A Study on Physical and Chemical Properties of Cellulose Paper Immersed in Various Solvent Mixtures

The cellulose paper treated in proportional mixture systems showed higher liquid absorption compare to only EtOH and MeOH treatments. It was approximately 40–70% and 50–91% higher for EtOH-NaOH and MeOH-NaOH treated papers, respectively. All conditions apparently bring about an effect of decreased strength for papers. The lowest tensile strength of 13.0 N/mm was found with EtOH and NaOH treated samples after 5th repeating wetting-drying stage. But, some conditions gave approximately 21–59.5% higher stretch than untreated samples. The pore size distributions of papers were evaluated with Simons stain procedure and experimental results usually consisted with sorption data. The less intense CH2–CH2- vibrations (1450–1700 cm−1) and C-C and C-O-C peak areas in FTIR spectra indicates lowering H-bonds in solvent treated and dried paper network structure

Conifer Cones: An Alternative Raw Material for Industry

The cone is an organ of conifers that contains the reproductive structures. There is growing interest products from natural materials in worldwide. However, the chemical compounds from cones are great interest because of its residue products. A number of studies on conifer cones haveavailable in literature. Majority of these studies are on morphological, chemical and material properties of cones. All these findings have contribute to better utilization of materials from conifer cones as new medicinal plant products. However, it was consistently reported that the chemical constituents of cones changed depend on geographical, seasonal, genotypic and environmental situations. It was reported that conifer cones have similar chemical constituents like wood but in various proportion. They markedly contain rich of phenoloic compounds and some extractives. They primarilly consists cellulose, lignin, and hemicelluloses as major constituents. They have also some condense tannins, resin acids, stilbenes, flavonoids, etc. Many of researchers have already reported that these extracts, which have various proportions in different species may offer some advantages in terms of utilization from waste materials and may show exceptional medicinal properties. A number of different approaches have applied to find alternative and economical utilization from coniferous cones. It has also used for manufacturing various kinds of composite and paper material as substituent of wood. It has already tried to use for particleboard, fiberboard and plastic composite process aiming to without lowering properties. The results reported in that area is promising. It has been utilized for purifying of waters as bioabsorbent or scavengers for heavy metals from waste streams. It has also found to be useful for producing cellulose with its intrinsic viscosity and molecular weight. However, it has already well explained that some extracts from cones show antioxidant, antifungal, antimicrobial properties and may cure some disorders of humans. The utilization of these constituents from as a forest residue material may offer many possible applications as raw material

Geri kazanılmış sekonder liflerin yeniden kullanılması üzerine bir inceleme

Kağıt yapısının ana iskelet elemanı selülozdur. Kullanımın tamamlayarak atık durumuna gelmiş kağıtların yapısında bulunan selülozun geri kazanılmasıyla yeniden kağıt üretiminde değerlendirilmesi mümkündür. Geri kazanılmış selüloz liflerinden (sekonder lif) yeniden kağıt üretimi esnasında, geleneksel odun hamurundan kağıt üretimine göre bazı farklı uygulamalar gereklidir. Zira daha önce kurumuş ve yeniden kağıt üreti,minde kullanılan selülozun yapısı modifiye olmuştur. Sekonder liflerden yeniden üretilen kağıtların kalite ve direnç özellikleri odun hamurundan üretilenlere göre belirgin seviyede düşmektedir. Geri dönüşüm işlemleriyle selülozun yapısında meydana gelen değişiklerin bilinmesi, kağıt fabrikasyonu esnasında bazı ilave işlemlerle fiziksel ve optik kalite düşmeleri belli sınırlar içersinde tutulabilir. Anahtar kelimeler: Selüloz, Kağıt geri dönüşüm, Kağıt özellikleri, Stok hazırlama, Optik özellikle

A Study on Composite Panels Prepared from Mixture of Mineral Adducts with Calabrian Pine Tree (Pinus brutia) Residues

The heat transfer coefficient values of 0.250 W/mK and l: 0.261 W/mK were found for Type 1 boards (bark based experimental boards of XBI and YBV)and l: 0.321 W/mK and l: 0.311 W/mK were found for Type 2 boards (cone based experimental boards of XCV and YCII), respectively. But all these are lower than standard value of 0.065 W/mK. However, visual evaluation show that all samples have low flame spreading properties which did not reach the threshold limit of 150 mm under a single flame combustion test. All Type 1 boards show lower mass loss (w, %) than control sample (B0: 11.97%), regardless of mineral additive type and proportions. The lowest mass loss of 6.36% was obtained with sample of YBIV. It is noticeable that olivine-cone (YC) and olivine-bark (YB) based panels usually show lower mass loss than dolomite-cone and dolomite-bark based panels at similar experimental conditions. The surface burning tests clearly indicate that the both mineral additions have lowering effects on burning feature of boards. This is probably olivine and dolomite could be absorbing heat and release water. Hence the burning area might become colder during evaporation of water with increasing charring and improve insulation of materials. The heat insulation levels of boards have found to be closely related with mineral content. But olivine seems to more effective for improving insulation properties for Type 1 boards. It is also found that both type panels (Type 1 and 2) which prepared from various proportions of dolomite and olivine as additives (10-50%) were show higher resistance against thermal degradation than control panels which prepared only (100%) from lignocellulosic material (cone and bark)

Mineral-Bonded Wood Composites: An Alternative Building Materials

The manufacturing of cost-efficient construction materials is at the center of attention these days. The development of engineeringly design products has occurred mostly over the past few decades. However, the term of mineral bonded wood composite is relatively new, covers many of the products, and is used to describe a material that is produced by bonding woody material with mineral-based substrates. At present, millions of tons of bio-based composite materials are now manufactured annually from many wood species. Woods are sustainable and engineeringly have enough performance properties in composite matrix systems for many end-use areas. Thus, their utilization processes and intended uses vary accordingly. But at manufacturing, many variables affect binder hydration in composite structure and the networking/bonding between wood and binder. The mineral bonded wood products are high in density and the appropriate strength in the construction industry, an important advantage to engineering applications appears to lie in their ability to absorb and dissipate mechanical energy. Despite their higher weight-to-strength ratio, especially cement and gypsum bonded wood composites have become popular, for use in many internal and external applications to meet increasingly stringent building design regulations for insulation, and failure in service due to deterioration

Weathering performance of particleboards manufactured from blends of forest residues with red pine (Pinus brutia) wood

Red pine cone and barks combined with red pine wood particles in various proportions were used as the raw materials for one and three layered experimental particleboard manufacturing in laboratory conditions. The pine cones and barks have higher lignin, but lower holocellulose content compare to wood. For bark-based panels, the highest MOR (2.52 MPa) corresponded to the lowest thickness swelling (9.3%) and marginally highest IB at 150oC and 8% adhesive level. The 24 hour thickness swelling (TS) values obtained in this study were lower than the required TS-EN 312 (2005) value of 14% for all bark-based boards. However, the single-layer bark-based boards demonstrated higher mechanical properties compared to three-layer boards using similar manufacturing conditions. The boards exposed to atmospheric conditions have considerably darkened (-DL) and lower surface roughness changes. Meanwhile, for single-layer cone boards, the highest MOR (4.66 MPa) was found at 150oC and 8% adhesive level, whereas the highest IB (1.54 MPa) and lowest TS (32.9%) were found at 150oC and 10% adhesive content. The cone-based panels had higher surface color changes (lightness and total color difference) compared to red pine wood panels. The particleboards produced using cone in the proportion of wood resulted in lower TS compared to boards made from only red pine wood

Nano-based surface treatment effects on swelling, water sorption and hardness of wood

Untreated and nano-based compound treated chestnut, wild cherry, fir, and black pine wood samples were immersed in water at four different temperature levels. It was found that the nano-based compound was a very effective agent for lowering both the initial and maximum equilibrium transverse swelling of wood. However, the latter were found to have similar trends as the initial swelling properties. The surface treatment appeared not to improve the maximum water absorption. The highest average activation energy was calculated for chestnut (23.1 kJ/mole), followed by pine (20.2 kJ/mole), cherry (18.1 kJ/mole), and fir (16.2 kJ/mole). However, the nano-based treatment resulted in a small increase in activation energies of all wood species. It was found that absorption of water into wood as well as increasing temperature had a lowering effect on shore D hardness

Dieulafoy Lesion in the Stomach

Dieulafoy disease is an uncommon cause of gastrointestinal system bleeding. Although the exact cause is not known, it is characterized by bleeding from abnormal submucosal vessels. There are many methods for diagnosis and treatment. In this case, a patient with a long-time undiagnosed stomach Dieulafoy lesion had a surgical resection. During the postoperative period the patient was discharged without any complication

Stereological analysis of sciatic nerve in chickens following neonatal pinealectomy: an experimental study

<p>Abstract</p> <p>Background</p> <p>Although the injury to the peripheral nervous system is a common clinical problem, understanding of the role of melatonin in nerve degeneration and regeneration is incomplete.</p> <p>Methods</p> <p>The current study investigated the effects of neonatal pinealectomy on the sciatic nerve microarchitecture in the chicken. The chickens were divided into two equal groups: unpinealectomized controls and pinealectomized chickens. At the end of the study, biochemical examination of 10 sciatic nerve samples from both groups was performed and a quantitative stereological evaluation of 10 animals in each group was performed. The results were compared using Mann-Whitney test.</p> <p>Results</p> <p>In this study, the results of axon number and thickness of the myelin sheath of a nerve fiber in newly hatched pinealectomy group were higher than those in control group. Similarly, surgical pinealectomy group had significantly larger axonal cross-sectional area than the control group (p < 0.05). In addition, the average hydroxyproline content of the nerve tissue in neonatal pinealectomy group was higher than those found in control group. Our results suggest that melatonin may play a role on the morphologic features of the peripheral nerve tissue and that melatonin deficiency might be a pathophysiological mechanism in some degenerative diseases of peripheral nerves. The changes demonstrated by quantitative morphometric methods and biochemical analysis has been interpreted as a reflection of the effects of melatonin upon nerve tissue.</p> <p>Conclusion</p> <p>In the light of these results from present animal study, changes in sciatic nerve morphometry may be indicative of neuroprotective feature of melatonin, but this suggestion need to be validated in the human setting.</p

Parametric investigation of a non-constant cross sectional area air to air heat exchanger

The present article addresses the design, mathematical modelling and analysis of a novel highly exergy-efficient air to air heat exchanger. An intricate design based on an hexagonal mesh is proposed for the cross-sectional area of the heat exchanger with aims to explore the performance gains that can be obtained by exploiting the capabilities and benefits offered by modern fabrication techniques such as additive manufacturing. Special attention is paid to understanding the relationship or trade-off that exists between the overall exergy efficiency of the heat exchanger and its cost. The iterative algorithm used to find the geometrical parameters that yield the best performance in terms of volume of material required per unit of exergy transfer at a certain level of efficiency, as well as the assumptions and simplifications made, are comprehensively explained. It has been found through the analyses carried out performed, which are thoroughly discussed throughout the paper, that if the characteristic dimension of the heat exchanger is scaled up by a factor of n, the volume of material per kW of exergy transfer at certain exergy efficiency will increase by a factor of n squared. This is a very important observation, possibly applicable to other types of heat exchangers, that indicates that performance improves dramatically at smaller scales. The overall performance of the case study presented is satisfactory, a volume of material as low as 84.8 cm3 for one kW of exergy transfer can be achieved with a 99% exergy efficiency