Selection of Eucalyptus camaldulensis Families for Sustainable Pulpwood Production by Means of Anatomical Characteristics

Sustainable pulpwood production from fast-growing tree plantations is needed for pulp and paper industries. To increase the pulpwood production efficiency, the anatomical characteristics and derived-wood properties of 75 trees from 15 half-sib families of Eucalyptus camaldulensis Dehnh. planted in Thailand were investigated, and then the family was classified by suitability of wood as raw material for pulp and paper products using principal component analysis and clustering. The mean values of vessel diameter, vessel frequency, fibre diameter, fibre lumen diameter, and fibre wall thickness at 2 cm from the cambium were 128 µm, 16 no./mm2, 11.1 µm, 7.1 µm, and 1.88 µm, respectively. In addition, the Runkel ratio, Luce’s shape factor, flexibility coefficient, slenderness ratio, solids factor, and wall coverage ratio (i.e., derived-wood properties) were 0.53, 0.42, 0.64, 85.3, 68 × 103 µm3, and 0.34, respectively. Significant differences in fibre diameter, fibre lumen diameter, and Runkel ratio were found among families. Although significant differences among families were not found for other anatomical characteristics and derived-wood properties, the p-values obtained by an analysis of variance test ranged from 0.050 to 0.088. Based on the results of a principal component analysis and cluster analysis, 15 families were classified into four clusters with different expected pulp and paper characteristics. The suitability of wood from E. camaldulensis half-sib families for pulp and paper can be evaluated by principal component analysis using anatomical characteristics and physical properties as variables. Based on the results, desirable pulp and paper quality may be obtained through the selection of families from this species.

Impact of Apparatus Orientation and Gravity in Electrospinning—A Review of Empirical Evidence

Electrospinning is a versatile fibre fabrication method with applications from textile to tissue engineering. Despite the appearance that the influencing parameters of electrospinning are fully understood, the effect of setup orientation has not been thoroughly investigated. With current burgeoning interest in modified and specialised electrospinning apparatus, it is timely to review the impact of this seldom-considered parameter. Apparatus configuration plays a major role in the morphology of the final product. The primary difference between spinning setups is the degree to which the electrical force and gravitational force contribute. Since gravity is much lower in magnitude when compared with the electrostatic force, it is thought to have no significant effect on the spinning process. But the shape of the Taylor cone, jet trajectory, fibre diameter, fibre diameter distribution, and overall spinning efficiency are all influenced by it. In this review paper, we discuss all these developments and more. Furthermore, because many research groups build their own electrospinning apparatus, it would be prudent to consider this aspect as particular orientations are more suitable for certain applications.

The efficacy of Hibiscus sabdariffa as a fibre-reinforcement material for denture base acrylic resins

The poor mechanical properties of denture base acrylic resins can cause dentures to fracture either through impact or stress fatigue. Various metal reinforcing materials such as powders, nets, plates and wires together with synthetic fibres are therefore used to improve the strength properties of denture base acrylic resins. Despite their benefits, they are difficult to apply during fabrication, are costly, non-recyclable, and not environmentally friendly. The suitability of Hibiscus sabdariffa (H. sabdariffa) as a fibre reinforcement material for denture base acrylic resins was therefore investigated. A quantitative research paradigm and a two-phased experimental research design was used. The preliminary study used Fourier transform infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA) and field emission scanning electron microscope (FE-SEM) to assess the characteristics of, and the effect of, mercerisation on H. sabdariffa fibres. In determining the suitability of H. sabdariffa fibres, fibre diameter, fibre density, moisture content and absorption were examined. The main study investigated the mechanical and physical properties of two sample groups namely: the unreinforced (control) group and the H. sabdariffa fibre-reinforced (test) group denture base acrylic resins. The flexural strength, impact strength, specific wear rate, hardness and water absorption behaviour were determined in line with ASTM D 790 and D 256, G 99, D 2583 and D 570 methods of testing, respectively. Parametric and non-parametric tests were used to analyse the mean differences (p = 0.05) between the unreinforced and the H. sabdariffa fibre-reinforced denture base acrylic resins. The preliminary study revealed that H. sabdariffa fibres favourably compared to other lignocellulosic fibres in terms of fibre diameter, fibre density, water content and absorption behaviour. In the main study, a t-test revealed that there were significant differences in flexural strength at 0oC (p < 0.0001) and at 65oC (p < 0.0025) between the two sample groups. Similarly, there were significant differences in the impact strength between the two sample groups at 0oC (p < 0.031) and at 65oC (p < 0.0001). In contrast to the 200g load, there were significant differences (p < 0.044) in the specific wear rate of the unreinforced and the H. sabdariffa fibre-reinforced denture base acrylic resins at the 500g load. The hardness values revealed no significant differences (p > 0.707) between the two sample groups. There were however, significant differences (p < 0.041) in the water absorption rate between the two sample groups. Overall, the prominent features of this study showed that H. sabdariffa fibre is a suitable reinforcement fibre material for denture base acrylic resins and is in compliance with ISO 1567: 1999. Although this study found that H. sabdariffa fibres can be used as reinforcement material for denture base acrylic resins, the results cannot be generalised to clinical conditions, therefore in vitro and in vivo investigations are recommended.

Anatomical properties of Anthocephalus cadamba (Roxb.) Miq. at five different ages

Anthocephalus cadamba is an important tree species for pulp and paper industry. Anatomical studies were conducted between trees of different age viz., 2, 4, 6, 8 and 10 were selected from different plantation. One plus tree from each age was felled for the study. The transverse discs of 10 cm thickness were collected from three different heights of tree representing base, middle and top positions. Anatomical properties like Fibre Length, Fibre Diameter, Fibre Lumen Width, Fibre Wall Thickness, Flexibility, Slenderness ratio, Runkel ratio, Vessel Length, Vessel Diameter, Vessel Area, Vessel Frequency, Ray Height, Ray Width and Ray Frequency were studied. Present study revealed that the average Runkel ratio of Anthocephalus cadamba was 0.48; hence it is suitable for pulp and paper production. Fibre length at the ages of 6, 8 and 10 were at par. Fibre wall thickness were not significantly different at 2, 4, 6 and 8 age but 10 years of age fibre wall thickness differed significantly from other five different ages. Fibre diameter, fibre lumen width and slenderness were at par for all the five ages. Flexibility was at par in the ages of 2, 4, 6, and 8. Best practice of harvesting Anthocephalus cadamba would be at the age of six. Ray and vessel morphology did not show any specific trend from two to ten years old tree.

Anatomía comparada del leño de Maytenus en el Noroeste de Argentina (Sudamérica)

Comparative wood anatomy of Maytenus in Northwestern Argentina (South America)This paper is a comparative wood anatomy study of four species of the genus Maytenus living in Northwest Argentina: Maytenus vitisidaea, M. viscifolia, M. spinosa and M. cuezzoi. The specimens were collected in Santiago del Estero and Salta, Argentina and wood samples are safeguarded in the collection of the LAM (Laboratory of Wood Anatomy), Faculty of Forestry of Santiago del Estero University (UNSE), Argentina. The terminology used followed the IAWA List of Microscopic Features for Hardwood Identification. The diagnostic features of wood anatomical characters were evaluated by employing statistical methods such as Cluster Analysis (CA) and Principal Component Analysis (PCA). PCA showed vessel diameter, fibre wall, and ray width to be significant variables. CA showed M. cuezzoi and M. viscifolia to have the highest affinity.Anatomía comparada del leño de Maytenus en el Noroeste de Argentina (Sudamérica)El presente trabajo es un estudio de anatomía comparada de madera de cuatro especies del género Maytenus del Noroeste Argentino:Maytenus vitis-idaea, M. viscifolia, M. spinosa y M. cuezzoi. Las muestras fueron recolectadas en Santiago del Estero y Salta, Argentinay se salvaguardan en la colección del LAM (Laboratorio de Anatomía de Madera), Facultad de Ciencias Forestales de la Universidad deSantiago del Estero (UNSE), Argentina. Se empleó la terminología de IAWA (Lista de caracteres anatómicos del xilema de angiospermas).Los caracteres anatómicos de madera fueron evaluados mediante métodos estadísticos tales como análisis de conglomerados (AC) y elAnálisis de Componentes Principales (PCA). El PCA mostró como variables significativas el diámetro de vasos, el espesor de pared de lasfibras y el ancho de radios. El CA mostró que M. cuezzoi y M. viscifolia tienen alta afinidad específica.

Effects of site of assessment and variation in wool quality traits on the tactile assessment of textural greasy wool handle

Variation in textural greasy wool handle across the fleece of Merino sheep was explored. Results demonstrate that there were significant differences across nine sites on the fleece. The inclusion of the covariates fibre diameter, fibre diameter co-efficient of variation, staple length, dust penetration, staple structure, greasy wool colour and resistance to compression, helped to explain some of the variation in textural greasy wool handle between sites such that site of assessment was no longer a significant factor (P = 0.065). However, in practice, those involved with clip preparation or sheep selection based on textural greasy wool handle assessment are unlikely to have these measurements available. The results highlight the importance of nominating a site of assessment when recording textural greasy wool handle.

Chiral edge-shared octahedral chains in liskeardite, [(Al,Fe)32(AsO4)18(OH)42(H2O)22]·52H2O, an open framework mineral with a pharmacoalumite-related structure

The type specimen of liskeardite, (Al, Fe)3AsO4(OH)6·5H2O, from the Marke Valley Mine, Liskeard District, Cornwall, has been reinvestigated. The revised composition from electron microprobe analyses and structure refinement is [Al29.2Fe2.8(AsO4)18(OH)42(H2O)22]·52H2O. The crystal structure was determined using synchrotron data collected on a 2 μm diameter fibre at 100 K. Liskeardite has monoclinic symmetry, space group I2, with the unit-cell parameters a = 24.576(5), b = 7.754(2) Å, c = 24.641(5) Å, and β = 90.19(1)º. The structure was refined to R = 0.059 for 9769 reflections with I > 3σ(I). It is of an open framework type in which intersecting polyhedral slabs parallel to (101) and (10) form 17.4 Å × 17.4 Å channels along [010], with water molecules occupying the channels. Small amounts (<1 wt.%) of Na, K and Cu are probably adsorbed at the channel walls The framework comprises columns of pharmacoalumite-type, intergrown with chiral chains of six cis edge-shared octahedra. It can be described in terms of cubic close packing, with vacancies at both the anion and cation sites. The compositional and structural relationships between liskeardite and pharmacoalumite are discussed and a possible mechanism for liskeardite formation is presented.