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علوم پزشکی و محیط زیست

This article reviews recent research related to biosorption – the use of plant-derived materials to remove various pollutants from aqueous systems. Emphasis is placed on biosorption studies dealing with the removal of heavy metal ions, dyes, and spilled oil from water. Much progress already had been achieve in understanding the factors that affect adsorption capacities, rates of uptake, and possible release back into the water. It has been shown that the performance of cellulose-based sorbent materials often can be improved by physical of chemical modification of the sorbent. There is a critical need for research related to strategies for dealing with the adsorbent materials after their use. In addition to regeneration and re-use of sorbent materials, attention also needs to be paid to the incineration of contaminated sorbents, as well as the biodegradation of sorbent material after uptake of various pollutants.
Martin A Hubbe
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Yellowing and brightness stability of newsprint are very important phenomena mostly dominated by residual organic compounds. In this research, effects of cooking and bleaching on organically chemical compounds in CMP pulp and newsprint were investigated. For this purpose, samples were chosen randomly from chips, CMP pulp after cooking, after bleaching, and in newsprint produced in Mazandaran Pulp and Paper Mill (in north of Iran). At first stage, the paper flour was provided, and then the quantity of extractives was measured in percent by TAPPI standards. The GC diagram was used for identification of the compounds. The results of GC analysis showed that in chips, CMP pulp after cooking, after bleaching, and in newsprint paper, were 90, 76, 68, and 58 compounds, respectively. The common and important chemical components in the samples were benzaldehyde, dodecane, bibanzyl, 1,2-benzendicarboxylic acid, didutyl phthalate, and bis (2-ethylhexyl) phthalate. The benzaldehyde (32.56%), bis (2-ethylhexyl) phthalate (6.98%), gamma-sitosterol (4.84%) were the most abundant compounds, and the dodecanoic acid (0.14%), decane (0.18%), xylene (0.19%), and benzene,1-methyl-4-phenylmethyl (0.2%) were also present
Ramin Vaysi
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The aim of this paper was to evaluate the properties of three bleached pulps made of bagasse. Pulping was carried out with NaOH (15% o.d. bagasse) and Na2SO3:Na2CO3 with two different ratios (20:10% and 26.25:8.75% on oven-dried weight (o.d.) bagasse), with a time of 15 minutes time and a temperature of 170°C. Bleaching was done with sodium hypochlorite (8% o.d. pulp) at 120 minutes, 50°C temperature and 10% stock concentration at one stage. Some handsheets at 70 g/m2 basis weight were made. The characteristics such as, total yield, screen yield, shives content, kappa number, bulk, tear index, burst index, breaking length, brightness, and opacity were measured according to TAPPI and ISO standards and then compared to each other. The results indicated that bagasse soda pulp had the highest screen yield (57.77%), and the least yield (42.07%) was obtained with 30% neutral sulfite solution. The strength properties showed that pulp obtained with neutral sulfite solution had better tear index (2.23 mN.m2/g), whereas that from soda solution had better breaking length (1.3 km) and burst index (0.73 kpa.m2/g). The pulps cooked with neutral sulfite solution had better bleachability, whereas the bagasse soda pulp had better opacity.
Parizad Sheikhi, Peyman Ghobadifar, Fatemeh Rezaei-Arjomand
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This study was carried out for identification of chemical compounds in acetone extractives of elm wood. Wood samples were selected from Arasbaran forest, Iran. Extracts from the elmwood (Ulmus glabra) were obtained using acetone solvent (according to the TAPPI standards). BSTFA reagent was added to extractive soluble in acetone and then samples were kept in Ben Marry Bath at 70 °C for an hour. Then chemical components of acetone-extraction were analyzed by gas chromatography mass spectroscopy. The most important identified component chemicals were bis‌(2-ethylehxl) phthalate (93.40%), 4-(N-Isopropylamino)-6-phenyl (1.89%) and 1-naphthalenol, 5,6,7,8-tetrahydro (1.80%). Chemical composition of elm wood was compared to other Iranian hardwood species.
majid kiaei, milad tajik
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The present paper aims at assessment and prioritizing of branding factors affecting the furniture industry and offering appropriate solutions to branding in furniture industry. To this end, after basic studies and review of other researches, 23 patterns and sub-patterns under 5 basic criteria of brand equity, effect of brand, client satisfaction, promotions, and the effectiveness of the brand were recognized, and prioritized through hierarchical analysis procedure method (AHP). Results showed that the factors of client faithfulness, appropriate quality, understood quality, appropriate price, exhibitions, and client-friendliness have respectively the highest scores, and also solutions, the training of skilled managers, as well as the influence of brand and effect of brand have respectively been the most appropriate solution and the most sensitive criteria.
Vajihe Farshchi, majid azizi
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Effects of screw type, screw diameter, and drive direction (perpendicular to the face and edge of specimens), as well as wood-composite panel type, on the withdrawal resistance in bagasse-fiber particleboard (BPB), medium density fiber board (MDF), and plywood were investigated in the present study. Two sizes of fine-thread drywall screw (sizes 8 and 10), and two sizes of sheet-metal screw (sizes 8 and 10), were chosen. All screws were 50 mm in length. The results showed that an increase in the screw size would result in higher withdrawal resistance in both screw types. Furthermore, plywood showed higher withdrawal resistance in comparison to the other two wood-composites. Due to higher integrity in the wood-composite, withdrawal resistance perpendicular to the face of the composites was higher in comparison to the edge direction. Longer thread in sheet-metal screws caused better involvement with the composites and therefore more connecting surface; consequently, stronger involvement with it, resulting in higher withdrawal resistance of sheet-metal screws.
Hamid Reza Taghiyari, mehdi Faezipour
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The objective of this study is to determine the effects of some fire retardants on physical and mechanical properties of the resin-impregnated paper covered high density fiberboard (HDF) panels. Fire retardants (FR) in a powder form (borax (BX), boric acid (BA), ammonium polyphosphate (APP) and alpha-x (AX) powders were used at 3%, 6% and 9%. HDF panels were produced (400x400x6.5mm). Surfaces of HDF panels were coated with resin- impregnated papers. The physical and mechanical properties of panels were investigated. The results showed that FR the addition diminished the thickness swelling (TS) and water absorption (WA) values of the panels. In addition, they also reduced the modulus of rapture (MOR), modulus of elasticity (MOE), and internal bond (IB) strengths. It was found that concentration and type of FR chemicals significantly affected the physical and mechanical properties of resin-impregnated paper covered HDF panels.
Ferhat Özdemir, Ahmet Tutuş
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In the most recent decade the utilization of lignocellulosic substances for the sequestering of heavy metal ions and toxic dyes has gained momentum. These substances are the most suitable and preferred candidates and are valued by researchers around the world due to their great potential and capabilities. Hundreds of the lignocellulosic materials have been explored either in their natural form or after modifying them physically or chemically. Whether studies have involved synthetic metal ion solutions or real industrial wastewater loaded with heavy metal ions, cellulosic sorbent materials have been demonstrated as the best cheap, reusable, and sustainable choice in a competition with synthetic-chemical-based, technology-intensive options. The character of easy availability and the phenomenal components acting as functional moieties for the binding of persistent metals or dyes have led to their utilization that takes advantage of “waste to waste clean development mechanisms”. There has been a great need to investigate the kind of substances that may come out as winners in the race to achieve sustainability; lignocellulosic substances have achieved competitive levels of performance in wastewater remediation
Garima Mahajan, Dhiraj Sud
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