Academic literature on the topic 'NH4OAc'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'NH4OAc.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Journal articles on the topic "NH4OAc"
1
Affinnih, Kehinde. "Assessment of extractants for soil available potassium determination in the selected soils of Kwara state, Nigeria." Agricultural Sciences 15, no. 36 (2023): 39–45. http://dx.doi.org/10.22620/agrisci.2023.36.003.
Full textAbstract:
Response of potassium (K) correlated with extracted K using five laboratory methods: neutral N NH4OAc pH 7.0; NH4OAc pH 4.8, 0.01M CaCl2, 1N Hot HNO3 and 0.5N NaHCO3 pH 7.0 by sorghum were determined in four selected soils from twenty locations in Kwara State, Nigeria in the green house to ascertain the ideal procedure for routine analysis. Regression equations were derived for each soil between K uptake by sorghum and level of K applied and, by extrapolation, the A-value, which represented the amount of soil K available as applied K, was determined. The data from the five laboratory methods were correlated with A-value, the zero-level K uptake, and with one another. The results showed that 0.01M CaCl2 only, extracted more K than the A-value, which was greater than the K extracted by the other methods. The data of all methods were, however, significantly correlated (p<0.05) with A-value while zero-level K uptake had a highly significant correlation with data of 0.01M CaCl2 (0.99) and low values with that of the other methods. The neutral normal NH4OAc pH 7.0 correlated relatively high and positively with N NH4OAc pH 4.8, 0.01M CaCl2, and 0.5N NaHCO3 pH 7.0, but negatively (-0.60) with 1N Hot HNO3. However, the neutral N NH4OAc pH 7.0; NH4OAc pH 4.8 correlated relatively higher and positively with one another (0.93) although they both extracted unequal amounts of K. Thus, both could be conveniently handled in the routine work in place of hot 1 N HNO3 for the evaluation of K availability indices for sorghum in the region.
2
CHUDE, V. O., G. O. OBIGBESAN, and N. E. EGBE. "MICRONUTRIENT STATUS OF SELECTED CACAO-GROWING SOILS IN SOUTHWESTERN NIGERIA: PROFILE DISTRIBUTION OF TOTAL AND AVAILABLE ZINC." Canadian Journal of Soil Science 65, no. 1 (1985): 21–24. http://dx.doi.org/10.4141/cjss85-003.
Full textAbstract:
A study was conducted to determine the content and distribution of total 1.0 M NH4OAc-, 0.1 M HCl-, 1 M MgCl2-, and 0.005 M DTPA-extractable Zn in the genetic horizons of 16 soil profiles from major cacao-growing areas in Southwestern Nigeria. The content of total Zn for all the soils varied from 12 to 92 μg/g with soils derived from igneous and metamorphic rocks containing more than those of sedimentary origin. Most of the soils had the highest concentration of total Zn in the surface horizons. There was a strong association between total Zn and organic matter, total Zn and silt/clay content. The 1 M NH4OAc-, 0.1 M NCl-, 1 M MgCl2- and 0.005 M DTPA-extractable Zn in all the soils and horizons varied from 0.17 to 5.6, from 0.06 to 2.37, from 0.20 to 1.20 and from 0.022 to 1.14 μg Zn/g, respectively. The NH4OAc generally removed more Zn than the other three extractants. The amount of Zn extracted showed a general decrease with depth. A significant amount of MgCl2-extractable Zn appeared to be associated with silt content while soil pH influenced the quantity of Zn extracted by the NH4OAc method. Key words: Total Zn, NH4OAc-extractable N, HCl-extractable N, MgCl2-extractable N, DTPA-extractable Zn, soil profile
3
Gunawan, Endang, Anas D. Susila, Atang Sutandi, and Edi Santosa. "Penetapan Metode Ekstraksi Kalium Terbaik untuk Tanaman Tomat (Solanum lycopersicum L.) pada Tanah Andisol." Jurnal Hortikultura Indonesia 10, no. 3 (2019): 173–81. http://dx.doi.org/10.29244/jhi.10.3.173-181.
Full textAbstract:
Penetapan rekomendasi dosis kalium (K) berdasarkan uji tanah untuk tanaman tomat pada tanah Andisol belum banyak dikaji di Indonesia. Penelitian diawali dengan pembuatan status hara K tanah di Kebun Percobaan IPB Pasirsarongge Cianjur dilanjutkan dengan uji korelasi di rumah plastik PKHT IPB Tajur Bogor pada Desember 2015 sampai Mei 2016. Tujuan penelitian adalah menetapkan metode ekstraksi K terbaik bagi tanaman tomat di tanah Andisol. Status K tanah dibuat dengan larutan kalium sulfat (K2SO4) sebesar 0, ¼X, ½X, ¾X, dan X dimana X adalah 413.4 kg K ha-1 sebagai dosis K maksimum yang ditambahkan untuk mencapai kadar K maksimum dalam larutan tanah. Larutan K2SO4 disiram merata pada bedengan tanah dan diinkubasi selama 4 bulan. Ekstraksi K tanah menggunakan 5 metode yaitu: Bray 1 (HCl 5N), HCl 25%, Morgan Wolf (NaC2H3O2.3H2O), Mechlich (HCl 0.05N + H2SO4 0.025N) dan NH4OAc (NH4OAc, pH 7). Hasil penelitian menunjukkan adanya perbedaan respon tinggi tanaman, bobot kering biomas, kandungan K tanaman terhadap tingkat status hara K tanah. Pola respon kuadratik ditunjukkan pada tinggi tanaman umur 6 dan 7 minggu setelah tanam, dan bobot kering total. Metode ekstraksi K Andisols terbaik untuk tomat adalah NH4OAc dengan nilai koefisien korelasi (r): 0.75.
 Kata kunci: biomas, K2SO4, metode ekstraksi, NH4Oac, status K
4
Salam, Abdul Kadir. "The correlation study of several chemical extractants to assess plant copper uptake from tropical soils polluted with heavy metals." IOP Conference Series: Earth and Environmental Science 1314, no. 1 (2024): 012003. http://dx.doi.org/10.1088/1755-1315/1314/1/012003.
Full textAbstract:
Abstract Glass-house experiments were conducted to study the correlation between Cu uptake by several plants and soil Cu extracted by several chemical extractants. Heavy-metal contaminated soils from Lampung, the southern part of Sumatra, Indonesia, with different levels of Cu were used. Eight different plants including amaranth (Amaranthus tricolor), caisim (Brassica chinensis var. Parachinensis), corn (Zea mays L.), land spinach (Ipomoea reptans Poir), lettuce (Lactuca sativa), napier grass (Penissetum purpureum), thorny amaranth (Amaranthus spinosus L.) and water spinach (Ipomoea aquatica) were employed. The uptake of Cu for amaranth is well predicted by N HCl, Buffered DTPA pH 7.30, N NH4OAc pH 7.00, and M CaCl2; for corn by N HCl and N NH4OAc pH 7.00; for land spinach by N HNO3, N HCl, Buffered DTPA, N NH4OAc pH 7.00, and M CaCl2; for napier grass by N HCl and Unbuffered DTPA. N HNO3 is good in predicting the uptake of Cu by land spinach, N HCl by amaranth, corn, land spinach, and napier grass; Buffered DTPA by amaranth and land spinach; Unbuffered DTPA by napier grass; N NH4OAc pH 7.00 by amaranth, corn and land spinach, and M CaCl2 by amaranth and land spinach. None of the tested methods is good in predicting the uptake Cu by caisim, lettuce, thorny amaranth, and water spinach
5
Meyer, Wietse L., and Paul A. Arp. "Exchangeable cations and cation exchange capacity of forest soil samples: Effects of drying, storage, and horizon." Canadian Journal of Soil Science 74, no. 4 (1994): 421–29. http://dx.doi.org/10.4141/cjss94-055.
Full textAbstract:
Concentrations of Ca, Mg, K, Na, Al, Fe, Mn, and Si extractable with 1 N ammonium chloride (NH4Cl, pH 4.5) and 1 N ammonium acetate (NH4OAc, pH 4.5) were determined for forest soil samples as follows: (1) before drying, and (2) at several time intervals after air-drying (1, 5, 11 and 14 wk). Values for CEC were obtained for the same samples by determining (1) the sum of cations (Al3+, Ca2+, Mg2+, K+, Na+, Fe3+, and Mn2+) in the extracts [denoted [Formula: see text] and [Formula: see text]], and (2) the amount of ammonium retained by the soil samples against water washing [denoted CEC(NH4OAc) and CEC (NH4Cl)]. The soils used in this investigation were taken from four New Brunswick upland forest sites (two sugar maple sites, one mixed wood site, and one spruce site). It was round that (1) extractable Mg, K, Na, and Mn levels were generally not affected by drying, storing, and type of extradant; (2) extractable Al and Fe levels increased immediately after drying; (3) NH4OAc-extracted Al, Fe, and Si exceeded NH4Cl-extracted Al, Fe, and Si; (4) extracted Al and Fe levels tended to drop after 11 wk of storage; (5) small drying effects were also noticed for NH4Cl-extracted Ca; (6) CEC(NH4OAc) and CEC(NH4Cl) values decreased with increasing time of storage; this effect was noticed most for soil samples with high levels of organic matter (Ah, Ahe, Bm, Bf, and Bfh), and was noticed least for sod samples taken from leached horizons (Ae) and subsoil horizons (BC and C); (7) in some cases, storage time increased CEC(NH4OAc) in subsoils; (8) values for [Formula: see text] remained fairly independent or increased slightly with storage time and were closely related with CEC(NH4Cl) values obtained with non-dried samples; (9) values for [Formula: see text] did not relate well with CEC(NH4OAc) and CEC(NH4Cl). Differences for extractable Al were likely due to Al complexation by acetate ions. Drying effects on extractable Al and Fe (and possibly Ca) were likely due to drying-induced fragmentation of soil organic matter. Drying and storage effects on CEC(NH4OAc) and CEC(NH4Cl) were likely due to (1) water-washing and related loss of organic matter, and (2) sensitivity of subsoil minerals to air exposure. Apparent drying and storage effects on CEC were most noted with [Formula: see text] and were least noted with [Formula: see text]. Key words: Cation exchange capacity, ion exchange, drying, storage, ammonium acetate, ammonium chloride extractions
6
Sutriadi, Mas Teddy, Diah Setyorini, Deddi Nursyamsi, and Andarias Makka Murni. "Penentuan Kebutuhan Pupuk Kalium dengan Uji K-Tanah untuk Tanaman jagung di Typic Kandiudox." Journal of Tropical Soils 13, no. 3 (2018): 179–87. http://dx.doi.org/10.5400/jts.2008.v13i3.179-187.
Full textAbstract:
Fertilization of K is very important to increase product agriculture besides fertilization of N and P. In this time usage fertilizer not yet proportional and rational, such as those which happened in usage rice field fertilizer of K for the crop of paddy tend to excessively. The other way in the upland needing more fertlizer but fertilized slimmer or is not fertlized K. Proportional and rational fertilization can reach if pay attention the nutrients dynamics and soil status, and also requirement of nutrient for this crop to reach optimum production. This approach can be executed better and profit if fertilization recommendation based on by result of research soil testing. Research goal to to determine requirement of K fertilizer for maize in Typic Kandiudox. The experiments used split-plot design, as main plot are five status nutrients and as sub plot are five treatments of K levels, three replications. The levels of K treatment were 0, 20, 40, 80, and 160 kg K/ha from KCl fertilizer and as indicator crop was maize cultivar P-12. The result showed that NH4OAc. pH 4,8, NH4OAc. pH 7,0, and HCl 25% were selected extraction methode to estimate K fertilizer requirement for Maize (Zea mays L.) in Typic Kandiudox and NH4OAc. 1 N pH 4,8 was the best extractan, because get highest coefisien corelation. The K status can be grouped into three classes of availability of K are low, medium, and high with the critical limit for each extractan are 5,0; 10,0; dan 130 mg kg-1 K2O for NH4OAc. 1 N pH 4,8, NH4OAc. 1 N pH 7,0, and HCl 25 % extractants respectively. Optimum dosages of K fertilizer was 150 kg ha-1 and 75 kg ha-1 KCl each for the low and medium status and do not be fertilized for the high status.
7
RICHARDS, JOHN E., THOMAS E. BATES, and S. C. SHEPPARD. "STUDIES ON THE POTASSIUM-SUPPLYING CAPACITIES OF SOUTHERN ONTARIO SOILS. I. FIELD AND GREENHOUSE EXPERIMENTS." Canadian Journal of Soil Science 68, no. 2 (1988): 183–97. http://dx.doi.org/10.4141/cjss88-019.
Full textAbstract:
The response of grain corn (Zea mays L.) to applied K was studied for 10 yr on three southern Ontario soils. On a Conestogo L, the most profitable rate of K application was 2.5 times higher than expected and the critical concentration of NH4OAc-K, above which no response occurred to either applied K or increasing NH4OAc-K concentrations, was higher (2 ×) than expected, based on 1 M NH4OAc-extractable K and interpretation by the Ontario Ministry of Agriculture and Food soil test. All soils fixed substantial quantities of applied K, but the amount fixed by the Conestogo L was not greater than that fixed by the other two soils. When no K was applied, corn removed less nonexchangeable K (NEK) from the Conestogo L than from the other two soils. A greenhouse experiment was conducted to determine if either the availability of NH4OAc-K or NEK to alfalfa (Medicago sativa L. 'Banner') was lower on highly responsive soils than on less responsive soils. By the end of the experiment, soils on which crops were very responsive to applied K (Guelph L, Conestogo L, and Teeswater SiL) had supplied less K to alfalfa than had soils (Brookston L and Fox SL) on which response to applied K in field trials was similar to that predicted by the soil test. Total K uptake was related to NEK uptake suggesting that differences in the K-supplying capacities of the soils were associated with the availability of NEK to alfalfa. It was concluded that the responses to higher rates of applied K than expected in field trials were due to lower uptake of NEK. The clay mineralogy of the soils was dominated by illite with lesser amounts of vermiculite. No appreciable differences in mineralogy were found between the two groups of soils and NEK uptake was not significantly related to the amount of clay nor to the illite content of the coarse clay and fine clay fractions. Key words: NH4OAc-K, nonexchangeable K, illite, vermiculite, alfalfa, corn
8
Salam, A. K., M. Milanti, G. Silva, et al. "The use of N HNO3 to determine copper and zinc levels in heavy-metal polluted tropical soils." IOP Conference Series: Earth and Environmental Science 905, no. 1 (2021): 012001. http://dx.doi.org/10.1088/1755-1315/905/1/012001.
Full textAbstract:
Abstract This study compared N HNO3 to other methods to determine plant available heavy metals in heavy-metal polluted soils. Soil samples were obtained from an experimental field treated with industrial waste after 22 years of the amendment and employed to conduct the comparative and correlation study. Soil samples were analyzed for Cu using various methods, planted in a glass house with several plants, and analyzed for soil and plant Cu and Zn. The relative strength of the chemical extractants followed the order of N HNO3 ≈ N HCl > Buffered DTPA ≈ Unbuffered DTPA > M CaCl2 ≈ N NH4OAc pH 7. A high correlation was observed for soil extracted Cu by M CaCl2 or N NH4OAc pH 7 or N HCl vs. Buffered DTPA and N HNO3 or N NH4OAc pH 7 vs. N HCl. High correlations of plant and soil Cu extracted by N HNO3 were shown by caisim, water spinach, land spinach, and corn, while plant and soil Zn were shown by caisim, water spinach, land spinach, and lettuce.
9
Prasad, PN Siva, and CT Subbarayappa. "Suitability of Multinutrient Extractants for Evaluation Of Available Soil Zinc for Tomato Nutrition Of Karnataka Soils." Bangladesh Journal of Botany 51, no. 4 (2022): 655–62. http://dx.doi.org/10.3329/bjb.v51i4.63482.
Full textAbstract:
Pot experiment was conducted at University of Agricultural Sciences, Bangalore, Karnataka, which received five treatments i.e., 0, 5, 10, 15, 20 kg ZnSO4/ha. Among all the treatments Recommended NPK + ZnSO4 @ 20 kg/ha recorded highest mean dry matter yields of tomato. The amount of zinc extracted by different extractants were in the following order as Mehlich-3 - Zn > 0.1 N HCl - Zn > AB-DTPA - Zn > 0.01 N EDTA - Zn > DTPA - Zn > 0.01 M EDTA + 1 N NH4OAc - Zn > 1 N NH4OAc (pH 4.6) - Zn > 1 N NH4OAc (pH 7) - Zn. Among the various extractants tried DTPA - Zn gave positive and higher significant correlation with Brays per cent Yield (r = 0.781). The next better extractants were Mehlich-3 (r = 0.726) and AB-DTPA (r = 0.576) which were also significantly positively correlated with Brays per cent yield. The critical limits of DTPA, Mehlich-3, AB-DTPA, tomato plant and tomato fruit by graphical method were 1.12, 2.15, 1.20, 34 and 58 mg/kg, respectively. Bangladesh J. Bot. 51(4): 655-662, 2022 (December)
10
SHUMAN, L. M. "COMPARISON OF EXCHANGEABLE Al, EXTRACTABLE Al, AND Al IN SOIL FRACTIONS." Canadian Journal of Soil Science 70, no. 3 (1990): 263–75. http://dx.doi.org/10.4141/cjss90-028.
Full textAbstract:
Previous results indicated that the activity of Al3+ in soil solution, Al saturation of the CEC, and 0.01 M CaCl2-extractable Al were related to plant growth. Exchangeable Al values determined by 1 M KCl and 1 M NH4Cl, extractable Al values determined by 1 M NH4OAc, pH 4.8, 0.01 M CaCl2, 0.5 M CuCl2, 0.33 M LaCl3, and 0.005 M NTA, were compared with each other and to the activity of Al3+ in soil solution as well as Al in soil fractions. Aluminum in fractions was measured to determine the forms solubilized by the extradants. The fractions extracted were exchangeable [M Mg(NO3)2], organic bound, Mn oxide, amorphous Fe and Al oxide, and crystalline Fe and Al oxide. The order of Al extracted was CuCl2 > NH4OAc, [Formula: see text]. One M KCl and NH4Cl, and CuCl2, LaCl3, NTA, and NH4OAc, pH 4.8, gave similar relative Al values, especially for topsoils, and were not correlated with CaCl2-Al values. The exchangeable fraction Al [M Mg(NO3)2] was well correlated with the activity of Al3+ in the soil solution and Al saturation of the CEC. Organic fraction Al was negatively correlated with the activity of Al3+ in the soil solution indicating that organic matter can bind Al lowering its concentration in the soil solution. Aluminum in the crystalline Fe/Al oxide fraction correlated well with that extracted by CuCl2, LaCl3, NTA, and NH4OAc, pH 4.8, leading to the possible conclusion that these extradants solubilize Al from plant-unavailable fractions. Key words: Soil aluminum, aluminum extractants, aluminum fractions, exchangeable aluminum
Dissertations / Theses on the topic "NH4OAc"
1
Olofsson, Jonas. "Base cations in forest soils : A pilot project to evaluate different extraction methods." Thesis, Institutionen för mark och miljö, Sveriges lantbruksuniversitet, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-308442.
Full textAbstract:
The acidification has been a known problem in Sweden for several decades. Sulphurous compounds, spread from the British Isles and the European continent led to a decrease in the pH-value of the rain that fell over Sweden. Since the acidification was discovered in the 1960s, active measures against the sulphurous deposition have been undertaken. The sulphurous deposition has decreased by 90 %, and the problem was for some time considered under control, until recently when a new era of the acidification may have started. Due to the increased demand of renewable energy, and Sweden’s potential to use biomass instead of fossil fuels, whole tree harvesting has been more utilized. Studies indicate that the forest soils are depleted in base cations in a faster rate when whole tree harvesting is performed compared to regular stem harvesting. Mass balance calculations and simulations indicate that an increased bio uptake of base cations due to whole tree harvesting leads to an increased biological acidification. However, although many studies agree that the impact of the whole tree harvest on the base cation supply of the soils is significant, long running Swedish experiments indicate that the difference between whole tree harvesting and regular stem harvesting diminishes over time. After a 40 year period, the difference in base cation supply between whole tree harvested soils and stem harvested soils are small. The reason for this could be different processes that reallocate base cations from different pools, which are not usually studied. The aim has been to investigate and evaluate different chemical extraction methods (Aqua Regia, HCl, EDTA, BaCl2, NH4OAc and water) capability to extract the base cations calcium, potassium, magnesium and sodium from four different Swedish forest soils and what this means for our understanding of how much base cations a soil contains. The extractions indicated that there is a statistical significant difference between the methods ability to extract base cations. Generally Aqua Regia was the most potent method, followed by HCl, EDTA, BaCl2, NH4OAc and water in decreasing order of effectiveness to extract the base cations. Linear correlations were found between EDTA, BaCl2 and NH4OAc. The internationally widely used method NH4OAc was considered to be at risk of underestimating the amount of base cations in the soil.<br>Försurningsproblematiken har länge varit ett känt problem i Sverige. Svavelhaltiga föroreningar som spreds från de brittiska öarna och den europeiska kontinenten ledde till att pH-värdet i regnet som föll över Sverige sjönk. Sedan upptäckten på 60-talet har aktiva åtgärder vidtagits mot utsläppen vilket har lett till en minskning av de försurande föroreningarna med 90 %. På grund av den stora utsläppsreduktionen som skett ansågs försurningsproblematiken vara under kontroll, tills nyligen då en ny etapp av för- surningen kan ha påbörjats. På grund av den ökande efterfrågan av förnyelsebar energi, i kombination med Sveriges stora skogstillgångar, har helträdsskörd av träd blivit alltmer nyttjad. Studier visar att markens baskatjonförråd utarmas i större utsträckning av helträdsskörd, då även grenar, rötter och toppar tas om hand jämfört med vanlig stamskörd då endast stammen tas med från skogen. Massbalanssimuleringar antyder att ett ökat bioupptag av baskatjoner på grund av helträdsskörd leder till en ökad biologisk försurning. Trots att många studier är överens om helträdsskördens inverkan på markens innehåll av baskatjoner visar lång- liggande försök i Sverige att skillnaderna mellan uttag av hela träd och stamved minskar med tiden. Efter en period på 40 år återstår endast små skillnader mellan avverknings- metoderna. Orsakerna till varför mätningarna och massbalansberäkningarna och simuleringarna inte stämmer överens kan vara många, t.ex. att det finns processer som kan omfördela baskatjoner från de som vanligtvis studeras. Syftet har varit att undersöka och utvärdera olika kemiska extraktionsmetoders (Aqua Regia, HCl, EDTA, BaCl2, NH4OAc och vatten) förmåga att extrahera baskatjonerna kalcium, kalium, magnesium och natrium från fyra olika skogsjordar i Sverige och vad resultaten betyder för vår uppfattning av mängden baskatjoner i marken. Extraktionerna visade att en statistiskt signifikant skillnad fanns mellan metodernas förmåga att extrahera de olika baskatjonerna. Generellt var Aqua Regia den metod som extraherade den största mängden baskatjoner, HCl, EDTA, BaCl2, NH4OAc och vatten följde i fallande ordning efter förmåga att extrahera baskatjonerna. Linjära korrelationer mellan EDTA, BaCl2 och NH4OAc upptäcktes. Den internationellt ofta använda metodiken för att extrahera baskatjoner, NH4OAc, ansågs riskera att underskatta mängden baskatjoner i marken.
2
García, Torres Gerardo Alexis. "Electro Deposicion de Renio a Partir de Soluciones de Re-Mo-Cu-H2so4, Re-Mo-Cu-Nh4oh y Re-Mo-Cu-H2so4- Nh4oh." Tesis, Universidad de Chile, 2011. http://www.repositorio.uchile.cl/handle/2250/104012.
Full textAbstract:
El objetivo principal de este estudio fue comprobar el efecto de tener cobre (Cu) en solución al momento de electro-depositar renio (Re), luego se cambiaron distintos parámetros de trabajo (como la temperatura, agitación y concentraciones de Cu y Re entre otros). Esto último con el fin entregar una dirección en la que mejoren los resultados obtenidos tales como las eficiencias de corriente, los consumos específicos de energía (CEE) y los contenidos metálicos.
Como se vió en la bibliografía, el uso de esta técnica a escala industrial es inexistente, pero existe un número reducido de publicaciones de diferentes autores que estudian la electro-deposición de este metal a escala de laboratorio.
Toda la experimentación realizada durante esta memoria se desarrolló en el laboratorio de electrometalurgia de la Universidad de Chile y el análisis químico y morfológico de las muestras obtenidas se realizó mediante análisis en un microscopio electrónico de barrido (SEM) y microsonda (EDS).
Una primera parte de la experimentación entregó una dirección de mejora, en términos de la eficiencia de corriente de Re y el CEE, de los resultados de la electro-deposición disminuyendo la densidad de corriente, aunque este resultado podría verse acotado por el aumento de la deposición de óxidos. A pesar de este problema es importante notar que se obtuvieron depósitos con bajo contenido de oxígeno (con un porcentaje en peso de Re cercano al 97%). La segunda parte indicó que cuando existe Cu en solución, se co-depositan ambos metales. Para el Re, la proporción en peso máxima que se obtuvo fue de un 11% la que se consiguió con 0,5 g/l de Cu en solución y aumentando la temperatura del electrólito. Uno de los problemas de incrementar la temperatura fue el aumento de las impurezas encontradas durante el análisis químico. Este problema se pudo mejorar cambiando el cátodo de acero AISI 304 por uno de titanio.
El mejor CEE se obtuvo usando un cátodo de titanio (Ti) y aumentando la temperatura, llegando a ser 5 kWh/kg y a su vez se logró una buena eficiencia de corriente tanto para Re (de 9,4 %) como para Cu (de 25,1 %). Esto último podría ser aún mejor, en función de los resultados obtenidos, aumentado la cantidad de Cu en solución. En todas las imágenes obtenidas, tanto de depósitos de Re como en los de Cu-Re, se observa que la deposición ocurre en forma globular. Pero los depósitos de Cu-Re resultaron ser de un espesor suficiente como para ocultar casi completamente el substrato, no así los depósitos de Re.
Es importante notar que a pesar de que se trabajó con soluciones del tipo Re-Mo-Cu-H2SO4 (ácido sulfúrico) yRe-Mo-Cu-NH4OH (hidróxido de amonio), en esta memoria únicamente se incluyen los resultados para las experimentaciones del tipo Re-Mo-Cu-H2SO4- NH4OH, ya que sólo estas últimas presentaron resultados plausibles de ser analizados.
3
Bryce, Christine. "A kinetic study of gallium arsenide etching in H2O2-NH4OH-H2O solutions /." Thesis, McGill University, 1996. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=41991.
Full textAbstract:
Gallium arsenide, a compound semiconductor commonly used in optoelectronic devices, is often subjected to wet etching techniques during microelectronic device manufacture. In this work, the wet chemical etching of gallium arsenide in $ rm H sb2O sb2$-$ rm NH sb4OH$-H$ sb2$O solutions was studied using a batch stirred-tank reactor. A kinetic control regime was established and the influence of each component's concentration on the intrinsic etch rate was determined. The reaction rate was found, in the presence of excess NH$ sb4$OH, to fit a rate equation, r = k (H$ rm sb2O sb2 rbrack sp{0.75}$ at 15, 25, and 40$ sp circ$C with an activation energy of 33.7 kJ/mol. Using NaOH instead of NH$ sb4$OH resulted in greatly reduced reaction rates, and it was concluded that the presence of the ammonium ion increases the rate by forming soluble compounds with oxidized species of Ga and As. When mass transfer resistances are introduced, using a flow reactor to simulate an industrial etching apparatus, the reaction rates are considerably reduced and the rate's dependence on $ rm H sb2O sb2$ concentration is shifted closer to linear. Convective mass transfer expressions for flow past a flat plate were successfully used to predict the etch rate. The two reactors were used to etch samples masked by a circuit pattern, and the crystallography of GaAs dictated the shape of the etch profiles rather than the mass transfer limitations of the system.
4
Silva, Audrey Roberto 1964. "Texturização da superfície de silício monocristalino com NH4OH e camada antirrefletora para aplicações em células fotovoltaicas compatíveis com tecnologia CMOS = Texturing the surface of monocrystalline silicon with NH4OH and anti-reflective coating for applications in photovoltaic cells compatible with CMOS technology." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/259291.
Full textAbstract:
Orientador: José Alexandre Diniz<br>Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação<br>Made available in DSpace on 2018-08-21T10:50:41Z (GMT). No. of bitstreams: 1
Silva_AudreyRoberto_M.pdf: 3023922 bytes, checksum: ee750f675d01f2b3ceebd5d74149b16e (MD5)
Previous issue date: 2012<br>Resumo: Este trabalho apresenta o desenvolvimento de células fotovoltaicas de junção n+/p em substratos de Si com processos de fabricação totalmente compatíveis com a tecnologia CMOS (Complementary Metal Oxide Semiconductor). Os processos compatíveis desenvolvidos neste trabalho sao as técnicas: i) de texturização da superfície do Si, com reflexao da superficie texturizada de 15% obtida com a formação de micro-pirâmides (alturas entre 3 e 7 ?m), utilizando-se solução alcalina de NH4OH (hidróxido de amônia), que e livre da contaminação indesejável por íons de Na+ e K+ quando se utiliza soluções tradicionais de NaOH e de KOH, respectivamente, e ii) de deposição ECR-CVD (Electron Cyclotron Resonance - Chemical Vapor Deposition) da camada antirrefletora (ARC) de SiNX (nitreto de silício), que e executada em temperatura ambiente, portanto pode ser feita apos a finalização da célula sem danificar trilhas metálicas e alterar a profundidade da junção n+/p. A caracterização desta camada ARC mostrou que o nitreto tem índice de refração de 1,92 e refletância mínima de 1,03%, o que e um excelente resultado para uso em células solares (ou fotovoltaicas). Foram fabricadas cinco series de células fotovoltaicas, utilizando-se a texturização com NH4OH e a camada antirrefletora de nitreto de Si. Em quatro series utilizou-se o processo de implantação de íons de fósforo (31P+), com posterior recozimento, para a formação da região n+, enquanto que na quinta serie foi utilizado o processo de difusão térmica. As eficiências máximas para as células fabricadas são de 9% e de 12%, respectivamente, para as células feitas utilizando os processos de implantação e de difusão térmica, indicando que a implantação de íons causa danos na rede cristalina do silício, que o posterior recozimento não consegue corrigir, o que reduz a eficiência da célula<br>Abstract: This work presents the development of photovoltaic cells based on n+/p junction in Si substrates, with fully compatible fabrication processes with CMOS technology. The compatible processes, which are developed in this study, are the techniques: i) of Si surface texturing, with the textured surface reflection of 15% obtained by the formation of micro-pyramids (heights between 3 and 7 ?m) using NH4OH (ammonium hydroxide) alkaline solution, which is free of undesirable contamination by Na + and K + ions, when NaOH and KOH traditional solutions are used, respectively, and ii) of the ECR-CVD (Electron Cyclotron Resonance - Chemical Vapor Deposition) deposition of SiNx (silicon nitride) anti-reflective coating (ARC), which is carried out at room temperature and can be performed after the end of cell fabrication without damage on metallic tracks and without variation of n+/p junction depth. The ARC coating characterization presented that the silicon nitride has a refractive index of 1.92 and a minimum reflectance of 1.03%, which is an excellent result for application in solar (or photovoltaic) cells. Five series of photovoltaic cells were fabricated, using the NH4OH solution texturing and the silicon nitride antireflective coating. In the first four series, phosphorus (31P+) ion implantation process, with subsequent annealing to get the region n+, was used, while, in the fifth series was used the thermal diffusion process. The maximum efficiency values are of 9% and 12%, respectively, for cells, which were fabricated using the ion implantation and thermal diffusion processes, indicating that the ion implantation damages the silicon crystal lattice and the subsequent annealing cannot rectify, which reduces the cell efficiency<br>Mestrado<br>Eletrônica, Microeletrônica e Optoeletrônica<br>Mestre em Engenharia Elétrica
5
Cuéllar, Velásquez Renzo Vladimir. "Estudio de Separación de Renio por Electrodiálisis a Partir de Soluciones que Contienen Re, Mo, Cu, H2SO4 y NH4OH." Tesis, Universidad de Chile, 2011. http://www.repositorio.uchile.cl/handle/2250/104112.
Full textAbstract:
No autorizada por el autor a ser publicada a texto completo<br>Existe poca información acerca de la obtención y refino del Renio, que se obtiene como subproducto y posee un alto valor económico. Lo anterior hace interesante el estudio de los procesos que permiten la obtención de soluciones concentradas de Renio y/o del metal puro. Es posible obtener compuestos de Renio por medio de la aplicación del proceso de electrodiálisis, el que presenta ventajas en cuanto a costos y continuidad, respecto a otros procesos utilizados actualmente.
Mediante el estudio de la electrodiálisis de soluciones sintéticas de Re-Cu-Mo-H2SO4-NH4OH se buscó separar compuestos de Re de compuestos de Mo y Cu en solución.
Se utilizó una celda de 5 compartimentos, donde el compartimento central, Solución de Trabajo (ST), contenía la solución inicial de Re-Cu-Mo-H2SO4-NH4OH, cuyas concentraciones dependían del experimento a realizar, según las matrices planteadas previamente. En los compartimentos contiguos, Aniónico y Catiónico (CA y CC respectivamente), que contenían H2SO4 con concentración de 1 [M], se esperaba concentrar los compuestos de Re (CA), de Cu y Mo (CC), teniendo como referencia el resultado de trabajos previos. Para lograr la separación se utilizaron membranas catiónicas y aniónicas, las que se ubicaron entre los compartimentos de la celda, de modo de permitir el paso de sólo un tipo de iones (cationes o aniones respectivamente).
Las variables de estudio planteadas fueron las concentraciones de Re (1 a 3 [g/l]), Mo (0,1 a 1 [g/l]), H2SO4 (1 a 2 [M]), NH4OH (0 a 40 [g/l]), Cu (0.1 a 0.5 [g/l]) y la temperatura, (25 a 40 [ºC]). Estos rangos coinciden con los usados a nivel industrial.
De los resultados, el transporte de Re se produce en dirección a CA, en forma de ReO4-. Mientras que el Cu y el Mo se transportan hacia CC, este último permanece casi totalmente en el compartimento ST.
En el mejor caso se obtuvo una concentración de 39.62 % del Re inicial en CA, con una tensión de celda promedio de 16.1 [V], una tasa de transporte de 0,476 [mol/m2h] y un consumo específico de energía (SEC) de 194 [kWh/kg]. Esta solución contenía 0,1 [g/l] de Mo, 0.1 [g/l] de Cu, 1 [M] de H2SO4 y 3 [g/l] de Re. Se operó a 40 [ºC].
El uso de NH4OH no es beneficioso, puesto que eleva considerablemente la tensión de celda y el SEC. Sin embargo, su presencia evita la deposición de compuestos sobre la membrana sin afectar la tasa de transporte.
Las experiencias realizadas permitieron establecer que por medio de electrodiálisis es posible separar, en solución ácida, Cu, Re, y Mo debido al transporte hacia CC, CA y permanencia en ST respectivamente.
6
Chiu, Chiu-Ling, and 邱久玲. "Developing Variation in Brahms’s Chamber Music." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/nh4ugc.
Full textAbstract:
碩士<br>國立臺北藝術大學<br>音樂學研究所碩士班<br>98<br>When it comes to pieces in Brahmas’ Chamber Music, the melody is elegant and the structure is compact. Brahms’ works are considered role models of Romance. Born in the North of Germany, Brahms respected the complete counterpoint in Bach’s and Beethoven’s works a lot and the complete structure thus features his works. Developing variation was formed thanks to Brahms’ care for complete structures.
In the Brahms’ late work, he utilizes Developing variation to perfection and thus he makes music tighter, more compact, and complete. To understand Brahms’ techniques will assist us in getting into the meanings of his works when listening to them.This essay probes into the Developing variation used in Chamber Music, including its period of formation, its period of growth, and its period of maturity.
7
Tein-ZenBai and 白添壬. "Study on the funtion of Ur-Pho Gully." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/nh448c.
Full textAbstract:
碩士<br>國立成功大學<br>土木工程學系碩士在職專班<br>104<br>Taiwan is abundant in water resources but is unable to make good use of them. Although there are several dams across Taiwan, their effective capacities are usually decreased by siltation. Due to this, Taiwan is ranked the 18th country globally with most severe water shortage problems, re-gardless of its high annual precipitation of 2,500 mm- 2.5 times of the world’s average. In this study, the hyporheic water engineering as a measure to preserve the water resources was discussed through the analyses of water supply and site selection conditions of a subsurface weir jetty, con-sidering the regional environment of Ur-Pho Gully and Lin-Bian Creek watershed, as well as me-teorological and surface hydrological data. The results showed that surface dams are prone to sediment siltation, which substantially affects the storage capacity of the reservoir and leads to the salinization of the tidal uprush water. In addition, the over-extraction of the groundwater would result in damages such as land subsidence. Therefore, alternative water sources must be made available if groundwater is to be managed through restricting water extraction or sealing wells; otherwise all measures applied would be of no significant effectiveness. The exploitation of the hyporheic water can avoid problems such as siltation and high expenditure of construction and management of a water dam. Meanwhile, it also improves water quality and ecological preserva-tion, mitigating the water shortage and making a breakthrough in the engineering construction for water resources utilization in Taiwan.
8
Dinh, Linh Thi Thuy. "Reactivity of ethylene oxide in contact with contaminants." 2008. http://hdl.handle.net/1969.1/ETD-TAMU-2683.
Full textAbstract:
Ethylene oxide (EO) is a very versatile compound with considerable energy in its ring
structure. Its reactions proceed mainly via ring opening and are highly exothermic.
Under some conditions, it is known to undergo a variety of reactions, such as
isomerization, polymerization, hydrolysis, combustion and decomposition
Due to its very reactive characteristic and widely industrial applications, EO has been
involved in a number of serious incidents such as Doe Run 1962, Freeport 1974, Deer
Park 1988 and Union Carbide Corporation’s Seadrift 1991. The impacts can be severe in
terms of death and injury to people, damage to physical property and effects on the
environment. For instance, the Union Carbide incident in 1991 caused one fatality and
extensive damage to the plant with the property damage of up to 80 million dollars.
Contamination has a considerable impact on EO reactivity by accelerating substantially
its decomposition and playing a key role on EO incidents.
In this work, the reactivity of EO with contaminants such as KOH, NaOH, NH4OH, and
EDTA is evaluated. Useful information that is critical to the design and operation of
safer chemical plant processes was generated such as safe storage temperatures (onset
temperature), maximum temperature, maximum pressure, temperature vs. time, heat and
pressure generation rates as a function of temperature and time to maximum rate using
adiabatic calorimetry. A special arrangement for the filling-up of the cell was
constructed due to the gaseous nature and toxicity of EO. A comparison of their thermal
behavior is also presented since several contaminants are studied.
9
LinChin-Ming and 林進明. "Relation Study between NH4OH/DI Solution Behavior and Monitor System of Clean Process in TFT Factory." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/93652321691188813712.
Full textAbstract:
碩士<br>崑山科技大學<br>環境工程研究所<br>95<br>This study is mainly to establish the relationship between the solution behaviors and process monitoring variables at substrate clean process in TFT industry in order to reduce the amount of chemicals usage. The relationship between the concentration of NH4OH and solution pH values, conductivity and redox potential was studied at various dosage of SiO2 and Al2O3. The solution pH value and conductivity was increased with the increase of NH4OH concentration without the dosage of SiO2. The conductivity will be increased with the dosage of SiO2 but the solution pH values was decreased with the dosage of SiO2 at the same concentration of NH4OH. That might be due to the generation of HSiO3- resulted from the reaction of SiO2 with hydroxide ion. The results in this study will be good for finding an optimum sensor in order to reduce the chemicals dosage.
10
高毓駿. "長鏈型(C8-C18)一級胺對碳鋼在含Cl-/CN-/H2S/NH4OH之油水混合溶液中緩蝕行為研究". Thesis, 1998. http://ndltd.ncl.edu.tw/handle/89501578220532586121.
Full textBook chapters on the topic "NH4OAc"
1
Morrison, Clyde Arthur. "NH4Al(SO4)2." In Crystal Fields for Transition-Metal Ions in Laser Host Materials. Springer Berlin Heidelberg, 1992. http://dx.doi.org/10.1007/978-3-642-95686-7_6.
Full text
2
Holze, Rudolf. "Ionic conductance of NH4OH." In Electrochemistry. Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-49251-2_1123.
Full text
3
Holze, Rudolf. "Ionic conductance of NH4Ag(NO3)2." In Electrochemistry. Springer Berlin Heidelberg, 2016. http://dx.doi.org/10.1007/978-3-662-49251-2_1103.
Full text
4
Thakur, Abhinay, Praveen Kumar Sharma, Ashish Kumar, et al. "Plant Extracts as Corrosion Inhibitors for Brass in KOH and NH4OH Solutions." In Phytochemistry in Corrosion Science. CRC Press, 2024. http://dx.doi.org/10.1201/9781003394631-18.
Full text
5
Taber, Douglass F. "Heteroaromatic Construction: The Wipf Synthesis of Cycloclavine." In Organic Synthesis. Oxford University Press, 2013. http://dx.doi.org/10.1093/oso/9780199965724.003.0068.
Full textAbstract:
Wesley J. Moran of the University of Huddersfield cyclized (Tetrahedron Lett. 2011, 52, 2605) a propargylated ketone 1 with Au to give the furan 2. Shengming Ma of the Shanghai Institute of Organic Chemistry found (Synlett 2011, 931) that tri(2-furyl)phosphine catalyzed the rearrangement of cyclopropene diesters, prepared by the addition of diazomalonate to alkynes, to the corresponding alkoxy furan 4. Xihe Bi and Qian Zhang of Northeast Normal University established (Chem. Commun. 2011, 47, 809) that a simple Fe catalyst effected the condensation of 5 with 6 to give the pyrrole 7. Gianfranco Favi of the Università degli Studi di Urbino showed (J. Org. Chem. 2011, 76, 2860) that the three-component coupling of 8 with an amine 9 and a ketone 10 proceeded without catalyst to deliver the pyrrole 11. Timothy J. Donohoe of the University of Oxford homologated (Org. Lett. 2011, 13, 1036) 12 by cross-metathesis with methyl vinyl ketone, to give, after oxidation and condensation with NH4OAc, the substituted pyridine 13. Dale L. Boger of Scripps/La Jolla condensed ( Org. Lett. 2011, 13, 2492) the unsubstitued 1,2,3-triazine 15 with an enamine 14 to give 16. Shunsuke Chiba of Nanyang Technological University prepared (J. Am. Chem. Soc. 2011, 133, 6411) the pyridine 19 by oxidizing the cyclopropanol 17 in the presence of the alkenyl azide 18. Limin Wang of the East China University of Science and Technology prepared (Tetrahedron Lett. 2011, 52, 509) the 2-aminopyridine 23 by the four-component coupling of the aldehyde 20 and the ketone 22 with NH4OAc and malononitrile 21. Taking advantage of the Knochel protocol for aryl Grignard formation, Christopher J. Moody of the University of Nottingham combined (Chem. Commun. 2011, 47, 788) the adduct from 24 with the ketone 25 to give the indole 26. Carsten Bolm of RWTH Aachen extended (Org. Lett. 2011, 13, 2012) the Fe catalysis reported by Zheng to the azide 27 to give 28. Sang-gi Lee of Ewha Womans University found (Org. Lett. 2011, 13, 1350) that the Blaise adduct from the addition of 29 to the nitrile could be cyclized to the indole 30.
6
Taber, Douglass F. "Preparation of Heterocycles: The Boukouvalas Synthesis of (−)-Auxofuran." In Organic Synthesis. Oxford University Press, 2017. http://dx.doi.org/10.1093/oso/9780190646165.003.0065.
Full textAbstract:
Nabyl Merbouh and Robert Britton of Simon Fraser University developed (Eur. J. Org. Chem. 2013, 3219) a general route to a 2,5-disubstituted furan 3 by taking advantage of the ready α-chlorination of an aldehyde 1, followed by coupling with a ketone enolate 2. Jérôme Waser of the Ecole Polytechnique Fédérale de Lausanne used (Angew. Chem. Int. Ed. 2013, 52, 6743) 5 to oxidize the allene 4 to the furan 6. Qian Zhang and Xihe Bi of Northeast Normal University used (Angew. Chem. Int. Ed. 2013, 52, 6953) Ag catalysis to prepare the pyrrole 9 by coupling the alkyne 7 with the isonitrile 8. Aiwen Lei of Wuhan University reported (Angew. Chem. Int. Ed. 2013, 52, 6958) similar results. Professor Lei also developed (Chem. Commun. 2013, 49, 5853) the Pd-catalyzed oxidation of the allyl imine 10 to the pyrrole 11. Kamal K. Kapoor of the University of Jammu reduced (Tetrahedron Lett. 2013, 54, 5699) the Michael adduct 12 to the pyrrole 13 with triethyl phosphite. Edgar Haak of the Otto-von-Guericke-Universität, Magdeburg condensed (Eur. J. Org. Chem. 2013, 7354) the alkynyl carbinol 14 with aniline to give the N-phenyl pyrrole 15. Jean Rodriguez and Thierry Constantieux of Aix-Marseille Université prepared (Eur. J. Org. Chem. 2013, 4131) the pyridine 18 by combining the ketone 16 and the unsaturated aldehyde 17 with NH4OAc. Teck-Peng Loh of the University of Sciences and Technology of China and Nanyang Technological University found (Angew. Chem. Int. Ed. 2013, 52, 8584) that TMEDA was an effective organocatalyst for the assembly of the pyridine 21 from 19 and 20. Andrew D. Smith of the University of St Andrews showed (Angew. Chem. Int. Ed. 2013, 52, 11642) that the pyridyl tosylate 24, available by the combination of 22 and 23, readily coupled with both carbon and amine nucleophiles. In a related development, D. Tyler McQuade of Florida State University prepared (Org. Lett. 2013, 15, 5298) the 2-bromopyridine 26 from the alkylidene malononitrile 25. Two versatile approaches to substituted indoles were recently described. David F. Wiemer of the University of Iowa cyclized (J. Org. Chem. 2013, 78, 9291) the Stobbe product 27 to the 3-bromo indole 28.
7
Oliveira, Daniele S., Tiago P. Braga, Alexander Sachse, Vinícius P. S. Caldeira, and Sibele B. C. Pergher. "VALORIZAÇÃO DO GLICEROL ATRAVÉS DA DESIDRATAÇÃO EM PRODUTOS DE MAIOR VALOR AGREGADO EMPREGANDO ZEÓLITA BETA HIERARQUIZADA POR TRATAMENTO ALCALINO." In Anais do II Congresso da Rede Brasileira de Bioquerosene e Hidrocarbonetos Sustentáveis de Aviação. Editora Científica Digital, 2023. http://dx.doi.org/10.37885/230914487.
Full textAbstract:
Para o desenvolvimento sustentável da indústria de biodiesel, a valorização do glicerol é fundamental, mirando benefícios econômicos e ambientais. Assim, o uso da zeólita Beta e Beta hierarquizada na desidratação de glicerol é uma alternativa promissora, devido as suas propriedades como alta área específica, elevada estabilidade térmica e hidrotérmica e acidez de Lewis e Brønsted. Portanto, o objetivo deste trabalho foi gerar mesoporos na zeólita Beta afim de obter estrutura zeolítica hierarquizada por um método econômico e fácil, e avaliar sua atividade catalítica na reação de desidratação de glicerol visando a obtenção de produtos de maior valor agregado. As amostras hierarquizadas foram obtidas através do tratamento alcalino com NH4OH, na presença e ausência do surfactante brometo de cetiltrimetilamônio (CTAB). As amostras hierarquizadas sem CTAB apresentaram formação de mesoporos com ampla distribuição de tamanho de poros. Já as amostras hierarquizadas com CTAB exibiram mesoporos ordenados controlados. Tais materiais demostraram ser promissores na reação de desidratação do glicerol, obtendo como produtos principais ácido acético (32,48%) e ácido propanoico (43,70%), essas amostras também foi seletiva a acetol (16,68%) e álcool alélico (7,17%).
8
Roelofsen, J. W., H. Mathies, and R. L. de Groot. "On the Relation Between NH3 Adsorption Data and Lattice Constant of Steamed NH4NaY and NH4 RENaY Zeolites." In Studies in Surface Science and Catalysis. Elsevier, 1989. http://dx.doi.org/10.1016/s0167-2991(08)61762-0.
Full text
9
Kungang, Tu, and Xu Ruren. "The Influence of Alkali Metal Cations on the Formation of Silicalite in NH4OH-TBAOH Systems." In Studies in Surface Science and Catalysis. Elsevier, 1985. http://dx.doi.org/10.1016/s0167-2991(08)65270-2.
Full text
10
Schweitzer, George K., and Lester L. Pesterfield. "The Nitrogen Group." In The Aqueous Chemistry of the Elements. Oxford University Press, 2010. http://dx.doi.org/10.1093/oso/9780195393354.003.0011.
Full textAbstract:
The Nitrogen Group of the Periodic Table contains the elements nitrogen N, phosphorus P, arsenic As, antimony Sb, and bismuth Bi. The outer electron structure ns2np3 characterizes all five of the elements, with n representing principal quantum numbers 2, 3, 4, 5, and 6, respectively. The ns2np3 indicates the possibility of oxidation states V, III, and -III. As one goes down the group, the metallic character increases, with N and P being distinctly non-metals, As a metalloid, and Sb and Bi metals. However, the major bonding in most of the compounds of the group is covalent, aqueous cationic species being formed only by Sb and Bi. A covalency of 5 is exhibited by all the elements except N, this being assignable to the considerable energy required to place 10 electrons around the atom. The pentavalent state is the most stable for P, with its stability falling off down the group, as the trivalent state stability increases. Covalent radii in pm are as follows: N (75), P (110), As(122), and Sb(143). Ionic radii (most hypothetical) in pm are these: Sb+3 (90), Sb+5 (74), Bi+3 (117), and Bi+5 (90). a. E–pH diagram. Figure 9.1 depicts the E–pH diagram for N with the soluble species (except H+) at 10−1.0 M. Equations for the lines that separate the species are displayed in the legend. The colorless strong acid nitric acid HNO3, its colorless anion nitrate NO3−, the colorless weak acid nitrous acid HNO2, its colorless anion NO2−, the colorless ammonium ion NH4+, and the colorless hypothetical compound ammonium hydroxide NH4OH are involved.
Conference papers on the topic "NH4OAc"
1
Gui, F., J. A. Beavers, and N. Sridhar. "Evaluation of Ammonia Hydroxide for Mitigating Stress Corrosion Cracking of Carbon Steel in Fuel Grade Ethanol." In CORROSION 2011. NACE International, 2011. https://doi.org/10.5006/c2011-11138.
Full textAbstract:
Abstract Carbon steel is susceptible to stress corrosion cracking (SCC) in fuel grade ethanol (FGE). It has been found that SCC in FGE can be inhibited by adding inhibitors. This paper reports the work conducted to evaluate NH4OH as an inhibitor to mitigate SCC of carbon steel in simulated FGE (SFGE). The efficacy of the inhibitor was tested using slow strain rate (SSR) testing and crack growth rate (CGR) tests in simulated FGE (SFGE). Furthermore, the electrochemical response of carbon steel in inhibited SFGE was studied in order to understand the observed SCC inhibition by NH4OH.
2
Meletis, E. I., and K. Lian. "Environment-Induced Deformation Localization and Its Role in Transgranular Stress Corrosion Cracking." In CORROSION 1995. NACE International, 1995. https://doi.org/10.5006/c1995-95180.
Full textAbstract:
Abstract The long term objective of the present work is to provide an insight to the nucleation and evolution of deformation patterns occurring during transgranular (TG) stress corrosion cracking (SCC) and produce new alternatives for addressing the nature of the embrittlement process. Flat, tensile α- brass (72Cu-28Zn) specimens were tested in 5M NH4OH solution at a strain rate of 1x10−5s−1. Slip band spacing (SBS) and slip band heights (SBH) were measured as a function of strain by conducting interrupted experiments in the SCC environment and were compared with those developed in specimens tested in laboratory air. The results showed that the presence of the SCC environment during straining promotes localized plastic deformation at the near-surface region, but more importantly produces a completely different deformation pattern compared to that developed in laboratory air. The deformation evolved in the presence of the electrolyte was highly localized, exhibiting a fine SBS but coarse SBH and slip band length. In addition, a periodicity was observed in the spacing of the crack initiation sites. The amount of localized strain developed at the specimen near-surface region prior to nucleation of stress corrosion cracks was found to be equivalent to the strain required for ductile fracture of the material in air, suggesting the existence of a fundamental fracture criterion. The TGSCC process is considered in view of the presently observed deformation patterns.
3
Rocchini, Gabriele. "pH Influence on Magnetite Stability in Steam Generator Tubes." In CORROSION 1992. NACE International, 1992. https://doi.org/10.5006/c1992-92252.
Full textAbstract:
Abstract Magnetite solubility, as a function of temperature and partial hydrogen pressure and with reference to the typical conditions of the operating fluid of a steam generator of a thermal power plant, has been studied by rigorously solving the problem of chemical equilibria and adopting the scheme proposed by Sweeton and Baes. Stoichiometric calculations have proved that magnetite solubility attains its maximum value, which depends on the characteristics of the electrolytic solution, when temperature is about 100°C, independently of the type of environment. The rigorous pH calculation was carried out using the method of the characteristic function, which can be applied also to complex systems, and assuming that the effect of the ionic strength may be neglected. The main aim of this study, besides helping power plant chemists to select a proper feed water conditioning, was to calculate the pH, on molal basis, of a solution through the best-fitting of its exact values, as a function of ammonia concentration inside the interval [1.E-8, 9.E-3] m with a third-degree logarithmic polynomial. The results, which were obtained in the case of a solution containing NH4OH and H2CO3, demonstrate the validity of this technique which permits us to compute accurately the pH of a fairly complex system. It also allows the correct amount of magnetite dissolution products to be evaluated without considering in detail its chemical equilibria when the solution temperature is above 200 °C. This remark was derived from the pH calculations of an ammonia containing solution, which showed its independence of partial hydrogen pressure in the high temperature region, at least as far as the interval [0,1] atm was concerned. Finally, the determination, at temperatures of 200 °C, 250 °C, 300 °C and 350 °C, of the pH, on molar basis, of a solution, contaminated with sea water so that its acid conductivity was 300 µ mohs/cm, has been performed. These results have shown that the buffering effectiveness of ammonia is negligible when its concentration falls within the interval [1 .E-6, 2.E-5] M, whereas in the range [6.E-5, 3.E-4] M its effect is quite pronounced.
4
Tyrewala, Daanish S., David Rothamer, and Jaal Ghandhi. "Investigation of Aqueous Ammonia/Hydrogen Blends for Use In Advanced Dual-Fuel Combustion." In ASME 2024 ICE Forward Conference. American Society of Mechanical Engineers, 2024. https://doi.org/10.1115/icef2024-138672.
Full textAbstract:
Abstract Aqueous ammonia (NH4OH, a solution of 29.1% NH3 in water) and aqueous ammonia/hydrogen (NH4OH/H2) premixed blends were explored using a dual-fuel strategy with #2 diesel directly injected. Diesel fuel was substituted (at constant energy) with NH4OH and NH4OH/H2 blends at constant fuel energy while maintaining phasing using the diesel SOI timing. NH4OH/H2 blends were evaluated to investigate the efficacy of hydrogen for improving ignition quality and flame speed of the premixed mixture, and to determine if aqueous ammonia/hydrogen blends could be used as substitutes to represent the performance of anhydrous ammonia. The hydrogen concentration in the blends was adjusted to match adiabatic flame temperature (TAd) to anhydrous ammonia. Substitution of diesel fuel energy for aqueous ammonia was limited to 50% by energy at low-loads due to combustion instability, and challenges maintaining intake runner temperature at mid-loads due to significant enthalpy required to vaporize the aqueous ammonia. NH4OH/H2 blends exhibited improved combustion stability and led to over 4% decrease in unburned-to-supplied premixed energy, but were not suitable surrogates for NH3 combustion due to controlled end-gas autoignition (c-EGAI) and hydrogen preignition issues.
5
Soares, Guilherme M. B., Audrey R. Silva, Lucas Stucchi Zucchi, et al. "NH4OH Wet Etching for Silicon Nano or Sub-Micron Wires." In 2018 33rd Symposium on Microelectronics Technology and Devices (SBMicro). IEEE, 2018. http://dx.doi.org/10.1109/sbmicro.2018.8511599.
Full text
6
Özkan, Alican, Yusuf Keleştemur, Hilmi Volkan Demir, and E. Yegan Erdem. "Silica Synthesis and Coating of Quantum Dots in Droplet Based Microreactors." In ASME 2015 13th International Conference on Nanochannels, Microchannels, and Minichannels collocated with the ASME 2015 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/icnmm2015-48765.
Full textAbstract:
We present a microfluidic reactor that utilizes meandering microchannel shape to mix reagents inside droplets in a carrier fluid to synthesize silica and silica coated nanoparticles. Meandering channels decrease mixing time due to reduced diffusion lengths. Moreover, droplet-based flow provides uniform reaction times due to the circulating flow profile inside droplets as opposed to parabolic flow profile in straight channels. Before fabricating our device, we have simulated the mixing performance of droplets at different channel cross-sections and meandering geometries using Comsol Multiphysics©. As a result, we have concluded that channel cross-section and meandering dimensions should be as small as possible for faster mixing. Accordingly, we have fabricated our device in PDMS by using soft lithography technique and introduced chemicals to the microsystem by using syringe pumps. We will use this system to understand the effect of solvent concentration and residence time on silica formation to obtain better coating thickness distribution than in batch-wise methods. As a preliminary study, we tested the silica formation inside droplets and we obtained 102 nm ± 4 nm of silica nanoparticles. In the synthesis we followed a modified method of synthesis in the literature where droplets of solution composed of 20 mL Cyclohexane, 2.6 mL IGEPAL and 300 μL TEOS were formed inside the carrier fluid NH4OH at a flow rate ratio of 2:1. It is observed that nanoparticles were synthesized as a result of diffusion and mixing of NH4OH inside droplets. Currently, we are working on introducing QDs in droplets and coating them with silica shells inside the microreactor. We will also study the effects of NH4OH concentration, residence time on silica shell thickness and compare with batch-wise silica synthesis and coating of quantum dots and present these results at the conference.
7
Jia, Hao, Jaesung Lee, Zenghui Wang, and Philip X. L. Feng. "High-frequency SiC microdisk resonators operating in water with responses to H2O2 and NH4OH." In 2014 IEEE International Frequency Control Symposium (FCS). IEEE, 2014. http://dx.doi.org/10.1109/fcs.2014.6859846.
Full text
8
Malanova, N. V., V. I. Kosintcev, and A. I. Sechin. "The physicochemical bases of calcium carbonate formation in modeling system CaCl2 + NaHCO3 + NH4OH." In 2012 7th International Forum on Strategic Technology (IFOST). IEEE, 2012. http://dx.doi.org/10.1109/ifost.2012.6357496.
Full text
9
Stucchi-Zucchi, Lucas, Audrey R. Silva, and Jose A. Diniz. "Junctionless-FET device fabrication using silicon etching in NH4OH solution: device behaviour according to etching time." In 2019 34th Symposium on Microelectronics Technology and Devices (SBMicro). IEEE, 2019. http://dx.doi.org/10.1109/sbmicro.2019.8919301.
Full text
10
Xiao, Cong-Han, Ciao-Yi Syu, Yu-Lin Shen, et al. "Collagen Films with Extra Cellular Matrix via Combination of Supercritical Carbon Dioxide Fluid and NH4OH Treatments." In Proceedings of the 2019 International Conference on Electronical, Mechanical and Materials Engineering (ICE2ME 2019). Atlantis Press, 2019. http://dx.doi.org/10.2991/ice2me-19.2019.39.
Full text