10,701 research outputs found
Worm-like carbon shell chains produced from wood
No full textLarge-scale utilization of wood which command absolute majority in biomass for functional carbon precursors contributes to reduce greenhouse effect. Wood char generally has a limit on material usage because of its non-graphitic structure^1^, so we developed a new functional wood char by iron-, or nickel-catalyzed carbonization, which has a graphite-like structure with mesopores good for electroconductivity and liquid phase adsorption capacity for macro molecules^2-5^. However the fine structure of the wood char is still not clear. Here we report more than 70 wt % of iron-catalyzed wood char is filled with chained carbon shells formed by 3~20 defective stacking layers of carbon hexagonal planes, which look like nanometer-sized worms swarm. We name them "carbon shell chains". The discussion of the formation mechanism reveals that the wood cell wall plays an important role for their efficient production. They are stable at 1800 ºC under vacuum, but in air, burn under 600 ºC, and are perfectly conversed into hydrogen and carbon monoxide in a short time by steam at 900 ºC. The control of their decomposition will bring out a new talent in the wood char as a big source of supply for nano-graphite or nano-graphene, for which nanometer size and edge effects have recently attracted considerable attention^6^. In addition, a simple and easy preparation of carbon shell chains implies that they may be naturally produced on or in the earth rich in iron, and might be misinterpreted as nano-worms, though most of them may decompose into organic gases
Wood Properties of Three Fruit Tree Species Planted in Central Kalimantan, Indonesia
No full textThe objective of this study was to evaluate the properties for wood utilization of fruit trees planted in Central Kalimantan, Indonesia. A total of 9 jambu bol (Syzygium malaccense), rambutan (Nephelium lappaceum), and durian (Durio zibethinus) trees were randomly selected from the plot (20 by 30 m) and measured for stem diameter, tree height, stress-wave velocity (SWV), and Pilodyn penetration of the trees. Mean values of stem diameter were 11.8, 15.9, and 29.3 cm for S. malaccense, N. lappaceum, and D. zibethinus, respectively. Mean values of stress-wave velocity were 3.16, 3.95, and 3.63 km/s for S. malaccense, N. lappaceum, and D. zibethinus, respectively. Core samples (5 mm in diameter) were collected from these trees to investigate the wood properties [basic density (BD) and compressive strength parallel to grain (CS)], anatomical characteristics [vessel diameter (VD), cell wall thickness (CWT) in wood fiber, and cell length (CL) of wood fiber and vessel element], and amounts of chemical components. In VD, CWT in wood fiber, and CL in wood fiber and vessel element, almost the same radial variation patterns were found in the three species. Relatively higher values in SWV, BD, and CS were found in N. lappaceum, suggesting that its wood can be used for construction lumber. On the other hand, S. malaccense and D. zibethinus had relatively thicker CWT in wood fiber, longer CL in wood fiber, and lower Klason lignin content. It is considered that the wood of these two species may be suitable for pulpwood
Exploring the Possibility of Ionic Liquid as a Dimensional Stabilizer for Well-Preserved Waterlogged Archaeological Wood
No full textDehydration is the principal conservation process for waterlogged archaeological wood (WAW), with the aim of preventing shrinkage and cracking. For well-preserved WAW, shrinkage mainly takes place when the moisture content is below the fiber saturation point. Here, we conduct a new trial using ionic liquid as a dimensional stabilizer to maintain a stable swollen state of WAW. Molecular dynamics simulation (MD), shrinkage measurement, Fourier transform infrared spectroscopy (FTIR), and dynamic vapor sorption (DVS) were adopted to investigate the interactions and effects of 1-Butyl-3-methylimidazolium chloride ([Bmim][Cl]) on WAW (Dipterocarpaceae Dipterocarpus sp. with a maximum moisture content of 80.3%) in comparison with the conventional material polyethylene glycol (PEG). The results show that [Bmim][Cl] and its water mixtures have a comparable or slightly greater ability to swell amorphous cellulose than does water at room temperature, while crystalline cellulose is left intact. The samples treated with [Bmim][Cl] show less shrinkage than the PEG 300- and PEG 2000-treated samples at all tested concentrations after air-drying. The best dimension control was achieved by 40 wt% [Bmim][Cl], with volumetric shrinkage reduced from 5.03% to 0.47%. DVS analysis reveals that [Bmim][Cl] reduces moisture contents at moderate and low relative humidity (<80%) when the concentration is at or below 20 wt%, which suggests that good dimensional stability was not achieved by simply preserving the moisture content but possibly through the interaction of the ionic liquid with the wood polymers
Wood Propionylation in the Presence of Catalysts
No full textEffects of potassium and sodium salts as catalysts on propionylation of wood and on the color change of propionylated wood have been investigated. It was found that potassium acetate, sodium acetate, sodium propionate, and sodium thiosulfate as catalysts were effective for propionylation of wood, and the catalyst loadings (CLs) of them had an effect on weight percent gains. The color of propionylated wood catalyzed with potassium acetate, sodium acetate, or sodium propionate changed very slightly, while sodium thiosulfate-catalyzed wood changed greatly with the increase of CL. Otherwise, potassium sulfate and sodium sulfate showed little or no catalytic effect, and sodium tetraborate decahydrate showed a negative catalytic effect on propionylation of wood
EXAFS, DFT, light-induced nucleobase binding, and cytotoxicity of the photoactive complex cis-[Ru(bpy)2(CO)Cl]+
No full textThe aqueous photochemistry of cis-[Ru(bpy)2(CO)Cl]+ (1) was investigated at 310 K and under visible light (white) irradiation by NMR and ESI-HR-MS. Complex 1 releases a Cl ligand, coordinates a solvent molecule, and forms the complex cis-[Ru(bpy)2(CO)(H2O)]2+ (2). Also, irradiation experiments were performed in the presence of the nucleobase derivatives 9-ethylguanine (9-EtG) and 9-ethyladenine (9-EtA). Formation of Ru-9-EtG adducts was observed after 3 h irradiation by NMR and HR-MS, while only very small amounts of a Ru-9-EtA adduct could be detected by HR-MS. Solution structural data were obtained by X-ray absorption spectroscopy (XAS) for both 1 and 2. EXAFS gave a Ru−Cl distance of 2.416(7) Å for 1 and a Ru−OH2O distance of 2.102(6) Å for 2. DFT and TDDFT were employed to study the photophysical and photochemical properties of 1. Calculations show that dissociative metal-centered states can be related to the light-induced release of a Cl ligand and subsequent coordination of a solvent molecule. The compound showed no antiproliferative activity in three human carcinoma cell lines (lung, bladder, pancreas) under the testing conditions, either with or without irradiation with UV light
Fungal biodiversity in extreme environments and wood degradation potential
No full textThis doctoral thesis reports results from a multidisciplinary investigation of fungi from extreme locations, focusing on one of the driest and thermally broad regions of the world, the Taklimakan Desert, with comparisons to polar region deserts. Additionally, the capability of select fungal isolates to decay lignocellulosic substrates and produce degradative related enzymes at various temperatures was demonstrated.
The Taklimakan Desert is located in the western portion of the People's Republic of China, a region of extremes dominated by both limited precipitation, less than 25 mm of rain annually and tremendous temperature variation. The organisms that inhabit this region are required to function in conditions that preclude most forms of life. Fungi are particularly interesting organisms for consideration of life in extreme environments since they absorb nutrients from their surroundings with diffusion taking place through the cell wall and plasma membrane requiring free water. The regions near the poles are another example of areas with extreme environmental conditions, with the north and south polar regions having similarities and differences to each other and to the Taklimakan Desert. All three regions experiences extreme cold but only the Taklimakan Desert has exceedingly warm temperatures. The Taklimakan Desert is diurnal and the polar regions have long periods of light and dark in summer and winter months, respectively. The annual precipitation in the specific polar sites is between 100-200 mm, 5-20 fold more than the Taklimakan Desert.
From soil, rock and wood collected in the Taklimakan Desert, 194 independent fungal isolates were generated and identified based on extracted DNA and analysis of the internal transcribed spacer (ITS) region of the rDNA. Dominant taxa were from closely related Thielavia, Embellisia and Alternaria genera. Total DNA extracted directly from environmental samples and subjected to molecular fingerprinting identified 51 consensus sequences almost entirely of taxa not represented by culturing, with the dominant taxa in the Penicillium and Colletotrichum genera.
The sequence data from the Taklimakan Desert cultured fungi were phylogenetically investigated by means of neighbor-joining analysis and compared to fungal sequences derived from various substrates collected at sites in Antarctica and the Arctic with wood as the common substrate from which isolates were obtained among all three locations. Based on comparisons of consensus sequences to the polar fungi and fungal databases, 72 isolates appear to represent novel taxa that may be endemic to the Taklimakan Desert and warrant further investigation.
Selected fungal isolates from the Taklimakan Desert, Arctic and Antarctic research were investigated to determine and compare their ability to degrade two types of lignocellulose substrates, Pinus resinosa and Populus tremuloides, the latter being a genera of tree identified in some locations of the Taklimakan Desert and the former as a model softwood example. Fungi from all regions were able to degrade these substrates to varying degrees though minimal weight loss was common. These isolates did not produce cellulase or lignin peroxidase concurrent to the temperatures prevalent in the regions from which they were collected, posing interesting possibilities for their wood degradation pathways
3D Model of Petrified Wood (Cod. CL-001-078-3-1717)
No full textCÓDIGO DE LA PIEZA: CL-001-078-3-1717
CATEGORÍA: Fósil
CLASIFICACIÓN: Madera fósil
ADQUISICIÓN: Donación
FECHA DE REGISTRO: 22-09-2022ITEM CODE: CL-001-078-3-1717
CATEGORY: Fossil
CLASSIFICATION: Petrified wood
ACQUISITION: Donation
REGISTRATION DATE: 22-09-202
3D Model of Petrified Wood (Cod. CL-001-078-3-D1)
No full textCÓDIGO DE LA PIEZA: CL-001-078-3-D1
CATEGORÍA: Fósil
CLASIFICACIÓN: Xilopalo
ADQUISICIÓN: Donación
FECHA DE REGISTRO: 22-09-2022ITEM CODE: CL-001-078-3-D1
CATEGORY: Fossil
CLASSIFICATION: Petrified Wood
ACQUISITION: Donation
REGISTRATION DATE: 22-09-202
Comparison between frame in CL-wood and light beams
No full textIn the beginning stage when a building is to be constructed it can be difficult to choose the material for the supporting frame. Today there is a lot of different materials with different properties, each material often has good properties while at the same time there is a worse property, heavy weight for example. The growing debate about climate change has led to an increased use of building with wood, as it is positive from a climate perspective. Structor Byggteknik Umeå AB has in their work as construction consultants received questions from customers who want to know more about the differences between cross-laminated wood (CL-wood) and light beams. These questions are the foundation to this project, in which the differences between how the chosen material affects the living area will be compared. The project will also include a comparison to see which material that consumes the most amount of wood. The aspect of climate impact will also be compared in the unit CO2-equivalents, which is a topical question today. To produce the data that will be used to compare the material two buildings where dimensioned, one with CL- wood and one with light beams. To perform the dimensioning a reference building made with concrete was used, from which a section of the building was retrieved as well as loads. In consultations with Structor, requirements were set for sound, U-value, and fire for the buildings that were dimensioned. The load countdown was performed with the program Statcon structure where the most loaded walls and floor slabs were checked in both serviceability limit state (SLS) and ultimate limit state (ULS). From the structure of the floor slabs and walls the amount of wood per 1 m2 were calculated for every building component. With known wall thickness two 3D-modells were produced, one for each material. From the 3D-modells the living area was compared. For the comparison of climate impact two climate declarations including module A1-A5 was created with the construction sector’s environmental calculating program (BM). The comparison of the living area resulted in a difference of 0,8 m2 per floor where the CL-wood was the larger one, despite that the exterior walls and the dividing walls were thicker for the building with CL-wood. This might be because the load-bearing inner walls in the light beam building were a lot thicker than the inner walls in the CL-building. The material consumption was compared by calculating the volume of wood for 1 m2 for every building component. The result showed a difference of 327 % where the light beam building consumed a smaller amount of wood. Most likely this is because the CL-slabs are homogeneous wood elements which increase the amount of wood per m2, while the light beam in the construction is placed with a center distance of 600 mm. One climate declaration was made for each building, the climate impact was compared both component against component and with a total of 1 m2 of every building component. The result showed that when all the building components is compared the CL-building generated a higher climate impact. A closer comparison between component against component shows that the floor slabs in the CL-building has a lower climate impact than the floor with light beams. The conclusion of the project is that both CL-wood and light beams have its advantage, but it can be difficult to say exactly which material is the better one. Despite this, light beams have two advantages in this project while CL-wood only has one. To facilitate the choice a check should be done where all the conditions and requirements are listed. With that list it’s possible to compare which material suits for the specific project.I den initierande fasen för en byggnad kan det vara svårt att välja material för den bärande stommen. Idag finns det många olika material med olika egenskaper, varje material har någon eller några fördelar samtidigt som de också har en eller flera sämre egenskaper. I och med den växande klimatdebatten har allt fler valt att bygga med trä, då det är positivt ur ett klimatperspektiv. Structor Byggteknik Umeå AB (hädanefter Structor) har i sitt arbete som byggnadskonsulter fått frågor från kunder som vill veta mer om skillnaden mellan KL-trä och lättbalkar. Structor vill ha ett underlag för att kunna visa sina kunder vilket av de två alternativen som lämpar sig bäst för deras projekt. Detta är de som låg till grund för det här projektet där KL-trä och lättbalkar jämfördes med aspekter på hur materialvalet påverkar boarean samt materialåtgången av volymen trä. Även en jämförelse av klimatpåverkan i CO2-ekvivalenter utfördes för att belysa skillnader i ett dagsaktuellt ämne. För att ta fram det underlag som senare användes för att bedöma materialens för- och nackdelar dimensionerades två byggnader, en byggnad med KL-trä samt en byggnad med lättbalkar. Dimensioneringen utgick från en betongbyggnad som Structor dimensionerat under 2021, från den hämtades en sektion av byggnaden som gav bestämda mått samt laster. I samråd med Structor sattes krav på ljud, U-värde och brand för byggnaderna som dimensionerades. Lastnedräkningen utfördes med hjälp av programmet Statcon där de mest belastade väggarna och bjälklagen sedan kontrollerades i både bruksgränstillstånd samt i brottgränstillstånd. Den färdiga uppbyggnaden av bjälklag och väggar användes för att sammanställa mängden trä för 1 m2 av respektive byggdel. Med kända väggtjocklekar 3D-modellerades en våning av varje byggnad, 3D-modellerna användes därefter för att jämföra boarean. För jämförelsen av klimatpåverkan skapades en klimatdeklaration för modul A1-A5 med byggsektorns miljöberäkningsprogram (BM). Boarean som jämfördes utifrån 3D-modellerna resulterade i en skillnad på 0,8 m2 vilket blev cirka 0,47 % per våning där KL-byggnaden var den större, trots att ytterväggarna och de lägenhetsavskiljandeväggarna var tjockare i KL-byggnaden. Detta kan bero på att de bärande innerväggarna var tjockare för lättbalks-byggnaden, vilket var den avgörande faktorn för boarean. Materialåtgången jämfördes genom att beräkna volymen trä för 1 m2 av varje byggdel för respektive byggnad. Resultatet visade en skillnad på 327 % där lättbalksbyggnaden förbrukade mindre trä. Detta beror mest sannolikt på att KL-skivorna är homogena träelement som ökar mängden trä / m2, medan väggar med lättreglar endast placeras med centrumavstånd på 600 mm. En klimatdeklaration för varje byggnad gjordes i BM, klimatpåverkan jämfördes både byggdel mot byggdel och totalt där 1 m2 av varje byggdel sammanställdes. Resultatet visade här att KL-byggnaden genererade en högre klimatpåverkan när alla byggdelar jämförs. Granskas i stället varje byggdel för sig så har bjälklagen i KL-byggnaden en lägre klimatpåverkan än bjälklagen i lättbalksbyggnaden. Slutsatsen från projektet är att KL-trä och lättbalkar har sina fördelar och att det är svårt att dra en tydlig slutsats och säga vilket av dem som är det bättre. Dock så har lättbalkar två fördelar i detta projekt och KL-trä har endast en. Kontroll av förutsättningar och krav bör göras för varje projekt där materialet sedan jämförs för att ta reda på vilket som lämpar sig bäst för just det projektet
Unexpected promotion of PCDD/F formation by enzyme-aided Cl-2 bleaching in non-wood pulp and paper mill
No full textEnzyme-aided Cl-2 bleaching is widely considered as promising replacements for conventional Cl-2 bleaching in wood pulp and paper mills. However, the effects of using enzyme-aided bleaching on the formation of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in the non-wood pulp and paper mills are unclear. A field study was performed to investigate PCDD/F formation when enzyme aided Cl-2 bleaching was used to replace conventional Cl-2 bleaching in non-wood pulp and paper mills. Unexpectedly, the PCDD/F toxic equivalents (TEQs) in solid samples were higher when using enzyme aided bleaching (0.49-5.4 pg TEQ/g) than that using conventional Cl-2 bleaching (0.15-2.44 pg TEQ/g). Large amounts of octachlorodibenzo-p-dioxin were formed during the enzyme-aided bleaching process. This could have been because enzyme strongly promoted the release of organic molecules bound to lignin and thus accelerated the formation of octachlorodibenzo-p-dioxin through organic molecular precursors. Although enzyme-aided Cl-2 bleaching was previously considered to be efficient for reducing PCDD/F releases and to be the best available technologies and best environmental practices for wood pulp and paper mills, the results obtained in this study suggested the necessity and urgency to evaluate the suitability of enzyme-aided Cl-2 bleaching for non-wood pulp and paper mills that intensively practiced in developing countries. (C) 2016 Elsevier Ltd. All rights reserved
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