105 research outputs found
Karakterizacija pulpe i papira izrađenih od stabljika bamije (Abelmoschus esculentus)
In this study, the usability of okra (Abelmoschus esculentus) stalks in pulp and paper production was investigated. Firstly, chemical components and fiber morphological properties were determined to investigate the suitability of okra stalks for pulp and paper production. Holocellulose, cellulose and lignin contents were found as 76.1 %, 46.4 % and 16.0 %, respectively and the fiber length, fiber width and cell wall thickness were measured as 0.64 mm, 16.97 μm and 3.66 μm, respectively. According to these data, it has been determined that okra stalks are suitable for pulp and paper production. Four different cooking experiments were carried out by adding sodium borohydride (NaBH4) in different proportions (0 %, 0.3 %, 0.5 %, 0.7 %) to okra stalks by the alkali sulfite method. The yield, chemical, physical and optical properties of the pulps were determined and optimum properties were obtained from the cooking experiment by adding up to 0.7 % NaBH4 into cooking liquor. With the addition of 0.7 % NaBH4, pulp yield, breaking length, and burst index increased about 7.73 %, 3.84 %, and 11 %, respectively. Consequently, it has been concluded that pulp produced from okra stalks can be used in the paper industry by blending with long or recycled fibers in certain proportions.U ovom je radu istraživana upotrebljivost stabljika bamije (Abelmoschus esculentus) za proizvodnju celuloze i papira. Radi ispitivanja prikladnosti stabljika bamije za proizvodnju celuloze i papira, najprije su određeni udjeli kemijskih komponenata i morfološka svojstva vlakana. Utvrđeni udjeli holoceluloze, celuloze i lignina iznosili su 76,1 %, 46,4 % i 16,0 %. Duljina vlakana, širina vlakana i debljina stanične stijenke bili su 0,64 mm, 16,97 μm i 3,66 μm. Prema tim podatcima utvrđeno je da je stabljika bamije pogodna za proizvodnju celuloze i papira. Zatim su provedena četiri različita pokusa kuhanja alkalno sulfitnim postupkom, uz varijabilni dodatak natrijeva borhidrida (NaBH4): 0 %; 0,3 %; 0,5 %; 0,7 % s obzirom na količinu stabljika bamije. Određeni su prinos pulpe, njezina kemijska, fizikalna i optička svojstva te su postignuta optimalna svojstva pulpe u procesu kuhanja uz dodatak 0,7 % NaBH4 smjesi kemikalija za kuhanje (bijeli lug). Uz dodatak 0,7 % NaBH4, prinos pulpe, duljina loma i indeks pucanja papira izrađenoga od vlakana bamije povećali su se za oko 7,73 %, 3,84 %, odnosno 11 %. Posljedično, zaključeno je da se pulpa proizvedena od stabljika bamije može upotrebljavati u industriji papira u određenim omjerima pomiješana s dugim ili recikliranim vlaknima
Procjena linter celuloze kao alternativne sirovine za proizvodnju upijajućeg papira
The study was carried out to evaluate Linter Cellulose (LC) as an alternative raw material for tissue paper production. Since LC is generally dark brown in color, it must be bleached before being used in tissue paper production. Bleaching process was applied to LC after impurities and oils were removed. LC was bleached in 9 different conditions with sodium hypochlorite (NaClO). The optical and physical properties of LC were measured in accordance with relevance standards in order to determine optimum bleaching condition. The best results in the optical properties were obtained by bleaching with 12 % NaClO. The whiteness, brightness, and yellowness values were found as 67.54, 64.39, and 6.20, respectively. The physical properties of bleached LC were not suitable for tissue paper production. For this reason, LC and wood fi bers (WF) were mixed at certain rates to produce tissue paper. The physical and optical properties of the paper obtained from the mixtures were analyzed to determine the optimum mixing ratio. The results showed that 40 % LC and 60 % WF mixtures can be used in tissue paper products. The important physical properties for tissue paper were Water Retention Value(WRV) and Water Absorption Time (WAT) and these values were found as 293.6 g·m-2 and 1.67 s. WRV and WAT of LC were found to be better than those of WF (267 g·m-2 and 2.62 s). As a result, when considering the shortage of pulp and paper raw material, the use of LC in tissue paper production would contribute signifi cantly to procuring the raw material and providing economic production.Istraživanje je provedeno radi procjene linter celuloze (LC) kao alternativne sirovine za proizvodnju upijajućeg papira. Budući da je LC tamnosmeđe boje, prije uporabe za proizvodnju upijajućeg papira potrebno ga je izbijeliti. Procesi izbjeljivanja LC-a primijenjeni su nakonuklanjanja nečistoća i ulja. LC je izbijeljen natrijevim hipokloridom (NaClO) pri devet različitih uvjeta. Izmjerena su optička i fizikalna svojstva LC-a u skladu s odgovarajućim standardima kako bi se odredili optimalni uvjeti izbjeljivanja. Najbolji rezultati optičkih svojstava dobiveni su izbjeljivanjem 12-postotnim NaClO. Vrijednost bjeline iznosila je 67,54 %, sjajnosti 64,39 % i žutila 6,20 %. Fizikalna svojstva izbijeljenog LC-a nisu prikladna za proizvodnju upijajućeg papira. Stoga je LC pomiješan s drvnim vlakancima (WF) u određenom omjeru kako bi se dobila sirovina prikladna za proizvodnju upijajućeg papira. Fizikalna i optička svojstva papira proizvedenoga od pripremljene smjese analizirana su radi određivanja optimalnog omjera miješanja LC-a i WF-a. Rezultati su pokazali da je smjesa od 40 % LC-a i 60 %WF-a može upotrebljavati za izradu proizvoda od upijajućeg papira. Važna fizikalna svojstva upijajućeg papira jesu sposobnost zadržavanja vode (WRV) i vrijeme upijanja vode (WAT). Za proizvedeni upijajući papir izmjerena je vrijednost WRV-a od 293,6 g·m-2 i WAT-a od 1,67 s. Utvrđeno je da su vrijednosti WRV-a i WAT-a za LC bolje nego vrijednosti za WF (267 g·m-2 i 2,62 s). Kada se uzme u obzir nedostatak sirovine za proizvodnju celuloze i papira, može se reći da bi upotreba LC-a za proizvodnju upijajućeg papira mogla znatno pridonijeti lakšoj nabavi sirovina i ekonomičnosti proizvodnje
Utjecaj razlika između bjeljike i srži na mehanička svojstva drva brzorastućih vrsta
In most uses where wood material needs impregnation or dimensional stability is essential, the properties of sapwood and heartwood should be taken into account. Also, due to the structural differences between heartwood and sapwood, differences in the strength of wood materials should be predicted. Therefore, the aim of this study was to reveal the differences between the mechanical properties of sapwood and heartwood of some important fast-growing forest trees. For this purpose, two softwoods (Pinus sylvestris) and (Pinus brutia) and two hardwoods (Populus usbekistanica) and (Eucalyptus grandis) were selected as test trees. Compression strength parallel to grain (CS ǁ), static quality value (IS), bending strength (MOR), modulus of elasticity (MOE), tensile strength perpendicular to grain (TS⊥), shearing strength parallel to grain (SS ǁ), impact bending strength (IBS), dynamic quality value (ID) and Janka hardness values (JH) of sapwood and heartwood of test trees were determined in laboratory studies. The results of the t-test analysis showed that all mentioned mechanical properties of sapwood and heartwood of test trees were separated from each other as significant, except the shear strength of Eucalyptus, dynamic quality values of red pine and Scots pine and Janka hardness value of red pine. Finally, the results of the study revealed that the differences between sapwood and heartwood strength should be taken into account when wood species are used in constructions and other sensitive areas.U većini primjera uporabe drva u kojima je potrebna impregnacija ili je postojanost dimenzija iznimno važna treba uzeti u obzir različita svojstva drva bjeljike i srži. Usto, zbog strukturnih razlika između srži i bjeljike treba predvidjeti i razlike u njihovoj čvrstoći. Cilj je ovog istraživanja bio utvrditi razlike između mehaničkih svojstava srži i bjeljike nekih važnih brzorastućih šumskih vrsta drva. Stoga su za izradu uzoraka odabrane dvije vrste četinjača (Pinus sylvestris i Pinus brutia) i dvije vrste listača (Populus usbekistanica i Eucalyptus grandis). U laboratorijskim su uvjetima za uzorke drva četinjača i drva listača određena ova svojstva: tlačna čvrstoća paralelno s vlakancima (CS ǁ), vrijednost statičke kvalitete (IS), čvrstoća na savijanje (MOR), modul elastičnosti (MOE), vlačna čvrstoća okomito na vlakanca (TS⊥), smična čvrstoća paralelno s vlakancima (SS ǁ), čvrstoća drva na udarce (IBS), vrijednost dinamičke kvalitete (ID) i tvrdoća po Janki (JH). Rezultati usporedbe uz pomoć t-testa pokazali su da se istraživana mehanička svojstva drva bjeljike i srži znatno razlikuju, osim smične čvrstoće drva eukalipta, dinamičkih vrijednosti kvalitete drva crvenog bora i običnog bora te tvrdoće drva crvenog bora po Janki. Zaključno, rezultati studije pokazali su da je pri upotrebi drva brzorastućih vrsta u graditeljstvu i drugim osjetljivim područjima nužno uzeti u obzir razlike među mehaničkim svojstvima drva bjeljike i srži
Procjena mogućnosti uporabe biljaka Rhododendron luteum i Rhododendron ponticum kao sirovine za proizvodnju celuloze i papira
In this study, Rhododendron luteum and Rhododendron ponticum were evaluated as raw material for pulp and paper production. 12 different sodium borohydride (NaBH4) added cooking trials were performed for each sample and kraft method was used for pulp production. Pulp properties, such as yield, kappa number and viscosity, and physical properties, such as breaking length and burst index, were determined for each trial. Besides, the effects of active alkali and NaBH4 on the pulp and paper properties were also examined. Optimum cooking conditions were obtained by using 18 % active alkali for NaBH4-free cooking experiments and 0.5 % NaBH4 and 18 % active alkali for NaBH4-added cooking experiments. In NaBH4-added pulping condition, the screened yield, kappa number and viscosity of R. luteum were found to be 43.4 %, 40.1 and 949 cm3/g1, respectively. The respective values for R. ponticum were 41.9 %, 44.5 and 885 cm3/g1. The screened yields of R. luteum and R. ponticum increased by about 2.8 % and 5.3 %, respectively, with 5 % addition of NaBH4 compared to NaBH4-free cooking experiments. Furthermore, with the addition of NaBH4, the kappa numbers decreased while the viscosity increased. The physical properties of the produced papers were also improved by using NaBH4 in cooking liquor. According to the obtained results, it was found that R. luteum and R. ponticum species can be evaluated for pulp and paper production.U ovom je radu istražena mogućnost uporabe biljaka Rhododendron luteum i Rhododendron ponticum kao sirovine za proizvodnju celuloze i papira. Za svaki uzorak provedeno je 12 različitih ispitivanja kuhanja s natrijevim borhidridom (NaBH4), a celuloza je proizvedena kraft postupkom. Za svako ispitivanje određena su svojstva celuloze poput prinosa, kappa broja i viskoznosti, te fizička svojstva kao što su duljina lomljenja i indeks pucanja papira. Osim toga, ispitani su učinci aktivne lužine i NaBH4 na svojstva celuloze i papira. Optimalni uvjeti kuhanja postignuti su upotrebom 18 % aktivne lužine za eksperimentalno kuhanje bez NaBH4 i upotrebom 0,5 % NaBH4 i 18 % aktivne lužine za eksperimentalno kuhanje s dodatkom NaBH4. U proizvodnji celuloze iz biljke R. luteum s dodatkom NaBH4 utvrđeno je da prinos prosijavanja iznosi 43,4 %, da je kappa broj 40,1, a viskoznost 949 cm3/g, dok su vrijednosti za celulozu dobivenu iz biljke R. ponticum redom 41,9 %, 44,5 i 885 cm3/g. Prinos prosijavanja biljaka R. luteum i R. ponticum uz dodatak 5 % NaBH4 povećao se oko 2,8 % i 5,3 % u usporedbi s eksperimentalnim kuhanjem bez dodatka NaBH4. Nadalje, uz dodatak NaBH4 smanjuju se kappa brojevi, a viskoznosti se povećavaju. Fizička svojstva proizvedenih papira također se poboljšavaju dodavanjem NaBH4 tekućini za kuhanje. Iz dobivenih je rezultata utvrđeno da se biljke R. luteum i R. ponticum mogu upotrebljavati u proizvodnji celuloze i papira
Effects of sodium borohydride on peroxide bleaching of Pinus brutia Ten. and wheat straw pulps
The addition of sodium borohydride (NaBH4) to peroxide bleaching has been investigated for its effects on the bleaching yield, mechanical and optical properties of Pinus brutia and wheat straw pulps. The pulps were subjected to four different bleaching conditions by adding charges of NaBH4 at 0%, 0.5%, 1.0%, and 1.5%, while keeping a constant hydrogen peroxide charge of 7%. The use of NaBH4 in the peroxide bleaching processes of the two pulps increased the bleaching yields. The results show that the addition of NaBH4 significantly improved the mechanical properties of the pulps, including tensile and burst indices. The optical properties of the pulps were also improved with the addition of NaBH4. The increase in mechanical and optical properties can be attributed to the reduction of residual hydrogen peroxide and the removal of metal ions, while the decrease in yellowness is due to the removal of metal ions that can cause oxidative degradation of the pulp. The findings of this study suggest that the addition of NaBH4 as an additive in peroxide bleaching is a promising approach to improve the mechanical and optical properties of P. brutia and wheat straw pulps, which can be further explored in future research
Yüksek yoğunluklu lif levhanın ısı iletkenliği ve limit oksijen indeksi üzerine yanmayı geciktiricilerin etkisi
Bu çalışmada, yanmayı geciktirici bazı kimyasal maddeler değişik oranlarda lif ile muamele edilmiş ve yüksek yoğunluklu liflevha (HDF) üretilmiştir. Hammadde olarak %50 kayın ve %50 sarıçam lifleri kullanılmıştır. Liflerin içine tam kuru lif miktarına oranla %3, %6, %9 oranlarında toz halinde boraks, borik asit, amonyum polifosfat ve alfa-x kimyasalları ilave edilerek HDF levhalar elde edilmiştir. Elde edilen yüksek yoğunluklu lif levhanın ısı iletkenliği ve limit oksijen indeksi (LOI) değerleri belirlenmiştir. Yanmayı geciktirici kimyasal maddelerin ısı iletkenliği ve limit oksijen miktarını artırdığı ancak kimyasal madde türü ve konsantrasyon oranına göre farklı etki yaptıkları tespit edilmiştir. Isı iletkenliği için en iyi sonuç %9’ luk borik asit (0.2815 W/moK) ile sağlanırken LOI testi için en iyi sonuçlar %6 ve %9’ luk amonyum polifosfat (%45) için elde edilmiştir.
Anahtar Kelimeler: HDF, Boraks, Borik asit, Isı iletkenliği, LO
The valueo of prone scintimammography with technetium-99m tetrofosmin in the diagnosis of breast cancer and lymph node metastases: Comparison with mammographic and histological results
Tissue Papers in Turkey and Some Physical and Optical Properties
The objective of study was to determine some properties of tissue papers and identify the position in Turkey. Napkins, toilet papers and paper towels used in this study were supplied from 5 different companies. Physical and optical properties of these papers were investigated and compared them to each other. Grammage, moisture content, crepe, bulk, density, tensile strength, thickness, water retention value and water absorption time were determined as physical properties and brightness and whiteness values were measured as optical properties. According to obtained results, the best results in physical and optical properties of napkins, toilet papers and paper towels belong to C, E and A Company, respectively
Effects of Coating with Calcite together with Various Fire Retardants on the Fire Properties of Particleboard
The fire properties of particleboard coated with calcite and a variety of fire-retardants (FR) was investigated. Four different chemicals, boric acid (BA), borax (BX), dolomite (DOL), and melamine (MEL), were added at the concentration of 1.0%, 3.0%, and 5.0% by oven-dry weight of calcite. The particleboard panels were tested according to the ASTM-E 69 standard to investigate their fire-retardant properties. The determination of weight loss, temperature, and the release of O2, CO, and NO by the samples was measured and recorded over 30 s intervals during combustion of the materials. The results indicated that the BA coatings exhibited better thermal stability than the other chemicals. Consequently, the lowest weight loss and temperature was found for specimens treated with 5.0% BA. These chemicals were effective relative to the fire properties of coated particleboard surfaces, depending on the type and ratio of the chemicals to the calcite
Investigation on Resistance against White-rot and Brown-rot Fungi of some Fire Retardant Chemicals in Laminate Flooring
The objective of this study is to determine the effects of some fire retardants on decay resistance of the high density fiberboard (HDF) panels covered with overlay, decorative and balance papers. Borax (BX), boric acid (BA), ammonium polyphosphate (APP) and alpha-x (AX) as fire retardant (FR) chemicals were added as powder into the fibers made from 50% pine and 50% beech woods at 3%, 6% and 9% levels based on oven-dry fiber weight. HDF panels (400x400x6.5mm) were produced. After, surfaces of the panels were coated with overlay, decorative and balance papers. The panels were exposed to white (Ceriporiopsis subvermisphora) and brown (Coniophora puteana) decay fungi. The decay resistance of panels was investigated. The results showed that the addition of FR chemicals increased resistance against white and brown rot fungi of the panels. Thus, it was ascertained that concentration and type of FR chemicals are effective on decay resistance of laminate floorin
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