Anatomical, morphological and chemical characteristics of kaun straw (Seetaria-ltalika)

2020 ◽  
Vol 35 (2) ◽  
pp. 288-298 ◽  
Author(s):  
Taslima Ferdous ◽  
M. Abdul Quaiyyum ◽  
Shahriar Bashar ◽  
M. Sarwar Jahan
Keyword(s):  
Wheat Straw ◽  
Rice Straw ◽  
Lignin Content ◽  
Slenderness Ratio ◽  
Ash Content ◽  
Pulp Yield ◽  
Chemical Characteristics ◽  
Cellulose Content ◽  
Fiber Wall ◽  
Flexibility Coefficient

AbstractAnatomical, morphological and chemical characteristics of kaun straw were examined to assess their suitability for paper production and the properties were compared with wheat straw and rice straw. It was found that the fiber length of kaun straw is slightly shorter than that of wheat straw and longer than that of rice straw. It has wider fiber wall thickness than that of wheat straw and rice straw. It had acceptable derived values, especially slenderness ratio, which was lower than that of wheat straw and rice straw, and higher runkel ratio and lower flexibility coefficient. Chemical analysis of kaun straw revealed satisfactory levels of α-cellulose content (35.9 %) and klason lignin content (19.3 %). The ash content in kaun straw (7.32 %) showed lower value than that of wheat straw and rice straw. In optimum cooing conditions, kaun straw produced pulp yield of 30.0 % and 41.7 % with kappa number 15.1 and 22.5 in soda-AQ and formic acid pulping processes, respectively, the values of which were lower than that of wheat straw and rice straw.

scholarly journals DISSOLVING PULP FROM NON-WOOD PLANTS BY PREHYDROLYSISPOTASSIUM HYDROXIDE PROCESS

2021 ◽  
Vol 55 (1-2) ◽  
pp. 117-124
Author(s):  
AKASH MAMON SARKAR ◽  
JANNATUN NAYEEM ◽  
M. MOSTAFIZUR RAHAMAN ◽  
M. SARWAR JAHAN
Keyword(s):  
Wheat Straw ◽  
Rice Straw ◽  
Potassium Hydroxide ◽  
Dissolving Pulp ◽  
Pulp Yield ◽  
Cellulose Content ◽  
Corn Stalk ◽  
Long Time ◽  
Pulp Production ◽  
Rayon Fiber

The garment industry is the backbone of Bangladesh’s economy, which imports 30000 metric tons of rayon fiber every year. Bangladesh used to have a rayon plant, but it was shut down a long time ago. At present, the establishment of a new rayon plant in Bangladesh has become an objective. As a forest deficient country, non-wood plants need to be explored for rayon grade dissolving pulp production. Therefore, in this paper, prehydrolysis potassium hydroxide (KOH) pulping process has been investigated for dissolving pulp production from rice and wheat straws, corn stalk, dhaincha and jute stick. The lowest prehydrolysis yield was 70.1% obtained for corn stalks and the highest prehydrolysis yield was 92.1% for wheat straw. The KOH cooking of prehydrolysed rice straw, wheat straw and corn stalks with 14% alkali charge produced pulps with kappa numbers of 5.7, 4.5 and 8.8, respectively, while prehydrolysed dhaincha and jute stick needed 18% alkali charge to get a bleachable pulp. Dhaincha showed the highest pulp yield (37.3%) with the highest α-cellulose content (92.24%) and the lowest residual pentosan content (5.37%). Further purification with cold KOH extraction increased purity by 3% for rice straw pulp and by 1% for dhaincha, wheat straw, corn stalks and jute stick pulp. Thus, the dissolving pulp produced in this study by the prehydrolysis KOH process can meet the criteria for rayon grade pulp.

scholarly journals Suitability of Aquatic Plant Fibers for Handmade Papermaking

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Nordiah Bidin ◽  
Muta Harah Zakaria ◽  
Japar Sidik Bujang ◽  
Nur Aznadia Abdul Aziz
Keyword(s):  
Aquatic Plants ◽  
Aquatic Plant ◽  
Lignin Content ◽  
Slenderness Ratio ◽  
Cyperus Rotundus ◽  
Cellulose Content ◽  
Typha Angustifolia ◽  
Plant Fibers ◽  
Narrow Lumen ◽  
Flexibility Coefficient

Increasing concerns for future fiber supplies in pulp and paper industries has shifted interest in nonwood sources from agriculture residues and aquatic plants. Aquatic plants with short growth cycles, in abundance, and with low lignin are a potential fiber source. Five aquatic plant species,Cyperus digitatus, Cyperus halpan, Cyperus rotundus, Scirpus grossus, andTypha angustifolia, were examined for fiber dimensions and chemical composition (cellulose, lignin) and compared with other nonwood plants. All aquatic plants possessed short (length, 0.71–0.83 mm) and thin (diameter, 9.13–12.11 µm) fibers, narrow lumen (diameter, 4.32–7.30 µm), and thin cell wall (thickness, 2.25–2.83 µm) compared with most other nonwood plants. Slenderness ratio ranged from 73.77 to 89.34 withTypha angustifoliahaving the highest ratio. Except forScirpus grossus, the flexibility coefficient ranged from 52.91 to 58.08.Scirpus grossushas low Runkel ratio, 0.84 ± 0.17. Fiber characteristics, short and thin fibers, Slenderness ratio >60, flexibility coefficient within 50–75, and Runkel ratio <1, are suitable for papermaking. Cellulose content ofCyperus rotundus(42.58 ± 1.32%),Scirpus grossus(36.21 ± 2.81%), andTypha angustifolia(44.05 ± 0.49%) >34% is suitable for pulp and papermaking. Lignin content in aquatic plants in the present study ranged 9.54–20.04% and below the wood lignin content of <23–30% encountered in pulp and papermaking. Handmade paper sheets produced for paperboard, craft, and decorative purposes are with permissible tensile strength, breaking length, and low moisture content.

scholarly journals Chemical characteristics and Kraft pulping of tension wood from Eucalyptus globulus labill

2012 ◽  
Vol 36 (6) ◽  
pp. 1163-1172 ◽  
Author(s):  
María Graciela Aguayo ◽  
Regis Teixeira Mendonça ◽  
Paulina Martínez ◽  
Jaime Rodríguez ◽  
Miguel Pereira
Keyword(s):  
Eucalyptus Globulus ◽  
Lignin Content ◽  
Strength Properties ◽  
Kraft Pulping ◽  
Pulp Yield ◽  
Chemical Characteristics ◽  
Kraft Pulps ◽  
Opposite Wood ◽  
Alkali Consumption ◽  
Pulp Strength

Tension (TW) and opposite wood (OW) of Eucalyptus globulus trees were analyzed for its chemical characteristics and Kraft pulp production. Lignin content was 16% lower and contained 32% more syringyl units in TW than in OW. The increase in syringyl units favoured the formation of β-O-4 bonds that was also higher in TW than in OW (84% vs. 64%, respectively). The effect of these wood features was evaluated in the production of Kraft pulps from both types of wood. At kappa number 16, Kraft pulps obtained from TW demanded less active alkali in delignification and presented slightly higher or similar pulp yield than pulps made with OW. Fiber length, coarseness and intrinsic viscosity were also higher in tension than in opposite pulps. When pulps where refined to 30°SR, TW pulps needed 18% more revolutions in the PFI mill to achieve the same beating degree than OW pulps. Strength properties (tensile, tear and burst indexes) were slightly higher or similar in tension as compared with opposite wood pulps. After an OD0(EO)D1 bleaching sequence, both pulps achieved up to 89% ISO brightness. Bleached pulps from TW presented higher viscosity and low amount of hexenuronic acids than pulps from OW. Results showed that TW presented high xylans and low lignin content that caused a decrease in alkali consumption, increase pulp strength properties and similar bleaching performance as compared with pulps from OW.

scholarly journals A comparative fiber morphological analysis of major agricultural residues (used or investigated) as feedstock in the pulp and paper industry

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7935-7952
Author(s):  
Dimitrios Tsalagkas ◽  
Zoltán Börcsök ◽  
Zoltán Pásztory ◽  
Vladimir Gryc ◽  
Levente Csóka ◽  
...  
Keyword(s):  
Cell Wall ◽  
Rice Straw ◽  
Sugarcane Bagasse ◽  
Wall Thickness ◽  
Fiber Length ◽  
Slenderness Ratio ◽  
Agricultural Residues ◽  
Lumen Diameter ◽  
Coconut Husk ◽  
Flexibility Coefficient

The suitabilities of major agricultural residues were assessed as papermaking feedstocks. All the examined agricultural residues were assumed as potential candidates for substituting hardwood fibers in mixed pulp blends from a fiber morphological perspective. Wheat, barley, rice, rapeseed, maize, sunflower, sugarcane bagasse, coconut husk, and two genotypes of miscanthus grass underwent identical maceration. The fiber length, fiber width, cell wall thickness, and lumen diameter were measured to calculate the slenderness ratio, flexibility coefficient, and Runkel ratio. The average fiber length ranged from 0.50 mm ± 0.32 mm (MG-S-02-V) to 1.15 mm mm ± 0.58 mm (sugarcane bagasse). The fiber width ranged from 10.77 μm ± 3.28 μm (rice straw) to 22.99 mm ± 5.20 mm (sunflower stalk). The lumen diameter ranged from 4.52 μm ± 2.52 μm (rice straw) to 13.23 μm ± 4.87 μm (sunflower stalk). The cell wall thickness ranged from 3.02 μm ± 0.95 μm (rice straw) to 4.80 μm ± 1.48 μm (sunflower stalk). The slenderness ratio, flexibility coefficient, and Runkel ratio values ranged between 28.08 to 58.11, 37.97 to 60.8, and 0.62 to 1.68, respectively. Wheat, maize, rapeseed, sugarcane bagasse, and coconut husk were found to be appropriate residue sources for papermaking feedstocks.

Nitric Acid-Potassium Hydroxide Fractionation of Rice Straw: an Integrated Biorefinery Initiative

2021 ◽  
Author(s):  
Md. Mostafizur Rahman ◽  
Nur-Al-Sarah Rafsan ◽  
Jannatun Nayeem ◽  
Mohammad Moniruzzaman ◽  
M. Sarwar Jahan
Keyword(s):  
Nitric Acid ◽  
Rice Straw ◽  
Potassium Hydroxide ◽  
Lignin Content ◽  
Soil Nutrient ◽  
Pulp Yield ◽  
Agricultural Residue ◽  
Low Potassium ◽  
Spent Liquor ◽  
Final Effluent

Abstract Rice straw was fractionated with nitric acid in order to avoid the cooking liquor recovery in pulp production from agricultural residue (rice straw). The rice straw treated with 11.03% nitric acid at 90 ℃ for 3hr yields 53.09% pulp. The nitric acid treated rice straw pulp had high amount of lignin and minerals. However, further treatment of nitric acid pulp with low potassium hydroxide reduced the lignin and ash sufficiently as well as the pulp yield. Pulp yield reduced from 53.09 to 34.27%. The papermaking properties of the nitric acid followed by KOH treated pulp showed better quality than the nitric acid pulp. Nitric acid liquor was used several times. Pulp yield decreased in every step of reusing of the nitric acid spent liquor although residual lignin content increased. The final effluent liquor was rich with potassium, nitrogen and biomass that can be used as soil nutrient for cultivation.

Dissolving pulp from white press cuttings

TAPPI Journal ◽  
2016 ◽  
Vol 15 (4) ◽  
pp. 277-282 ◽  
Author(s):  
M. SARWAR JAHAN ◽  
RAJESH CHANDRA DEB ◽  
M. MOSTAFIZUR RAHAMAN ◽  
M.A. QUAIYYUM
Keyword(s):  
Acid Treatment ◽  
Ash Content ◽  
Dissolving Pulp ◽  
Pulp Yield ◽  
Cellulose Content ◽  
Alkaline Extraction ◽  
Rayon Production ◽  
Oligomeric Form ◽  
White Press ◽  
Pentose Sugars

Upgrading of white press cuttings into dissolving pulp was carried out by acidification followed by alkaline extraction. Acid treatment decreased ash content of white press cutting pulp from 11.25% to 0.33% at pH 2. The yield after acidification and screening was 87%. Alkaline extraction removed hemicelluloses and increased α-cellulose content to 92% with viscosity value of 4.3 mPa.s. The overall pulp yield after alkaline extraction was 76.6%. Alkaline extracted liquor contains 9.2% total organics, mostly pentose sugars in the oligomeric form. The produced dissolving pulp can be used for rayon production.

scholarly journals Studi Mutu Kayu Jati di Hutan Rakyat Gunungkidul. V. Sifat Kimia Kayu

2016 ◽  
Vol 10 (2) ◽  
pp. 108
Author(s):  
Ganis Lukmandaru ◽  
Arsyi Rahman Mohammad ◽  
Pito Wargono ◽  
Vendy Eko Prasetyo
Keyword(s):  
Lignin Content ◽  
Chemical Properties ◽  
Tectona Grandis ◽  
Ash Content ◽  
Water Soluble ◽  
Hot Water ◽  
Cellulose Content ◽  
Radial Cross Section ◽  
Community Forests ◽  
Teak Wood

Penelitian ini bertujuan untuk mengeksplorasi sifat kimia kayu jati dari hutan rakyat Kabupaten Gunungkidul. Pohon (dbh 28-37 cm) diambil dari tempat tumbuh berbeda yaitu Nglipar, Panggang, dan Playen. Setiap tempat diambil 3 pohon sebagai ulangan dan sampel yang digunakan adalah disk yang diambil dari bagian pangkal. Penampang radial disk dibagi menjadi 3 bagian, yaitu gubal, teras luar, dan teras dalam. Sifat kimia yang diuji adalah kadar holoselulosa, á-selulosa, hemiselulosa, lignin, ekstraktif etanol-toluena, kelarutan dalam air panas, kelarutan dalam NaOH 1%, dan abu. Sebagai pembanding, digunakan kayu jati dewasa dari tegakan Randublatung (Perhutani). Kisaran nilai kimia dari komponen dinding sel kayu jati Gunungkidul adalah kadar holoselulosa 75,76-79,74%, á-selulosa 46,72-50,90%, hemiselulosa 27,41-30,14%, lignin 29,22-32,80%, dan kelarutan dalam NaOH 1% sebesar 16,43-17,35%. Selanjutnya, kadar ekstraktif etanol-toluena, kelarutan dalam air panas, dan abu adalah 5,04-10,77%, 2,74-7,85%, dan 0,60-1,66%, secara berurutan. Interaksi antara kedua faktor berpengaruh nyata pada kadar holoselulosa, á-selulosa, hemiselulosa, dan ekstraktif etanol-toluena. Faktor tempat tumbuh berpengaruh nyata pada kadar abu sedangkan faktor radial berpengaruh nyata pada kadar kelarutan dalam air panas dan abu. Kayu jati dari Gunungkidul memberikan nilai rerata kadar ekstraktif etanol-toluena dan abu yang lebih rendah sedangkan nilai di parameter lainnya masih dalam kisaran nilai kayu jati dari Randublatung.Kata kunci: Tectona grandis, sifat kimia, hutan rakyat, arah radial, Gunungkidul AbstractThis study aimed to explore the chemical properties of teak wood grown in community forests from Gunungkidul Regency. Trees (dbh 28-37 cm) were selected from three different sites i.e. Nglipar, Panggang, and Playen. Three trees were cut from each site and disks were taken from the base of the trees. The disk in radial cross section was divided into 3 parts: sapwood, outer heartwood, and inner heartwood. Chemical properties tested were holocellulose, á-cellulose, hemicellulose, lignin, ethanol-toluene extractives, hot-water soluble extractives, solubility in NaOH 1%, and ash contents. Mature teakwoods from Randublatung (Perhutani plantation) were used for comparison purpose.The values range of chemical composition in the cell wall components of the Gunungkidul teak wood were holocellulose content 75.76-79.74%, , á-cellulose content 46.72-50.90%, hemicellulose content 27.41-30.14%, lignin content 29.22-32.80%, and solubility in NaOH 1% 16.43-17.35%. Further, the ethanol-toluene extractive, hot-water soluble, and ash content values ranged from 5.04 to 10.77%, 2.74-7.85%, and 0.60-1.66%, consecutively. Interaction between two factors affects significantly to holocellulose, á-cellulose, hemicellulose, and ethanol-toluene extractive contents. The growth-site significantly influence on the ash contents as radial factor has significantly affect on the levels of hot water soluble extractives and ash content. The amounts of ethanol-toluene extractive and ash contents of Gunungkidul teak wood showed the lower values than those of teak from Randublatung. The values of other parameters were remain in the range of value of teak from Randublatung. 

Pulp and paper making potentials of elaeis guineensis (oil palm) grown in south east, Nigeria

2015 ◽  
Vol 12 (1) ◽  
pp. 1-12 ◽  
Author(s):  
E.O. Onuorah ◽  
J.T. Nwabanne ◽  
E.L.C. Nnabuife
Keyword(s):  
Chemical Analysis ◽  
Oil Palm ◽  
Fibrous Material ◽  
Slenderness Ratio ◽  
Raw Material ◽  
Pulp Yield ◽  
Cellulose Content ◽  
Paper Making ◽  
Morphological Studies ◽  
Tear Index

The objective of this study was to determine the pulping and paper making potentials of oil palm (E guineensis). Fibrous material from the whole trunk (WT), empty fruit bunch (EFB, fronds (FDS) and depithed trunk (DT) were evaluated using proximate chemical analysis, fiber morphological and related characteristics. Effect of active alkali (AA) % as Na2O on kraft pulping properties and the handsheet paper propertie was studied. Proximate chemical analysis reveal acceptable cellulose content for EFB (43.51%), FDS (51.13%) and DT (53.80%) while WT (32.44) is unacceptable. Low lignin content obtained (17.8−21.8%) suggests easier pulping characteristics. The high % NaOH solubility of WT (26.05%) and FDS (32.1%) suggest potential of high effluent loads. Fiber morphological studies revealed that approximately 83% of fibers are ≤ 1.5 mm in length thus putting oil palm as a short fiber source. The slenderness ratio ranges from 33.44 to 82.80; Runkelratio from 0.40 to 0.63; flexibility co-efficient from 57.20 to 71.46 and rigidity co-efficient from 0.29 to 0.43. Studies of pulping properties reveal that as active alkali % was increased the percentage total pulp yield, % screened pulp yield, % screened rejects, pulp kappa number, klason lignin and tear index of resultant pulp/handsheet all/each decreased. Conversely, as active alkali % was increased the Brust index, double fold number, breaking length, tensile index of paper handsheets and pulp brightness were each enhanced. It was concluded that in pulping of WT AA% should be < 14 and EFB pulping should be ≤ 14 in order to have acceptable yield. Also in order to have acceptable tear index, AA% should be ≤ 16. It is being recommended that trunks should be depithed in order to have acceptable yield. The fibrous material from oil palm make acceptable raw material for paper making and are good hardwood substitutes. Paper produced when bleached can be used for printing and writing papers while the unbleached grades can be used for wrapping and package papers and for corrugated boards.

scholarly journals The Effects of Iron Rust on the Ageing of Woods and Their Derived Pulp Paper

Polymers ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 3483
Author(s):  
Wael A. A. Abo Elgat ◽  
Ayman S. Taha ◽  
Mohamed Z. M. Salem ◽  
Yahia G. D. Fares ◽  
Martin Böhm ◽  
...  
Keyword(s):  
Wood Species ◽  
Lignin Content ◽  
Chemical Properties ◽  
Biological Properties ◽  
Accelerated Ageing ◽  
Pulp Yield ◽  
Cellulose Content ◽  
Fungal Activity ◽  
Pulp Paper ◽  
And Chemical Properties

The accelerated ageing of wood in terms of heating or iron rusting has a potential effect on the physio-mechanical, chemical and biological properties of wood. The effects of accelerated ageing on the mechanical, physical and fungal activity properties of some wood materials (Schinus terebinthifolius, Erythrina humeana, Tectona grandis, Pinus rigida and Juglans nigra) were studied after several cycles of heating and iron rusting. The fungal activity was assayed against the growth of Aspergillus terreus, Aspergillus niger, Fusarium culmorum and Stemphylium solani. In addition, the mechanical and optical properties of paper sheets produced from those wood pulps by means of Kraft cooking were evaluated. The mechanical and chemical properties of the studied wood species were affected significantly (p < 0.05) by the accelerated ageing, compared to control woods. With Fourier transform infrared (FTIR) spectroscopy, we detected an increase in the intensity of the spectra of the functional groups of cellulose in the heated samples, which indicates an increase in cellulose content and decrease in lignin content, compared to other chemical compounds. For pulp properties, woods treated by heating showed a decrease in the pulp yield. The highest significant values of tensile strength were observed in pulp paper produced from untreated, heated and iron-rusted P. rigida wood and they were 69.66, 65.66 and 68.33 N·m/g, respectively; we calculated the tear resistance from pulp paper of untreated P. rigida (8.68 mN·m2/g) and T. grandis (7.83 mN·m2/g) and rusted P. rigida (7.56 mN·m2/g) wood; we obtained the values of the burst strength of the pulp paper of untreated woods of P. rigida (8.19 kPa·m2/g) and T. grandis (7.49 kPa·m2/g), as well as the fold number of the pulp paper of untreated, heated and rusted woods from P. rigida, with values of 195.66, 186.33 and 185.66, respectively. After 14 days from the incubation, no fungal inhibition zones were observed. Accelerated ageing (heated or iron-rusted) produced significant effects on the mechanical and chemical properties of the studied wood species and affected the properties of the produced pulp paper.

scholarly journals Features of obtaining cellulose from flax straw by peroxide acetate method of cooking

2019 ◽  
Author(s):  
Д.Ю. Арсеньева ◽  
Я.В. Казаков ◽  
Е.О. Окулова
Keyword(s):  
Fiber Length ◽  
Lignin Content ◽  
Ash Content ◽  
Kappa Number ◽  
Cellulose Content ◽  
Hygroscopic Properties ◽  
One Step ◽  
Water Holding ◽  
Cooking Conditions ◽  
Flax Straw

Рассмотрены свойства целлюлозы, полученной из костры льна – отходов льняного производства пероксидно-ацетатным методом. Изучено влияние концентрации основного реагента на результаты варки. Костру льна с содержанием целлюлозы 38,5%, лигнина 15%, зольностью 4,1% варили в лабораторных условиях при гидромодуле 7,5 : 1, 6,25 : 1, 5,0 : 1. Для варки использовали препарат надуксусной кислоты (НУК) с концентрацией 15%. Условия варки регулировали изменением общего объема варочного раствора соотношением НУК : вода 1 : 0 и 2 : 1. В полученных образцах определены химические, структурно-морфологические и гигроскопические свойства по стандартным методикам. Установлено, что использование пероксидно- ацетатного способа варки целлюлозы из костры льна позволяет в одну ступень получить полуфабрикат с выходом 52%, белизной до 78%, зольностью 0,6% и числом Каппа на уровне 2–3 единиц. Разбавление варочного раствора в соотношении НУК : вода 2 : 1 приводит к получению продукта с пониженным выходом (34%), белизной (75%) и повышенной зольностью (1,5%). Снижение гидромодуля до 6,25 : 1 позволяет снизить расход НУК на варку на 44% и способствует улучшению качественных показателей льняной целлюлозы – уменьшению содержания лигнина, снижению зольности до 0,8%, сохранению средней длины волокна и увеличению водоудерживающей способности. The paper discusses the properties of cellulose obtained from flax fires – waste flax production, by using peroxide-acetate method. The influence of the concentration of the main reagent on the results of cooking was studied. Flax fire with a cellulose content of 38.5%, lignin content 15%, ash content of 4.1% was cooked under laboratory conditions at a liquor ratio of 7.5 : 1, 6.25 : 1, 5.0 : 1. The peracetic acid (NAA) with a concentration of 15% was used for cooking. Cooking conditions were regulated by changing the total volume of the cooking solution by the ratio of NAA : water 1 : 0 and 2 : 1. In the obtained samples, chemical, structural-morphological and hygroscopic properties were determined by standard methods. It has been established that the use of the peroxide-acetate pulping method from flax fires makes it possible to obtain a semi- finished product in one step with a yield of 52%, whiteness up to 78%, ash content of 0.6% and a kappa number of 2-3 units. Dilution of the cooking solution in the ratio of NAA : water 2 : 1 results in a product with a reduced yield of 34%, a whiteness of 75% and an increased ash content of 1.5%. Reducing the liquor module to 6.25 : 1 reduces the consumption of NAA for cooking by 44% and contributes to improving the quality indicators of flax pulp – reducing the lignin content, reducing ash content to 0.8%, maintaining the average fiber length and increasing water-holding capacity.

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