde hay emisión de Acrilamida, el método higiénico seguido ha sido el PV2004, de NIOSH, para la toma de muestra y el análisis. Resultados: La concentración de Acrilamida detectada en la fase de pesada es de 723% del Valor Limite de Exposición Profesional para exposición diaria y del 145% del Valor Limite de Exposición Profesional para Corta Exposición. En la fase de agitación no se detecto Acrilamida en la muestra. Conclusiones: Es necesario tomar medidas preventivas inmediatamente. Se proponen varias medidas. Una vez aplicadas, se recomienda realizar la evaluación higiénica según UNE-EN 689.Aims: To know the approximate level of Acrylamide, carcinogenic type 2, in air, during the preparation of Polyacrylamide-Gel in the laboratory, in order to determine if the occupational hygiene situation is acceptable or not, in order to, if not, to implement immediately preventive measurements, before carring out an hygienical assessment following the UNE-EN 689 standard, with much higher costs. Methods: After the selection of the gel-preparation stages, where evaporation of Acrylamide takes place, the followed method was PV2004, from NIOSH, for the sample collection and for the analyse. Results: The detected level of Acrylamide in the weighting stage is 723 % of the TLV-TWAand 145% of the TLV-C. In the stirring stage there was found no Acrylamide. Conclusions: It is necessary to implement immediately preventive measurements. Some of them are proposed. Once implemented it is recommended to carry out an hygienical assessment according to UNE-EN 689.

  4. Pocket book {sup E}xpectations of operating personnel action and card criteria, previous meeting and precursor of error; Libro de bolsillo expectativas de actuacion del personal de operacion y tarjeta criterios reunion previa y precursores de error

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigo Gonzalez, M.

    2012-07-01

    We have developed a pocket manual of performance expectations of operating personnel. Additionally, it has created a card pocket systematizing the application of previous meetings (pre-job) depending on the existence of error precursors and following the commission of an error. This manual serves to communicate expectations and performance expected to the Operation Staff. The results show a positive change in a short period of time working practices, both in training (simulator) and control room.

  5. Chemical State of Radiobromine Formed by the Rb{sup 85}(n, {alpha}) Br{sup 82} Reaction; Etat Chimique Du Ra Diobrome Forme Par La Reaction {sup 85}Rb (n, {alpha}) {sup 82}Br; 0425 0418 041c 0418 0427 0415 0421 041a 041e 0415 0421 041e 0421 0422 041e 042f 041d 0418 0415 0420 0410 0414 0418 041e 0410 041a 0422 0418 0412 041d 041e 0413 041e 0411 0420 041e 041c 0410 , 041e 0411 0420 0410 0417 041e 0412 0410 041d 041d 041e 0413 041e 041f 0420 0418 0420 0415 0410 041a 0426 0418 0418 Rb{sup 85}(n, {alpha}) Br{sup 82}; Estado Quimico Del Radiobromo Formado Por La Reaccion {sup 85}Rb (n, {alpha}) {sup 82}Br

    Energy Technology Data Exchange (ETDEWEB)

    Vlatkovic, M.; Kauiic, S. [' ' Ruder Boskovic' ' Institute, Zagreb, Yugoslavia (Croatia)

    1965-04-15

    composes de rubidium examines. (author) [Spanish] En la presente memoria se estudia la distribucion quimica del radiobromo entre los estados de oxidacion superior (BrO{sup -}{sub 3}) e inferiores (Br{sup -}, Br{sub 2}, BrO{sup -}) producidos por la reaccion nuclear Rb{sup 85}(n, {alpha}) Br{sup 82} en cierto numero de solidos inorganicos que contienen rubidio. Los autores irradiaron con neutrones de 14 MeV procedentes de un generador neutronico (T+d) muestras secas de Rb{sub 2}SO{sub 4}, Rb{sub 2}S{sub 2}O{sub 8}, RbMnO{sub 4}, RbNO{sub 3}, Rb{sub 2}CO{sub 3} y RblO{sub 3}. En el caso del Rb{sub 2}SO{sub 4} irradiado a temperatura ambiente o a -195 Degree-Sign C, aproximadamente el 8% de la actividad total del {sup 82}Br aparece en la fraccion bromato y el resto en la fraccion bromuro. La irradiacion del RbMnO{sub 4} y del RbNO{sub 4} a temperatura ambiente produjo alrededor del 1% de actividad en el estado de oxidacion superior del bromo, mientras que en el caso del Rb{sub 2}S{sub 2}O{sub 8}, Rb{sub 2}CO{sub 3} y RbIO{sub 3}, la actividad solo pudo medirse en la fase bromuro. Observaron un ligero aumento de la actividad del bromato cuando el Rb{sub 2}SO{sub 4} irradiado con neutrones se calento a 250 Degree-Sign C. A temperaturas mas elevadas (hasta 500 Degree-Sign C), la actividad paso al estado de oxidacion inferior. El calentamiento del RbMnO{sub 4} y del RbNO{sub 3} irradiados no provoco ninguna oxidacion del radiobromo. Si bien la irradiacion previa del RbNO{sub 4} con dosis gamma de 22 Mrad no afecto la distribucion de los atomos de bromo de retroceso, el analisis del Rb{sub 2}SO{sub 4} previamente expuesto a los rayos gamma (55 Mrad) puso de manifiesto una actividad de bromato superior a la de las muestras que antes de la irradiacion neutronica solo se habian secado a 150 Degree-Sign C. En conclusion, los autores subrayan la importancia de la constitucion quimica del compuesto utilizado, como blanco y de los medios no isotopicos en lo que atane a la distribucion de

  6. Case report

    African Journals Online (AJOL)

    abp

    2015-05-18

    May 18, 2015 ... Abstract. Vasa previa is a rare but clinically important obstetrical complication that can be associated with a low-lying placenta or placenta previa. We aim to present one case of vasa previa diagnosed during the placenta examination after the caesarean indicated for triple uterus scar. A 26-year-old.

  7. El impacto del Flipped Classroom como proceso para la revisión previa de los contenidos y materiales de los cursos o talleres de capacitación del personal administrativo del Instituto Tecnológico y de Estudios Superiores de Monterrey, Campus Guadalajara

    OpenAIRE

    Robledo Martínez, Rosario Sarahí

    2015-01-01

    La presente investigación se llevó a cabo en la ciudad de Guadalajara, Jalisco, México, en las instalaciones del Tecnológico de Monterrey. El estudio se dirigió en su totalidad a los empleados administrativos que laboran en las distintas áreas de la institución, como lo son los profesionistas de apoyo, los auxiliares, las secretarias, los jefes de área, entre otros, con el firme propósito de involucrar la metodología basada...

  8. Multinodular goiter treatment with radioiodine aided by recombinant human TSH in different doses: a randomized, double-blind, placebo-controlled study;Administracao previa do TSH humano recombinante, em diferentes doses, no tratamento do bocio multinodular com iodo radioativo: um estudo randomizado, duplo cego, controlado com placebo

    Energy Technology Data Exchange (ETDEWEB)

    Albino, Claudio Cordeiro

    2009-07-01

    Background: There is not an optimal treatment for multinodular goiter (MNG). Surgery is the main therapeutic option because it decreases thyroid volume, reduces compression symptoms and provide histological diagnosis. Radioiodine ({sup 131}I) is an efficient therapeutic option for the treatment of MNG mainly when surgery is not indicated or when the patient refused it. However, high activities of {sup 131}I are frequently required for clinically significant results. This procedure increases the body radiation exposure and the hospitalization costs. Recombinant human TSH (rh TSH) allows a reduction in the administered activity of {sup 131}I with effective thyroid volume (TV) reduction. However, this combination therapeutic can increase collateral effects. Objective: To evaluate the efficacy and safety of low and intermediate doses of rh TSH compared to placebo, associated with a fixed activity of {sup 131}I in MNG treatment. Patients and Methods: Thirty patients with MNG received 0.1 mg of rh TSH (group I, n=10), 0.01 mg of rh TSH (group II, n=10), or placebo (control group, n=10). After 24 hours, 30 mCi of {sup 131}I was given to all patients. Radioactive iodine uptake (RAIU) was determined before and 24 hours after rh TSH. Before and 2, 7, 180 and 360 days after the TV was measured by magnetic resonance image (MRI). The smallest cross-sectional area of tracheal lumen (Scat) was also measured with MRI before, 2 and 7 days after treatment. Antithyroid antibodies, TSH, T3 and free T4 were assessed regularly. Results: After 6 months, the decrease in TV was more significant in groups I (30.3 +- 16.5%) and II (22.6 +- 14.5%), than in control group (5.0 +- 14.6%; p=0.01). After 12 months, TV decreased more in group I (39.2 +- 16.9%) and group II (38.8 +- 24.4%) than in group III (23.4 +- 23.59%) but it was not statistically significant (p=0.205). During the first 30 days,total T3 and free T4 increased, without reaching thyrotoxic levels and TSH decreased. After 12 months, 8 patients developed hypothyroidism (3 in group I, 3 in group II and 2 in group III). Anti-thyroglobulin antibodies (anti-TG) titers increased after 6 months and returned to basal levels after 12 months similarly in all groups. There was more patients with anti-thyroperoxidase antibodies (anti-TPO) titers increased after 12 months on group I. There was not TV increase after {sup 131}I on the first week ,with or without rh TSH. Conclusion: The previous stimulus with rh TSH using a fixed {sup 131}I activity lead to a greater and more significant goiter reduction after six months of treatment than {sup 131}I alone. After twelve months this tendency was maintained, but without statistic relevance. (author)

  9. Quality of previous diabetes care among patients receiving services at ophthalmology hospitals in Mexico Calidad de la atención previa de los pacientes diabéticos atendidos en hospitales de oftalmología en México

    Directory of Open Access Journals (Sweden)

    Joel Rodríguez-Saldana

    2010-12-01

    Full Text Available OBJECTIVE: To survey a large sample of type 2 diabetes mellitus (T2DM patients in Mexico City to determine if patient experience, access to basic services, treatment, and outcomes differed between those with social security coverage and those without. METHODS: From 2001-2007 a total of 1 000 individuals with T2DM were surveyed in outpatient clinics of the three largest public ophthalmology hospitals in Mexico City. Patients reported information about their health status and receipt of basic diabetes services, such as laboratory glycemic monitoring and diabetes education. Rates were compared between those with (n = 461 and without (n = 539 social security. RESULTS: Almost half of the patients (46% in these public facilities were social security patients that were unable to access other services and had to pay out-of-pocket for care. Half of respondents were originally identified as potentially diabetic based on symptom complaints (51%, including 11% with visual impairment. Most patients (87.9% reported that their glycemic level was being monitored exclusively via fasting blood glucose testing or random capillary blood glucose tests; only 5.3% reported ever having a glycated hemoglobin test. While nearly all respondents reported an individual physician encounter ever, only 39% reported ever receiving nutrition counseling and only 21% reported attending one or more sessions of diabetes education in their lifetime. Processes of care and outcomes were no different in patients with and those without social security coverage. CONCLUSIONS: In Mexico, the quality of diabetes care is poor. Despite receiving social security, many patients still have to pay out-of-pocket to access needed care. Without policy changes that address these barriers to comprehensive diabetes management, scientific achievements in diagnosis and pharmacotherapy will have limited impactOBJETIVO: Determinar si hay diferencias en cuanto a las experiencias de atención de la diabetes, el acceso a los servicios básicos, el tratamiento y la evolución clínica entre las personas que disponen o no de seguro social de salud mediante la encuesta de una muestra amplia de pacientes que padecen diabetes mellitus tipo 2 en la Ciudad de México. MÉTODOS: Se encuestó a 1 000 pacientes con diabetes tipo 2 en la consulta externa de los tres hospitales públicos de oftalmología más importantes de la Ciudad de México. Los pacientes proporcionaron información acerca de su estado de salud y su experiencia respecto de la atención básica de diabetes; por ejemplo, el control de la glucemia mediante análisis de laboratorio y la información que recibieron acerca de la enfermedad. Se compararon los datos estadísticos entre quienes disponían de un seguro social de salud (n = 461 y quienes carecían de este tipo de seguro (n = 539. RESULTADOS: Casi la mitad de los pacientes (46% que se atienden en estos hospitales públicos disponen de seguro social de salud, pero no pudieron acceder a otros servicios y debieron pagar de su bolsillo para recibir atención. La mitad de los entrevistados (51% eran pacientes que habían sido considerados presuntos diabéticos a partir de los síntomas que habían referido, de los cuales 11% presentaron discapacidad visual. La mayoría de los pacientes (87,9% refirieron que solo se controlaban mediante análisis glucemia en ayunas o análisis aleatorios (sin ayunar de una muestra de sangre capilar; solo 5,3% refirieron que alguna vez se habían efectuado el análisis de glucohemoglobina (HbA1c. Si bien prácticamente la totalidad de los encuestados refirieron haber tenido alguna consulta médica, solo 39% informaron haber recibido orientación nutricional en alguna ocasión y solo 21% refirieron haber asistido a una o más sesiones informativas sobre la diabetes. No se registraron diferencias en la atención ni la evolución clínica entre los pacientes que disponen de un seguro social de salud y aquellos que carecen de este tipo de seguro. CONCLUSIONES: En México, es deficiente la calidad de la atención en materia de diabetes. A pesar de contar con un seguro social de salud, muchos pacientes deben pagar de su bolsillo para acceder a la atención que necesitan. De no modificarse las políticas con el fin de abordar los obstáculos que encuentran los pacientes para acceder al tratamiento integral de la diabetes, serán limitadas las repercusiones de los avances científicos que tengan lugar en materia de diagnóstico y farmacoterapia

  10. Información financiera al servicio de la imagen. Estados contables del nuevo banco español de San Fernando y su sucesor el Banco de España, en la etapa previa al privilegio de emisión (1847-1873

    Directory of Open Access Journals (Sweden)

    Rafael Moreno Fernández

    2008-12-01

    cualitativo y diferente del puramente contable o legalista, que es el que se practicaba en la época, y también con posterioridad. En el mundo actual con la normalización contable de los estados financieros, no puede hacerse, en general, este tipo de análisis directo, si bien la imagen exterior que se transmite en la Memorias de cualquier empresa no suele dejarse al azar, puesto que es componente de su reputación.

  11. Influence of the Previous History of the Raw Material on Sintering of UO{sub 2}; Influence des antecedents de la matiere premiere sur le frittage de UO{sub 2}; Vliyanie obrabotki iskhodnogo veshchestva na spekanie UO{sub 2}; Influencia de la historia previa de la materia prima sobre la sinterizacion del UO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Aparicio, E.; Alonso, J. A.; Pedregal, J. D. [Junta de Energia Nuclear Madrid (Spain)

    1963-11-15

    An account is given of the experimental principles underlying the production process of a UO{sub 2} pellet plant. In this process, advance determination of the particle-size distribution characteristics of the raw material is secured not by means of controlled precipitation but by the crushing and grading of powders. The uranium oxides tested in this work are conventional materials, representing types of fabrication which differ by origin and method used. A study of the pellets obtained shows the potentialities and limitations of each type of oxide in the process adopted. A description is given of the characteristics of the powders as regards specific area, particlesize distribution, differential and thermogravimetric thermal analyses, and stoichiometry, and of the density, contraction, structure and stoichiometry of the pellets. (author) [French] Les auteurs decrivent les experiences qui ont servi de base aux operations d'une installation de fabrication de pastilles d'UO{sub 2}. Selon la methode employee, pour fixer a l'avance les caracteristiques granulometriques de la matiere premiere, on ne procede pas a une precipitation controlee, mais a un broyage et a un criblage des poudres. Les uranes qui ont fait l'objet de ce travail sont des produits classiques provenant de fabrications qui different par l'origine et le procede de transformation. De l'etude des pastilles obtenues, on deduit les possibilites et les limites de chaque type d'urane par rapport au procede adopte. On controle les caracteristiques suivantes: pour les poudres, la surface specifique, la granulometrie; les proprietes thermiques differentielles et thermogravimetrique et la stoechiometrie; pour les pastilles, la densite, la contraction, la structure et la stoechiometrie des pastilles. (author) [Spanish] Se exponen los fundamentos experimentales sobre los que se basa el proceso de una planta de fabricacion de pastillas de UO{sub 2} . En este proceso no se emplea la precipitacion controlada como medio de prefijar las caracteristicas granulometricas de la materia prima, sino la molienda y clasificacion de los polvos. Las uranias ensayadas en este trabajo son materiales convencionales representantes de tipos diferentes de fabricacion por el origen y metodo operatorio. Del estudio de las pastillas obtenidas se deducen las posibilidades y limitaciones de cada tipo de urania en el proceso adoptado. Se controlan las caracteristicas de superficie especifica, granulometria, analisis termico diferencial y termogravimetricoy estequiometria de los polvos, asi como la densidad, contraccion, estructura y estequiometria de las pastillas. (author) [Russian] Izlagayutsya ehksperimental'nye dannye, na kotorykh osnovan primenyaemyj odnim zavodom metod izgotovleniya tabletok UO{sub 2}. Soglasno ehtomu metodu granulometricheskaya kharakteristika iskhodnogo veshchestva opredelyaetsya zaranee ne putem upravlyaemogo osazhdeniya, a razmel'cheniem i sortirovkoj poroshka. V dannoj rabote ispol'zovalis' obraztsy obychnoj okisi urana, otlichayushchiesya po sposobu izgotovleniya i po proiskhozhdeniyu. Issledovanie privelo k nekotorym vyvodam otnositel'no vozmozhnostej i ogranichenij metoda v zavisimosti ot tipa ispol'zuemoj okisi urana. Privodyatsya rezul'taty izmereniya udel'noj poverkhnosti, granulometrii, termicheskikh differentsial'nogo i termogravimetricheskogo analizov i stekhiometrii poroshkov, a takzhe po plotnosti usadki, strukture i stekhiometrii tabletok. (author)

  12. La Investigación Básica. La Investigación en Ciencias Fisiológicas: Bioquímica, Biología Molecular y Fisiología. Cuestiones Previas Basic Research. Research in Physiological Sciences: Biochemistry, Biophysics, Molecular Biology and Physiology. Some prior considerations

    Directory of Open Access Journals (Sweden)

    Constancio González Martínez

    2004-03-01

    Full Text Available La conferencia impartida los últimos días de enero de 2004 en las Dependencias del Instituto Carlos III (Madrid ante un grupo de colegas latinoamericanos, y que transcribo en el escrito que sigue, ha tenido como objetivo fundamental tratar de conjugar algunas ideas sobre investigación con la realidad socioeconómica de los países de Latinoamérica. En la primera parte de la conferencia he dado un concepto de Investigación y he enfatizado el valor que la consideración de la teleología de los fenómenos biológicos tiene en el avance de las propias ciencias biológicas. A continuación, he pasado revista de forma muy rápida a las Normas del Bien Hacer en le Laboratorio o Good Laboratory Practices, y he presentado unos pocos datos objetivos sobre la realidad económica de los países latinoamericanos. En una segunda parte, he tratado de promover en nuestros colegas latinoamericanos una actitud reivindicativa que les ayude a pedir a sus gobernantes y a defender frente a sus conciudadanos, la necesidad de implementar una política científica clara como una prioridad nacional. Tal reivindicación estaría apoyada en el reconocimiento de que la investigación es una herramienta para aprovechar la capacidad intelectual de los ciudadanos de cada país, de que la investigación es un medio para aprovechar recursos de organismos internacionales, de que la investigación es una fuente de cultura que contribuye a la creación de una identidad nacional y, finalmente, de que la investigación es una actividad generadora de riqueza y bienestar. Concluyo la conferencia señalando que la investigación básica, y por tanto la investigación en Ciencias Fisiológicas, está ensamblada tan estrechamente con la investigación aplicada que constituyen una realidad única.This article is a transcription of a conference addressed to a group of colleagues from Latin America at the end of January 2004, in the Instituto Carlos III (Madrid. Its main purpose was to conjugate some general ideas on scientific research with known facts on the socioeconomic reality of Latin American countries. In the initial part of the talk I put forward a definition of research, emphasizing the great value of considering the teleology of biological phenomena for the advance of biological sciences. A succinct consideration of the importance of Good Laboratory Practices, especially if there is not a tradition of research, drove my talk to the presentation of some basic data on the socioeconomic situation of the Latin American countries. In the second half of the conference my efforts were directed to incite our Latin American colleagues to demand from their politicians, and to justify in front of their fellow citizens, the necessity of implementing a program on scientific research as a national priority. Such demand should be justified on the basis of the recognition that research represents a way to correctly use the intellectual capital of the citizens of every country and a mean to profit from free international resources, that research is a source of culture, contributing to the national identity of any given country, and finally, on the fact that research is an activity that generates wealth. I concluded my talk pointing out that basic research, and therefore research in physiological sciences, is assembled so tight with basic research that they conform a unique reality.

  13. Application of the new requirements of safety of the IAEA for the previous management to the final disposal of radioactive waste in the region: a personal vision; Aplicacion de los nuevos requisitos de seguridad del OIEA para la gestion previa a la disposicion final de desechos radiactivos en la region: una vision personal

    Energy Technology Data Exchange (ETDEWEB)

    Sed, Luis Andres Jova, E-mail: jovaluis@gmail.com [Centro Nacional de Seguridad Nuclear (CNSN), La Habana (Cuba)

    2013-07-01

    The work includes the requirements for the responsibilities associated with the management prior to the final disposal of radioactive waste and as they are referred to in the Region. Also discusses the requirements for the main stages of the management prior to the final disposal of radioactive waste. A very important section of the new requirements is that establish requirements for safe operation of facilities management prior to the final disposal of radioactive wastes and the implementation of activities under conditions of safety and development. The work is emphatic on the importance of safety justification since the beginning of the development of a facility as a basis for the decision-making and approval process. Emphasis is also on the gradual approach which should provide for the collection, analysis and interpretation of the relevant technical data, plans for the design and operation, and the formulation of the justification of the security. This paper gives a personal view of the situation in the Region.

  14. The effect of oxidation time on the parameters of ITO/Si solar cell prepared by spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Kandil, S. A; Afifi, H. H; El-hefnawi, S. H; Eliwa, A.Y [Electronic Research Institute, Dokki, Cairo (Egypt)

    2000-07-01

    The indium tin oxide (ITO/N-Si) solar cells have been fabricated by spray pyrolysis technique. The silicon wafers are heated at 500 Celsius degrees with different oxidation time (2-20 min). The best values obtained for ITO/Si solar cell output parameters; open circuit voltage V{sub o}c, short circuit current density J{sub s}c, fill factor FF and efficiency {eta} are 0.48 V, 15 mA/cm{sup 2}, 0.7 and 10.1% respectively. The preceding results were obtained under conditions of 5 minutes oxidation time and the surface area equal to 8 mm{sup 2} when the light intensity is 50 MW/ cm{sup 2}. The values of V{sub o}c, J{sub s}c, FF and {eta} are affected strongly by the varying the oxidation time. This paper is devoted to explain the effect of the interfacial layer SiO{sub 2} thickness on the ITO/Si solar cell parameters as deduced from the I-V and C-V measurements. [Spanish] Mediante tecnicas de pirolisis de dispersion se han fabricado celdas solares de oxido de Indio estanado ITO/N-Si. Las obleas de silicon se calientan a 500 con diferentes tiempos de oxidacion (2-20 min.) Los mejores valores obtenidos para los parametros de produccion de las celdas solares ITO-Si de voltaje en circuito abierto V{sub o}c densidad de corriente de corto circuito J{sub s}c factor de llenado FF y eficiencia {eta} son de 0.48 V, 15 mA/cm{sup 2}, 0.7% y 10.1% respectivamente los resultados precedentes se obtuvieron bajo condiciones de 5 minutos de tiempo de oxidacion y la superficie del area=8 mm{sup 2} cuando la intensidad de la luz es de 50mW/Cm{sup 2}. Los valores de V{sub o}c, J{sub s}c, FF y {eta} se afectan fuertemente por la variacion del tiempo de oxidacion. Este articulo esta dedicado a explicar el efecto del espesor de la capa interfacial de SiO{sub 2} en los parametros de la celda solar ITO-Si como se deduce de las mediciones I-V y C-V.

  15. Medline Plus

    Full Text Available ... head is too large to fit through the birth canal If labor is prolonged and the mother's ... placenta previa, where the placenta is blocking the birth canal If there are signs of fetal distress ...

  16. Placenta: How It Works, What's Normal

    Science.gov (United States)

    ... placental problems include placental abruption, placenta previa and placenta accreta. These conditions can cause potentially heavy vaginal bleeding. ... health care provider will recommend a C-section. Placenta accreta. This condition occurs when the blood vessels and ...

  17. Role of MRI versus ultras

    Directory of Open Access Journals (Sweden)

    Lamiaa Bassam Hashem

    2016-06-01

    Conclusion: Magnetic resonance imaging is complementary to Ultrasound and it is important for the accurate diagnosis of placental abnormalities especially placenta previa and the seriously co-existing placenta accreta.

  18. Useful life extension of steam turbine rotors; Alargamiento de la vida en rotores de turbina de vapor

    Energy Technology Data Exchange (ETDEWEB)

    Garcia Arelle, Carlos [Turbomaquinas S. A. de C.V., La Piedad, Michoacan (Mexico)

    2007-11-15

    The continuous use of steam turbines, the chemistry of the steam itself and the variations of operation velocities, cause the gradual deterioration by erosion, oxidation and/or corrosion of the rotors and blades. When this happens most of the original manufacturers recommend to rectify the areas, diminishing the surfaces, or to compare with a new rotor. TURBOMAQUINARIAS S.A. de C.V. has developed the most reliable and safe methods to return the rotor to its original dimensions and in case of recurrent problems such as erosion, oxidation and/or wear, it offers the alternative of attaching coatings metallurgically compatible with which these problems are eliminated or diminished that might show up on the rotor surface as well as in the body of the discs or of the blades. These restoring methods are recommended by the international standards such as API 687. [Spanish] El uso continuo de las turbinas de vapor, la quimica del mismo vapor y la variacion de las velocidades de operacion, ocasionan el deterioro gradual por erosion, oxidacion y/o corrosion de los rotores y de los alabes. Al ocurrir esto la mayoria de los fabricantes originales recomiendan rectificar las areas, disminuyendo las superficies, o bien comparar un rotor nuevo. TURBOMAQUINARIAS S.A. de C.V. ha desarrollado los metodos mas confiables y seguros para devolver a su rotor las dimensiones originales y en caso de problemas recurrentes tales como erosion, oxidacion y/o desgaste, ofrece la alternativa de agregar recubrimientos metalurgicamente compatibles con los cuales se eliminan o se disminuyen estos problemas que pueden presentarse tanto en la superficie del rotor como del cuerpo de los discos o bien de los alabes. Estos metodos de restauracion son recomendados por las normas internacionales tales como la API 687.

  19. Risk factors for blood transfusion in patients undergoing high-order Cesarean delivery.

    Science.gov (United States)

    Spiegelman, Jessica; Mourad, Mirella; Melka, Stephanie; Gupta, Simi; Lam-Rachlin, Jennifer; Rebarber, Andrei; Saltzman, Daniel H; Fox, Nathan S

    2017-11-01

    The objective was to identify risk factors associated with blood transfusion in patients undergoing high-order Cesarean delivery (CD). This was a retrospective cohort study of patients undergoing third or more CD by a single maternal-fetal medicine practice between 2005 and 2016. We compared risk factors between women who did and did not receive a red blood cell transfusion during the operation or before discharge. Repeat analysis was performed after excluding women with placenta previa. A total of 514 patients were included, 18 of whom (3.5%; 95% confidence interval [CI], 2.2%-5.5%) received a blood transfusion. Placenta previa was the most significant risk factor for transfusion (61.1% of patients who received a transfusion vs. 1% of patients who did not; p blood transfusion. After women who had placenta previa were excluded, the incidence of blood transfusion was seven of 498 (1.4%; 95% CI, 0.7%-2.9%). Risk factors significantly associated with blood transfusion in the absence of previa were prophylactic anticoagulation during pregnancy and having labored. The incidence of transfusion in patients with no placenta previa, no anticoagulation, and no labor was 0.7% (95% CI, 0.3%-2.1%). Placenta previa was the most predictive risk factor for transfusion with a positive predictive value of 68.8% and a negative predictive value of 98.4%. In patients undergoing a third or more CD, only placenta previa, prophylactic anticoagulation during pregnancy, and having labored are independently associated with requiring a blood transfusion. These data can be used to guide physician ordering of prepared blood products preoperatively. © 2017 AABB.

  20. Fabrication and corrosion behavior of fresh porous silicon in sodium hydroxide solution

    International Nuclear Information System (INIS)

    Lai, Chuan; Li, Xueming; Zhang, Daixiong; Xiang, Zhen; Yang, Wenjing; Guo, Xiaogang

    2014-01-01

    The corrosion behavior of fresh porous silicon (f-PS) in sodium hydroxide (NaOH) solution in the presence and absence of ethanol was studied by weight loss measurements and scanning electron microscope (SEM) technique. The phenomena and progress of f-PS corrosion in 1.0 M NaOH at 318 K was obtained and described. Weight loss measurements show that the corrosion rate increases with increasing temperature and concentration of NaOH solution. Meanwhile, the corrosion rate first increases with increasing volume ratio of ethanol in 1.0 M NaOH, and then decreases. Additionally, the thermodynamic and kinetic parameters (E a , A, ΔH a and ΔS a ) for f-PS corrosion were obtained and discussed. And the effect factors (T, c and v) of f-PS corrosion in NaOH solution were studied in this paper. - Highlights: • The corrosion behavior of f-PS in NaOH solution was studied for the first time. • Phenomena and progress of f-PS corrosion in NaOH solution was obtained and described. • The effect factors (T, c and v) of f-PS corrosion in NaOH solution were studied. • The kinetic and thermodynamic parameters were obtained and discussed. • The corrosion rate can be improved by adding ethanol into NaOH solution

  1. Novel Extraction Process Of Rare Earth Elements From NdFeB Powders Via Alkaline Treatment

    Directory of Open Access Journals (Sweden)

    Chung K.W.

    2015-06-01

    Full Text Available The alkaline treatment of NdFeB powders in NaOH solution at various equivalent amounts of NaOH at 100°C was performed. The resultant powders were then leached in 0.5M H2SO4 solution at 25°C for 2 minutes. At 5 equivalents of NaOH, neodymium in NdFeB powders was partially transformed to neodymium hydroxide. The transformation of neodymium to neodymium hydroxide actually occurred at 10 equivalents of NaOH and was facilitated by increasing the equivalent of NaOH from 10 to 30. In addition, iron was partially transformed to magnetite during the alkaline treatment, which was also promoted at a higher equivalent of NaOH. The leaching yield of neodymium from alkaline-treated powders was increased with an increasing equivalent of NaOH up to 10; however, it slightly decreased with the equivalent NaOH of over 10. The leaching yield of iron was inversely proportional to that of rare earth elements. NdFeB powders treated at 10 equivalents of NaOH showed a maximum leaching yield of neodymium and dysprosium of 91.6% and 94.6%, respectively, and the lowest leaching yield of iron of 24.2%, resulting in the highest selective leaching efficiency of 69.4%.

  2. Effect of heat and alkaline hydrolysis on the amino acid profile of ...

    African Journals Online (AJOL)

    5 M NaOH treated seed cake, respectively with the 2 M NaOH treated seed cake having the highest yield. The amino acid profile of the treated seed cake was similar and comparable to the values of WHO/FAO standard and those of soybeans. The seed can thus be used as an alternative protein source in animal feed ...

  3. Effects of Chemical Peeling and Cultivars on the Antinutritional and ...

    African Journals Online (AJOL)

    2205, TMS30572) roots were peeled using three different methods: manual peeling, chemical peeling with either 10% NaOH followed by treatment with 3% citric acid, or 10% NaOH solution followed by treatment with 15% NaCl. Peeled roots ...

  4. The influence of Na2O on the hydration of C3A II. Suspension hydration

    NARCIS (Netherlands)

    Spierings, G.A.C.M.; Stein, H.N.

    1976-01-01

    The influence of Na2O on the hydration of C3A was studied in suspensions from the start of the reaction onwards. The heat evolution rate in very early stages of the hydration, measured at varying NaOH concentrations, and SEM, indicate that at NaOH concentrations larger then 0.1 M the reaction

  5. Sugar cane bagasse pretreatment: An attempt to enhance the ...

    African Journals Online (AJOL)

    +1.5%NaOH. The pretreatment of bagasse with 2.0% H2O2 along with 1.5% NaOH enhanced the biosynthesis of cellulases by H. insolens. Production rate was also optimized with different parameters like thickness of fermentation medium, ...

  6. Preparation and properties of biodegradable films from Sterculia urens short fiber/celluose green composites

    CSIR Research Space (South Africa)

    Jayaramudu, J

    2013-04-01

    Full Text Available cellulose matrix composite films. The morphologies of the untreated and 5% NaOH (alkali) treated S. urens fibers were observed by SEM. The effect of 5% NaOH treated S. urens fiber (5, 10, 15 and 20% loading) on the mechanical properties and thermal stability...

  7. A Raman Study of Titanate Nanotubes | Liu | South African Journal ...

    African Journals Online (AJOL)

    The effect of the addition of NaOH or KOH on commercial Degussa Titania P25 was investigated using TEM, Raman and in situ Raman spectroscopy. Treatment of titania with conc. NaOH generated a tubular material corresponding to a sodium titanate. An in situ Raman study on the sodium titanate nanotubes as a function ...

  8. 40 CFR 796.1050 - Absorption in aqueous solution: Ultraviolet/visible spectra.

    Science.gov (United States)

    2010-07-01

    ... applied to measure the absorption spectra. (b) Method—(1)(i) Introduction, purpose, scope, relevance... volume of HCl or NaOH in aqueous solution ([HCl], [NaOH]=1 mol/L). (4) In theory, all chemical species...) Katelaar, J.A.A., Photoelectric Spectrometry Group Bulletin, 8, (Cambridge, 1955). (3) Chemical Rubber...

  9. Pretreatment of sweet sorghum bagasse for hydrogen production by Caldicellulosiruptor saccharolyticus

    NARCIS (Netherlands)

    Panagiotopoulos, I.A.; Bakker, R.R.; Vrije, de G.J.; Koukios, E.G.; Claassen, P.A.M.

    2010-01-01

    Pretreatment of sweet sorghum bagasse, an energy crop residue, with NaOH for the production of fermentable substrates, was investigated. Optimal conditions for the alkaline pretreatment of sweet sorghum bagasse were realized at 10% NaOH (w/w dry matter). A delignification of 46% was then observed,

  10. Características musculares y producción de fuerza máxima/explosiva durante acciones isométricas/dinámicas de los músculos extensores de los miembros inferiores en jóvenes no entrenados

    OpenAIRE

    Izquierdo, M.; Aguado, X.; González, J. L.; López, J. L.; Ribas, T.; Linares, F.; Vila, L.; Voces, J. A.; Álvarez, A. I.; Prieto, J. G.

    1997-01-01

    Participaron en el estudio, de forma voluntaria cinco sujetos de sexo masculino, estudiantes de educación Física (22-26 años). El objetivo fue observar las relaciones entre el test de salto horizontal con los tests de salto vertical con contramovimiento y con flexión previa, tests de fuerza isométrica máxima y la distribución de los tipos de fibras musculares. Los resultados en la distancia y altura de vuelo conseguidas en los tests de salto horizontal, salto desde flexión previa sin cont...

  11. Formación cognoscitiva y rendimiento táctico

    OpenAIRE

    Solà Santesmases, Josep

    1998-01-01

    Este trabajo experimental trata de demostrar que la formación cognoscitiva previa (variable independiente) a la acción táctica deportiva (variable dependiente) es significativamente positiva para el correcto desarrollo de la misma. Esta formación cognoscitiva previa consistirá en la muestra de gráficos y dibujos de los movimientos tácticos a realizar. De esta manera, se ofrece a cada jugador del grupo experimental el conocimiento cognoscitivo que tendrá que guiar sus acciones tácticas en el j...

  12. Synthesis and electrochemical characterization of highly tolerant Pd electrocatalysts as cathodes in direct ethylene glycol fuel cells (DEGFC)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez Varela, F.J.; Fraire Luna, S. [Cinvestav, Unidad Saltillo, Ramos Arizpe, Coahuila (Mexico)] e-mail: javier.varela@cinvestav.edu.mx; Savadogo, O. [Laboratoire d' Electrochimie et de Materiaux Energetiques, Ecole Polytechnique de Montreal, Montreal, QC (Canada)

    2009-09-15

    Highly selective Pd electrocatalysts were synthesized by the formic acid method and evaluated as cathodes for DEGFC applications. In rotating disc measurements in acid medium, the Pd/C cathode showed important catalytic activity for the Oxygen Reduction Reaction (ORR). In the presence of ethylene glycol (EG, C{sub 2}H{sub 6}O{sub 2}), Pd/C exhibited an excellent electrochemical behavior and full tolerance to the organic molecule. No current density peaks associated to the EG oxidation reaction emerged and the shift in onset potential for the ORR (Eonset) toward more negative potentials was negligible on this cathode. Moreover, the evaluation of Pd/C in a DEGFC operating at 80 degrees Celsius demonstrated its high performance as cathode. As a comparison, commercial Pt/C was tested under the same conditions showing a limited selectivity for the ORR. The detrimental effect of EG on the Pt electrocatalysts resulted in high intensity current density peaks due to the oxidation of EG and a significant shift in Eonset. Given these results, it is expected that highly efficient Pd-based cathodes can find application in DEGFCs. [Spanish] Se sintetizaron electrocatalizadores altamente selectivos mediante el metodo de acido formico y se evaluaron como catodos en aplicaciones de CCGED. En mediciones de disco rotatorio en medio acido, el catodo Pd/C mostro importante actividad catalitica en la reaccion de reduccion de oxigeno (RRO). En la presencia de glicol de etileno (GE, C{sub 2}H{sub 6}O{sub 2}), Pd/C exhibio un excelente comportamiento electromecanico y tolerancia total a la molecula organica. No surgieron picos de densidad de corriente asociados con la reaccion de oxidacion de GE y el corrimiento en el potencial de inicio para la RRO (Einicio) hacia potenciales mas negativos fue despreciable en este catodo. Como comparacion, se probo un Pt/C bajo las mismas condiciones y se observo una selectividad limitada para el RRO. El efecto perjudicial de GE en el electrocatalizador

  13. Experimental Investigation and Analysis of Mercerized and Citric Acid Surface Treated Bamboo Fiber Reinforced Composite

    Science.gov (United States)

    De, Jyotiraman; Baxi, R. N., Dr.

    2017-08-01

    Mercerization or NaOH fiber surface treatment is one of the most popular surface treatment processes to make the natural fibers such as bamboo fibers compatible for use as reinforcing material in composites. But NaOH being a chemical is hazardous and polluting to the nature. This paper explores the possibility of use of naturally derived citric acid for bamboo fiber surface treatment and its comparison with NaOH treated Bamboo Fiber Composites. Untreated, 2.5 wt% NaOH treated and 5 wt% citric acid treated Bamboo Fiber Composites with 5 wt% fiber content were developed by Hand Lay process. Bamboo mats made of bamboo slivers were used as reinforcing material. Mechanical and physical characterization was done to compare the effects of NaOH and citric acid bamboo fiber surface treatment on mechanical and physical properties of Bamboo Fiber Composite. The experiment data reveals that the tensile and flexural strength was found to be highest for citric acid and NaOH treated Bamboo Fiber Composite respectively. Water absorption tendency was found more than the NaOH treated Bamboo Fiber Composites. SEM micrographs used to analyze the morphology of fracture surface of tensile test specimens confirm improvement in fiber-matrix interface bonding due to surface treatment of bamboo fibers.

  14. Leaching of the antimony and accompanying of elements Sb2S3 in the alkaline medium

    Directory of Open Access Journals (Sweden)

    Dagmar Remeteiová

    2007-06-01

    Full Text Available This paper presents results of the laboratory investigation of alkaline leaching of stibnite that is an important mineral occuring in the antimony-bearing raw materials. The following components were present in stibnite: Sb2S3, SiO2, ZnS, FeS2. The aim of this study was to establish the effect of composition of the aqueous alkaline leaching medium (1 % NaOH, 1 % NaOH + 1 % Na2S2O3, 1 % NaOH + 1 % Na2S on the recoveries of Sb, Fe, Pb, Zn, Cu, Ni and Hg. The antimony recoveries in the leaching solutions NaOH and NaOH + Na2S2O3 solutions were lower in comparison with the leaching in NaOH + Na2S. The Fe, Pb, Zn recoveries in alkaline solutions were found to decrease in the following order: Fe, Pb, Zn. The mercury recovery in the leaching test with the solution containing 1 % NaOH+1 % Na2S was 3,7 %.

  15. Sulfate resistance of fly ash-based geopolymer mortar

    Science.gov (United States)

    Saloma, Iqbal, Maulid Muhammad; Aqil, Ibnu

    2017-09-01

    This paper presents sulfuric acid attack of fly ash-based geopolymer mortar. Precursor used in this study was fly ash, and activator used was NaOH and Na2SiO3. The ratio of activator/precursor, ratio of Na2SiO3/NaOH, and ratio of fine aggregate/precursor is 0.42, 2.00, and 2.00, respectively. The molar concentration of NaOH which was used were 8, 10, 12, 14, and 16 M. This study used cube specimen with 5 cm x 5 cm x 5 cm. The results showed that the higher the molar concentration of NaOH, the lower the weight loss. Maximum percentage of weight loss is 3.54% occured for the specimen with molar concentration of NaOH 8 M. The compressive strength for all specimens decreased due to the longer duration of immersion in sulfuric acid solution. However, this percentage of decreasing for compressive strength will be as lower as increasing the molar concentration of NaOH used. The maximum percentage of decreasing is 35.49% for specimen with NaOH 8 M with 90 days of immersion.

  16. Enhancement of enzymatic hydrolysis of wheat straw by gamma irradiation–alkaline pretreatment

    International Nuclear Information System (INIS)

    Yin, Yanan; Wang, Jianlong

    2016-01-01

    Pretreatment of wheat straw with gamma irradiation and NaOH was performed to enhance the enzymatic hydrolysis of wheat straw for production of reducing sugar. The results showed that the irradiation of wheat straw at 50 kGy decreased the yield of reducing sugar, however, the reducing sugar yield increased with increasing dose from 50 kGy to 400 kGy. The irradiation of wheat straw at 100 kGy can significantly decrease NaOH consumption and treatment time. The reducing sugar yield could reach 72.67% after irradiation at 100 kGy and 2% NaOH treatment for 1 h. The combined pretreatment of wheat straw by gamma radiation and NaOH immersion can increase the solubilization of hemicellulose and lignin as well as the accessible surface area for enzyme molecules. - Highlights: • Pretreatment of wheat straw by gamma radiation and NaOH was investigated. • Irradiation pretreatment can significantly decrease NaOH consumption. • Reducing sugar yield reached 72.67% at 100 kGy and 2% NaOH treatment for 1 h.

  17. Comparison between solid-state and powder-state alkali pretreatment on saccharification and fermentation for bioethanol production from rice straw.

    Science.gov (United States)

    Yeasmin, Shabina; Kim, Chul-Hwan; Islam, Shah Md Asraful; Lee, Ji-Young

    2016-01-01

    The efficacy of different concentrations of NaOH (0.25%, 0.50%, 0.75%, and 1.00%) for the pretreatment of rice straw in solid and powder state in enzymatic saccharification and fermentation for the production of bioethanol was evaluated. A greater amount of biomass was recovered through solid-state pretreatment (3.74 g) from 5 g of rice straw. The highest increase in the volume of rice straw powder as a result of swelling was observed with 1.00% NaOH pretreatment (48.07%), which was statistically identical to 0.75% NaOH pretreatment (32.31%). The surface of rice straw was disrupted by the 0.75% NaOH and 1.00% NaOH pretreated samples as observed using field-emission scanning electron microscopy (FE-SEM) and atomic force microscopy (AFM). In Fourier-transform infrared (FT-IR) spectra, absorbance of hydroxyl groups at 1,050 cm(-1) due to the OH group of lignin was gradually decreased with the increase of NaOH concentration. The greatest amounts of glucose and ethanol were obtained in 1.00% NaOH solid-state pretreated and powder-state hydrolyzed samples (0.804 g g(-1) and 0.379 g g(-1), respectively), which was statistically similar to the use of 0.75% NaOH (0.763 g g(-1) and 0.358 g g(-1), respectively). Thus, solid-state pretreatment with 0.75% NaOH and powder-state hydrolysis appear to be suitable for fermentation and bioethanol production from rice straw.

  18. PENURUNAN KADAR PROTEIN LIMBAH CAIR TAHU DENGAN PEMANFAATAN KARBON BAGASSE TERAKTIVASI (Protein Reduction of Tofu Wastewater Using Activated Carbon Bagasse

    Directory of Open Access Journals (Sweden)

    Candra Purnawan

    2014-10-01

    Full Text Available ABSTRAK Penurunan kadar protein limbah tahu telah dilakukan dengan pemanfaatan karbon Bagasse teraktivasi. Tujuan dari penelitian ini adalah untuk mengetahui kondisi optimum dari karbon teraktivasi NaOH dan H2SO4 dalam menurunkan kadar protein limbah cair tahu dan mengetahui jenis isoterm adsorpsi dari karbon aktif yang digunakan untuk menyerap protein limbah cair tahu. Hasil penelitian menunjukkan konsentrasi NaOH yang optimum untuk aktivasi karbon aktif 15%, massa optimum karbon bagasse teraktivasi NaOH adalah 2 g dan penurunan kadar proteinnya 71,95%, sedangkan massa optimum karbon bagasse teraktivasi H2SO4 adalah 1 g dengan penurunan kadar protein sebesar 38,19%. Waktu kontak optimum karbon bagasse teraktivasi  NaOH dan H2SO4 adalah 12 jam. Adsorpsi protein oleh karbon bagasse teraktivasi NaOH mengikuti isoterm adsorpsi Langmuir dan Freundlich sedangkan karbon bagasse teraktivasi H2SO4 dominan mengikuti isoterm Freundlich.   ABSTRACT The protein reduction of tofu wastewater using activated carbon from bagasse  had been conducted. The purposes of this research were to analysis optimum condition of activated carbon bagsse using NaOH and H2SO4 for reduction protein in tofu wastewater, and analysis adsorption isotherm of activated carbon with protein. The result showed that optimum mass of carbon bagasse activated NaOH was  2 g with 71.95% protein reduction, while carbon bagasse activated H2SO4 has 1 g with 38.19% protein reduction. The optimum contact time between protein and activated carbon (with NaOH and H2SO4 was happened in 12 hours. Adsorption protein with carbon bagasse activated NaOH had followed Langmuir and Freundlich adsorption isotherm, while adsorption with carbon bagasse activated H2SO4 dominantlyhad followed Freundlich adsorption isotherm

  19. Synergistic effect of alkaline pretreatment and Fe dosing on batch anaerobic digestion of maize straw

    International Nuclear Information System (INIS)

    Khatri, Shailendra; Wu, Shubiao; Kizito, Simon; Zhang, Wanqin; Li, Jiaxi; Dong, Renjie

    2015-01-01

    Highlights: • Synergistic effect of NaOH treatment and Fe dosage to maize straw was investigated. • Combining NaOH treatment and Fe dosing resulted in 57% and 56% higher biogas and methane yield respectively. • Combined treatment shortened the technical digestion time from 48 days to 7 days. • Methane content did not differ significantly among the straw treatments. - Abstract: The synergistic effect of alkaline pretreatment and Fe dosing on anaerobic digestion of maize straw was investigated using mesophilic batch reactors. Three straw treatments were investigated as follows: NaOH (4% and 6%) pretreatment, Fe dosage (50, 200, 1000 and 2000 mg/L), and combined NaOH pretreatment and Fe dosage. Compared to the control, NaOH pretreatment alone increased methane yield by 3.5% (313.3 mL CH_4/gVS) and 22.5% (370.9 mL CH_4/gVS) and shortened the technical digestion time (TDT) from 48 days to 19 days and 10 days in 4% NaOH and 6% NaOH pretreatment respectively. Moreover, Fe dosing (200–1000 mg/L) alone gave a methane yield higher (9.4%) than that obtained from 4% NaOH and 7.5% less than the methane yield from 6% NaOH pretreatment; however, the TDT was 10 days longer. Combining NaOH pretreatment and Fe dosage (200–1000 mg/L) significantly increased the methane yield even further to 21.8% (368.8 mL CH_4/gVS) and 56.2% (472.9 mL CH_4/gVS), and shortened TDT from 48 days to 13 days and 7 days in 4% NaOH and 6% NaOH pretreatment respectively. This synergistic effect may be attributed to the fact that the alkaline treatment improved accessibility of the biodegradable fraction of the straw while Fe contributed to increased microbial enzyme activity.

  20. The discrimination of the oxidation states of neptunium in sodium hydroxide solutions by means of chromatography on alumina

    International Nuclear Information System (INIS)

    Shiokawa, Yoshinobu; Yamana, Hajimu; Sato, Akiko; Suzuki, Shin

    1982-01-01

    A method of discriminating the oxidation states of Np in a NaOH solution by means of chromatography on alumina is proposed. In a NaOH solution of 0.5 - 1.7 M (1 M = 1 mol dm - 3 ), the separation of Np (VI) from Np (VII) can be made effectively by means of chromatography on alumina. Only a little Np (VI) is adsorbed on alumina the Np (VII) adsorbed to some extent, and the Np (V), strongly, under the same conditions. By applying this chromatographic method, the method of preparing Np (VI) and Np (VII) of a tracer quantity in 1 M NaOH is established. (author)

  1. Tooth enamel sample preparation using alkaline treatment in ESR dosimetry

    International Nuclear Information System (INIS)

    Yongzeng, Zhou; Jiadong, Wang; Xiaomei, Jia; Ke, Wu; Jianbo, Cong

    2002-01-01

    Tooth enamel sample preparation using alkaline treatment was studied and compared with traditional mechanical method in this paper. 20 adult teeth were used. Samples were placed into NaOH solution. This method requires 4-5 weeks and the enamel was separated from dentin. Experimental results show that 8M NaOH was appropriate for separating enamel from dentin and that there is no difference in background signal relative intensity between samples prepared by mechanical and by chemical methods. There is also no difference in radiosensitivity between samples prepared by two methods mentioned above. Dose response curve for tooth enamel samples isolated by 8M NaOH solution was obtained

  2. Effect of Gamma Irradiation and Chemical Process on Gas Production Parameters of some Agricultural By-products in in vitro

    Directory of Open Access Journals (Sweden)

    S. Sobhanirad

    2013-03-01

    Full Text Available The aim of this study was investigating the effect of gamma irradiation and NaOH treatment of some agricultural by products (tomato pulp, orange pulp, pistachio hull and wheat straw on fermentation parameters and gas production test. Treatments of gamma irradiation (50, 100 and 200 kGy and %5 NaOH was done on each source of by products. The results showed that gamma irradiation at the dose of 200 kGy numerically and %5 NaOH increased (P

  3. The Association Between Interpersonal Relationships and the Mental and Physical Health of Postpartum Active Duty Military Women

    Science.gov (United States)

    2011-05-25

    diabetes , preeclampsia, placenta previa, placental abruption, and anemia, and these complications may have lasting effects (Adams et al., 1993...8217l’o: Chair, Insti tutional Review Soard 24 SEP 0? Subj : REQUEST TO ADD/ MODI FY RECRUITMENT BROCHURES INMCS0.2007.01C)2 Encl : (1) Recruitment Pos

  4. 77 FR 19155 - Federal Motor Vehicle Safety Standards; Seat Belt Assembly Anchorages; Incorporation by Reference

    Science.gov (United States)

    2012-03-30

    ... LeSabre, MY 2002 Toyota MR-2, MY 1995 Plymouth Neon, MY 1995 Toyota Previa, MY 2000 Chevrolet S-10, MY... FAD2 2005 VW Passat Pass Pass. 2005 Acura RL Pass Pass. 2005 Toyota Avalon Pass Pass. 2005 Buick... levels of government.'' NHTSA rules can preempt in two ways. First, the National Traffic and Motor...

  5. Placenta accreta: MRI antenatal diagnosis and surgical correlation.

    Science.gov (United States)

    Ha, T P; Li, K C

    1998-01-01

    We describe a case of a placenta previa accreta that was diagnosed antenatally by MRI with subsequent surgical confirmation. We show the advantages of ultrafast MRI single shot (SS) fast spin echo (FSE) techniques for accurate diagnosis with minimal scan time and fetal motion artifacts.

  6. Cesarean scar defects and placental abnormalities; a 3 year survey study

    Directory of Open Access Journals (Sweden)

    Denisa O. Bălălău

    2017-10-01

    Full Text Available The placenta is an essential organ for embryonic and fetal development, ensuring nutrient uptake, gas exchange (via the mother's blood supply, waste elimination, thermo-regulation, immunological and hormonal factors, etc. The most common placental abnormalities are represented by placenta previa, and a morbidly adherent placenta (in the form of accreta, increta, and percreta placenta. This study was performed on a sample of 99 patients diagnosed with abnormalities of placentation who underwent cesarian delivery during a period of 3 years in Bucur Maternity Hospital. Seven patients were diagnosed with morbidly adherent placenta (5 accreta and 2 percreta subtypes, the others having placenta previa (65 with lateral disposition, 18 marginal, and 9 central insertion. All patients had been diagnosed by ultrasound (which was also used for general monitoring, being confirmed during operation and histopathologically. Complications required 4 emergency peripartum hysterectomies, with no maternal mortality but with fetal death in one case. The research literature shows that about half of women with placenta previa have several episodes of bleeding, being the leading cause of antepartum hemorrhage. For some women with placenta previa/accrete, hemorrhaging is severe and requires hysterectomy as a necessary step to control the life-threatening situation. Thus, such patients should be carefully monitored to avoid as much as possible the medical, social, and psychological implications of this critical therapeutic procedure.

  7. Montelukast reduces asthma exacerbations in 2- to 5-year-old children with intermittent asthma

    DEFF Research Database (Denmark)

    Bisgaard, Hans; Zielen, Stefen; Garcia-Garcia, María Luz

    2005-01-01

    The PREVIA study was designed to investigate the role of montelukast, a leukotriene receptor antagonist, in the prevention of viral-induced asthma exacerbations in children aged 2 to 5 years with a history of intermittent asthma symptoms. The study was a 12-month multicenter, double-blind, parall...

  8. Protracted People’s War in the Philippines: A Persistent Communist Insurgency

    Science.gov (United States)

    2007-03-01

    regarding both public and private sector corruption within Metro Manila, Metro Cebu and Metro Davao, Cavite- Laguna -Batangas, and Cagayan de Oro...his family such as a Toyota Previa, a Mitsubishi L-300 Van de Luxe, and a 1997 Honda Civic. Additionally, deposits and investments he made in the

  9. Repercusión de los esguinces de tobillo sobre el equilibrio postural

    Directory of Open Access Journals (Sweden)

    Laura Martín-Casado

    2015-09-01

    Full Text Available Objetivo. Analizar las diferencias intrasujeto en el equilibrio postural durante la realización de test de equilibrio estáticos y dinámico – funcionales, entre una extremidad que presentó signo de bostezo articular en el tobillo, fruto de una lesión previa de esguince lateral, frente a una extremidad sin bostezo.

  10. Los refranes en el quijote (Estudio critico de la traducción al esloveno

    Directory of Open Access Journals (Sweden)

    Juan Carlos Oven

    1991-12-01

    Full Text Available Antes de afrontar el tema de los refranes en el Quijote será útil acercarnos a este campo específico de la literatura con algunasconsideraciones previas que nos ayuden a iluminar determinados aspectos de este estudio.

  11. Impact of Cesarean Section Number on Maternal and Obstetric Outcome

    Directory of Open Access Journals (Sweden)

    Deniz Arıkan

    2009-12-01

    CONCLUSION: Among the causes of morbidity clinically most important was the triad of placenta previa, placenta accreta and hysterectomy, was also responsible for the most serious risk to the mother with increasing number of C/S.

  12. Soluble FLT-1 rules placental destiny.

    Science.gov (United States)

    Yamashita, Michiko; Kumasawa, Keiichi; Nakamura, Hitomi; Kimura, Tadashi

    2018-02-19

    Placenta previa is an abnormality in which the placenta covers the internal uterine os, and it can cause serious morbidity and mortality in both mother and fetus due to catastrophic hemorrhage. Some pregnant women recover from placenta previa due to a phenomenon called "migration." However, the mechanism of "migration" of the placenta has not been elucidated. Human placentas were collected from patients with placenta previa and those with no abnormal placentation (control). A microarray analysis was performed to detect the genes up- or down-regulated only in the caudal part in the previa group. Specific mRNA expression was evaluated using real-time quantitative reverse transcription PCR (qRT-PCR). Unilateral uterine artery ablation of 8.5 dpc mice was performed to reproduce the reduction of placental blood supply, and weights of the placentas and fetuses were evaluated in 18.5 dpc. Specific mRNA expression was also evaluated in mice placentas. According to the result of the microarray analysis, we focused on soluble fms-like tyrosine kinase-1 (sFLT-1) and hypoxia-inducible factor-1 (HIF-1) alpha. The sFLT-1 expression level is locally high in the caudal part of the human placenta in patients with placenta previa. In mice experiments, the weights of the placentas and fetuses were significantly smaller in the ablation side than those in the control side, and the sFlt-1 expression level was significantly higher in the ablation side than in the control side. Our study suggests that "migration" of the placenta is derived from placental degeneration at the caudal part of the placenta, and sFlt-1 plays a role in this placental degeneration. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. Maternal plasma levels of cell-free β-HCG mRNA as a prenatal diagnostic indicator of placenta accrete.

    Science.gov (United States)

    Zhou, J; Li, J; Yan, P; Ye, Y H; Peng, W; Wang, S; Wang, X Tong

    2014-09-01

    Several biomarkers, including maternal serum creatinine kinase and α-fetoprotein, have been described as potential tools for the diagnosis of placental abnormalities. This study aimed to determine whether maternal plasma mRNA levels of the β subunit of human chorionic gonadotropin (β-HCG) could predict placenta accreta prenatally. Sixty-eight singleton pregnant women with prior cesarean deliveries (CDs) were classified into three groups: normal placentation (35 women, control group); placenta previa alone (21 women, placenta previa group); and both placenta previa and placenta accreta (12 women, placenta previa/accreta group). Maternal plasma concentrations of cell-free β-HCG mRNA were measured by real-time reverse-transcription polymerase chain reaction and were expressed as multiples of the median (MoM). Cell-free β-HCG mRNA concentrations (MoM, range) were significantly higher in women with placenta accreta (3.65, 2.78-7.19) than in women with placenta previa (0.94, 0.00-2.97) or normal placentation (1.00, 0.00-2.69) (Steel-Dwass test, P accreta group, the concentration of cell-free β-HCG mRNA was significantly higher among women who underwent CDs with hysterectomy (4.41, 3.49-7.19) than among women whose CDs did not result in hysterectomy (3.20, 2.78-3.70) (Mann-Whitney U test, P = 0.012). An increased level of cell-free β-HCG mRNA in the maternal plasma of women with placenta accreta may arise from direct uteroplacental transfer of cell-free placental mRNA molecules. The concentration of cell-free β-HCG mRNA in maternal plasma may be applicable to the prenatal diagnosis of placenta accreta, especially to identify women with placenta accreta likely to require hysterectomy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Design and manufacture of an atmospheric burner of biogas with rural application; Diseno y construccion de un quemador atmosferico de biogas con aplicaciones rurales

    Energy Technology Data Exchange (ETDEWEB)

    Nunez Nunez, Jorge; Suarez Pacheco, Jose; Novelo Navarrete, Jose H; Soto Apolinar, Efrain [Universidad de Quintana Roo, Chetumal, Quintana Roo (Mexico)

    2000-07-01

    In this text it's resumed the methodology that was carried out to make an atmospheric burner of biogas, as the criteria that were taken in account in order to determine the main parameters of it. It introduces a synthesis of the stages of design and manufacture of the device. The utility of this type of burner increase the efficiency of the oxidation of the biogas compared with the use of conventional burners that aren't designed for this purpose. [Spanish] En este trabajo se resume la metodologia que se llevo a cabo para la construccion de un quemador de biogas tipo atmosferico, asi como los criterios que se tomaron para la determinacion de los parametros principales del mismo. Se presenta una sintesis de las etapas de diseno y manufactura del dispositivo. El uso de este tipo de quemadores aumenta la eficiencia de la oxidacion del biogas en comparacion con el uso de quemadores convencionales que no estan disenados para quemar biogas.

  15. Radioinitiation of Chain Branched Reactions and its Sensitization; Amorcage sous rayonnement des reactions par ramification en chaine; sensibilisation du processus; Radiatsionnoe initsiirovanie tsennykh razvetvlennykh reaktsij i ego sensibilizatsiya; Radioiniciacion de reacciones en cadena ramificadas y medios para aumentar su sensibilidad

    Energy Technology Data Exchange (ETDEWEB)

    Barelko, E V; Kartashova, L I; Komarov, P N; Proskurnin, M A [Karpov Physico-Chemical Institute, Moscow, Union of Soviet Socialist Republics (Russian Federation)

    1960-07-15

    fondamentales de la reaction d'oxydation par radiolyse du benzene : accumulation des divers produits de la reaction, action de la temperature, de la pression, de la puissance et de la dose d'irradiation sur le processus d'accumulation des produits de la reaction. Quelques conclusions sont exposees sur le mecanisme de la reaction. Les auteurs decrivent la construction de l'installation qui fonctionne en circuit ferme. (author) [Spanish] Figuran en esta memoria los resultados de los trabajos efectuados por los autores sobre la radioiniciacion de las reacciones de oxidacion de compuestos organicos en cadenas ramificadas. Se demuestra el papel que desempenan las radiaciones como agente de iniciacion, tomando como ejemplo la oxidacion del butanol y de varios hidrocarburos no saturados. La reaccion tiene caracter autoacelerador y prosigue espontaneamente al cesar la irradiacion. Se ha estudiado detalladamente el proceso de oxidacion del benceno, compuesto que se caracteriza por una elevada resistencia a las radiaciones. Los autores han ideado un metodo para sensibilizar la radioiniciacion de la oxidacion de compuestos radioresistentes por sustancias quimicamente inertes, pero inestables frente a las radiaciones. En la memoria se examinan los principales factores de que depende la radiooxidacion del benceno, a saber, concentracion de los distintos productos de reaccion e influencia de la temperatura, de la presion, de la energia y de la dosis de radiacion en el proceso de acumulacion de esos productos. Los autores formulan tambien algunas conclusiones sobre el mecanismo del proceso y describen la construccion de la instalacion de circulacion. (author) [Russian] V doklade predstavleny rezul'taty issledovanij avtorov po radiatsionnomu initsiirovaniyu tsepnykh razvetvlennykh reaktsij okisleniya organicheskikh soedinenij. Na primere okisleniya nekotorykh nenasyshchennykh uglevodorodov i butanola pokazana rol' izlucheniya kak initsiiruyushchego agenta. Reaktsiya imeet

  16. Determination of the bulk modulus of hydroxycancrinite, a possible zeolitic precursor in geopolymers, by high-pressure synchrotron X-ray diffraction

    KAUST Repository

    Oh, Jae Eun; Clark, Simon M.; Monteiro, Paulo J.M.

    2011-01-01

    Crystalline zeolitic materials, such as hydroxycancrinite, hydroxysodalite, herschelite and nepheline, are often synthesized from geopolymerization using fly-ash and solutions of NaOH at high temperatures. Comprised mainly of 6-membered

  17. Preparation and Evaluation of Alcohol-Alkaline-Treated Rice Starch ...

    African Journals Online (AJOL)

    ) as a disintegrant for tablets. Methods: The preparation of MRS was carried out using 3 M NaOH and 40 % ethanol solution. Characterization carried out for MRS include morphology, swelling capacity, thermal and pasting properties.

  18. Design and Development of a Continuous-Flow Countercurrent Metal Extraction System to Remove Heavy Metals from Contaminated Soils

    National Research Council Canada - National Science Library

    Neale, Christopher M. U

    1997-01-01

    .... The research focused on eight contaminated soils from Army installations and the metal extraction capabilities of eight extracting agents including HNO3, HCI, fluorosilicic acid, citric acid, EDTA, DTPA, NTA, and NaOH...

  19. Facile synthesis of improved room temperature gas sensing properties of TiO2 nanostructures: Effect of acid treatment

    CSIR Research Space (South Africa)

    Tshabalala, Zamaswazi P

    2016-03-01

    Full Text Available TiO2 nanoparticles were synthesized via a simple hydrothermal method in a sodium hydroxide (NaOH) aqueous solution and washed with distilled water and different concentrations of hydrochloric acid which acted as the morphological...

  20. Study on the Thermal Properties of Some Inorganically Modified Pre- Baked Clay Samples

    International Nuclear Information System (INIS)

    Ahmad, I.; Shakirullah, M.; Ishaq, M.

    2013-01-01

    The paper is focused on the influence of some inorganic modifiers on the thermal stability of the clay-inorganic intercalates. The inorganic modifiers used were NaOH and KOH. Solvent intercalation procedure was used. Clay was modified at 150, 500 and 750 degree C, separately with NaOH and KOH. TGDTA study was performed to evaluate the thermal stability of the resultant intercalates. Intercalation with NaOH and KOH performed at 150 degree C showed significant mass loss. Intercalation with NaOH performed at 500 and 750 degree C, separately showed less mass loss compared to the ones prepared at 150 degree C and hence exhibited thermal stability. In case of intercalation performed with KOH at 500 and 750 degree C separately, the mass loss was comparable to the original pre-baked clay. (author)

  1. Natural fabric of Hildegardia populifolia composites

    CSIR Research Space (South Africa)

    Guduri, BBR

    2006-12-01

    Full Text Available The influence of Hildegardia populofolia fabric content, fabric orientation, sodium hydroxide (NaOH) and silane coupling agent treatment on the surface properties of the fabric, mechanical and fracture properties of Hildegardia populifolia...

  2. Production of water-soluble sago waste - HAMPAS

    International Nuclear Information System (INIS)

    Norhazlin Zainuddin; Kamaruddin Hashim; Kamaruddin Bahari; Mansor Ahmad; Wan Md Zin Wan Yunus

    2002-01-01

    Carboxylmethyl sago waste (CMSW) was prepared in completely heterogeneous conditions as a product of the reaction of sago waste and sodium monochloroacetate (MCA) in mixed solution of isopropanol and sodium hydroxide (NaOH). The results showed that the DS values depend on the concentration of NaOH, ratio of MCA to anhydroglucose unit (AGU), (MCA:AGU), and also time and temperature of the reaction. DS value increased with increasing the concentration of NaOH and reaction temperature, but further increase will reduce the value of DS. Increasing the reaction time will increase the DS value and achieve a constant value after 2 hours. The study showed that the highest value of DS i.e. 1.04, could be achieved at 2:1 of MCA:AGU ratio, NaOh concentration of 25% and 2 hours reaction time at 55 degree C. (Author)

  3. Assessment of effect of chemical treatment to carnauba's fibers straw

    International Nuclear Information System (INIS)

    Carvalho, T.M.P. de; Carvalho, L.F.M.; Oliveira, R.R. de; Sousa, F.M.S. de; Sousa, R.C. de; Marques, J.R.

    2016-01-01

    The use of natural fibers in composite materials has been highlighted in the scientific field. However, its application in polymer matrices usually requires surface modifications. The objective of this work was to treat carnauba's straw fibers with NaOH 1 % and NaOH 5% solutions and measure the water absorption. We used the X-ray diffraction (XRD configuration “Bragg- Brentano) for verification of the crystalline phases and Fourier Transform Infrared Spectroscopy (FTIR) to identify functional groups. The alkali treatment allowed the solubilization of the hemicellulose and lignin without causing changes to cellulose, as indicated by FTIR spectrophotometry and by the increase in crystallinity content. The samples showed the typical peaks of constituents of the fiber. The natural fiber showed an average water absorption of 256 %; fiber treated with NaOH 1%, 315 %; and treated with NaOH 5%, 405 %. Therefore, it is evident improvement in hydrophilicity, fundamental aspect in the interaction fiber / matrix. (author)

  4. An in situ Fourier transform infrared spectroelectrochemical study on ethanol electrooxidation on Pd in alkaline solution

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Xiang; Wang, Lianqin; Shen, Pei Kang [The State Key Laboratory of Optoelectronic Materials and Technologies, School of Physics and Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Cui, Guofeng [School of Chemistry and Chemical Engineering, Sun Yat-Sen University, Guangzhou 510275 (China); Bianchini, Claudio [Istituto di Chimica dei Composti Organometallici (ICCOM-CNR), via Madonna del Piano 10, 50019 Sesto Fiorentino (Italy)

    2010-03-01

    The mechanism of ethanol electrooxidation on a palladium electrode in alkaline solution (from 0.01 to 5 M NaOH) has been investigated by cyclic voltammetry and in situ Fourier transform infrared spectroelectrochemistry. The electrode performance has been found to depend on the pH of the fuel solution. The best performance was observed in 1 M NaOH solution (pH = 14), while the electrochemical activity decreased by either increasing or decreasing the NaOH concentration. In situ FTIR spectroscopic measurements showed the main oxidation product to be sodium acetate at NaOH concentrations higher than 0.5 M. The C-C bond cleavage of ethanol, put in evidence by the formation of CO{sub 2}, occurred at pH values {<=}13. In these conditions, however, the catalytic activity for ethanol oxidation was quite low. No CO formation was detected along the oxidation of ethanol by FTIR spectroscopy. (author)

  5. Chemical characterization of exopolysaccharides from the marine fouling diatom Amphore coffeaeformis

    Digital Repository Service at National Institute of Oceanography (India)

    Bhosle, N.B.; Sawant, S.S.; Garg, A.; Wagh, A.B.; Evans, L.V.

    NaOH or 1.5 M NaCl treatment removed most exopolysaccharides. Glucose (81%) was the most abundant monosaccharide in the exopolysaccharides. The chemical composition data suggest that the exopolymers were acidic sulphate polysaccharides containing high...

  6. Hyperfine interactions and structures of ferrous hydroxide and green rust II in sulfated aqueous media

    International Nuclear Information System (INIS)

    Olowe, A.A.; Genin, J.M.R.; Bauer, P.

    1988-01-01

    A sulfated ferrous hydroxide is obtained by mixing NaOH with melanterite depending on the R = [SO 4 -- ]/[OH - ] ratio and leading by oxidation to the green rust II transient compound. Hyperfine parameters are presented. (orig.)

  7. Adsorption of Free Fatty Acid (FFA) in Low-Grade Cooking Oil Used Activated Natural Zeolite as Adsorbent

    Science.gov (United States)

    Larasati Tres Ayu Putranti, Monika; Kompiang Wirawan, Sang; Made Bendiyasa, I.

    2018-01-01

    Adsorption of free fatty acid (FFA) in low-grade cooking oil using active natural zeolite adsorbent was done as an effort to improve the quality of low-grade cooking oil so that it can fulfill the standard of fried oil which has been set on SNI 01-3741-2013. Adsorption was carried out with natural zeolite which activated with HCl and NaOH solution followed by the calcination process. The results showed that the NaOH activated zeolite decreased FFA content in low-grade cooking oil more than the HCl activated natural zeolite, with optimum NaOH concentration was 0.75 M. In the adsorption equilibrium analysis with temperature variation (25 °C, 40 °C, 80 °C ), obtained that adsorption of FFA with NaOH activated natural zeolite follows Adsorption Isotherm Freundlich Model with equilibrium constant value was 20,5873; 0,9629 dan 0,8053.

  8. Effect of strong electrolytes on edible oils part II: vViscosity of maize ...

    African Journals Online (AJOL)

    DR. MIKE HORSFALL

    dioxane in the presence of HCl, NaOH and NaCl at different temperatures. 1A. RASHEED KHAN; 2SHAMA, REHANA SAEED; 2*FAHIM UDDIN. 1Department of Chemistry, Federal Urdu University of Arts, Science & Technology,. Karachi Pakistan.

  9. Improving anaerobic digestion of sugarcane straw for methane production: Combined benefits of mechanical and sodium hydroxide pretreatment for process designing

    International Nuclear Information System (INIS)

    Janke, Leandro; Weinrich, Sören; Leite, Athaydes F.; Terzariol, Filippi K.; Nikolausz, Marcell; Nelles, Michael; Stinner, Walter

    2017-01-01

    Highlights: • NaOH pretreatment was tested to improve degradation of SCS for methane production. • Low NaOH concentration accelerated AD of SCS but not increased the methane yield. • Mild and high NaOH concentrations accelerated and increased methane yield of SCS. • NaOH use increased OPEX but provided a higher profitability than the untreated SCS. • Anaerobic reactor price showed a high influence on sensitivity analysis. - Abstract: Sodium hydroxide (NaOH) as an alkaline pretreatment method to enhance the degradation kinetics of sugarcane straw (SCS) for methane production was investigated with a special focus on the benefits for designing the anaerobic digestion process. For that, SCS was previously homogenized by milling in 2 mm particle size and pretreated in NaOH solutions at various concentrations (0, 3, 6 and 12 g NaOH/100 g SCS) and the methane yields were determined in biochemical methane potential (BMP) tests. The obtained experimental data were used to simulate a large-scale semi-continuous process (100 ton SCS day"−"1) according to a first-order reaction model and the main economic indicators were calculated based on cash flows of each pretreatment condition. The BMP tests showed that by increasing the NaOH concentration the conversion of the fibrous fraction of the substrate to methane was not only accelerated (higher α value), but also increased by 11.9% (from 260 to 291 mL CH_4 gVS"−"1). By using the experimental data to simulate the large-scale process these benefits were translated to a reduction of up to 58% in the size of the anaerobic reactor (and consequently in electricity consumption for stirring), while the methane yield increased up to 28%, if the liquid fraction derived from the pretreatment process is also used for methane production. Although the use of NaOH for substrate pretreatment has considerably increased the operational expenditures (from 0.97 up to 1.97 € × 10"6 year"−"1), the pretreatment method was able to

  10. Effect of Alkali Concentration on Fly Ash Geopolymers

    Science.gov (United States)

    Fatimah Azzahran Abdullah, Siti; Yun-Ming, Liew; Bakri, Mohd Mustafa Al; Cheng-Yong, Heah; Zulkifly, Khairunnisa; Hussin, Kamarudin

    2018-03-01

    This paper presents the effect of NaOH concentration on fly ash geopolymers with compressive up to 56 MPa at 12M. The physical and mechanical on fly ash geopolymer are investigated. Test results show that the compressive strength result complied with bulk density result whereby the higher the bulk density, the higher the strength. Thus, the lower water absorption and porosity due to the increasing of NaOH concentration.

  11. Ball Milling Treatment of Black Dross for Selective Dissolution of Alumina in Sodium Hydroxide Leaching

    OpenAIRE

    Thi Thuy Nhi Nguyen; Man Seung Lee; Thi Hong Nguyen

    2018-01-01

    A process consisting of ball milling followed by NaOH leaching was developed to selectively dissolve alumina from black dross. From the ball milling treatment, it was found that milling speed greatly affected the leaching behavior of silica and the oxides of Ca, Fe, Mg, and Ti present in dross. The leaching behavior of the mechanically activated dross was investigated by varying NaOH concentration, leaching temperature and time, and pulp density. In most of the leaching conditions, only alumi...

  12. Fiber degradability of sugar cane bagasse treated by alkaline solutions, through the “in situ” nylon bag technique

    Directory of Open Access Journals (Sweden)

    Sérgio Carlo Franco Morgulis

    1996-09-01

    treated bagasse (A was higher than in B or C treatments; degradability of B was higher than in C at 72h and 96h of incubation time. NDF degradability at 48 hour incubation time showed the following results: A = 74.0%; B = 41.6% and C = 35.7%. In conclusion, alkaline (NaOH and wood ash treated sugar cane bagasse improves ruminal degradability, and NaOH is better than wood ash.

  13. Electrophoretic comparison of nuclear and nucleolar proteins II. Rat pancreas

    NARCIS (Netherlands)

    Poort, C.

    1961-01-01

    The nuclei and nucleoli from rat pancreas were isolated and extracted successively with 0.14 M NaCl, 1 M NaCl, and 0.1 N NaOH. In the 0.14 M NaCl and 0.1 N NaOH extracts agar electrophoresis revealed differences between the nucleolar proteins and those from the non-nucleolar part of the nucleus.

  14. Electrophoretic comparison of nuclear and nucleolar proteins : I. Beef Pancreas

    NARCIS (Netherlands)

    Poort, C.

    1961-01-01

    Nuclei and nucleoli, isolated from beef pancreas, are extracted with 0.14 M NaCl, 1 M NaCl and 0.1 N NaOH in the order given. The 0.14 M NaCl and 0.1 N NaOH extracts lend themselves to paper and agar electrophoresis and the electropherograms obtained from these extracts of nuclei and nucleoli are

  15. Synthesis and up-conversion luminescence of Yb –Ho co-doped Na ...

    Indian Academy of Sciences (India)

    chemicals like NaF, NaOH, ethanol and oleic acid were of analytical grade. The samples used in this work were pre- pared by facile hydrothermal method, which can be reffered to in Wang and Li (2007) and Zhang et al (2007) with some subtle modifications. First, accurately weighed 0·35 g. (8·75 mmol) of NaOH, 8 ml oleic ...

  16. Green Synthesis of Silver Nanoparticles and the Study of Optical Properties

    OpenAIRE

    Vasireddy, Ramakrishna; Paul, Rima; Mitra, Apurba Krishna

    2012-01-01

    The synthesis of silver nanoparticles of varying size has been achieved using different molar concentrations of NaOH while the effect of changing the temperature has been studied. AgNO3, gelatine, glucose and NaOH are used as a silver precursor, stabilizer, reducing agent and accelerator respectively. The synthesized nanoparticles have been characterized by a FESEM study, X‐ray diffractometry, Raman spectroscopy and UV‐vis spectroscopy. The colloidal sols of the silver nanoparticles in a biop...

  17. Pengaruh Proses Delignifikasi Pada Produksi Glukosa Dari Tongkol Jagung Dengan Hidrolisis Asam Encer

    OpenAIRE

    Mardina, Primata; Talalangi, Adelina I; Sitinjak, Jhon F. M; Nugroho, Andri; Fahrizal, M. Reza

    2013-01-01

    Hidrolisis asam encer dari tongkol jagung untuk produksi glukosa mengalami hambatan karena adanya lignin. Penelitian ini bertujuan mengetahui pengaruh dari proses Perusakan lignin dengan proses menggunakan hidrolisis basa Hidrolisis basa yang biasa disebut delignifikasi dilakukan pada suhu 55oC selama 4 jam dengan konsentrasi larutan basa, yaitu NaOH 5%, 10% dan 15% berat Hasil menunjukkan bahwa konsentrasi NaOH yang optimal untuk pengurangan lignin adalah 15% berat dengan persentase penguran...

  18. Surface effects of corrosive media on hardness, friction, and wear of materials

    Science.gov (United States)

    Miyoshi, K.; Buckley, D. H.; Ishigaki, H.; Rengstorff, G. W. P.

    1985-01-01

    Hardness, friction, and wear experiments were conducted with magnesium oxide exposed to various corrosive media and also with elemental iron and nickel exposed to water and NaOH. Chlorides such as MgCl2 and sodium containing films were formed on cleaved magnesium oxide surfaces. The MgCl2 films softened the magnesium oxide surfaces and caused high friction and great deformation. Hardness was strongly influenced by the pH value of the HCl-containing solution. The lower the pH, the lower the microhardness. Neither the pH value of nor the immersion time in NaOH containing, NaCl containing, and HNO3 containing solutions influenced the microhardness of magnesium oxide. NaOH formed a protective and low friction film on iron surfaces. The coefficient of friction and the wear for iron were low at concentrations of NaOH higher than 0.01 N. An increase in NaOH concentration resulted in a decrease in the concentration of ferric oxide on the iron surface. It took less NaOH to form a protective, low friction film on nickel than on iron.

  19. A Fundamental study of remedial technology development to prevent stress corrosion cracking of steam generator tubing

    Energy Technology Data Exchange (ETDEWEB)

    Park, In Gyu; Lee, Chang Soon [Sunmoon University, Asan (Korea)

    1998-04-01

    Most of the PWR Steam generators with tubes in Alloy 600 alloy are affected by Stress Corrosion Cracking, such as PWSCC(Primary Water Stress Corrosion Cracking) and ODSCC(Outside Diameter Stress Corrosion Cracking). This study was undertaken to establish the background for remedial technology development to prevent SCC. in the report are included the following topics: (1) General: (i) water chemistry related factors, (ii) Pourbaix(Potential-pH) Diagram, (iii) polarization plot, (iv) corrosion mode of Alloy 600, 690, and 800, (v) IGA/SCC growth rate, (vi) material suspetibility of IGA/SCC, (vii) carbon solubility of Alloy 600 (2) Microstructures of Alloy 600 MA, Alloy 600 TT, Alloy 600 SEN Alloy 690 TT(Optical, SEM, and TEM) (3) Influencing factors for PWSCC initiation rate of Alloy 600: (i) microstructure, (ii) water chemistry(B, Li), (iii) temperature, (iv) plastic deformation, (v) stress relief annealing (4) Influencing factors for PWSCC growth rate of Alloy 600: (i) water chemistry(B, Li), (ii) Scott Model, (iii) intergranular carbide, (iv) temperature, (v) hold time (5) Laboratory conditions for ODSCC initiation rate: 1% NaOH, 316 deg C; 1% NaOH, 343 deg C; 50% NaOH, 288 deg C; 10% NaOH, 302 deg C; 10% NaOH, 316 deg C; 50% NaOH, 343 deg C (6) Sludge effects for ODSCC initiation rate: CuO, Cr{sub 2}O{sub 3}, Fe{sub 3}O{sub 4} (7) Influencing factors for PWSCC growth rate of Alloy 600: (i) Caustic concentration effect, (ii) carbonate addition effect (8) Sulfate corrosion: (i) sulfate ratio and pH effect, (ii) wastage rate of Alloy 600 and Alloy 690 (9) Crevice corrosion: (i) experimental setup for crevice corrosion, (ii) organic effect, (iii) (Na{sub 2}SO{sub 4} + NaOH) effect (10) Remedial measures for SCC: (i) Inhibitors, (ii) ZnO effect. (author). 30 refs., 174 figs., 51 tabs.

  20. Comparison of methods for glycogen analysis of in vitro fermentation pellets produced with strained ruminal inoculum.

    Science.gov (United States)

    Hall, Mary Beth; Hatfield, Ronald D

    2015-11-01

    Microbial glycogen measurement is used to account for fates of carbohydrate substrates. It is commonly applied to washed cells or pure cultures which can be accurately subsampled, allowing the use of smaller sample sizes. However, the nonhomogeneous fermentation pellets produced with strained rumen inoculum cannot be accurately subsampled, requiring analysis of the entire pellet. In this study, two microbial glycogen methods were compared for analysis of such fermentation pellets: boiling samples for 3h in 30% KOH (KOH) or for 15min in 0.2M NaOH (NaOH), followed by enzymatic hydrolysis with α-amylase and amyloglucosidase, and detection of released glucose. Total α-glucan was calculated as glucose×0.9. KOH and NaOH did not differ in the α-glucan detected in fermentation pellets (29.9 and 29.6mg, respectively; P=0.61). Recovery of different control α-glucans was also tested using KOH, NaOH, and a method employing 45min of bead beating (BB). For purified beef liver glycogen (water-soluble) recovery, BB (95.0%)>KOH (91.4%)>NaOH (87.4%; PBB (93.8%)>KOH (91.0%; Pglycogen (water-insoluble granules) did not differ among KOH (87.0%), NaOH (87.6%), and BB (86.0%; P=0.81), but recoveries for all were below 90%. Differences among substrates in the need for gelatinization and susceptibility to destruction by alkali likely affected the results. In conclusion, KOH and NaOH glycogen methods provided comparable determinations of fermentation pellet α-glucan. The tests on purified α-glucans indicated that assessment of recovery in glycogen methods can differ by the control α-glucan selected. Published by Elsevier B.V.

  1. Valoración Médica de Psitácidas y Primates Neotropicales

    OpenAIRE

    Nestor Varela

    2008-01-01

    La evaluación clínica comienza desde el proceso de recepción, ya que permite hacer una apreciación sobre la urgencia del problema, si es que la hay. Aunque no es común en la práctica con especies silvestres, la comunicación telefónica previa al arribo del animal al consultorio, es útil para recolectar información y para dar recomendaciones sobre el transporte del espécimen. En muchos casos la recolección previa de datos importantes no sólo es útil para realizar un examen adecuado, sino tambié...

  2. El regreso a la escuela: evidencias para México

    Directory of Open Access Journals (Sweden)

    Guadalupe Fabiola Pérez Baleón

    2014-01-01

    Full Text Available El regreso a la escuela es una transición que forma parte de las trayectorias escolares de una parte de la población mexicana. Puede ser un punto de inflexión en la vida de las personas y una estrategia de avance socioeconómico. Los factores positivamente asociados con este retorno son: ser joven, tener una escolaridad previa de secundaria o más, no estar casado, haber vivido en zonas urbanas, tener experiencia migratoria previa, tener padres profesionistas o que se dediquen a actividades no manuales y pertenecer a cohortes jóvenes. Hay algunas diferencias en las tendencias del retorno por género que se pueden explicar por la influencia de los roles tradicionales.

  3. Effect of maternal age on maternal and neonatal outcomes after assisted reproductive technology

    DEFF Research Database (Denmark)

    Wennberg, Anna Lena; Opdahl, Signe; Bergh, Christina

    2016-01-01

    weeks), low birth weight (LBW; mortality (≥28 weeks). Adjusted odds ratios (AORs) were calculated. Associations between maternal age and outcomes were analyzed. RESULT(S): The risk of placenta previa (AOR 4.11-6.05), cesarean delivery (AOR 1......OBJECTIVE: To compare the effect of maternal age on assisted reproductive technology (ART) and spontaneous conception (SC) pregnancies regarding maternal and neonatal complications. DESIGN: Nordic retrospective population-based cohort study. Data from national ART registries were cross.......18-1.50), PTB (AOR 1.23-2.19), and LBW (AOR 1.44-2.35) was significantly higher in ART than in SC pregnancies for most maternal ages. In both ART and SC pregnancies, the risk of HDP, placenta previa, cesarean delivery, PTB, LBW, and SGA changed significantly with age. The AORs for adverse neonatal outcomes...

  4. Effects of Interviewee's Job Experience and Gender on Ratings and Reliability in a Behavioral Interview

    Directory of Open Access Journals (Sweden)

    Beata Choragwicka

    2009-01-01

    Full Text Available En este artículo se analiza si el uso de la entrevista de descripción de conducta (EDC puede implicar discriminación indirecta. Doce entrevistados, 6 con previa experiencia laboral y 6 sin experiencia, la mitad de ellos hombres y la mitad mujeres, fueron evaluados mediante una EDC. Se han calculado las puntuaciones medias de los entrevistados, al igual que la fiabilidad interjueces de la entrevista, utilizando un panel de 12 y de 6 evaluadores. No se han encontrado diferencias significativas entre los entrevistados con y sin experiencia laboral previa, al igual que entre hombres y mujeres. Se debaten las implicaciones de estos resultados para el uso de la EDC en los procesos de selección de personal.

  5. Efecto del montelukast sobre la concentración de mediadores inflamatorios en el modelo de artritis gotosa múrida

    OpenAIRE

    Ponce, Loida; Bermúdez, Mariangélica; Miranda, Jorgelin; Verzura, Julie; Tovar, Robert; Corado, José

    2016-01-01

    El tratamiento de la artritis gotosa controla parcialmente la enfermedad con efectos secundarios importantes. El montelukast es un antagonista selectivo de los receptores de leucotrienos LTD4, útil en el tratamiento de rinitis alérgica y asma bronquial. Investigaciones previas han reportado un potente efecto antiinflamatorio de montelukast en el modelo de artritis gotosa múrida. Este estudio investigó el efecto de montelukast sobre la concentración de leucotrienos cisteinil y LTB4, interleuci...

  6. Procesos de ozonación fotocatalítica para eliminar contaminantes emergentes de aguas residuales urbanas

    OpenAIRE

    Espejo Morán, María Azahara

    2016-01-01

    En este trabajo se ha estudiado la degradación de distintos contaminantes emergentes (CEs) añadidos a un agua residual urbana mediante procesos químicos integrados secuencialmente como etapa previa o etapa terciaria a un tratamiento biológico aerobio convencional por fangos activos. Los compuestos seleccionados son acetaminofeno, antipirina, bisfenol A, cafeína, carbamazepina, diclofenaco, hidroclorotiazida, ketorolaco, metoprolol, sulfametoxazol y testosterona. Estos CEs se eligieron ya que ...

  7. Real increasing incidence of hysterectomy for placenta accreta following previous caesarean section.

    LENUS (Irish Health Repository)

    Higgins, Mary F

    2013-11-01

    Placenta accreta, morbid adherence to the uterus to the myometrium, is commonest in association with placenta previa in women previously delivered by caesarean section (CS). It has become proportionally a greater cause of major maternal morbidity and mortality as the frequency of other serious obstetric complications has declined. The aim of this study was to examine the incidence of placenta accreta in the context of a rising caesarean delivery rate.

  8. Obstetric management after infertility treatment

    African Journals Online (AJOL)

    Les mesures de résultat obstétriques analysés comprennent : les complications antenatal et des enfants, le nombre de bébés livrées et le mode de livraison. Les données a été entrées dans la base .... became pregnant after assisted reproduction.[9,10]. Intrapartum complications like placenta previa and placental abruption ...

  9. El discurso en la mirada: los Españoles y la visión del Tawantinsuyo

    Directory of Open Access Journals (Sweden)

    Martha Barriga Tello

    2011-05-01

    Full Text Available El estudio ofrece las diversas lecturas de los monumentos del Imperio Inca realizadas por los primeros españoles. Sus apreciaciones varían de acuerdo a su experiencia previa, sus conocimientos y aquello con que les era posible compararlos. La primera impresión quedará como eje para las opiniones que posteriormente ofrecerán en sus escritos.

  10. Una propuesta para la implementación de un Taller de Desarrollo de Proyectos en una carrera de Ingeniería en Informática bajo el Modelo por Competencias

    Directory of Open Access Journals (Sweden)

    López, Gustavo

    2010-01-01

    Full Text Available El presente trabajo propone una innovación curricular en cuanto al dictado de un Taller de Desarrollo de Proyectos, enfocado desde la perspectiva del Modelo por Competencias. Por tratarse el Taller de una asignatura de carácter integrador respecto de las asignaturas previas, se hace necesario definir Competencias que resulten también integradoras. Este es el desafío que enfrenta la presente propuesta.

  11. Predicción del riesgo individual de alto coste sanitario para la identificación de pacientes crónicos complejos

    Directory of Open Access Journals (Sweden)

    Jordi Coderch

    2014-07-01

    Conclusiones: El consumo sanitario elevado se relaciona con la morbilidad crónica compleja. Un modelo basado en la edad, la morbilidad y la utilización previa es válido para predecir el riesgo de alto consumo, y así identificar la población diana de estrategias de atención proactiva para pacientes crónicos complejos.

  12. Derecho a la consulta y participación de los pueblos indígenas, la experiencia constitucional en los casos de México y Chile

    OpenAIRE

    Rea Granados, Sergio Alejandro

    2015-01-01

    En este artículo se analiza la importancia y los retos de la constitucionalización de los derechos a la consulta previa y la participación de los pueblos indígenas en los casos de México y Chile. This article analyses the importance and challenges of rights to previous consultation and participation of indigenous peoples in the Constitution of Mexico and Chile.

  13. Research

    African Journals Online (AJOL)

    abp

    18 août 2013 ... Apoyo nutricional perioperatorio en pacientes con neoplasia colorrectal. Nutr Hosp. 2010; 25(5):. 797-805. PubMed| Google Scholar. 13. Cid Conde L, Fernández López T, Neira Blanco P, Arias Delgado. J et al. Prevalencia de desnutrición en pacientes con neoplasia digestiva previa cirugía. Nutr Hosp.

  14. OUTCOME OF PREGNANCIES COMPLICATED BY THREATENED ABORTION IN THE SECOND TRIMESTER OF PREGNANCY - PROSPECTIVE STUDY

    OpenAIRE

    Rajeswary

    2015-01-01

    AIM: To compare the outcome of pregnancies complicated by bleeding per vaginum between 14- 20 weeks with those not complicated by bleeding per vaginum before 20 weeks. To evaluate the potential determinants of outcome such as gestational age at bleeding, number of bleeding episodes, extent of placental separation or sub chorionic bleed, incidence of complications as placenta previa, abruptio placenta, development of gestational hypertension and pre eclampsia, intra uterine gro...

  15. The SMILE Program: Does Timing and Dosing of Nurse Home Visits Matter in Reducing Adverse Birth Outcomes for African American Women

    Science.gov (United States)

    2013-03-13

    aspiration, prenatal drug exposure, anemia , sickle cell trait, or identification of any other adverse health condition to include premature birth...p=.840), preeclampsia (LBW: χ 2 = .034, df= 1, p=.967; Premature: χ 2 =.087, df= 1, p=.920), placenta previa (LBW: χ 2 = .173, df= 1, p=.845...interdisciplinary approaches to research and practice (1st ed.). San Francisco, CA: Jossey-Bass. HOME VISITATION & BIRTH OUTCOMES 29 Fry-Johnson, Y . W

  16. Registros adicionales del carrao (Aramus guarauna en el estado de Jalisco, México

    Directory of Open Access Journals (Sweden)

    Carlos Palomera-García

    2015-06-01

    Full Text Available Se reportan registros adicionales del carrao (Aramus guarauna para el interior del Estado de Jalisco, México. Esta información, en conjunto con la previa conocida, apoya la idea que dice que la distribución de la especie podría está relacionada con la del caracol (Pomacea flagellata, Gastropoda: Ampullaridae que le sirve de alimento.

  17. Validación de los modelos de predicción de Framingham y PROCAM como estimadores del riesgo cardiovascular en una población colombiana

    Directory of Open Access Journals (Sweden)

    Oscar M. Muñoz

    2014-07-01

    Conclusiones: La función de riesgo de Framingham debería usarse con precaución en población colombiana de riesgo bajo e intermedio sin historia previa de eventos cardiovasculares dado que sobrestima el riesgo y tiene baja capacidad de discriminación. La función de riesgo de PROCAM ajustada por sexo es una mejor opción para estimar el riesgo de enfermedad cardiovascular dura.

  18. Escuela de la Espalda. Factores Predictivos.

    OpenAIRE

    Ibáñez Campos, Teresa

    2017-01-01

    Una gran parte de los padecimientos dolorosos de la columna lumbar tiene su origen, en un envejecimiento prematuro de sus discos y segmentos asociados. Este proceso se acelera en los países industrializados, debido a una serie de factores negativos que conlleva la vida moderna: esfuerzos grandes o pequeños repetitivos sin preparación previa, abuso de las posturas erectas o sedentarias, obesidad, escaso uso de la movilidad vertebral, flexión incorrecta y, otros fa...

  19. EN BUSCA DE LA PALABRA EXACTA. OBSERVACIÓN DEL PROCESO TRASLATIVO

    OpenAIRE

    Schäpers, Andrea

    2008-01-01

    El objeto del presente estudio observacional es describir las estrategias aplicadas por un grupo de estudiantes españoles para resolver problemas léxicos que se plantean cuando han de traducir un texto desde su lengua materna al alemán. Se trata de un estudio cualitativo motivado por la investigación previa sobre métodos introspectivos y retrospectivos empleados para describir los procesos cognitivos inherentes a la traducción ...

  20. Endocarditis por Streptococcus bovis: ¿sólo una endocarditis?

    OpenAIRE

    Angelini, Julieta María; Díaz Perera, Rodrigo; Garay, María Eugenia; Martínez, Camilo; Occhiuzzi, Silvina; Rodríguez Russo, Paula; Sarlo, Ana Julia

    2012-01-01

    Paciente varón de 74 años de edad, con antecedentes de cáncer de vejiga en plan de tratamiento quimioterápico, que ingresa al servicio de guardia por presentar fiebre de 38,5º astenia, adinamia e hiporexia asociado a disnea clase funcional II. Refiere al ingreso haber realizado la última sesión de quimioterapia una semana previa a la consulta.

  1. Contribución al estudio de los reacciones de hidratación del cemento portland por espectroscopia infrarroja II. Estudio de clínkeres y de cementos portland anhidros

    Directory of Open Access Journals (Sweden)

    Vázquez-Moreno, Tomás

    1976-06-01

    Full Text Available Not availableEn un artículo anterior (1 se dio cuenta de los trabajos realizados sobre la aplicación de la espectroscopia IR al estudio de las principales fases sintetizadas del clínker de cemento portland como fase previa al estudio de diversos clínkeres, obtenidos por nosotros en el laboratorio a partir de crudos industriales, y de distintos cementos portland comerciales anhidros.

  2. Elephant grass treated with alkali Capim-elefante tratado com compostos alcalinos

    Directory of Open Access Journals (Sweden)

    Gleidson Giordano Pinto de Carvalho

    2009-09-01

    Full Text Available The objective was determine dry matter (DM, crude protein (CD, neutral detergent fiber (NDF, acid detergent (ADF, cellulose, hemicellulose, lignin, ash and digestibility of elephant grass, in advanced maturation stage, submitted to the application of alkali compounds with calcium oxide (CaO, sodium hydroxide (NaOH and CaO+NaOH, in two periods of treatment. The experiment was conducted according to a project of subdivided parcels that had been constituted by the controlled treatments, 3% of CaO, 3% of NaOH and 1.5% of CaO + 1.5% of NaOH, and subparcels for the two periods of treatment (24 and 48 hours. The treatment did not have any effect and nor neither for period of DM (35,8% nor of CD (2,7%. The contents of NDF, ADF and cellulose were lesser in the treatments with the addition of CaO, NaOH and CaO+NaOH, mainly to the treatment period of 48 hours. The lignin content was not affected by the applied treatments 10.2%. The application of 3% of CaO, 3% of NaOH and 1.5% of NaOH + 1.5% of CaO increases the digestibility of elephant grass, and the most significant effect occurs when using NaOH.Objetivou-se estimar os teores de matéria seca (MS, proteína bruta (PB, fibra em detergente neutro (FDN, fibra em detergente ácido (FDA, celulose, hemicelulose, lignina, cinza e digestibilidade do capim-elefante em estádio de maturação avançado, submetido à aplicação com óxido de cálcio (CaO, hidróxido de sódio (NaOH e CaO+NaOH, em dois períodos de tratamento. O experimento foi conduzido segundo um esquema de parcelas subdivididas em quatro tratamentos e quatro repetições, em que as parcelas foram constituídas da seguinte forma: sem aditivo, 3% de CaO, 3% de NaOH, e 1,5% de CaO + 1,5% de NaOH, com base na matéria natural. Já as subparcelas foram determinadas pelos períodos de tratamento (24 e 48 horas. Não houve diferença para teor de MS (35,8% e de PB (2,7%. Já os teores de FDN, FDA e celulose foram menores nos tratamentos com adi

  3. Singleton pregnancy outcomes after assisted and non-assisted reproductive technology in infertile patients.

    Science.gov (United States)

    Tsutsumi, Ryo; Fujimoto, Akihisa; Osuga, Yutaka; Ooi, Nagisa; Takemura, Yuri; Koizumi, Minako; Yano, Tetsu; Taketani, Yuji

    2012-07-01

    Singleton pregnancy after assisted reproductive technology (ART) has been associated with higher risks of adverse pregnancy outcome than naturally conceived singleton pregnancy. This study was to elucidate whether the ART procedure is responsible for abnormal pregnancy outcome comparing those after ART and non-ART in infertile patients. We compare the singleton pregnancy outcome of infertile patients in our university hospital between 2000 and 2008 following ART (351 pregnancies) and non-ART (213 pregnancies) procedures. Pregnancy outcome parameters were incidence of pregnancy induced hypertension, placenta previa, placental abruption, cesarean delivery, preterm birth, very preterm birth, stillbirth, low birth weight and very low birth weight. Most of the pregnancy outcome parameters were not significantly different between the ART group and the non-ART group. Only placenta previa was significantly higher in the ART group than in the non-ART group (odds ratio 4.0; 95 % CI 1.2-13.7). ART procedure may itself be a risk factor for the development of placenta previa. Some of the abnormal perinatal outcomes that had been previously attributed to ART, however, may be due to the baseline characteristics of infertile patients.

  4. Relationship between first trimester aneuploidy screening test serum analytes and placenta accreta.

    Science.gov (United States)

    Büke, Barış; Akkaya, Hatice; Demir, Sibel; Sağol, Sermet; Şimşek, Deniz; Başol, Güneş; Barutçuoğlu, Burcu

    2018-01-01

    The aim of this study is to determine whether there is a relationship between first trimester serum pregnancy-associated plasma protein A (PAPP-A) and free beta human chorionic gonadotropin (fβhCG) MoM values and placenta accreta in women who had placenta previa. A total of 88 patients with placenta previa who had first trimester aneuploidy screening test results were enrolled in the study. Nineteen of these patients were also diagnosed with placenta accreta. As probable markers of excessive placental invasion, serum PAPP-A and fβhCG MoM values were compared in two groups with and without placenta accreta. Patients with placenta accreta had higher statistically significant serum PAPP-A (1.20 versus 0.865, respectively, p = 0.045) and fβhCG MoM (1.42 versus 0.93, respectively, p = 0.042) values than patients without accreta. Higher first trimester serum PAPP-A and fβhCG MoM values seem to be associated with placenta accreta in women with placenta previa. Further studies are needed to use these promising additional tools for early detection of placenta accreta.

  5. Thermo-alkaline pretreatment of waste activated sludge at low-temperatures: effects on sludge disintegration, methane production, and methanogen community structure.

    Science.gov (United States)

    Kim, Jaai; Yu, Youngseob; Lee, Changsoo

    2013-09-01

    Low-temperature thermo-alkaline pretreatment of waste activated sludge (WAS) was studied, within the region of 0-0.2 M NaOH and 60-90°C, for the effects of NaOH concentration and temperature on sludge degradability in anaerobic digestion (AD). Significant disintegration of sludge solids (up to 75.6%) and an increase in methane production (up to 70.6%) were observed in the pretreatment trials. Two quadratic models were successfully generated by response surface analysis (R(2)>0.9, pdisintegration (SD) and methane production (MP) respond to changes in the pretreatment conditions. The maximum responses of SD (77.8%) and MP (73.9% increase over the control) were shown at [0.16 M NaOH, 90°C] and [0.10 M NaOH, 73.7°C], respectively. NaOH addition showed a significant influence on the evolution of methanogen community structure during AD, whereas temperature did not. Aceticlastic Methanosaeta and Methanosarcina speceies were likely the major methanogens. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Effect of Solids-To-Liquids, Na2SiO3-To-NaOH and Curing Temperature on the Palm Oil Boiler Ash (Si + Ca) Geopolymerisation System

    Science.gov (United States)

    Yahya, Zarina; Abdullah, Mohd Mustafa Al Bakri; Hussin, Kamarudin; Ismail, Khairul Nizar; Abd Razak, Rafiza; Sandu, Andrei Victor

    2015-01-01

    This paper investigates the effect of the solids-to-liquids (S/L) and Na2SiO3/NaOH ratios on the production of palm oil boiler ash (POBA) based geopolymer. Sodium silicate and sodium hydroxide (NaOH) solution were used as alkaline activator with a NaOH concentration of 14 M. The geopolymer samples were prepared with different S/L ratios (0.5, 1.0, 1.25, 1.5, and 1.75) and Na2SiO3/NaOH ratios (0.5, 1.0, 1.5, 2.0, 2.5, and 3.0). The main evaluation techniques in this study were compressive strength, X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), and Scanning Electron Microscope (SEM). The results showed that the maximum compressive strength (11.9 MPa) was obtained at a S/L ratio and Na2SiO3/NaOH ratio of 1.5 and 2.5 at seven days of testing.

  7. Investigation of the passive behaviour of AZ31B alloy in alkaline solutions

    Directory of Open Access Journals (Sweden)

    A. Fattah-alhosseini

    2014-06-01

    Full Text Available In this work, the passivity of AZ31B alloy in NaOH solutions was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS and Mott–Schottky analysis. Potentiodynamic polarization results indicated that decreasing NaOH concentration leads to decrease the corrosion rate of this alloy. EIS results showed that the reciprocal capacitance (1/C of the passive film is directly proportional to its thickness which increases with decreasing NaOH concentration. Therefore, it is clear that dilute NaOH solutions offer better conditions for forming the passive films with higher protection behaviour, due to the growth of a much thicker and less defective films. The Mott–Schottky analysis revealed that the passive films displayed n-type semiconductive characteristics, where the oxygen vacancies and interstitials (over the cation vacancies preponderated. Also, Mott–Schottky results showed that the donor densities evaluated from Mott–Schottky plots are in the range of 1020 cm−3 and decreased with decreasing NaOH concentration.

  8. Characterization of untreated and treated male and female date palm leaves

    International Nuclear Information System (INIS)

    AlMaadeed, M.A.; Kahraman, Ramazan; Noorunnisa Khanam, P.; Al-Maadeed, Somaya

    2013-01-01

    Highlights: ► Sheshi female and male date palm leaves were treated with NaOH concentrations. ► Male leaves have lower mechanical properties and improved when treated by NaOH 2%. ► Female leaves have higher thermal stability. ► There are different properties for different types of date leaves. ► Leaves can be used as reinforcements for thermoplastic materials. -- Abstract: This paper describes the characterization of male and female date palm leaves from two different cultivars, Sheshi female and unknown male leaves. Characterization was done for both untreated and NaOH treated date palm leaves by infrared spectroscopy, thermogravimetric analysis and scanning electron microscopic techniques. To our knowledge, the difference in specious reaction to the treatment type of date palm fiber has not been investigated earlier. These leaves were treated with different concentrations of NaOH, 0.5%, 1%, 2% and 5% (w/w). The results from this investigation indicate that female leaves have better tensile properties which deteriorate with the increase of the alkali. The male leaves have lower tensile properties than female leaves and their mechanical properties are improved slightly by NaOH treatment. Female leaves have more pores than male leaves, this was proved and calculated by image analysis. Untreated female leaves have higher thermal stability (353 °C) than male leaves (343 °C). Both can be used as reinforcements in thermoplastic matrix materials whose processing temperatures are below 300 °C.

  9. Radiation pre-treating straw hydrolyzed by cellulase resulted from immobilized Trichoderma reesei growing cells

    International Nuclear Information System (INIS)

    Lu Zhaoxin; Minoru Kumakura

    1992-01-01

    Wheat and rice straw was irradiated by electron beam with different dose at the presence of 4% NaOH or without 4% NaOH. The powder fraction above 200 meshes in pretreated rice straw increased with increasing doses and it was more at presence of 4% NaOH than that without 4% NaOH. The pretreated straw was hydrolyzed with 1% cellulase at 40 degree C for 48 h. The glucose yield (%) was given a rise with the increase of irradiation dose and it was 70% and 80% over that of un-pretreated rice and wheat straw, respectively. At the presence of 4% NaOH, the glucose yield increased as the irradiation dose increased from 0 to 5 x 10 5 Gy, reaching a maximum, 35% for wheat straw and 36.6% for rice straw, which increased by about 2.5 times in comparison with un-pretreated straw, then decrease with increasing the irradiation dose to 10 x 10 5 Gy. The glucose yield reached 19% and 22% for rice and wheat straw in 6 days of hydrolysis, respectively

  10. Alkali-assisted membrane cleaning for fouling control of anaerobic ceramic membrane bioreactor.

    Science.gov (United States)

    Mei, Xiaojie; Quek, Pei Jun; Wang, Zhiwei; Ng, How Yong

    2017-09-01

    In this study, a chemically enhanced backflush (CEB) cleaning method using NaOH solution was proposed for fouling mitigation in anaerobic membrane bioreactors (AnMBRs). Ex-situ cleaning tests revealed that NaOH dosages ranging from 0.05 to 1.30mmol/L had positive impacts on anaerobic biomass, while higher dosages (>1.30mmol/L) showed inhibition and/or toxic impacts. In-situ cleaning tests showed that anaerobic biomass could tolerate much higher NaOH concentrations due to the alkali consumption by anaerobic process and/or the buffering role of mixed liquor. More importantly, 10-20mmol-NaOH/L could significantly reduce membrane fouling rates (4-5.5 times over the AnMBR with deionized water backflush) and slightly improve methanogenic activities. COD removal efficiencies were over 87% and peaked at 20mmol-NaOH/L. However, extremely high NaOH concentration had adverse effects on filtration and treatment performance. Economic analysis indicated that 12mmol/L of NaOH was the cost-efficient and optimal fouling-control dosage for the CEB cleaning. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Pemanfaatan trimming kulit pikel sebagai flokulan melalui hidrolisis kolagen menggunakan basa untuk penjernihan air

    Directory of Open Access Journals (Sweden)

    Sugihartono

    2015-07-01

    Full Text Available Wastes in the form of skin derivatives from leather tanning industries remain serious problems if not managed properly and quickly, since they can cause environmental pollution. This research aimed at studying the influence of base type and concentration for the hydrolysis of trimmed collagen from pickled sheepskin to the yield and properties of gelatin, as well as the gelatin’s potential as flocculant. The hydrolysis of trimmed collagen from pickled sheepskin was performed using KOH or NaOH solution, each with varied concentrations of 1, 2, 3, and 4% w/v, for 16 hours. The extraction of the resulting gelatin was performed using water (2.5 water part : 1 waste part, at 70-80 oC, for 3 hours. The results show that the yield of gelatin from hydrolysis using KOH (16.50-28.60% is lower than that using NaOH (23.68-34.42%. The water and fat contents of the resulting gelatin were relatively similar, while the protein content from KOH treatment was higher than that from NaOH treatment. Hydrolysis with KOH 1% and NaOH 1% and 2% resulted in gelatin that can be used as flocculant. Hydrolysis with NaOH 2% was the best treatment to produce gelatin as flocculant.

  12. Optimization of Alkaline Extraction and Bioactivities of Polysaccharides from Rhizome of Polygonatum odoratum

    Science.gov (United States)

    Chen, Yong; Yin, Luoyi; Zhang, Xuejiao; Wang, Yan; Chen, Qiuzhi; Jin, Chenzhong; Wang, Jihua

    2014-01-01

    The present study is to explore the optimal extraction parameters, antioxidant activity, and antimicrobial activity of alkaline soluble polysaccharides from rhizome of Polygonatum odoratum. The optimal extraction parameters were determined as the following: NaOH concentration (A) 0.3 M, temperature (B) 80°C, ratio of NaOH to solid (C) 10-fold, and extraction time (D) 4 h, in which ratio of NaOH to solid was a key factor. The order of the factors was ratio of NaOH to solid (fold, C) > extraction temperature (°C, B) > NaOH concentration (M, A) > extraction time (h, D). The monosaccharide compositions of polysaccharides from P. odoratum were rhamnose, mannose, xylose, and arabinose with the molecular ratio of 31.78, 31.89, 11.11, and 1.00, respectively. The reducing power, the 1, 1-diphenyl-2-picryl-hydrazil (DPPH) radical scavenging rate, the hydroxyl radicals scavenging rate, and the inhibition rate to polyunsaturated fatty acid (PUFA) peroxidation of the alkaline soluble polysaccharides from P. odoratum at 1 mg/mL were 9.81%, 52.84%, 19.22%, and 19.42% of ascorbic acid at the same concentration, respectively. They also showed antimicrobial activity against pathogenic bacteria Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, and Escherichia coli. PMID:25093173

  13. Characteristics of Al Alloy as a Material for Hydrolysis Reactor of NaBH4

    International Nuclear Information System (INIS)

    Jung, Hyeon-Seong; Oh, Sung-June; Jeong, Jae-Jin; Na, Il-Chai; Chu, Cheun-Ho; Park, Kwon-Pil; Chu, Cheun-Ho

    2015-01-01

    Aluminum alloy was examined as a material of low weight reactor for hydrolysis of NaBH 4 . Aluminum is dissolved with alkali, but there is NaOH as a stabilizer in NaBH 4 solution. To decrease corrosion rate of aluminum, decrease NaOH concentration and this result in loss of NaBH 4 during storage of NaBH 4 solution. Therefore stability of NaBH 4 and corrosion of aluminum should be considered in determining the optimum NaOH concentration. NaBH 4 stability and corrosion rate of aluminum were measured by hydrogen evolution rate. NaBH 4 stability was tested at 20-50 .deg. C and aluminum corrosion was measured at 60-90 .deg. C. The optimum concentration of NaOH was 0.3 wt%, considering both NaBH 4 stability and aluminun corrosion. NaBH 4 hydrolysis reaction continued 200min in aluminum No 6061 alloy reactor with 0.3 wt% NaOH at 80-90 .deg. C.

  14. Characteristics of Al Alloy as a Material for Hydrolysis Reactor of NaBH{sub 4}

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyeon-Seong; Oh, Sung-June; Jeong, Jae-Jin; Na, Il-Chai; Chu, Cheun-Ho; Park, Kwon-Pil [Sunchon National University, Suncheon (Korea, Republic of); Chu, Cheun-Ho [ETIS Co, Gimpo (Korea, Republic of)

    2015-12-15

    Aluminum alloy was examined as a material of low weight reactor for hydrolysis of NaBH{sub 4}. Aluminum is dissolved with alkali, but there is NaOH as a stabilizer in NaBH{sub 4} solution. To decrease corrosion rate of aluminum, decrease NaOH concentration and this result in loss of NaBH{sub 4} during storage of NaBH{sub 4} solution. Therefore stability of NaBH{sub 4} and corrosion of aluminum should be considered in determining the optimum NaOH concentration. NaBH{sub 4} stability and corrosion rate of aluminum were measured by hydrogen evolution rate. NaBH{sub 4} stability was tested at 20-50 .deg. C and aluminum corrosion was measured at 60-90 .deg. C. The optimum concentration of NaOH was 0.3 wt%, considering both NaBH{sub 4} stability and aluminun corrosion. NaBH{sub 4} hydrolysis reaction continued 200min in aluminum No 6061 alloy reactor with 0.3 wt% NaOH at 80-90 .deg. C.

  15. Experimental Evaluation of Efficient Si Dissolution from Perlite at Low Level Activator’s Concentration

    Directory of Open Access Journals (Sweden)

    Georgia-Maria Tsaousi

    2018-04-01

    Full Text Available This paper deals with the Si dissolution of fine perlite in alkaline solutions for the determination of the SiO2/Na2O mass ratio in the aqueous phase of geopolymer slurries. In the present work, the effect of the main synthesis parameters such as NaOH concentration and curing temperature on the setting time of the paste were studied. The obtained results showed that the inorganic polymer pastes present fast hardening at low concentrations of NaOH solutions for both 70 and 90 °C. This observation was also identified by the Si dissolution study of perlite pastes as a function of different concentrations of NaOH solutions and different solid to liquid ratios of the slurries, under a constant temperature. The optimum synthesis conditions for geopolymer pastes proved to be a low initial NaOH concentration in the alkaline phase (2–4 M NaOH, where the fast hardening of the paste was attributed to the high SiO2/Na2O mass ratio, enhancing the polycondensation phenomena and promoting the geopolymerization process.

  16. The effect of pretreatment using sodium hydroxide and acetic acid to biogas production from rice straw waste

    Directory of Open Access Journals (Sweden)

    Budiyono

    2017-01-01

    Full Text Available Rice straw is agricultural waste containing high potency to be treated to biogas. However, the usage of rice straw is still limited due to high lignin content that will cause low biodegradability. The aim of this research was to study the effect of pretreatment using NaOH and acetic acid to biogas production from rice straw. NaOH was varied from 2%w, 4%w, and 6%w; and acetic acid was varied from 0,075 M, 0,15 M dan 0,75 M. The rice straw was cut into 1 cm size and submerged for 30 minutes in NaOH and acetic acid solution. The rice straw then filtered and neutralized before sending to anaerobic digestion process using rumen fluid bacteria. Biogas produced was measured using water displacement method. The result showed that the optimum concentration of NaOH solution was 4%w that resulted in biogas volume of 21,1 ml/gTS. Meanwhile, the optimum concentration of acetic acid pretreatment was 0,075 M that produced biogas volume of 14,5 ml/gTS. These results suggest that pretreatment using NaOH solution is more effective for decreasing the lignin content from rice straw.

  17. Application of Ion Torrent Sequencing to the Assessment of the Effect of Alkali Ballast Water Treatment on Microbial Community Diversity

    Science.gov (United States)

    Fujimoto, Masanori; Moyerbrailean, Gregory A.; Noman, Sifat; Gizicki, Jason P.; Ram, Michal L.; Green, Phyllis A.; Ram, Jeffrey L.

    2014-01-01

    The impact of NaOH as a ballast water treatment (BWT) on microbial community diversity was assessed using the 16S rRNA gene based Ion Torrent sequencing with its new 400 base chemistry. Ballast water samples from a Great Lakes ship were collected from the intake and discharge of both control and NaOH (pH 12) treated tanks and were analyzed in duplicates. One set of duplicates was treated with the membrane-impermeable DNA cross-linking reagent propidium mono-azide (PMA) prior to PCR amplification to differentiate between live and dead microorganisms. Ion Torrent sequencing generated nearly 580,000 reads for 31 bar-coded samples and revealed alterations of the microbial community structure in ballast water that had been treated with NaOH. Rarefaction analysis of the Ion Torrent sequencing data showed that BWT using NaOH significantly decreased microbial community diversity relative to control discharge (pbased principal coordinate analysis (PCoA) plots and UPGMA tree analysis revealed that NaOH-treated ballast water microbial communities differed from both intake communities and control discharge communities. After NaOH treatment, bacteria from the genus Alishewanella became dominant in the NaOH-treated samples, accounting for alkali ballast water treatment in reducing ballast water microbial diversity and demonstrated the application of new Ion Torrent sequencing techniques to microbial community studies. PMID:25222021

  18. Long term effect of alkali types on waste activated sludge hydrolytic acidification and microbial community at low temperature.

    Science.gov (United States)

    Jin, Baodan; Wang, Shuying; Xing, Liqun; Li, Baikun; Peng, Yongzhen

    2016-01-01

    The effect of four alkali reagents (NaOH, KOH, Ca(OH)2, mixed alkali) on waste activated sludge (WAS) hydrolytic acidification and microbial community was studied in semi-continuous fermentation systems at low temperature (15°C) over long term operational time (65day). The results showed that protein and polysaccharide of NaOH (124.26, 11.92) was similar to that of KOH (109.53, 11.30), both were higher than Ca(OH)2 (70.66, 3.74) and mixed alkali (90.66, 8.71). The short chain fatty acids (SCFAs) of NaOH (231.62) was higher than KOH (220.62mg chemical oxygen demand (COD)/g VSS). Although Ca(OH)2 system had strong acidification capacity, the shortage of SCFAs occurred due to the low activity of hydrolase. Illumina MiSeq sequencing revealed that Tissierella and Erysipelothrix were enriched in the NaOH and Ca(OH)2 systems, where Peptostreptococcaceae incertae_sedis was enriched in the NaOH and KOH systems, less Anaerolinea was involved in Ca(OH)2 condition. Copyright © 2015. Published by Elsevier Ltd.

  19. Evolution evidence of a basic fluid to an acid based in the analysis of hydrothermal alteration of the geothermic field of the Azufres, Michoacan; Evidencias de evolucion de un fluido basico a acido a partir del analisis de la alteracion hidrotermal del campo geotermico de los Azufres, Michoacan

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez Partida, Eduardo [Universidad Nacional Autonoma de Mexico, Mexico, D.F. (Mexico)

    2000-07-01

    zoneamiento evolutivo para los calcosilicatos predominando las zeolitas hacia la cima y la epidota-clinozoicita en los niveles mas profundos. Le sobreyace una zona de argilitizacion que domina las manifestaciones hidrotermales superficiales. En algunas zonas, se tiene la asociacion caolinita-alunita-azufre nativo-cuarzo (zona argilica avanzada) formada por la interaccion vapor-acuifero someros. En el sistema geotermico de Los Azufres el protofluido esta ligado a una salmuera clorurado-sodica de caracter neutro que propicia una alteracion hidrotermal propilitica profunda (zona productoras) y se caracteriza por tener una permeabilidad secundaria debido al fracturamiento. A profundiad el yacimiento es a liquido dominante presurizado para evolucionar a vapor en su parte mas somera. El cambio gradual de la fase liquida a vapor se da por ebullicion a profundidades del orden de 1,200 a 1,500 m, y esta acompanado por cambios igualmente presentes en la mineralogia de alteracion hidrotermal. Ella pasa de propilitica a argilica por un proceso de oxidacion-acidificacion, en donde la participacion de gases, principalmente de CO{sub 2}, es importante. De acuerdo a las caracteristicas fisicoquimicas de la salmuera y la evolucion en las fases parageneticas, el yacimiento de Los Azufres pudiera ser un modelo de comportamiento hidrotermal en el deposito de las menas que se dan por ebullicion y oxidacion de los fluidos hidrotermales fosiles de baja sulfidacion.

  20. Determining the optimal dose of Fenton reagent in a leachate treatment by Fenton-adsorption; Determinacion de la dosis optima de reactivo Fenton en un tratamiento de lixiviados por Fenton-adsorcion

    Energy Technology Data Exchange (ETDEWEB)

    Mendez Novelo, Roger Ivan; Pietrogiovanna Bronca, Jose Alfredo; Santos Ocampo, Beatriz; Sauri Riancho, Maria Rosa; Giacoman Vallejos, German; Castillo Borges, Elba Rene [Universidad Autonoma de Yucatan, Facultad de Ingenieria, Merida, Yucatan (Mexico)]. E-mail: mnovelo@uady.mx

    2010-07-01

    Leachates are formed as a result of the percolation of liquids, through the solid wastes in stabilization process. Their composition is variable and highly toxic; therefore, leachates treatment is a complex task. Due to the high permeability of the soil of the Yucatan Peninsula leachates represent a high risk to health. Fenton type oxidation and adsorption treatment have been tested, and they have showed better results than other types of biological or physicochemical treatment. Fenton process consists in treating the contaminant load with a combination of H{sub 2}O{sub 2} and FeSO{sub 4} under acidic conditions. Experiments were conducted in order to determine if filtration was better than the sedimentation of the sludges. The optimum contact time and the best relations [Fe{sup 2+}]/[H{sub 2}O{sub 2}] and [COD]/[H{sub 2}O{sub 2}] were determined. Subsequently, the oxidized samples were filtered and the adsorption process was tested using two columns in series packed with activated carbon. It was concluded that the sludge generated by the Fenton process was removed more efficiently through filtration than sedimentation. Optimal contact times were 5 min for COD removal, and 1 hour for colour removal; process time was set to one hour in order to protect the activated carbon. The best relations for [Fe{sup 2+}]/[H{sub 2}O{sub 2}] and [COD]/[H{sub 2}O{sub 2}] were 0.6 and 9 respectively. The maximum removal efficiency after the adsorption process was 98.9% for COD and 100% for colour at zero time of the column. A final biodegradability index of 0.24 was reached after the Fenton-adsorption tests. [Spanish] Los lixiviados son el resultado de la percolacion de liquidos a traves de los desechos solidos en proceso de estabilizacion. La complejidad de su tratamiento se debe a que su composicion es altamente toxica y variable. Lo anterior y el suelo altamente permeable de la peninsula de Yucatan, representan un alto peligro a la salud. Se ensayo un tratamiento de oxidacion

  1. Pilot study of iron and manganese removal from Mexican drinking water supply sources; Estudio piloto para remocion de fierro y manganeso en las fuentes de abastecimiento de Mexico

    Energy Technology Data Exchange (ETDEWEB)

    Simeonova, Verguinia Petkova; Mintchev, Mintcho Lliev; Rivera, Maria Lourdes [Instituto Mexicano de Tecnologia del Agua, Jiutepec, Morelos (Mexico)

    1999-08-01

    This study demonstrates the efficiency of a technique for manganese removal through adsorption-oxidation on zeolite. Several Mexican groundwater sources were selected for pilot installations. The results show that the final iron and manganese concentrations are within the limits set in the Official Mexican Standard, NOM-127-SSA1, referring to drinking water. An analysis was made of the effect of the operating rate and the granule size of the filtering material on iron and manganese removal and of calcium and magnesium salts associated with hardness. Zeolite covered with manganese precipitates was highly selective for iron and manganese; this made the treatment of groundwater with high iron and manganese concentrations possible, even in the presence of hardness and alkalinity. A description is given of the procedures to prepare the material and regenerate its filtration capacity without interrupting the filtration process. [Spanish] El presente estudio comprueba la eficiencia de la tecnica propuesta para la remocion de manganeso por adsorcion-oxidacion sobre zeolita a traves de estudios piloto en varias fuentes subterraneas de Mexico. Los resultados demuestran que la concentracion de fierro y manganeso en el agua producida cumple con la Norma Oficial Mexicana NOM-127-SSA1 para el consumo humano en todo los casos estudiados. Fueron analizadas la influencia de la tasa de operacion y la granulometria del material filtrante sobre el grado de remocion de fierro y manganeso, asi como el efecto de las sales de calcio y magnesio que originan la dureza del agua. Durante la experimentacion se comprobo que la zeolita recubierta con los precipitados de manganeso es altamente selectiva respecto al fierro y manganeso, lo que permite tratar el agua de las fuentes subterraneas con elevada concentracion de Fe y Mn en presencia de alta dureza y alcalinidad. En el articulo se describen los procedimientos para la preparacion del material filtrante y la regeneracion de su capacidad sin

  2. Evaluation of a process for the removal of gases contained in geothermal steam through condensation and re-evaporation; Evaluacion de un proceso de remocion de gases contenidos en el vapor geotermico, por medio de la condensacion y de revaporacion

    Energy Technology Data Exchange (ETDEWEB)

    Angulo C, Raul; Lam Rea, Luis; Garmino, Hector; Jimenez, Humberto [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1986-12-31

    The Cerro Prieto I Geothermal Field, developed and operated by the Comision Federal de Electricidad (CFE), has currently an installed electric power generation capacity of 180 MW and is at a very advanced stage in the development of Cerro Prieto II and III, which will allow to raise the generation capacity to 620 MW. During the exploitation of a geothermal field, in producing steam with the purpose of generating electricity, brines and waste gases are obtained. The hydrogen sulfide exhaust to the environment implies pollution problems, for this reason processes have been developed for the oxidation of these gases downstream the turbogenerator either in the flow of separated gases in the steam condensation or in the condensate produced. The Instituto de Investigaciones Electricas (IIE) has collaborated with CFE in the evaluation of the environmental impact of this gas and in the development of the processes for its abatement. [Espanol] El campo geotermico de Cerro Prieto I, desarrollado y operado por la Comision Federal de Electricidad (CFE), actualmente tiene una capacidad instalada de generacion de energia electrica de 180 MW, y se encuentra en etapa muy avanzada, el desarrollo de Cerro Prieto II y III, lo que permitira incrementar la capacidad de generacion a 620 MW. Durante la explotacion de un campo geotermico, al producir vapor con el proposito de generar electricidad, se obtienen salmueras y gases de desecho. La descarga de acido sulfhidrico a la atmosfera implica problemas de contaminacion, por esta razon se han desarrollado procesos para la oxidacion de este gas aguas abajo de la turbina generadora, ya sea en la corriente de gases que se separan en la condensacion del vapor o en el condensado producido. El Instituto de Investigaciones Electricas (IIE) ha colaborado con la CFE en la evaluacion del impacto ambiental de este gas y en el desarrollo de sus procesos de abatimiento.

  3. Evaluation of a process for the removal of gases contained in geothermal steam through condensation and re-evaporation; Evaluacion de un proceso de remocion de gases contenidos en el vapor geotermico, por medio de la condensacion y de revaporacion

    Energy Technology Data Exchange (ETDEWEB)

    Angulo C, Raul; Lam Rea, Luis; Garmino, Hector; Jimenez, Humberto [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1985-12-31

    The Cerro Prieto I Geothermal Field, developed and operated by the Comision Federal de Electricidad (CFE), has currently an installed electric power generation capacity of 180 MW and is at a very advanced stage in the development of Cerro Prieto II and III, which will allow to raise the generation capacity to 620 MW. During the exploitation of a geothermal field, in producing steam with the purpose of generating electricity, brines and waste gases are obtained. The hydrogen sulfide exhaust to the environment implies pollution problems, for this reason processes have been developed for the oxidation of these gases downstream the turbogenerator either in the flow of separated gases in the steam condensation or in the condensate produced. The Instituto de Investigaciones Electricas (IIE) has collaborated with CFE in the evaluation of the environmental impact of this gas and in the development of the processes for its abatement. [Espanol] El campo geotermico de Cerro Prieto I, desarrollado y operado por la Comision Federal de Electricidad (CFE), actualmente tiene una capacidad instalada de generacion de energia electrica de 180 MW, y se encuentra en etapa muy avanzada, el desarrollo de Cerro Prieto II y III, lo que permitira incrementar la capacidad de generacion a 620 MW. Durante la explotacion de un campo geotermico, al producir vapor con el proposito de generar electricidad, se obtienen salmueras y gases de desecho. La descarga de acido sulfhidrico a la atmosfera implica problemas de contaminacion, por esta razon se han desarrollado procesos para la oxidacion de este gas aguas abajo de la turbina generadora, ya sea en la corriente de gases que se separan en la condensacion del vapor o en el condensado producido. El Instituto de Investigaciones Electricas (IIE) ha colaborado con la CFE en la evaluacion del impacto ambiental de este gas y en el desarrollo de sus procesos de abatimiento.

  4. Synthesis and evaluation of Pt-alloys supported on MWCNTS as ethylene glycol-tolerant ORR cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acosta, D.; Arriaga, L.G. [Centro de Investigacion y Desarrollo Tecnologico en Electroquimica, Pedro Escobedo, Queretaro (Mexico); Alvarez-Contreras, L. [Centro de Investigacion en Materiales Avanzados S. C., Chihuahua, Chihuahua (Mexico); Fraire Luna, S.; Rodriguez Varela, F.J. [Cinvestav, Unidad Saltillo, Ramos Arizpe, Coahuila (Mexico)]. E-mail: javier.varela@cinvestav.edu.mx

    2009-09-15

    In this work, a Pt-Co/MWCNT alloy (atomic ratio 70:30) was synthesized and evaluated as oxygen reduction reaction (ORR) cathode for Direct Ethylene Glycol Fuel Cells (DEGFC) applications. The alloy showed good performance for the ORR in acid medium, while in the presence of 0.125M EG (C{sub 2}H{sub 6}O{sub 2}) the MWCNTs-supported electrocatalyst showed a very high selectivity for the cathodic reaction and a high degree of tolerance to the organic fuel, i.e., a very small shift in the onset potential for the ORR, Eonset, and no peak current densities associated to the oxidation of EG, a detrimental effect of organic fuels normally observed in the case of Pt-alone electrocatalysts. [Spanish] En este trabajo, se sintetizo y evaluo una aleacion Pt-Co/NTCMP (razon atomica 70/30) como catodo de reaccion de reduccion de oxigeno (RRO) para aplicaciones de celdas de combustible de glicol de etileno directo (CCGED). La aleacion mostro buen desempeno para la RRO en medio acido, en tanto que la presencia de 0.125M de GE (C{sub 2}H{sub 6}O{sub 2}) del electrocatalizador soportado por NTCMP mostro una muy alta selectividad para la reaccion catodica y un alto grado de tolerancia al combustible organico, es decir, un corrimiento muy pequeno del potencial de inicio para la RRO, Einicio, y no densidades de corriente asociadas a la oxidacion del GE, efecto perjudicial de los combustibles organicos que se observa en el caso del electrocatalizadores solo de Pt.

  5. Thermal analysis experiment for elucidating sodium-water chemical reaction mechanism in steam generator of sodium-cooled fast reactor

    International Nuclear Information System (INIS)

    Kikuchi, Shin; Kurihara, Akikazu; Ohshima, Hiroyuki

    2012-01-01

    For the purpose of elucidating the mechanism of the sodium-water surface reaction in a steam generator of sodium-cooled fast reactors, kinetic study of the sodium (Na)-sodium hydroxide (NaOH) reaction has been carried out by using Differential Thermal Analysis (DTA) technique. The parameters, including melting points of Na and NaOH, phase transition temperature of NaOH, Na-NaOH reaction temperature, and decomposition temperature of sodium hydride (NaH) have been identified from DTA curves. Based on the measured reaction temperature, rate constant of sodium monoxide (Na 2 O) generation was obtained. Thermal analysis results indicated that Na 2 O generation at the secondary overall reaction should be considered during the sodium-water reaction. (author)

  6. Studying VM-1 molybdenum alloy workability at high current density. II

    Energy Technology Data Exchange (ETDEWEB)

    Tatarinova, O M; Amirkhanova, N A; Zaripov, R A

    1976-01-01

    Under galvanostatic conditions, voltampere characteristics have been taken off for VM-1 alloy; determined are also the selective effect of electrolytes and the influence of hydrodynamical conditions on the rate of anodic dissolution in the electrolytes containing 15% NaNO/sub 3/; 15% NaNO/sub 3/ + 5% NaOH, and 15 % NaOH. In a composite electrolyte, the quality of the surface is improved, and higher current densities have been attained as compared with those for pure 15% NaNO/sub 3/. The process of dissolution in the above electrolytes is effected with diffuse limitations. For the electrochemical treatment of the VM-1 alloy under production conditions, a composite electrolyte containing 15% NaNO/sub 3/ and 5% NaOH has been suggested and tested.

  7. A Comparative Electrochemical Study of AZ31 and AZ91 Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    S. A. Salman

    2010-01-01

    Full Text Available A comparative study has been carried out on AZ31 and AZ91 magnesium alloys in order to understand the electrochemical behavior in both alkaline and chloride containing solutions. The open circuit potential (OCP was examined in 1 M NaOH and 3.5 mass % NaCl solutions. AZ31 magnesium alloy shows several potential drops throughout the immersion in 1 M NaOH solution, though AZ91 does not show this phenomenon. The specimens were anodized at a constant potential of 3 V for 30 minutes at 298 K in 1 M NaOH solution. The anticorrosion behavior of the anodized specimens was better than those of nonanodized specimens. The anodized AZ91 has better corrosion resistance compared to nonanodized specimen and anodized AZ31 magnesium alloy.

  8. Interaction of copper, magnesium, zinc, cadmium and lead formiates

    International Nuclear Information System (INIS)

    Gyunner, Eh.A.; Mel'nichenko, L.M.; Yakhkind, N.D.; Vel'mozhnyj, I.S.; Katseva, G.N.

    1979-01-01

    Measurements of the residual concentrations of the interacting ions and refraction index of liquid phases were useful in determining the precipitate composition in the system MA 2 -NaOH-H 2 O(A - -HCOO - ; M 2+ -Cu 2+ , Mg 2+ , Zn 2+ , Cd 2+ , Pb 2+ ). It is shown that in the system CdA 2 -NaOH-H 2 O containing as high as 40 mole% of NaOH the precipitate composition is approximately constant and corresponds to hydroxoformiate Cd(OH)A which is formed by the equation Cd 2+ +OH - +A - =Cd(OH)A. Further increase in the NaOH content leads to the formation of varying-composition precipitates and, at a NaOH content >=66.6 mole%, - to cadmium hydroxide

  9. Novel Bioactive Titanate Layers Formed on Ti Metal and Its Alloys by Chemical Treatments

    Directory of Open Access Journals (Sweden)

    Tadashi Kokubo

    2009-12-01

    Full Text Available Sodium titanate formed on Ti metal by NaOH and heat treatments induces apatite formation on its surface in a body environment and bonds to living bone. These treatments have been applied to porous Ti metal in artificial hip joints, and have been used clinically in Japan since 2007. Calcium titanate formed on Ti-15Zr-4Nb-4Ta alloy by NaOH, CaCl2, heat, and water treatments induces apatite formation on its surface in a body environment. Titanium oxide formed on porous Ti metal by NaOH, HCl, and heat treatments exhibits osteoinductivity as well as osteoconductivity. This is now under clinical tests for application to a spinal fusion device.

  10. Nutritive value of some agricultural wastes as affected by relatively low gamma irradiation levels and chemical treatments

    International Nuclear Information System (INIS)

    Al-Masri, M. R.

    2006-01-01

    An experiment was carried out to study the changes in the values of in-vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) of wheat straw, sunflower seed shell, olive cake wood, date palm seeds and peanut shell after irradiation by various levels of gamma radiation (0, 20, 40, 60 kGy) or after spraying with different amounts of hydrobromic acid (HBr; 47%) and sodium hydroxide (NaOH): 0, 3, 6 ml HBr and 3, 6 g NaOH in 25 ml water/100 g DM. The results indicated that chemical treatments increased the IVOMD and ME values significantly for all samples treated except the date palm seeds. There was no significant effect of irradiation on IVOMD and ME. Combined treatments of irradiation and HBr or NaOH were also found to be ineffective in increasing the IVOMD and ME values. (Author)

  11. Monazite processing of tin mining waste : rare earth separation from U and Th

    International Nuclear Information System (INIS)

    Hafni, L.N.; Faizal, R.; Sugeng, W.; Budi, S.; Arif, S.; Susilaningtyas

    2000-01-01

    Separation of Rare Earths from U and Th of Bangka monazite digestion solution, by using NaOH reagent and precipitation system has been carried out. The aim of the experiment is to find a condition of RE(OH) sub.3 precipitation to produce maximal RE recovery and high purity of RE that are free from radioelements U and Th. Parameters studied were pH, NaOH normality and precipitation time. The optimal conditions obtained were pH 9.8, 1N NaOH and 3 hours precipitation time. At this condition recovery of the RE(OH) sub.3 is 99.79 % and Th 4.52 %. However uranium and phosphate were not detected. Purity of the products are RE(OH) sub.3 98.868 %, Th(OH) sub.4 0.009 % and the others 1.123 %. (author)

  12. Bulk etching characteristics of CR-39 track detectors in hydroxide solutions

    International Nuclear Information System (INIS)

    Fonseca, E.S. da; Knoefel, T.M.J.; Tavares, O.A.P.

    1983-01-01

    A systematic study of the bulk etch rate of CR-39 track detectors in KOH and NaOH aqueous solutions is presented. A number of unirradiated and non-thermally treated CR-39 samples were chemically attacked in KOH and NaOH solutions of concentration and temperature in the range 2-10 N and 50-90 0 C, respectively. From measurements of the thickness of layers removed as a function of the etching time, the bulk etch rate υ β and the induction time T ο for surface removal were obtained for each etching condition. For both NaOH and KOH solution the activation energy of the process was derived as E = 0.76 ± 0.05 eV. It was observed that the induction time decreases both with increasing normality and temperature of the solution. (author) [pt

  13. Optimization of microwave pretreatment on wheat straw for ethanol production

    DEFF Research Database (Denmark)

    Xu, Jian; Chen, Hongzhang; Kádár, Zsófia

    2011-01-01

    An orthogonal design (L9(34)) was used to optimize the microwave pretreatment on wheat straw for ethanol production. The orthogonal analysis was done based on the results obtained from the nine pretreatments. The effect of four factors including the ratio of biomass to NaOH solution, pretreatment...... time, microwave power, and the concentration of NaOH solution with three different levels on the chemical composition, cellulose/hemicellulose recoveries and ethanol concentration was investigated. According to the orthogonal analysis, pretreatment with the ratio of biomass to liquid at 80 g kg−1......, the NaOH concentration of 10 kg m−3, the microwave power of 1000 W for 15 min was confirmed to be the optimal condition. The ethanol yield was 148.93 g kg−1 wheat straw at this condition, much higher than that from the untreated material which was only 26.78 g kg−1....

  14. Chemical composition and strength of dolomite geopolymer composites

    Science.gov (United States)

    Aizat, E. A.; Al Bakri, A. M. M.; Liew, Y. M.; Heah, C. Y.

    2017-09-01

    The chemical composition of dolomite and the compressive strength of dolomite geopolymer composites were studied. The both composites prepared with mechanical mixer manufactured by with rotor speed of 350 rpm and curing in the oven for 24 hours at 80˚C. XRF analysis showThe dolomite raw materials contain fewer amounts of Si and Al but high Ca in its composition. Dolomite geopolymer composites with 20M of NaOH shows greater and optimum compressive strength compared to dolomite geopolymer with other NaOH molarity. This indicated better interaction of dolomite raw material and alkaline activator need high molarity of NaOH in order to increase the reactivity of dolomite.

  15. Electrochemical determination of the oxidation potentials and the thermodynamic stability of the valence states of the transuranium elements in aqueous alkaline media

    International Nuclear Information System (INIS)

    Peretrukhin, V.F.; Spitsyn, V.I.

    1982-01-01

    The oxidation potentials of neptunium, plutonium, and americium in the valance states from (III) to (VII) have been determined experimentally in 0.1-15 M NaOH. Heptavalent plutonium and americium are thermodynamically able to oxidize water with the evolution of oxygen in 0.1-15 M NaOH, neptunium(VII) in 0.1-7 M NaOH. All valance states of plutonium resist disproportionation in alkaline solutions; in the case of neptunium and americium only one disproportionation reaction is possible; of the hexavalent state in to penta- and heptavalent states. The degree of completion of the reaction can be calculated accurately from the oxidation potentials determined

  16. Kinetics of dodecanoic acid adsorption from caustic solution by activated carbon.

    Science.gov (United States)

    Pendleton, Phillip; Wu, Sophie Hua

    2003-10-15

    This study examines the influences of adsorbent porosity and surface chemistry and of carbon dosage on dodecanoic acid adsorption kinetics from aqueous and 2 M NaOH solutions as batch adsorption processes. Both adsorbents are steam-activated carbons prepared from either coconut or coal precursors. Prior to use the adsorbents were washed in deionized water or 2 M NaOH. Mass transfer coefficients and effective overall diffusion coefficients indicate a minor contribution from adsorbent porosity. In contrast, high surface oxygen content impedes transport to and into the adsorbent structure. Carbon dosage shows a proportional increase in transport coefficients with increasing mass; these coefficients are constant when normalized per unit mass. Neither water nor NaOH treatment of the adsorbents has a significant influence on dodecanoic acid adsorption kinetics. Molecular and Knudsen diffusion coefficients are defined to demonstrate that the overall effective diffusion coefficient values and the diffusion process are controlled by surface diffusion.

  17. FLEXURAL PROPERTIES OF ALKALINE TREATED SUGAR PALM FIBRE REINFORCED EPOXY COMPOSITES

    Directory of Open Access Journals (Sweden)

    D. Bachtiar

    2010-06-01

    Full Text Available A study of the effect of alkaline treatment on the flexural properties of sugar palm fibre reinforced epoxy composites is presented in this paper. The composites were reinforced with 10% weight fraction of the fibres. The fibres were treated using sodium hydroxide (NaOH with 0.25 M and 0.5 M concentration solution for 1 hour, 4 hours and 8 hours soaking time. The purpose of treating fibres with alkali was to enhance the interfacial bonding between matrix and fibre surfaces. The maximum flexural strength occurred at 0.25 M NaOH solution with 1 hour of soaking time, i.e 96.71 MPa, improving by 24.41% from untreated fibre composite. But, the maximum flexural modulus took place at 0.5 M NaOH solution with 4 hours soaking time, i.e. 6948 MPa, improving by 148% from untreated composite.

  18. The interaction of Np(V), Pu(VI) and Tc(VII) with metal in alkaline solutions

    International Nuclear Information System (INIS)

    Silin, V.I.; Kareta, A.V.

    1998-01-01

    The interaction of Np(V), Pu(VI) and Tc(VII) with metal reductants Zn, Cr, Sn and their alloys was investigated in 0.5-4 mol l -1 NaOH solutions in static and dynamic conditions (by filtration of solutions through the column filled with grains of metal). In this paper, it was found that the reduction and succeeding precipitation hydroxides of these elements, on the surface of metal grains from 0.5 to 4 mol l -1 NaOH solutions, gives a decontamination factor (DF) from 1.1 to 67. The best result was achieved for Pu (DF=67) on Cr grains after 2.5 h contact at 60 C with 0.5 mol l -1 NaOH solution containing Pu(VI). Increasing the NaOH concentration, and the addition of chromate ions and complex-forming agents to alkaline solution results in a decrease of the decontamination factor (DF). A better result for Np sorption from 1 mol l -1 NaOH solutions was achieved after longer contact, than for Pu, with Cr and Zn grains. The maximum DF=8.9 was achieved for Tc on a column with Zn grains after filtration with a 3.5 mol l -1 NaOH solution containing Tc(VII). Washing out of Np and Pu, sorbed on the Cr grain surfaces, was achieved using an acid solution (1 mol l -1 HNO 3 ). The technetium was desorbed from metal surface by 10% H 2 O 2 solution. (orig.)

  19. Preparation of Chitin, Study of Physicochemical Properties and Biopesticide Activities

    Directory of Open Access Journals (Sweden)

    Yuli Rohyami

    2013-08-01

    Full Text Available Chitin was preparated from shrimp shells by chemically method. Preparation was carried out by deproteination shrimp shells powder < 150 mesh with 1 - 2 M NaOH, demineralization followed by reaction with 1.0 M HCl and depigmentation with (1 : 2 : 4, v/v of chloroform : methanol : water. Physicochemical properties of chitin was determined from characterization of infrared spectra, ash value, loss on drying and total of nitrogen. Biopesticide activities of chitin was done to pest Bemisia tabaci at guava leaves with various concentration from 0.5 to 2.0 % chitin on 3 % v/v acetic acid. This study indicated that concentration of NaOH on deproteination process effected to its physicochemicals properties. Effectivity of 2 M NaOH on deproteination reaction was higher than 1 M NaOH . The degree of chitin deacetylation from 2 M NaOH was 13.61% and had lower molar ratio of total nitrogen. The degree of deacetylation of chitin from 1 M NaOH had lower and had higher molar ratio of total nitrogen. Physicochemicals properties of chitin quite an impact on its ability to reduce pest Bemisia tabaci. Biopesticide activity assay showed that treatment for 2 days on average mortality rate of 13.83%. Deacetylation of chitin which has a higher degree have a greaterability biopesticide with a mortality rate of up to 38.24%. This study the effect of deproteination process to biopesticide activities of chitin.Key Words : chitin, degree of deacetilation, molar ratio, biopesticide, Bemisia tabaci

  20. Microstructure, morphology and magnetic properties of Ni nanoparticles synthesized by hydrothermal method

    Energy Technology Data Exchange (ETDEWEB)

    Bouremana, A. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria); Guittoum, A., E-mail: aguittoum@gmail.com [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Hemmous, M. [Nuclear Research Centre of Algiers, 02 Bd Frantz Fanon, BP 399, Alger-Gare, Algiers (Algeria); Martínez-Blanco, D. [SCTs, University of Oviedo, EPM, 33600 Mieres (Spain); Gorria, Pedro [Department of Physics & IUTA, EPI, University of Oviedo, 33203 Gijón (Spain); Blanco, J.A. [Department of Physics, University of Oviedo, Calvo Sotelo St., 33007 Oviedo (Spain); Benrekaa, N. [LPM, Faculty of Sciences, USTHB, BP 32, El-Alia, Bab Ezzouar, Algiers (Algeria)

    2015-06-15

    Powder samples containing high purity nickel nanoparticles (NPs) were prepared by hydrothermal method from Ni(II) chloride hexahydrate (NiCl{sub 2}·6H{sub 2}O) under the presence of sodium hydroxide (NaOH) with different concentrations between 5 and 25 mol/L. The synthesis of the NPs occurs through chemical reduction at relatively low temperature (140 °C). The Ni NPs have a face-centred cubic (fcc) crystal structure with a lattice parameter value close to that of pure Ni (a = 3.52 Å). The average crystallite size determined from x-ray diffraction is around 20 nm, except for the sample synthesized under the highest NaOH concentration (25 mol/L), which has the largest average size (>30 nm). The powder morphology at the sub-micrometre length scale looks like agglomerates of Ni-NPs that drastically changes their shape depending on the NaOH concentration, from flower (5 mol/L) to a dendritic-like (25 mol/L). All the samples are ferromagnetic at room temperature with saturation magnetization values between 50 and 52emu/g, and a coercive field that increases with the NaOH concentration from around 135 (5 mol/L) up to 180Oe (25 mol/L). - Highlights: • Pure Nickel nanoparticles have been synthesized by a chemical reaction process. • Different morphologies were observed with the change of NaOH concentration. • The coercive field increases with increasing the NaOH concentration and depends on the shape of nanoparticles.

  1. [Effects of hot-NaOH pretreatment on Jerusalem artichoke stalk composition and subsequent enzymatic hydrolysis].

    Science.gov (United States)

    Wang, Qing; Qiu, Jingwen; Li, Yang; Shen, Fei

    2015-10-01

    In order to explore the possibility of Jerusalem artichoke stalk for bioenergy conversion, we analyzed the main composition of whole stalk, pitch, and core of the stalk. Meanwhile, these parts were pretreated with different NaOH concentrations at 121 degrees C. Afterwards, enzymatic hydrolysis was performed to evaluate the pretreatment efficiency. Jerusalem artichoke stalk was characterized by relatively high lignin content (32.0%) compared with traditional crop stalks. The total carbohydrate content was close to that of crop stalks, but with higher cellulose content (40.5%) and lower hemicellulose (19.6%) than those of traditional crop stalks. After pretreatment, the lignin content in the whole stalk, pitch, and core decreased by 13.1%-13.4%, 8.3%-13.5%, and 19.9%-27.2%, respectively, compared with the unpretreated substrates. The hemicellulose content in the whole stalk, pitch, and core decreased 87.8%-96.9%, 87.6%-95.0%, and 74.0%-90.2%, respectively. Correspondingly, the cellulose content in the pretreated whole stalk, pitch, and core increased by 56.5%-60.2%, 52.2%-55.4%, and 62.7%-73.2%, respectively. Moreover, increase of NaOH concentration for pretreatment could improve the enzymatic hydrolysis of the whole stalk and pitch by 2.3-2.6 folds and 10.3-18.5 folds, respectively. The hydrolysis of pretreated stalk core decreased significantly as 2.0 mol/L NaOH was employed, although the increased NaOH concentration can also improve its hydrolysis performance. Based on these results, hot-NaOH can be regarded as an option for Jerusalem artichoke stalk pretreatment. Increasing NaOH concentration was beneficial to hemicellulose and lignin removal, and consequently improved sugar conversion. However, the potential decrease of sugar conversion of the pretreated core by higher NaOH concentration suggested further optimization on the pretreatment conditions should be performed.

  2. Cogon grass (Imperata cylindrica), a potential biomass candidate for bioethanol: cell wall structural changes enhancing hydrolysis in a mild alkali pretreatment regime.

    Science.gov (United States)

    Haque, Md Azizul; Barman, Dhirendra Nath; Kim, Min Keun; Yun, Han Dae; Cho, Kye Man

    2016-03-30

    Imperata cylindrica is being considered as a biomass candidate for bioethanol. This work aimed to evaluate a mild alkali pretreatment effect on the Imperata recalcitrant structure. Therefore, varied concentrations of NaOH (0, 7.5, 15, 20, and 25 g L(-1) ) were applied as treatments to Imperata at 105 °C for 10 min. Scanning electron microscopy, atomic force microscopy, and Fourier transform infrared spectroscopy studies revealed that 20 to 25 g L(-1) NaOH-treated Imperata exposed amorphous cellulose on surface granules composed of lignin, waxes, and partly hemicelluloses were abolished due to the comprehensive disruption of the linkages between lignin and carbohydrates. The cellulose crystalline index was increased with 7.5 to 20 g L(-1) NaOH treatments and reduced with a 25 g L(-1) NaOH treatment. In fact, the cellulose content in solids increased with the increasing NaOH concentration and was estimated to be 720 and 740 g kg(-1) for the 20 and 25 g L(-1) NaOH treatments, respectively. The yield of the reducing sugar was obtained 805 and 813 mg g(-1) from 20 and 25 g L(-1) NaOH-treated Imperata, respectively. Considering the cost of pretreatment, the 20 g L(-1) NaOH treatment is judged to be effective for disrupting Imperata recalcitrance in this pretreatment regime. © 2015 Society of Chemical Industry.

  3. Sorption Studies of Chromium(VI and Mercury(II by High Temperature Activated Carbon from Syzygium Jambolanum Nut

    Directory of Open Access Journals (Sweden)

    S. Sophie Beulah

    2010-01-01

    Full Text Available High temperature activated Syzygium Jambolanum nut carbon (HSJC has been effectively used for the removal of Cr(VI and Hg(II from aqueous solution by batch experiments. Effect of pH, carbon dose and equilibration time were determined. Adsorption followed Freundlich and Langmuir isotherms. Kinetic studies indicated that the removal process followed reversible first order equation. Desorption of Cr(VI was done with 1 M NaOH and 10% H2O2 mixture and Hg(II with 2% Na2S in 1% NaOH. The performance of HSJC was compared with a commercial activated carbon (CAC.

  4. Pengaruh perlakuan serat tapis kelapa terhadap kekuatan lentur skin komposit sandwich

    Directory of Open Access Journals (Sweden)

    I Made Astika

    2018-01-01

    Full Text Available Abstrak Penggunaan serat alam sebagai penguat komposit semakin berkembang. Indonesia sebagai negara beriklim tropis menghasilkan berbagai jenis serat alami seperti rami, abaca, agave, serat sabut kelapa dan serat tapis kelapa. Penelitian ini bertujuan untuk menyelidiki pengaruh perlakuan alkali serat (NaOH 5% terhadap kekuatan lentur komposit sandwich serat tapis kelapa bermatrik polyester dengan core kayu albasia Bahan penelitian adalah serat tapis kelapa dengan panjang 15 mm, resin unsaturated polyester 157 BQTN, kayu albasia dan NaOH. Hardener yang digunakan adalah MEKPO dengan konsentrasi 1%. Serat tapis kelapa yang digunakan terdiri dari serat tanpa perlakuan dan dengan perlakuan alkali 2 jam. Komposit sandwich tersusun atas dua skin dengan core ditengahnya dan dibuat dengan metode cetak tekan hidrolis. Lamina komposit sebagai skin terbuat dari serat tapis kelapa-polyester dengan fraksi volume serat 30%. Spesimen dan prosedur pengujian lentur mengacu pada standar ASTM C 393. Penampang patahan dilakukan foto makro untuk mengidentifikasi pola kegagalannya.Hasil penelitian menunjukkan serat yang mendapatkan perlakuan alkali 2 jam NaOH menghasilkan kekuatan lentur yang lebih tinggi. Hal ini disebabkan karena perlakuan alkali pada serat tapis kelapa dapat membersihkan lapisan lilin (lignin dan kotoran pada permukaan serat sehingga menghasilkan mechanical interlocking yang lebih baik antara serat dengan matrik poliester. Dengan ikatan yang lebih baik maka komposit tersebut akan mampu menahan beban lentur yang lebih tinggi. Kata kunci: komposit sandwich, serat tapis kelapa, perlakuan NaOH, kekuatan lentur Abstract The use of natural fibers as reinforcement composites is growing. Indonesia as a tropical country produces various types of natural fibers like coconut filter fiber. The purpose of this study is to investigate the effect of alkali treatment of the fiber (5% NaOH. The research material is coconut filter fiber, 157 BQTN unsaturated

  5. Characterization of Microbes Capable of Using Vinyl Chloride and Ethene as Sole Carbon and Energy Sources by Anaerobic Oxidation

    Science.gov (United States)

    2013-09-01

    NaOH to a 40 mM solution of FeCl3 until the pH reached 7. The solution was then allowed to settle in the beaker, followed by subsequent...of developing sulfate reducing conditions; and the amount of MgCl2·6H2O was increased to maintain the same concentration of magnesium . For both...oxidized to 14CO2 and then trapped in 3 mL of 0.5 M NaOH in a 10 mL glass test tube. Multiple test tubes were used, corresponding to the elution times

  6. Antibody-Functionalized Carbon Nanotube Transistors as Biosensors for the Detection of Prostate Cancer

    Science.gov (United States)

    2013-09-01

    NaOH . Note: Although the elution of the His-tagged protein from the magnetic beads was not 100% efficient, we obtained significant amounts of protein...ice. Cells were resuspended (2.5 mL per gram cells) in ice-cold PBS (Biowhittaker, without magnesium or calcium) containing Roche complete protease...NaH2PO4, 0.15 M NaCl, pH adjusted to 7.35 with NaOH ) for 2 h. Upon completion, the chipswerewashedwithwater and placed in a solution of 11.3mM NiCl2

  7. Extraction of Carbon Dioxide and Hydrogen from Seawater by an Electrochemical Acidification Cell. Part 4. Electrode Compartments of Cell Modified and Tested in Scaled-Up Mobile Unit

    Science.gov (United States)

    2013-09-03

    The catholyte is the water fed to the cathode compartment and it must be free from hardness ions such as calcium (Ca +2 ) and magnesium (Mg +2...4NaOH + 2H2 (6) Overall: 6H2O + 4NaCl  4HClIX + 4 NaOH  + 2H2Cathode + O2Anode (7) The amount of H + generated by the cathode...electrode that is operating as the cathode. Ions that impart hardness to seawater include calcium (Ca +2 ) and magnesium (Mg +2 ) ions, and their total

  8. Novel precipitation technique for uranium recovery from carbonate leach solutions

    International Nuclear Information System (INIS)

    Sujoy Biswas; Rupawate, V.H.; Hareendran, K.N.; Roy, S.B.; Chakravartty, J.K.

    2015-01-01

    The recovery of uranium from carbonate ore leach solution was studied using novel precipitation method. The uranium from leach liquor was recovered as magnesium diuranate with NaOH in presence of trace amount of Mg 2+ . Effects of various parameters such as addition of H 2 SO 4 , MgO, MgSO 4 as well as NaOH were investigated for maximum uranium recovery. Overall uranium recovery of the process was 97 % with improved particle size (∼57 µm). Based on the experimental findings, a process flow-sheet was developed for uranium recovery from carbonate ore leach solution with a uranium concentration of <1 g/L. (author)

  9. Adsorption of aqueous Cd(II) and Pb(II) on activated carbon nanopores prepared by chemical activation of doum palm shell

    OpenAIRE

    Gaya, Umar Ibrahim; Otene, Emmanuel; Abdullah, Abdul Halim

    2015-01-01

    Non-uniformly sized activated carbons were derived from doum palm shell, a new precursor, by carbonization in air and activation using KOH, NaOH and ZnCl2. The activated carbon fibres were characterised by X-ray diffraction, N2 adsorption–desorption, scanning electron microscopy, particle size analysis and evaluated for Cd(II) and Pb(II) removal. The 40–50 nm size, less graphitic, mesoporous NaOH activated carbon yielded high adsorption efficiency, pointing largely to the influence surface ar...

  10. Rendimientos de sustancias húmicas de ocho lombricompuestos

    OpenAIRE

    Gómez Zambrano, Jairo; Torrente Trujillo, Armando; Miranda V., José Carlos

    2010-01-01

    They were probed NaOH1KOH, Na4P2O7, NaOH + Na4P2O7, and urea in different concentration for extract humic and fulvic acids from lombricompost. It was found that NaOH 0.1 M is the desirable extractant because is efficient, low in salt and economic. It was made extractions of AH and FA from a eight lombricomposts (cow dung, filter-press cake, coffe pulp and grass residues,...

  11. Etching characteristics of a CR-39 track detector at room temperature in different etching solutions

    International Nuclear Information System (INIS)

    Dajko, G.

    1991-01-01

    Investigations were carried out to discover how the etching characteristics of CR-39 detectors change with varying conditions of the etching process. Measurements were made at room temperature in pure NaOH and KOH solutions; in different alcoholic KOH solutions (PEW solution, i.e. potassium hydroxide, ethyl alcohol, water); and in NaOH and KOH solutions containing different additives. The bulk etching rate of the detector (V B ) and the V (= V T /V B ) function, i.e. track to bulk etch rates ratio, for 6.1 MeV α-particles, were measured systematically. (author)

  12. Alternate radiolabeled markers for detecting metabolic activity of Mycobacterium leprae residing in murine macrophages

    Energy Technology Data Exchange (ETDEWEB)

    Prasad, H.K.; Hastings, R.C.

    1985-05-01

    This study demonstrated the utility of using 4% NaOH as a murine macrophage cell-solubilizing agent to discriminate between host macrophage metabolism and that of intracellular Mycobacterium leprae. A 4% concentration of NaOH had no deleterious effect on labeled mycobacteria. Thereby, alternate radiolabeled indicators of the metabolic activity of intracellular M. leprae could be experimented with. Significant incorporation of /sup 14/C-amino acid mixture, (/sup 14/C)leucine, (/sup 14/C)uridine, and carrier-free /sup 32/P was observed in cultures containing freshly extracted (''live'') strains of M. leprae as compared with control cultures containing autoclaved bacilli.

  13. Alternate radiolabeled markers for detecting metabolic activity of Mycobacterium leprae residing in murine macrophages

    International Nuclear Information System (INIS)

    Prasad, H.K.; Hastings, R.C.

    1985-01-01

    This study demonstrated the utility of using 4% NaOH as a murine macrophage cell-solubilizing agent to discriminate between host macrophage metabolism and that of intracellular Mycobacterium leprae. A 4% concentration of NaOH had no deleterious effect on labeled mycobacteria. Thereby, alternate radiolabeled indicators of the metabolic activity of intracellular M. leprae could be experimented with. Significant incorporation of 14 C-amino acid mixture, [ 14 C]leucine, [ 14 C]uridine, and carrier-free 32 P was observed in cultures containing freshly extracted (''live'') strains of M. leprae as compared with control cultures containing autoclaved bacilli

  14. Pengaruh Perlakukan Alkali terhadap Sifat Fisik, dan Mekanik Serat Kulit Buah Pinang

    Directory of Open Access Journals (Sweden)

    Cokorda Putri Kusuma Kencanawati

    2018-04-01

    Full Text Available Makalah ini menganalisis pengaruh perlakukan alkali dan tanpa perlakukan alkali terhadap karakateristik fisik, morfologi dan sifat mekanik serat kulit buah pinang (areca Catechu L.. Selama ini pemanfaatan limbah pertanian belum dilakukan secara maksimal, sehingga dapat menimbulkan pencemaran terhadap lingkungan. Serat kulit buah pinang (Areca Husk Fiber/AHF selama ini hanya dipergunakan sebagai bahan bakar biomassa dan media tanam sedangkan untuk pemanfaatan lain belum ada sama sekali. AHF diberi perlakukan NaOH 2,5%, 5%, 7,5% dan 10% dengan waktu perendaman 2 jam pada temperatur kamar, untuk mengetahui karakteristik fisik AHF maka dilakukan pengukuran panjang dan diameter serat, pengujian densitas, pengujian kadar air dan moisture sedangkan untuk mengetahui karakteristik mekanik dilakukan pengujian tarik serat tunggal sesuai dengan ASTM D 3379. Dari penelitian ini diketahui bahwa diameter AHF mengalami pengurangan diameter akibat perlakukan alkali, hal ini terkait dengan hilangnya kandungan lignin, pektin dan wax. Densitas AHF menurun dengan meningkatan prosentase NaOH bila dibandingkan dengan AHF tanpa perlakukan NaOH. Kekuatan tarik bervariasi dengan adanya perlakuan alkali.  Kekuatan tarik AHF tertinggi pada serat yang mengalami perlakukan NaOH 5% yaitu sebesar 165 Mpa dan kekuatan tarik terendah pada AHF dengan perlakuan Alkali 10% yaitu sebesar 137 MPa . This paper analyzes the effect of alkali and non-alkali treatments on the physical characteristics, morphology and mechanical properties of betel nut huks fiber (areca Catechu L.. the used of agricultural waste has not been done optimally, causing environmental pollution. Areca Husk Fiber (AHF only used as biomass fuel and planting medium, while for the other uses it has not existed. AHF was given 2.5%, 5%, 7.5% and 10% NaOH treatment with 2 hours immersion at room temperature, to known the physical characteristics of AHF then measured the length and diameter of fiber, density test, water

  15. One-Step Synthesis of Hierarchical ZSM-5 Using Cetyltrimethylammonium as Mesoporogen and Structure-Directing Agent

    OpenAIRE

    Meng, Lingqian; Mezari, Brahim; Goesten, Maarten G.; Hensen, Emiel J. M.

    2017-01-01

    Hierarchical ZSM-5 zeolite is hydrothermally synthesized in a single step with cetyltrimethylammonium (CTA) hydroxide acting as mesoporogen and structure-directing agent. Essential to this synthesis is the replacement of NaOH with KOH. An in-depth solid-state NMR study reveals that, after early electrostatic interaction between condensed silica and the head group of CTA, ZSM-5 crystallizes around the structure-directing agent. The crucial aspect of using KOH instead of NaOH lies in the faster...

  16. Pembuatan Dan Karakterisasi Kertas Dari Campuran Serat Jambul Nanas Dan Serat Jerami Padi

    OpenAIRE

    Mufridayati

    2015-01-01

    The Research for making and characterization of paper has been made by using crested pineapple and straw fiber. The study was conducted to determine the optimum mixture of crested pineapple fiber and straw fiber composition that varied to 100%:0%, 80%:20%, 60%:40%, 40%:60%, 20%:80%, 0%:100%. Dried crested pineapple cooked by using 1,5 % NaOH with 225 gr in 100 0C. Dried rice straw was cooked with by using 1,5 % NaOH in 100 0C. Then , the pulp was dried under the sun. The pulp was washed and w...

  17. Study on the Pretreating Approaches for the Potato Straws

    OpenAIRE

    An Yumin; Wang Jukui; Huang Ye; Xu Xiaomei

    2016-01-01

    This paper proposes an approach to pretreat the potato straws. Specifically, potato straws are handled using various kinds of chemical solutions, including HCI, H2SO4, NaOH and NaOH+H2O2, under different concentrations. For each kind of solution, particular indicators, such as the cellulose content as well as scarification ratio of the treated straws, are studied in the paper. Based on orthogonal experiments, the best pretreatment effect is obtained by using the solution of 4% NaOH under temp...

  18. Investigation of interaction of phosphorotungstenvanadium heteropolyacids with sodium hydroxide by the methods of calorimetric and potentiometric titration

    International Nuclear Information System (INIS)

    Ganelina, E.Sh.; Borgoyakov, S.A.

    1985-01-01

    Interaction of phosphorotungstenvanadium heteropolyacids (HPA) with alkali (NaOH) is studied by the methods of calorimetric and potentiometric titration. Three stages are singled out: 1) neutralization of ''strong'' hydrogen atoms with a constant thermal effect of 52.0+-1.6 kJ/mol; 2) neutralization of ''weak'' protons, which acidity constant is of order 10 -2 ; 3) interaction of NaOH with hydrogen atoms combined with the internal sphere of HPA, and completed by HPA destruction. The data obtained are compared with the results, calculating the composition of polymer particles inside HPA, and they are discussed from the view point of their micellar structure

  19. The influence of temperature, pH/molarity and extractant on the removal of arsenic, chromium and zinc from contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Rastas Amofah, Lea; Maurice, Christian; Kumpiene, Jurate [Luleaa Univ. of Technology, Luleaa (Sweden). Dept. of Civil, Environmental and Natural Resources; Bhattacharya, Prosun [Royal Institute of Technology (KTH), Stockholm (Sweden). Dept. of Land and Water Resources Engineering

    2011-12-15

    Normal soil washing leave high residual pollutant content in soil. The remediation could be improved by targeting the extraction to coarser fractions. Further, a low/high extraction pH and higher temperature enhance the pollutant removal, but these measures are costly. In this study, the utility of NaOH, oxalate-citrate (OC) and dithionite-citrate-oxalate (DCO) solutions for extracting of arsenic, chromium and zinc from contaminated soil were assessed and compared. In addition the effects of NaOH concentration and temperature on NaOH extractions, and those of temperature and pH on OC and DCO extractions, were evaluated. A two-level, full-factorial design with a centre point was implemented. Two factors, concentration and temperature,were evaluated in NaOH extractions, and pH and temperature for OC and DCO solutions. In all cases, the extraction temperature was 20 C, 30 C and 40 C. The studied NaOH concentrations were 0.05, 0.075 and 0.1 M. The pH in OC solutions was 3, 5 and 7, and in DCO solutions, 4.7, 6.3 and 6.7. Water-washed and medium coarse soil fraction of arsenic, chromium and zinc contaminated soil was agitated for 15 min with the extraction solution. In NaOH extractions, the temperature and (less strongly) NaOH concentration significantly affected As and Cr mobilisation, but only the latter affected Zn mobilisation. Both pH and temperature significantly (and similarly) influenced As and Cr mobilisation in OC extractions, while only the pH influenced Zn mobilisation. In contrast, the extraction temperature (but not pH) influenced As, Cr and Zn mobilisation in DCO extractions. For all extractants, mobilisation was most efficient at elevated temperature (40 C). None of the extractants reduced the soil's As content to below the Swedish EPA's guideline value. Use of DCO is not recommended because dithionite has a short lifetime and residual arsenic contents in DCO-extracted soil are relatively high. Instead, sequential extraction with NaOH followed

  20. PENGARUH PROSES DELIGNIFIKASI PADA PRODUKSI GLUKOSA DARI TONGKOL JAGUNG DENGAN HIDROLISIS ASAM ENCER

    OpenAIRE

    Primata Mardina; Adelina I. Talalangi; Jhon F. M. Sitinjak; M. Reza Fahrizal; Andri Nugroho

    2013-01-01

    The dilute acid hydrolysis of corn cob for glucose production has faced barrier because of lignin. In this research, an effective lignin destruction process by alkali hydrolysis which affects glucose production from corn cob as lignocellulose biomass was investigated. Alkali hydrolysis called delignification was performed at 55oC for 4 hr with various NaOH concentrations: 5%, 10% and 15%-wt. It was found that optimal NaOH concentration for lignin reduction was 15%-wt and the percentage of red...

  1. Ultrasound-assisted swelling of bacterial cellulose

    OpenAIRE

    Song, J.; Su, Jing; Loureiro, Ana; Sá, M.; Cavaco-Paulo, Artur; Kim, Hye Rim; Silva, Carla

    2017-01-01

    Bacterial cellulose (BC) was obtained by static cultivation using commercial BC gel from scoby. BC membranes (oven dried and freeze-dried) were swelled with 8% NaOH, in absence and in presence of ultrasound (US), for 30, 60 and 90 min. The influence of swelling conditions on both physico-chemical properties and molecules entrapment was evaluated. Considering the highest levels of entrapment, an optimum swelling procedure was established: 8% NaOH for 30 min. at room temperature in the presence...

  2. Effect of pre-treatments on the germination of jasmin box (Phillyrea latifolia) seeds in Greece

    OpenAIRE

    Spyroglou, Gavriil; Radoglou, Kalliopi

    2017-01-01

    The major problem in seedlings production of jasmin box (Phillyrea latifolia) is the poor and irregular germination due to seed dormancy. The objective of the present study was to evaluate methods of seed pre-treatments to increase germination. The effect of different solutions of KOH and NaOH, wood ash lye, GA3 and cold or warm stratification on germination were evaluated. Sets of four replicates of 25 seeds were soaked for 24 hours in KOH and NaOH solutions of 0.2, 0.5, 1 and 2 %, in wood a...

  3. Carbon fuel particles used in direct carbon conversion fuel cells

    Science.gov (United States)

    Cooper, John F.; Cherepy, Nerine

    2012-10-09

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  4. Carbon Fuel Particles Used in Direct Carbon Conversion Fuel Cells

    Science.gov (United States)

    Cooper, John F.; Cherepy, Nerine

    2008-10-21

    A system for preparing particulate carbon fuel and using the particulate carbon fuel in a fuel cell. Carbon particles are finely divided. The finely dividing carbon particles are introduced into the fuel cell. A gas containing oxygen is introduced into the fuel cell. The finely divided carbon particles are exposed to carbonate salts, or to molten NaOH or KOH or LiOH or mixtures of NaOH or KOH or LiOH, or to mixed hydroxides, or to alkali and alkaline earth nitrates.

  5. Synthesis of C60(OH)18-20 in aqueous alkaline solution under O2-atmosphere

    International Nuclear Information System (INIS)

    Alves, Gustavo Catao; Ladeira, Luiz Orlando; Righi, Ariete; Krambrock, Klaus; Pinheiro, Mauricio Veloso B.; Calado, Hallen Daniel; Gil, Rossimiriam Pereira de Freitas

    2006-01-01

    In this work we report on an alternative synthesis of water-soluble fullerenes known as fullerols, aiming for biomedical applications. The synthesis is based on a process in which polyethylene glycol (PEG400) is used as phase-transfer catalyst between fullerene/benzene and aqueous NaOH solutions. The polyhydroxylation of the fullerenes occurs in the NaOH solution under a continuous flow of O 2 to enhance the reaction yield. The resulting compound was characterized with infrared spectroscopy, nuclear magnetic resonance, thermo-gravimetric analysis and optical absorption. The formation of C 60 (OH) 18-20 in high yields was confirmed. (author)

  6. Short Communications

    African Journals Online (AJOL)

    NaOH treatment. P.H. Henning* and D.G. Steyn. Animal and Dairy Science Research Institute, Private Bag X2,. Irene, 1675 Republic of South Africa. Different portions (stalks, cobs, plant leaves, and cob leaves) from mature dry maize plants remaining after grain harvest were collected on two occasions, 8 weeks apart.

  7. Microwave-Assisted Synthesis of Some 1H-1,2,4-Triazol-3-one ...

    African Journals Online (AJOL)

    NICO

    ester, hydrazide, oxadiazole and acetic acid derivatives of. 1,2,4-triazol-3-one by using microwave irradiation and conven- tional heating. Our research group has ..... 1 equiv. of. NaOH in absolute ethanol for 4 h. Then, the mixture was cooled at room temperature , poured into cold water and acidified to. pH 5 with conc. HCl.

  8. Extraction of pigments from seeds of Bixa orellana L.: an alternative for experimental courses in organic chemistry; Extracao de pigmentos das sementes de Bixa orellana L.: uma alternativa para disciplinas experimentais de quimica organica

    Energy Technology Data Exchange (ETDEWEB)

    Costa, Charllyton Luis S. da; Chaves, Mariana H. [Piaui Univ., Teresina, PI (Brazil). Dept. de Quimica]. E-mail: mariana@ufpi.br

    2005-02-01

    This paper describes methodologies for the extraction and characterization by TLC, UV-VIS, IR and NMR of bixin from Bixa orellana L. (urucum) seeds. Based on the results, the extraction with NaOH 5% is the fastest, uses low cost materials, requires two to four laboratory hours and is a useful alternative for an experimental Organic Chemistry discipline. (author)

  9. Resistance of surface-dried virus to common disinfection procedures

    NARCIS (Netherlands)

    Terpstra, F. G.; van den Blink, A. E.; Bos, L. M.; Boots, A. G. C.; Brinkhuis, F. H. M.; Gijsen, E.; van Remmerden, Y.; Schuitemaker, H.; van 't Wout, A. B.

    2007-01-01

    It is believed that surface-dried viruses can remain infectious and may therefore pose a threat to public health. To help address this issue, we studied 0.1 N NaOH and 0.1% hypochlorite for their capacity to inactivate surface-dried lipid-enveloped (LE) [human immunodeficiency virus (HIV), bovine

  10. Analyse statistique et effet des traitements chimique sur le ...

    African Journals Online (AJOL)

    The results show that the chemical treatment improves the mechanical properties (failure stress and Young's modulus) and the optimum was found for the fibres treated with 2% concentration of NaOH for 48h immersion. XRD tests were performed to determine the degree of crystallinity of the treated and untreated fibres.

  11. Enhancing the enzymatic hydrolysis of corn stover by an integrated wet-milling and alkali pretreatment.

    Science.gov (United States)

    He, Xun; Miao, Yelian; Jiang, Xuejian; Xu, Zidong; Ouyang, Pingkai

    2010-04-01

    An integrated wet-milling and alkali pretreatment was applied to corn stover prior to enzymatic hydrolysis. The effects of NaOH concentration in the pretreatment on crystalline structure, chemical composition, and reducing-sugar yield of corn stover were investigated, and the mechanism of increasing reducing-sugar yield by the pretreatment was discussed. The experimental results showed that the crystalline structure of corn stover was disrupted, and lignin was removed, while cellulose and hemicellulose were retained in corn stover by the pretreatment with 1% NaOH in 1 h. The reducing-sugar yield from the pretreated corn stovers increased from 20.2% to 46.7% when the NaOH concentration increased from 0% to 1%. The 1% NaOH pretreated corn stover had a holocellulose conversion of 55.1%. The increase in reducing-sugar yield was related to the crystalline structure disruption and delignification of corn stover. It was clarified that the pretreatment significantly enhanced the conversion of cellulose and hemicellulose in the corn stover to sugars.

  12. Effect of heat treatments and minor elements on caustic stress corrosion cracking of type 304 stainless steel

    International Nuclear Information System (INIS)

    Yamanaka, Kazuo; Kowaka, Masamichi

    1983-01-01

    The effect of heat treatments and minor elements (C, S, P, N) on caustic stress corrosion cracking of Type 304 stainless steel in boiling 34% NaOH solution at 393 K was studied. The results obtained as follows: (1) Susceptibility to IGSCC (intergranular stress corrosion cracking) in NaOH solution was increased with the intergranular precipitation of chromium carbides by the sensitizing heat treatments, but was not completely consistent with the susceptibility to IGC (intergranular corrosion) by Strauss test in H 2 SO 4 + CuSO 4 solution. (2) SCC in NaOH solution took place in three potential ranges of about -100 to +150 mV (vs SCE), -600 to -300 mV and -1100 to -900 mV. Transglanular cracking predominantly occurred in the first region and intergranular cracking occurred in the latter two regions. IGC occurred in the potential range of about -400 to 0 mV. No IGC was observed at corrosion potential. (3) Among minor elements carbon and sulfur had a detrimental effect on SCC, but no effect of phosphorus and nitrogen was almost observed on SCC in NaOH solution. (author)

  13. Direct anodic hydrochloric acid and cathodic caustic production during water electrolysis

    Science.gov (United States)

    Lin, Hui-Wen; Cejudo-Marín, Rocío; Jeremiasse, Adriaan W.; Rabaey, Korneel; Yuan, Zhiguo; Pikaar, Ilje

    2016-02-01

    Hydrochloric acid (HCl) and caustic (NaOH) are among the most widely used chemicals by the water industry. Direct anodic electrochemical HCl production by water electrolysis has not been successful as current commercially available electrodes are prone to chlorine formation. This study presents an innovative technology simultaneously generating HCl and NaOH from NaCl using a Mn0.84Mo0.16O2.23 oxygen evolution electrode during water electrolysis. The results showed that protons could be anodically generated at a high Coulombic efficiency (i.e. ≥ 95%) with chlorine formation accounting for 3 ~ 5% of the charge supplied. HCl was anodically produced at moderate strengths at a CE of 65 ± 4% together with a CE of 89 ± 1% for cathodic caustic production. The reduction in CE for HCl generation was caused by proton cross-over from the anode to the middle compartment. Overall, this study showed the potential of simultaneous HCl and NaOH generation from NaCl and represents a major step forward for the water industry towards on-site production of HCl and NaOH. In this study, artificial brine was used as a source of sodium and chloride ions. In theory, artificial brine could be replaced by saline waste streams such as Reverse Osmosis Concentrate (ROC), turning ROC into a valuable resource.

  14. Biological treatment of sulfidic spent caustics under haloalkaline conditions using soda lake bacteria

    NARCIS (Netherlands)

    Graaff, de C.M.

    2012-01-01

    In this thesis, the development of a newbiotechnological process for the treatment of undiluted sulfidic spent caustics (SSC’s) using soda lake bacteria is described. SSC’s are waste solutions that are formed in the oil and gas industry due to the caustic (NaOH) scrubbing of hydrocarbon streams

  15. Increased amounts of D-enantiomer dependent on alkaline concentration in the synthesis of L-[methyl-11C]methionine

    International Nuclear Information System (INIS)

    Ishiwata, Kiichi; Ido, Tatsuo; Vaalburg, W.

    1988-01-01

    The presence of D-enantiomer in L-[methyl- 11 C]methionine prepared from [ 11 C]CH 3 I and L-homocysteine thiolactone, was measured by high performance liquid chromatography using a reverse-phase column with an eluent containing L-proline and cupric acetate. The amount of D-enantiomer increased with concentration of NaOH used. The reaction time, 2-10 min, and the reaction temperature, 40 0 -80 0 C, have only minor effect on the formation of D-enantiomer. No significant difference was found for three different lots of L-homocysteine thiolactone. At the highest concentration investigated, 1.0 M NaOH in 50% aqueous acetone, the percentage of D-enantiomer was found to be 7.7%. With 0.025 M NaOH used only 2.1% was measured. When L-[methyl- 11 C]methionine was incubated in 1.0 M NaOH, no conversion of L- into D-enantiomer was observed. (author)

  16. Study of Fiber Treatment and Water Absorption toward Tensile Stength of Coconut Filtrate/Polyester Composite

    Directory of Open Access Journals (Sweden)

    Putu Lokantara

    2012-11-01

    Full Text Available Tapis Kelapa (coconut filter as natural fiber, in this time it resourches very copius but no longer be exploited off hand andwaste though in fact it used for alternative to be composite. The objective of this research is to investigated tensile strength ofcomposite tapis kelapa as reinforcement and epoxy 7120 and hardener versamid 140 as matrix. The fiber is treated with thechemical NaOH with percentage 0,5%, 1% dan 2% in weight, respectively. This research used coconut-tapis fibre which cutas long as 1cm with 0%,5%,7,5%,10% fiber volume fraction, respectively. Soaking time on the water are 24 hour, 48 hour,98 hour and 196 hour, respectively. For testing of speciment in tensile test with ASTM D3039. The result of this researchshown that the composite with no treatment with NaOH have soak the water better than the composite with treatment NaOH.The average of tensile strength with no treatment NaOH less than with treatment NaOH. The highest strength are reached bycomposite with 10% fraction volume on 48 hour soaking time equal to 52 MPa. While the lowest tensile strength are reachedby composite with 0% fraction volume fibre equal to 16,667 MPa. The average of tensile strength that soak in mineral waterbetter than sea water.

  17. Assessment of effect of chemical treatment to carnauba's fibers straw; Avaliacao do efeito de tratamento quimico as fibras da palha de carnauba

    Energy Technology Data Exchange (ETDEWEB)

    Carvalho, T.M.P. de; Carvalho, L.F.M.; Oliveira, R.R. de; Sousa, F.M.S. de; Sousa, R.C. de; Marques, J.R., E-mail: thaismarjore.pc@gmail.com [Instituto Federal de Educacao, Ciencia e Tecnologia do Piaui (IFPI), Teresina, PI (Brazil)

    2016-07-01

    The use of natural fibers in composite materials has been highlighted in the scientific field. However, its application in polymer matrices usually requires surface modifications. The objective of this work was to treat carnauba's straw fibers with NaOH 1 % and NaOH 5% solutions and measure the water absorption. We used the X-ray diffraction (XRD configuration “Bragg- Brentano) for verification of the crystalline phases and Fourier Transform Infrared Spectroscopy (FTIR) to identify functional groups. The alkali treatment allowed the solubilization of the hemicellulose and lignin without causing changes to cellulose, as indicated by FTIR spectrophotometry and by the increase in crystallinity content. The samples showed the typical peaks of constituents of the fiber. The natural fiber showed an average water absorption of 256 %; fiber treated with NaOH 1%, 315 %; and treated with NaOH 5%, 405 %. Therefore, it is evident improvement in hydrophilicity, fundamental aspect in the interaction fiber / matrix. (author)

  18. Skin barrier integrity and natural moisturising factor levels after cumulative dermal exposure to alkaline agents in atopic dermatitis

    NARCIS (Netherlands)

    Angelova-Fischer, Irena; Dapic, Irena; Hoek, Anne-Karin; Jakasa, Ivone; Fischer, Tobias W.; Zillikens, Detlef; Kezic, Sanja

    2014-01-01

    Dermal exposure to alkaline agents may lead to skin barrier damage and irritant contact dermatitis. The objective of this study was to investigate the effects of cumulative exposure to 0.5% sodium lauryl sulphate (SLS) and 0.15% NaOH on the barrier function and natural moisturising factor (NMF)

  19. Glass and antimony electrodes for long-term pH monitoring: a dynamic in vitro comparison

    NARCIS (Netherlands)

    Geus, W. P.; Smout, A. J.; Kooiman, J. C.; Lamers, C. B.; Gues, J. W.

    1995-01-01

    OBJECTIVE: To compare the performance of combined glass microelectrodes with monocrystalline and polycrystalline antimony electrodes with external reference in a 24-h dynamic in vitro study. DESIGN AND METHODS: In an artificial stomach, the pH of the contents titrated from pH1-7 and back by NaOH and

  20. Lime application for the efficient production of nutraceutical glucooligosaccharides from Leuconostoc mesenteroides NRRL B-742 (ATCC13146).

    Science.gov (United States)

    Moon, Young Hwan; Madsen, Lee; Chung, Chang-Ho; Kim, Doman; Day, Donal F

    2015-02-01

    We have previously demonstrated the production of glucooligosaccharides via a fermentation of sucrose with Leuconostoc mesenteroides NRRL B-742 using sodium hydroxide (NaOH) to control the pH. Because NaOH is expensive, we sought to minimize the cost of our process by substituting hydrated lime and saccharate of lime (lime sucrate) in its place. The yield of glucooligosaccharides using either 5 % lime (41.4 ± 0.5 g/100 g) or 5 % lime sucrate (40.0 ± 1.4 g/100 g) were both similar to the NaOH control (42.4 ± 1.5 g/100 g). Based on this, it appears that the cost associated with pH control in our process can be reduced by a factor of approximately 2.4 using lime instead of NaOH. Because our chromatographic stage is based on a Ca(2+)-form resin to separate glucooligosaccharides, the use of lime not only negates the need for costly de-salting via ion-exchange (elimination of two ion-exchange sections) prior to separation, but also greatly reduces the resin regeneration cost.

  1. Struvite pyrolysate recycling combined with dry pyrolysis for ammonium removal from wastewater.

    Science.gov (United States)

    Yu, Rongtai; Geng, Jinju; Ren, Hongqiang; Wang, Yanru; Xu, Ke

    2013-03-01

    The dry pyrolysis of magnesium ammonium phosphate (MAP) with NaOH powder for ammonium release was investigated, as well as the utility of MAP pyrolysate recycling. The identities of the MAP pyrolysate and its derivatives were experimentally validated. The results showed that the pyrolysate was amorphous magnesium hydrogen phosphate (MgHPO4) and magnesium pyrophosphate (Mg2P2O7). The best molar ratio of sodium hydroxide (NaOH) powder to ammonium was 1:1, at 110°C for 3h. The optimum pH for pyrolysate recycling was 9.5. The ammonia removal ratio could be maintained above 80% with MAP pyrolysate recycling. Seed crystal inoculation increased the rate of MAP crystallization by 20.86%, as well as the MAP grain size (2.08nm with seeding versus 1.72nm without). MAP particle size with NaOH treatment decreased: d(0.5)=19.34μm versus d(0.5)=30.35μm for direct pyrolysis. The results demonstrated that crystal growth was controlled by adding NaOH during MAP pyrolysis. Copyright © 2013 Elsevier Ltd. All rights reserved.

  2. Nanostructured magnesium has fewer detrimental effects on osteoblast function

    Directory of Open Access Journals (Sweden)

    Weng L

    2013-05-01

    Full Text Available Lucy Weng, Thomas J Webster School of Engineering and Department of Orthopedics, Brown University, Providence, RI, USA Abstract: Efforts have been made recently to implement nanoscale surface features on magnesium, a biodegradable metal, to increase bone formation. Compared with normal magnesium, nanostructured magnesium has unique characteristics, including increased grain boundary properties, surface to volume ratio, surface roughness, and surface energy, which may influence the initial adsorption of proteins known to promote the function of osteoblasts (bone-forming cells. Previous studies have shown that one way to increase nanosurface roughness on magnesium is to soak the metal in NaOH. However, it has not been determined if degradation of magnesium is altered by creating nanoscale features on its surface to influence osteoblast density. The aim of the present in vitro study was to determine the influence of degradation of nanostructured magnesium, created by soaking in NaOH, on osteoblast density. Our results showed a less detrimental effect of magnesium degradation on osteoblast density when magnesium was treated with NaOH to create nanoscale surface features. The detrimental degradation products of magnesium are of significant concern when considering use of magnesium as an orthopedic implant material, and this study identified a surface treatment, ie, soaking in NaOH to create nanoscale features for magnesium that can improve its use in numerous orthopedic applications. Keywords: nanostructured magnesium, degradation, detrimental effects, osteoblasts

  3. Nanostructured magnesium has fewer detrimental effects on osteoblast function.

    Science.gov (United States)

    Weng, Lucy; Webster, Thomas J

    2013-01-01

    Efforts have been made recently to implement nanoscale surface features on magnesium, a biodegradable metal, to increase bone formation. Compared with normal magnesium, nanostructured magnesium has unique characteristics, including increased grain boundary properties, surface to volume ratio, surface roughness, and surface energy, which may influence the initial adsorption of proteins known to promote the function of osteoblasts (bone-forming cells). Previous studies have shown that one way to increase nanosurface roughness on magnesium is to soak the metal in NaOH. However, it has not been determined if degradation of magnesium is altered by creating nanoscale features on its surface to influence osteoblast density. The aim of the present in vitro study was to determine the influence of degradation of nanostructured magnesium, created by soaking in NaOH, on osteoblast density. Our results showed a less detrimental effect of magnesium degradation on osteoblast density when magnesium was treated with NaOH to create nanoscale surface features. The detrimental degradation products of magnesium are of significant concern when considering use of magnesium as an orthopedic implant material, and this study identified a surface treatment, ie, soaking in NaOH to create nanoscale features for magnesium that can improve its use in numerous orthopedic applications.

  4. Developing Ionic Liquid Know-How for the Design of Modular Functionality, Versatile Platforms, and New Synthetic Methodologies for Energetic Materials

    Science.gov (United States)

    2013-12-05

    of BioRad AG 1-X8 strongly basic anion exchange resin in chloride form was eluted with ~20 bed volumes (~1 L) of 1 N NaOH and each eluted volume...over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure (bath 60–70 °C) to remove DMF and the residue was purified via

  5. Synthesis of high capacity cation exchangers from a low-grade Chinese natural zeolite

    International Nuclear Information System (INIS)

    Wang Yifei; Lin Feng

    2009-01-01

    The Chinese natural zeolite, in which clinoptilolite coexists with quartz was treated hydrothermally with NaOH solutions, either with or without fusion with NaOH powder as pretreatment. Zeolite Na-P, Na-Y and analcime were identified as the reacted products, depending on the reaction conditions such as NaOH concentration, reaction time and hydrothermal temperature. The products were identified by X-ray diffraction, and characterized by Fourier transform IR and ICP. With hydrothermal treatment after fusion of natural zeolite with NaOH, high purity of zeolite Na-Y and Na-P can be selectively formed, their cation exchange capacity (CEC) are 275 and 355 meq/100 g respectively, which are greatly higher than that of the natural zeolite (97 meq/100 g). Furthermore, the ammonium removal by the synthetic zeolite Na-P in aqueous solution was also studied. The equilibrium isotherms have been got and the influence of other cations present in water upon the ammonia uptake suggested an order of preference Ca 2+ > K + > Mg 2+ .

  6. Evaluation and Refinement of a Field-Portable Drinking Water Toxicity Sensor Utilizing Electric Cell-Substrate Impedance Sensing and a Fluidic Biochip

    Science.gov (United States)

    2014-01-01

    byproducts of cyanobacteria blooms) and humic/fulvic acids (by-products of plant decomposition). Hard water, which is high in calcium and magnesium and...with 20% HCl or 1.0 N NaOH until the color of the test sample was empirically similar to the control sample to ensure that ECIS responses were due to

  7. p Mil prepar k clott ation f ting an from P nd prot Pedioco pr teolytic ...

    African Journals Online (AJOL)

    SAM

    reasons, vegetarianism diet or consumer concern regarding genetically engineered foods as in Germany, .... adjusted to the set pH with 0.1 N NaOH or 0.1 M HCl with fast stirring. ..... similar behavior was reported for the crude extract from.

  8. Investigation of the effect of some parameters on the degree of leaching antimony from stibnite

    Directory of Open Access Journals (Sweden)

    Remeteiová Dagmar

    1998-12-01

    Full Text Available The paper presents results of experiments of agitation leaching of antimony from stibnite in alkaline solutions of Na2S +NaOH. The influence of different solution solutions ratio of the reacting phases and of different rate of stirring on the degree of leaching of antimony was investigated.

  9. The effect of different pH modifier on formation of CdS nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Xiaoxiao, Ren [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China); Zhao Gaoling [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)], E-mail: glzhao@zju.edu.cn; Hong, Li; Wei, Wu; Gaorong, Han [State Key Laboratory of Silicon Materials, Department of Materials Science and Engineering, Zhejiang University, Hangzhou 310027 (China)

    2008-10-06

    CdS nanoparticles were prepared by hydrothermal method. The effects of pH modifier on the properties of CdS particles were studied. NaOH and NH{sub 4}OH were chosen as the pH modifier. The morphology and optical properties of CdS particles were characterized by transmitted electron microscope (TEM) and optical absorption spectra analysis, respectively. The particle size of the samples whose pH modifier is NaOH was smaller than that of the CdS samples with NH{sub 4}OH at the same pH value. Optical absorption edge of CdS shifted to longer wavelength with increasing pH value. Optical absorption edge of the samples with NH{sub 4}OH as pH modifier shifted to the longer wavelength more significantly than that of those samples with NaOH as pH modifier. When CdS particles were adsorbed to the TiO{sub 2} electrodes, the photoelectrochemical property of CdS-sensitized TiO{sub 2} electrode showed that the samples with NH{sub 4}OH as pH modifier had higher photocurrent than those samples with NaOH.

  10. The effect of different pH modifier on formation of CdS nanoparticles

    International Nuclear Information System (INIS)

    Ren Xiaoxiao; Zhao Gaoling; Li Hong; Wu Wei; Han Gaorong

    2008-01-01

    CdS nanoparticles were prepared by hydrothermal method. The effects of pH modifier on the properties of CdS particles were studied. NaOH and NH 4 OH were chosen as the pH modifier. The morphology and optical properties of CdS particles were characterized by transmitted electron microscope (TEM) and optical absorption spectra analysis, respectively. The particle size of the samples whose pH modifier is NaOH was smaller than that of the CdS samples with NH 4 OH at the same pH value. Optical absorption edge of CdS shifted to longer wavelength with increasing pH value. Optical absorption edge of the samples with NH 4 OH as pH modifier shifted to the longer wavelength more significantly than that of those samples with NaOH as pH modifier. When CdS particles were adsorbed to the TiO 2 electrodes, the photoelectrochemical property of CdS-sensitized TiO 2 electrode showed that the samples with NH 4 OH as pH modifier had higher photocurrent than those samples with NaOH

  11. Optimization of Glucose Production of Cocopeat Using Whole Cell Trichoderma reesei

    Directory of Open Access Journals (Sweden)

    Zaki Muhammad

    2018-01-01

    Full Text Available The high content of cellulose in cocopeat makes this material convertible into glucose. The converting process of cellulose into glucose can be done by hydrolysis. In this research, the coocopeat hydrolyzed enzymatically using cellulose ezyme from Trichoderma reesei. The purpose of this study was to obtain optimum conditions of glucose yield and to know the effect of concentration of NaOH, molasses mass, and the effect of hydrolisis time on glucose yield produced. The variabel used was hydrolisis time (0; 124; and 240 hour, NaOH concenteration (1%; 2%; and 3%, and molasses mass (40; 50; and 60 gr/l. The result showed the higest glucose level obtained at 2% NaOH concenteration, molasses mass 60 gram, and hydrolysis time 240 hours, while the predicted resulted of the optimum conditions of glucose level produced using the software Design Expert 6.08 is 776.771 mg/l at NaOH concenteration 1,35%, molasses mass 59.96 mg/l and hydrolisis time 215.62 hours.

  12. Lithium-Vanadium bronzes as model catalysts for the selective reduction of nitric oxide

    NARCIS (Netherlands)

    Bosch, H.; Bongers, Annemie; Enoch, Gert; Snel, Ruud; Ross, Julian R.H.

    1989-01-01

    The effect of alkali metals on the selective reduction of nitric oxide with ammonia has been studied on bulk iron oxide and bulk vanadium oxide. The influence of additions of LiOH, NaOH and KOH on the activity was screened by pulse experiments carried out in the absence of gaseous oxygen; FTIR

  13. Influence of chemical treatment on the tensile properties of kenaf fiber reinforced thermoplastic polyurethane composite

    Directory of Open Access Journals (Sweden)

    Y. A. El-Shekeil

    2012-12-01

    Full Text Available In this study, the effect of polymeric Methylene Diphenyl Diisocyanate (pMDI chemical treatment on kenaf (Hibiscus cannabinus reinforced thermoplastic polyurethane (TPU/KF was examined using two different procedures. The first consisted of treating the fibers with 4% pMDI, and the second involved 2% NaOH + 4% pMDI. The composites were characterized according to their tensile properties, Fourier Transform Infrared Spectroscopy (FTIR and Scanning Electron Microscopy (SEM. The treatment of the composite with 4% pMDI did not significantly affect its tensile properties, but the treatment with 2% NaOH + 4% pMDI significantly increased the tensile properties of the composite (i.e., 30 and 42% increases in the tensile strength and modulus, respectively. FTIR also showed that treatment with 2% NaOH + 4% pMDI led to the strongest H-bonding. Additionally, the surface morphology of specimens after tensile fracture confirmed that the composite treated with 2% NaOH + 4% pMDI had the best adhesion and wettability.

  14. Acidity titration curves - a versatile tool for the characterisation of acidic mine waste water

    International Nuclear Information System (INIS)

    Fyson, A.

    2000-01-01

    Acidity titrations with NaOH are valuable tools for characterisation of acidic mine waters. - Titrations can be used to estimate metal concentrations. - Titrations can be carried out in the field, minimising changes in water chemistry due to sample handling time and procedure. (orig.)

  15. Effect of carbohydrate source and rumen pH on enteric methane from dairy cows

    DEFF Research Database (Denmark)

    Hellwing, Anne Louise Frydendahl; Brask, Maike; Lund, Peter

    2013-01-01

    The aim of this experiment was to measure the enteric methane emissions in dairy cows fed diets rich in starch or sugar with and without manipulation of rumen pH. The rations were based on grass-clover silage supplemented with either wheat (W), NaOH treated wheat (WNaOH), sugar beet molasses (M...

  16. Structural characteristics of wheat flour arabinoxylans = Structuurkenmerken van arabinoxylanen uit tarwebloem

    NARCIS (Netherlands)

    Gruppen, H.

    1992-01-01

    A procedure has been developed for the isolation of highly purified water-unextractable cell wall material (WUS) from wheat flour. From this material arabinoxylans were extracted via sequential extraction with Ba(OH) 2 , KOH and NaOH solutions. The first extract

  17. Biological and technological effects of some mulberry varieties and ...

    African Journals Online (AJOL)

    egyptian hak

    Rapid industrialization, increases in greenhouse gases in the atmosphere, ... entire agricultural production system through direct or indirect effects on crops, ... to India along with wheat grains under the PL 480 scheme from USA; it has .... water just before use; 1 N NaOH.0.5 grams fresh leaf material of Parthenium were.

  18. Interaction of water unextractable solids with gluten protein: Effect on dough properties and gluten quality

    NARCIS (Netherlands)

    Wang, M.; Oudgenoeg, G.; Vliet, T. van; Hamer, R.J.

    2003-01-01

    In a previous study, we have shown that water unextractable solids (WUS) interfere with gluten formation and affect the quality of the resulting gluten. In this study we aim to explain how WUS can affect the process of gluten formation. To this end, WUS were modified with NaOH, xylanase, horseradish

  19. Effect of γ-rays irradiation and alkali solution pretreatment on hydrolyzing enzyme and microcosmic structure of core straw

    International Nuclear Information System (INIS)

    Tang Hongtao; Wang Feng; Li Weiming; Li An; Ha Yiming; Li Yanjie

    2012-01-01

    To increase yield of reducing sugar enzymatic hydrolyzed from corn straw yield of corn stalk on Enzymatic hydrolysis, γ-rays radiation and NaOH solution pretreatment were used. The changes of microstructure of the corn straw before and after pretreatments were characterized by IR, X-rays diffraction and SEM. The results shows that the γ-rays radiation can significantly decrease the essential concentration of NaOH solution and shorten the immersion time, but it could not affected the yield of reducing sugar remarkably. The scanning electron microscopy (SEM) results show that the sample which was treated at the 200 kGy irradiation dose and NaOH solution circumstance has the biggest surface area increase. The reducing sugar content of enzyme hydrolyzed corn straw treated at 200 kGy irradiation dose and 2% NaOH solution was achieved 48.34%, which provides the theoretical basis for industry ethanol production using enzyme hydrolyzed corn straw. (authors)

  20. Fulltext PDF

    Indian Academy of Sciences (India)

    with Ac2O-Pyr on the C3 carbon side of aziridine.10. On the other ... hydrated acid-activated clays with N-acyl-2,2-dimethy- laziridines 1. ... 10% NaOH to neutral pH, and the aqueous mixture was ..... influence in the progress of these reactions.

  1. Arabinose and ferulic acid rich pectic polysaccharides extracted from sugar beet pulp.

    NARCIS (Netherlands)

    Oosterveld, A.; Beldman, G.; Schols, H.A.; Voragen, A.G.J.

    1996-01-01

    Arabinose and ferulic acid rich polysaccharides were extracted from sugar beet pulp using two extraction methods: a sequential extraction with H2O (2 times), NaOH/EDTA (2 times), and 4 M NaOH (2 times; method A) and a sequential extraction in which the NaOH/EDTA extraction was replaced by an

  2. Nitric acid titration in the presence of UO2(NO3)2, Th(NO3)4, U(NO3)4 or Zr(NO3)4

    International Nuclear Information System (INIS)

    Nakashima, T.; Lieser, K.H.

    1986-01-01

    Procedures are described for titration of HNO 3 in presence of UO 2 2+ , Th 4+ , U 4+ and Zr 4+ without formation of interfering precipitates. In the first step the hydrolysable ions are masked by addition of complexing agents and in the second step the acid is titrated by NaOH as usual. (orig.)

  3. Hydrolysis-precipitation studies of aluminum (III) solutions. I. Titration of acidified aluminum nitrate solutions

    NARCIS (Netherlands)

    Vermeulen, A.C.; Geus, John W.; Stol, R.J.; Bruyn, P.L. de

    Acidified aluminum nitrate solutions were titrated with alkali (NaOH or KOH) over a temperature range of 24°C to 90°C. A homogeneous distribution of added base was achieved by: (i) in situ decomposition of urea (90°C); and (ii) a novel method involving injection through a capillary submerged in the

  4. Compressive strength and hydrolytic stability of fly ash based geopolymers

    Directory of Open Access Journals (Sweden)

    Nikolić Irena

    2013-01-01

    Full Text Available The process of geopolymerization involves the reaction of solid aluminosilicate materials with highly alkaline silicate solution yielding an aluminosilicate inorganic polymer named geopolymer, which may be successfully applied in civil engineering as a replacement for cement. In this paper we have investigated the influence of synthesis parameters: solid to liquid ratio, NaOH concentration and the ratio of Na2SiO3/NaOH, on the mechanical properties and hydrolytic stability of fly ash based geopolymers in distilled water, sea water and simulated acid rain. The highest value of compressive strength was obtained using 10 mol dm-3 NaOH and at the Na2SiO3/NaOH ratio of 1.5. Moreover, the results have shown that mechanical properties of fly ash based geopolymers are in correlation with their hydrolytic stability. Factors that increase the compressive strength also increase the hydrolytic stability of fly ash based geopolymers. The best hydrolytic stability of fly ash based geopolymers was shown in sea water while the lowest stability was recorded in simulated acid rain. [Projekat Ministarstva nauke Republike Srbije, br. 172054 i Nanotechnology and Functional Materials Center, funded by the European FP7 project No. 245916

  5. (3-methyl-2-oxoquinoxalin-1(2H)-yl)acetamide-based azetidinone

    Indian Academy of Sciences (India)

    acid, filtered, washed with cold water, dried and finally recrystallized with ethyl .... nitrobenzylidene)acetohydrazide (4d): Grey solid, yield 52%, Rf (Benzene ...... thus obtained was purified by treatment with 5% w/v. NaOH. Compound (1) on ...

  6. Optimization of isolation of cellulose from orange peel using sodium hydroxide and chelating agents.

    Science.gov (United States)

    Bicu, Ioan; Mustata, Fanica

    2013-10-15

    Response surface methodology was used to optimize cellulose recovery from orange peel using sodium hydroxide (NaOH) as isolation reagent, and to minimize its ash content using ethylenediaminetetraacetic acid (EDTA) as chelating agent. The independent variables were NaOH charge, EDTA charge and cooking time. Other two constant parameters were cooking temperature (98 °C) and liquid-to-solid ratio (7.5). The dependent variables were cellulose yield and ash content. A second-order polynomial model was used for plotting response surfaces and for determining optimum cooking conditions. The analysis of coefficient values for independent variables in the regression equation showed that NaOH and EDTA charges were major factors influencing the cellulose yield and ash content, respectively. Optimum conditions were defined by: NaOH charge 38.2%, EDTA charge 9.56%, and cooking time 317 min. The predicted cellulose yield was 24.06% and ash content 0.69%. A good agreement between the experimental values and the predicted was observed. Copyright © 2013 Elsevier Ltd. All rights reserved.

  7. Polyester composites reinforced with corona-treated fibers from pine, eucalyptus and sugarcane bagasse

    Science.gov (United States)

    This study aims to evaluate plant fibers that were surface activated with NaOH and corona discharge before incorporating in ortho unsaturated polyester-based fiber composites. It demonstrates the potential use of lignocellulosic particles, especially eucalyptus that presented the higher values for a...

  8. Pennycress protein isolate: Pilot plant production and application in films polymeric composites

    Science.gov (United States)

    This work scaled up the process of producing pennycress protein isolates (PPI) using 5 kg starting material (previously 100 g in bench-scale research). Defatted press cake, produced by prepressing and hexane extraction, was mixed with preheated 50 L of aqueous NaOH (pH 10) for 90 min in a jacketed k...

  9. Strength Performance of Blended Ash Based Geopolymer Mortar

    Science.gov (United States)

    Zahib, Zaidahtulakmal M.; Kamaruddin, Kartini; Saman, Hamidah M.

    2018-03-01

    Geopolymer is a based on inorganic alumino-silicate binder system. Geopolymeric materials are formed using materials that containing silica and aluminium such as fly ash and rice husk ash, which activated by alkaline solution. This paper presents the study on the effect of replacement of SSA in RHA based geopolymer, types of curing and different molarity of NaOH used on the strength of Sewage Sludge Ash (SSA) and Rice Husk Ash (RHA) based geopolymer mortar incorporating with three (3) different mix proportions. Based geopolymer mortar was synthesized from treated sewage sludge and rice husk undergoing incineration process in producing ashes, activated with sodium silicate and sodium hydroxide solution by ratio of 2.5:1 and solution to ash ratio of 1:1. Molarity of 8M and 10M NaOH were used. The percentages of SSA replacement were 0%, 10% and 20% by weight. Compressive strength was conducted at age 7, 14 and 28 days to see the development of strength with two curing regimes, which are air curing and oven curing (60°C for 24 hours). From the research conducted, the ultimate compressive strength (6.28MPa) was obtained at zero replacement of SSA taken at 28 days of oven curing with 10M of NaOH. This shows that RHA, which is rich in silica content is enough to enhance the strength of geopolymer mortar especially with high molarity of NaOH.

  10. Ruthenacycles and Iridacycles as Catalysts for Asymmetric Transfer Hydrogenation and Racemisation

    NARCIS (Netherlands)

    Jerphagnon, Thomas; Haak, Robert; Berthiol, Florian; Gayet, Arnaud J.A.; Ritleng, Vincent; Holuigue, Alexandre; Pannetier, Nicolas; Pfeffer, Michel; Voelklin, Adeline; Lefort, Laurent; Verzijl, Gerard; Tarabiono, Chiara; Janssen, Dick B.; Minnaard, Adriaan J.; Feringa, Ben L.; Vries, Johannes G. de

    2010-01-01

    Ruthenacycles, which are easily prepared in a single step by reaction between enantiopure aromatic amines and [Ru(arene)Cl2]2 in the presence of NaOH and KPF6, are very good asymmetric transfer hydrogenation catalysts. A range of aromatic ketones were reduced using isopropanol in good yields with

  11. Influence of vermicompost humic acid on chlorophyll content and ...

    African Journals Online (AJOL)

    S

    2016-11-23

    Nov 23, 2016 ... cattle used was fed mainly with grasses, and the manure was processed with African red worm. This vermicompost was used for the humic substances extraction according to International humic substances society (2008) with NaOH (0.1 mol L-1) in a proportion of 1:10 (mg of vermicompost: mL dissolution) ...

  12. Determination of Titratable Acidity in Wine Using Potentiometric, Conductometric, and Photometric Methods

    Science.gov (United States)

    Volmer, Dietrich A.; Curbani, Luana; Parker, Timothy A.; Garcia, Jennifer; Schultz, Linda D.; Borges, Endler Marcel

    2017-01-01

    This experiment describes a simple protocol for teaching acid-base titrations using potentiometry, conductivity, and/or photometry to determine end points without an added indicator. The chosen example examines the titratable acidity of a red wine with NaOH. Wines contain anthocyanins, the colors of which change with pH. Importantly, at the…

  13. Visualization of Buffer Capacity with 3-D "Topo" Surfaces: Buffer Ridges, Equivalence Point Canyons and Dilution Ramps

    Science.gov (United States)

    Smith, Garon C.; Hossain, Md Mainul

    2016-01-01

    BufCap TOPOS is free software that generates 3-D topographical surfaces ("topos") for acid-base equilibrium studies. It portrays pH and buffer capacity behavior during titration and dilution procedures. Topo surfaces are created by plotting computed pH and buffer capacity values above a composition grid with volume of NaOH as the x axis…

  14. The Acid-Base Titration of a Very Weak Acid: Boric Acid

    Science.gov (United States)

    Celeste, M.; Azevedo, C.; Cavaleiro, Ana M. V.

    2012-01-01

    A laboratory experiment based on the titration of boric acid with strong base in the presence of d-mannitol is described. Boric acid is a very weak acid and direct titration with NaOH is not possible. An auxiliary reagent that contributes to the release of protons in a known stoichiometry facilitates the acid-base titration. Students obtain the…

  15. Effects of Electrolyte on Floating Water Bridge

    Directory of Open Access Journals (Sweden)

    Hideo Nishiumi

    2009-01-01

    spontaneously. In this paper, we examined flow direction of water bridge and what effects the addition of electrolytes such as NaCl, NaOH, and NH4Cl to the floating water bridge would give. We found that ionization degree reduced the length of water bridge though insoluble electrolyte Al2O3 had no effect on the length of water bridge.

  16. A process for the bituminization of radioactive wastes

    International Nuclear Information System (INIS)

    Bar-Ziv, E.; Manor, D.; Levin, I.

    1977-06-01

    A process is described for the incorporation of sodium nitrate solutions in bitumen, with a view to the bituminization of radioactive wastes. This process has involved the development of a chemical process and its technological application. A double jacket reactor equipped with an anchor-type stirrer has been built. Sodium nitrate (NaNO 3 ) solutions with sodium hydroxide (NaOH) are fed into the reactor simultaneously with a bitumen emulsion while heated oil is circulated through the double jacket. After all the water has evaporated, the mixture is ''simmered'' at 170/180 deg C for up to 5 hours in order to get a homogeneous product which will be suitable for final storage. The product contains small salt crystals (10/50 μm) and has high viscosity (200/2000 poise at 160 deg C and 12 rpm), so that the possibility of sedimentation is eliminated. In comparative experiments with molten bitumen, large salt aggregates, inhomogeneously distributed, make the product unsuitable. It has been found that NaOH is responsible for the polimerization of the bitumen, which raises its viscosity. The degree of polimerization depends on the NaOH concentration and ''simmering'' time and temperature. NaOH is added to NaNO 3 in order to raise the mixture's viscosity and thereby prevent sedimentation

  17. An effective method for extraction and polymerase chain reaction ...

    African Journals Online (AJOL)

    The PCR amplification with the NaOH and PBS treatment had a success rate of 30 to 100% for both mitochondrial and nuclear markers. The PBS method is the best method for extraction of DNA from formalin-preserved samples of longer period (two to seven years) because of higher success rate in amplifying mitochondrial ...

  18. A comparison of five extraction methods for extracellular polymeric ...

    African Journals Online (AJOL)

    Two physical methods (centrifugation and ultrasonication) and 3 chemical methods (extraction with EDTA, extraction with formaldehyde, and extraction with formaldehyde plus NaOH) for extraction of EPS from alga-bacteria biofilm were assessed. Pretreatment with ultrasound at low intensity doubled the EPS yield without ...

  19. Effect of alkali-treatment on the characteristics of natural zeolites with different compositions.

    Science.gov (United States)

    Ates, Ayten

    2018-08-01

    A series of natural zeolites with different compositions were modified by post-synthesis modification with sodium hydroxide (NaOH) solution. Natural and modified zeolites were characterized by XRD, SEM, nitrogen adsorption, FTIR, zeta potential and temperature programmed desorption of ammonia (NH 3 -TPD). The adsorption capacities of these samples were evaluated by the adsorption of manganese from aqueous solution. The treatment with NaOH led to a decrease in the surface area and microporosity of all natural zeolites as well as partly damage of the zeolite structure depending on zeolite composition. In addition, the amount of weak, medium and strong acid sites in the zeolites was changed significantly by NaOH treatment depending on zeolite composition. The NaOH treatment resulted in a four-fold improvement in adsorption capacity of natural zeolite originated from Bigadic and a twofold decrease in that of the natural zeolite originated from Manisa-Gordes. Although the improved adsorption capacity might be mainly due to modification of porosity in the zeolites and formation of hydroxysodalite, the reduced adsorption capacity of the zeolite might be mainly due to a significant deformation of the zeolite structure. The pseudo-second-order kinetic model for the adsorption of manganese on all natural and modified zeolites fits well. Copyright © 2018 Elsevier Inc. All rights reserved.

  20. Nanostructured magnesium has fewer detrimental effects on osteoblast function

    Science.gov (United States)

    Weng, Lucy; Webster, Thomas J

    2013-01-01

    Efforts have been made recently to implement nanoscale surface features on magnesium, a biodegradable metal, to increase bone formation. Compared with normal magnesium, nanostructured magnesium has unique characteristics, including increased grain boundary properties, surface to volume ratio, surface roughness, and surface energy, which may influence the initial adsorption of proteins known to promote the function of osteoblasts (bone-forming cells). Previous studies have shown that one way to increase nanosurface roughness on magnesium is to soak the metal in NaOH. However, it has not been determined if degradation of magnesium is altered by creating nanoscale features on its surface to influence osteoblast density. The aim of the present in vitro study was to determine the influence of degradation of nanostructured magnesium, created by soaking in NaOH, on osteoblast density. Our results showed a less detrimental effect of magnesium degradation on osteoblast density when magnesium was treated with NaOH to create nanoscale surface features. The detrimental degradation products of magnesium are of significant concern when considering use of magnesium as an orthopedic implant material, and this study identified a surface treatment, ie, soaking in NaOH to create nanoscale features for magnesium that can improve its use in numerous orthopedic applications. PMID:23674891

  1. Hydrodeoxygenation of Methyl Laurate over Ni Catalysts Supported on Hierarchical HZSM-5 Zeolite

    Directory of Open Access Journals (Sweden)

    Nana Li

    2017-12-01

    Full Text Available The hierarchical HZSM-5 zeolite was prepared successfully by a simple NaOH treatment method. The concentration of NaOH solution was carefully tuned to optimal the zeolite acidity and pore structure. Under NaOH treatment conditions, a large number of mesopores, which interconnected with the retained micropores, were created to facilitate mass transfer performance. There are very good correlations between the decline of the relative zeolite crystallinity and the loss of micropores volume. The Ni nanoclusters were uniformly confined in the mesopores of hierarchical HZSM-5 by the excessive impregnation method. The direct deoxygenation in N2 and hydrodeoxygenation in H2 of the methyl laurate were compared respectively over the Ni/HZSM-5 catalysts. In the N2 atmosphere, the deoxygenation rate of the methyl laurate on the Ni/HZSM-5 catalyst is relatively slow. In the presence of H2, the synergistic effect between the hydrogenation function of the metal and the acid function of the zeolite supports can make the deoxygenation level more obvious. The yield of hydrocarbon products gradually reached the maximum with the appropriate treatment concentration of 1M NaOH, which could be attributed to the improved mass transfer in the hierarchical HZSM-5 supports.

  2. Synthesis of Analcime Crystals and Simultaneous Potassium Extraction from Natrolite Syenite

    Directory of Open Access Journals (Sweden)

    Jian Chen

    2017-01-01

    Full Text Available Analcime single crystals were successfully synthesized from natrolite syenite powder (K2O 10.89% and 92.6% of potassium was extracted simultaneously by means of soda roasting followed by alkali-hydrothermal method. Effects of NaOH concentration, reaction temperature, and holding period on the analcime formation and potassium extraction were investigated systemically. The results indicated that NaOH concentration plays an important role in determining the chemical composition of zeolites and size distribution; by turning the NaOH concentrations, three different pure zeolites (i.e., the phillipsite-Na, the analcime, and the sodalite were prepared. Besides, a higher temperature could accelerate the dissolution of K+ ions and enhance the crystallinity degree of zeolite. The reactions involved in the analcime synthesis can be summarized as follows: sodium aluminum silicate dissolution → precipitation and dissolution of metastable zeolite-P → analcime nucleation → analcime growth. The extraction ratio of K+ is associated with the types of synthesized zeolites, among which analcime is the most effective to promote potassium leaching out from zeolite lattice position. The optimal condition for analcime crystallization and K+ leaching is found to be as follows: 175°C for 4 h in 0.5 mol/L NaOH solution.

  3. Effect of roasting on the carbohydrate composition of Coffea arabica beans.

    NARCIS (Netherlands)

    Oosterveld, A.; Voragen, A.G.J.; Schols, H.A.

    2003-01-01

    Coffee beans (arabica) with different degrees of roast were sequentially extracted with water (90 °C, 1 h), water (170 °C, 30 min), and 0.05 M NaOH (0 °C, 1 h). The amount and composition of polysaccharides, oligosaccharides and monosaccharides in the extracts and residues were analyzed. The results

  4. Optimization of Extraction Method of the Natural Coagulant from Descurainia Sophia Seed: Minimization of Color Generation

    Directory of Open Access Journals (Sweden)

    Mazyar Peyda

    2016-06-01

    Full Text Available Background: Water treatment sometimes needs a coagulation and flocculation process to remove suspended and colloidal materials. Inorganic coagulants used create concerns about pollution of the environment and harmful effects on the human’s health. The studies carried out previously indicated the capability of an active coagulant agent extracted from Descurainia Sophia seed to remove turbidity of water. Methods: The purpose of this study was to investigate the effect of NaCl (0.05-1 gL-1, NaOH (0.01-0.1 gL-1, extraction duration (1-25 min and the ultrasound frequency (0-45-75 kHz, used in the extraction of Descurainia Sophia seed, on the generation of color in purified water and to provide a model to predict the effects of the studied variables on color generation. Extraction was performed using water as solvent, supplemented with NaCl and NaOH and irradiated by ultrasound. Design of experiments and analysis of results were conducted by the D-optimal method based on the response surface methodology (RSM. Results: The results demonstrated that only the effect of concentration of NaOH is significant in color generation (with p<0.05. Conclusion: The effect of NaOH on color generation in purified water is predictable by the use of a statistically valid linear model at a confidence level of 95%.

  5. A saponification-triggered gelation of ester-based Zn(II) complex through conformational transformations.

    Science.gov (United States)

    Kumar, Ashish; Dubey, Mrigendra; Kumar, Amit; Pandey, Daya Shankar

    2014-09-11

    Novel saponification-triggered gelation in an ester-based bis-salen Zn(II) complex (1) is described. Strategic structural modifications induced by NaOH in 1 tune the dipolar-/π-interactions leading to J-aggregation and the creation of an inorganic gel material (IGM), which has been established by photophysical, DFT and rheological studies.

  6. Neutralization and Acid Dissociation of Hydrogen Carbonate Ion: A Thermochemical Approach

    Science.gov (United States)

    Koga, Nobuyoshi; Shigedomi, Kana; Kimura, Tomoyasu; Tatsuoka, Tomoyuki; Mishima, Saki

    2013-01-01

    A laboratory inquiry into the thermochemical relationships in the reaction between aqueous solutions of NaHCO[subscript 3] and NaOH is described. The enthalpy change for this reaction, delta[subscript r]H, and that for neutralization of strong acid and NaOH(aq), delta[subscript n]H, are determined calorimetrically; the explanation for the…

  7. Isolation of fish skin and bone gelatin from tilapia (Oreochromis niloticus): Response surface approach

    Science.gov (United States)

    Arpi, N.; Fahrizal; Novita, M.

    2018-03-01

    In this study, gelatin from fish collagen, as one of halal sources, was extracted from tilapia (Oreochromis niloticus) skin and bone, by using Response Surface Methodology to optimize gelatin extraction conditions. Concentrations of alkaline NaOH and acid HCl, in the pretreatment process, and temperatures in extraction process were chosen as independent variables, while dependent variables were yield, gel strength, and emulsion activity index (EAI). The result of investigation showed that lower NaOH pretreatment concentrations provided proper pH extraction conditions which combine with higher extraction temperatures resulted in high gelatin yield. However, gelatin emulsion activity index increased proportionally to the decreased in NaOH concentrations and extraction temperatures. No significant effect of the three independent variables on the gelatin gel strength. RSM optimization process resulted in optimum gelatin extraction process conditions using alkaline NaOH concentration of 0.77 N, acid HCl of 0.59 N, and extraction temperature of 66.80 °C. The optimal solution formula had optimization targets of 94.38%.

  8. Effects of Combining Minjingu Phosphate Rock and Triple ...

    African Journals Online (AJOL)

    for determination of NaOH- and Bray I -P. In addition, a P adsorption study was conducted to determine .... of combining MPR with GliriCidia leaves or maize atomic absorption' and. flame photometry, stover on .... DTPA zinc (mg Zn kg'l ). 1.04.

  9. Full Length Research Article

    African Journals Online (AJOL)

    Dr Ahmed

    In recent years, a new technique was introduced that combines both hydrolysis and ... Cassava Starch Preparation: The cassava starch used for this investigation was prepared ... One normal HCl and one normal NaOH were used to adjust the ...

  10. Micropropagation of Banana Varieties (Musa spp.) Using Shoot-Tip ...

    African Journals Online (AJOL)

    propagation method appears to be unable to supply the increasing demand for ... Explant Preparation and Surface Sterilization. Explants were excised ... of the medium was adjusted to 5.7 using NaOH or HCl (0.1 or 1N) before autoclaving.

  11. IMPROVING OF ANION EXCHANGERES REGENERATION

    Directory of Open Access Journals (Sweden)

    Muzher M. Ibrahim

    2013-05-01

    Full Text Available Inthis study, Different basis [NaOH and KOH] of variable concentration are usedto reactivate Anion exchangers employing different schemes .The Laboratoryresults showed large improvement in efficiency of these exchangers ( i.eoperating time was increased from 12 to 42 hours .The results of this work showed that the environmentalload (waste water can be reduced greatly when using the proposed regenerationscheme .

  12. The Surface Chemical Properties of Novel High Surface Area Solids ...

    African Journals Online (AJOL)

    fired power stations in South Africa by hydrothermal treatment of the raw ash with concentrated aqueous NaOH solutions. The zeolite was then further modified by acid leaching at elevated temperatures. This resulted in the formation of a novel ...

  13. Growth and characterization of hydroxyapatite nanorice on TiO2 nanofibers

    KAUST Repository

    Chetibi, Loubna; Hamana, Djamel; Achour, Slimane

    2014-01-01

    with anatase TiO2 nanofibers. These nanofibers were prepared by in situ oxidation of Ti foils in a concentrated solution of H 2O2 and NaOH, followed by proton exchange and calcinations. Afterward, TiO2 nanofibers on Ti substrate were coated with HA

  14. Impact of nitrogenous alkaline agent on continuous HTL of lignocellulosic biomass and biocrude upgrading

    DEFF Research Database (Denmark)

    Jensen, Claus Uhrenholt; Rosendahl, Lasse Aistrup; Olofsson, Göran

    2017-01-01

    quality slightly in terms of H/C ratio, density and HHV, but a significant coke formation of 11 wt.% is observed. Furthermore, ammonia pollutes the biocrude with 2.7 wt.% nitrogen, which is observed to inhibit hydrotreating conversion. In comparison, CHTL with NaOH is associated with a 43 wt.% yield...

  15. Optimization of Deacetylation Process for Regenerated Cellulose Hollow Fiber Membranes

    Directory of Open Access Journals (Sweden)

    Xuezhong He

    2017-01-01

    Full Text Available Cellulose acetate (CA hollow fibers were spun from a CA+ Polyvinylpyrrolidone (PVP/N-methyl-2-pyrrolidone (NMP/H2O dope solution and regenerated by deacetylation. The complete deacetylation time of 0.5 h was found at a high concentration (0.2 M NaOH ethanol (96% solution. The reaction rate of deacetylation with 0.5 M NaOH was faster in a 50% ethanol compared to a 96 vol.% ethanol. The hydrogen bond between CA and tertiary amide group of PVP was confirmed. The deacetylation parameters of NaOH concentration, reaction time, swelling time, and solution were investigated by orthogonal experimental design (OED method. The degree of cross-linking, the residual acetyl content, and the PVP content in the deacetylated membranes were determined by FTIR analysis. The conjoint analysis in the Statistical Product and Service Solutions (SPSS software was used to analyze the OED results, and the importance of the deacetylation parameters was sorted as Solution > Swelling time > Reaction time > Concentration. The optimal deacetylation condition of 96 vol.% ethanol solution, swelling time 24 h, the concentration of NaOH (0.075 M, and the reaction time (2 h were identified. The regenerated cellulose hollow fibers under the optimal deacetylation condition can be further used as precursors for preparation of hollow fiber carbon membranes.

  16. The Effect of Sodium Hydroxide Molarity on Strength Development of Non-Cement Class C Fly Ash Geopolymer Mortar

    Science.gov (United States)

    Wardhono, A.

    2018-01-01

    The use of fly ash as cement replacement material can overcome the environmental issues, especially the global warming problem caused by the greenhouse effect. This is attributed to the CO2 gas produced during the cement manufacturing process, which 1 ton of cement is equivalent to 1 ton CO2. However, the major problem of fly ash is the requirement of activators to activate the polymer reactions. The most common activator used in non-cement or geopolymer material is the combination of sodium hydroxide (NaOH) and sodium silicate. This study aims to identify the effect of NaOH molarity as activator on strength development of non-cement class C fly ash geopolymer mortar. The molarity variations of NaOH were 6 Molar (M), 8M, 10M, 12M, 14M and 15M. The compressive strength test was performed at the age of 3, 7 and 28 days in accordance with ASTM standard, and the specimens were cured at room temperature. The results show that the highest compressive strength was achieved by geopolymer mortar with a molarity of 12M. It exhibits a higher strength to that normal mortar at 28 days. However, the use of NaOH molarity more than 12M tends to decrease the strength of non-cement geopolymer mortar specimens.

  17. Assessment of the effect of Artemisia annua leave extract infusion ...

    African Journals Online (AJOL)

    The bacteria used were S. paratyphi, S. aureus and E. coli. Experiments were carried out in aquatic microcosms under dark conditions. The pH values considered were 4, 5, 6, 7, 8 and 9. These values were adjusted using diluted HCl and NaOH. The results showed the temporal changes of cell abundance from one bacteria ...

  18. Extraction and characterisation of gelatin from the skin of striped ...

    African Journals Online (AJOL)

    Prabjeet Singh

    2017-01-04

    Jan 4, 2017 ... squid skin in 1% H2O2 in 0.01 M NaOH for 48 h could improve the ... of fish skin gelatin. Gelatin was extracted from washed giant catfish skin as described ..... bleached, because the flesh could be stained by ink, viscera and ...

  19. Surface chemical properties of novel high surface area solids synthesized from coal fly ash

    CSIR Research Space (South Africa)

    Pretorius, PJ

    2003-07-23

    Full Text Available The zeolite, Na-P1, was synthesized from fly ash samples originating from coal-fired power stations in South Africa by hydrothermal treatment of the raw ash with concentrated aqueous NaOH solutions. The zeolite was then further modified by acid...

  20. Two new polyoxovanadate clusters templated through cysteamine

    Indian Academy of Sciences (India)

    Unknown

    variably formed.6–10 These may be salts between organic cations and discrete ... Vanadium pentoxide (V2O5), sodium hydroxide. (NaOH) and cysteamine were .... sulting in 2D layers and other nitrogen (N1) forming. H-bonding to one water ...