payam moradpour

Considering the large volume of waste banknotes and the high costs of disposal as well as the resulting environmental pollution, the possibility of converting these wastes into products such as cellulose acetate polymers, which are economically viable, and also their production process with the least environmental pollution It is very important to be accompanied. In this article, in order to obtain cellulose acetate after dyeing the banknotes, the acetylation process was carried out using acetic acid as a solvent, sulfuric acid as a catalyst, and acetic anhydride. The percentage efficiency of acetylation increased with increasing reaction time and temperature, and the maximum efficiency was obtained at 55 °C. The concentration of acetic anhydride and sulfuric acid as a catalyst changed the substitution degree of cellulose acetate polymer. Scanning electron microscope images showed that the diameter of cellulose acetate fibers decreased compared to pure cellulose (waste banknote). The results of the Fourier transform infrared spectrometer showed that practically a significant amount of hydroxyl groups were replaced by acetate groups. The X-ray diffraction patterns of the bleached banknote sample changed after the acetylation process, which is evident in the reduction of the peak at position 23 of the sample before and after acetylation

The lack of wood resources on the one hand and the increase in the demand for wood products on the other hand have caused the excessive harvesting of wood and the shortage of wood raw materials. Therefore, alternative materials should be used to solve this problem. But, in addition to providing raw materials, alternative materials must be approved from the economic point of view and the mechanical properties of the boards. Since CZ100 is a crystalline and homogeneous mineral, it is cheap and readily available. It also has high strength, stability, and mechanical resistance. Therefore, the aim of this research is the effect of CZ100 additive on the physical and mechanical properties of particleboard. For this purpose, boards were made with CZ100 additive in proportions (0, 2, 4, 6, 8, and 10%). Then, the mechanical and physical properties of particleboard made with CZ100 additive were measured. The results showed that the mechanical properties of particleboard increased with the addition of the CZ100 additive by up to 6 wt%, and with the addition of the additive, water absorption and thickness shrinkage (2 and 24 hours) decreased significantly. In general, according to the obtained results, the additive CZ100 has a high potential to improve the physical and mechanical properties of particleboard and also due to its low price compared to wood, its use reduces the costs of preparing raw materials.

Nail laminated timber (NLT) is one of the engineered wood products which is widely used in construction. Due to the structure of NLT, it has a high tendency to absorb moisture and its moisture loss rate also is very low. Therefore, it is necessary to protect it against humidity and degradation agents. In this study, the effect of ACC and ACQ preservatives on the performance of withdrawal resistance and lateral strength of the nail fastener in cypress wood with emphasis on the use in NLT was investigated. To treat the layers, preservative solutions with a concentration of 2% were used to achieve the minimum retention required for use with ground contact according to AWPA requirements. Withdrawal resistance and lateral strength of nail were compared with NDS standard and yield limit formulas, respectively. Results showed that ACC and ACQ preservatives had no adverse effects on the mechanical resistance tested in this study, and thus there is no restriction to use the treated wood for manufacturing NLT. Also, the results showed that there is a good agreement between the resistance predicted by the equations presented in NDS and the experimental results. IIIs failure mode was observed in the treated and control samples.

Poly vinyl acetate (PVAC) adhesive is one of the most important adhesives in wood and furniture industry, which has many advantages such as low cost, environment friendliness and non-toxicity. However, it has some disadvantages such as low water resistance and poor boning strength. In this study, the effect of nano silica (NS) on the properties of poly vinyl acetate adhesive was investigated. The adhesive formulation with different NS contents (2, 3 and 4%) was added to the PVAC. The structure of the prepared adhesive samples was studied by FT-IR and XRD. We used the wood of Acer tree (Acer cappadocicum) to make joints in this study. Two standards of D882 and ASTM D905 were used for tensile and shear tests, respectively. Results showed that adding NS to PVAC enhanced the tensile strength of films. For example, the tensile strength of prepared films was increased by 30% after adding 4% of NS. Moreover, shear strength test showed that NS up to 3% can improve PVAC bond strength. Viscosity results showed that increasing the weight of NS up to 3% to PVAC glue lead to an increase following a decrease in the viscosity

This research was carried out with the aim of making a stringer of wooden spiral stairs using laminated wood product from poplar wood and achieving an optimal connection to convert the stringer to smaller dimensions in order to achieve a suitable design for the construction of wooden spiral stairs. For this purpose, 3-layer plywood of poplar was made using two-part polyurethane glue with a surface layer thickness of 0.5 mm and a middle layer of 2 mm in dimensions of 120 x 120 cm, and then the produced plywood panels were used to make the desired laminated product. Mechanical properties and failure modes of the product were investigated. Then, 5 types of end to end joints including finger joint, tail joint, half and half, diagonal and modified diagonal joints were designed for the stringer of the wooden spiral stairs and made in the dimensions of length 65, width 20 and thickness 2.1 cm and subjected to out of plane bending test. Modulus of elasticity of the stringer in the in plane bending test was obtained as 1598 MPa, 2441 MPa, 1669 MPa, 1047 MPa, 957 MPa and 652 MPa, respectively for control sample, modified diagonal joint, diagonal joint, half-and-half joint, finger joint and tail joint. In addition, modulus of rupture of the stringer in the in plane bending test was obtained as 32 MPa, 27 MPa, 23 MPa, 19 MPa, 12 MPa and 13 MPa, respectively for control sample, modified diagonal joint, diagonal joint, half-and-half joint, finger joint and tail joint. The result of one- way ANOVA showed that there is a significant difference among bending strength and modulus of elasticity of the stringers at 99% confidence interval (α≤0.01). According to the results, the stringer with modified diagonal joint would be the most suitable alternative in wooden spiral stair.

Joints are important components of any structure that can be a warranty for the strength of structures. There are different methods for reinforcement of furniture joints that are used according to position and shape of joint. One of the reinforcement methods of corner joints is using wooden corner blocks. Therefore, in this study, the effect of species types and physical situation of wooden corner block on stress carrying capacity of L-shape joint under diagonal tension was investigated numerically and experimentally. For this purpose, L-shape mortise and tenon joints of beech were constructed.. The corner blocks of beech and poplar species were applied to reinforce the joints. The physical situation for beech in three levels (without groove and with grooves 5, and 10 mm) were selected as variables. Also, a control sample (without corner block) was used for comparing. Experimental results have shown that using corner block had a significant effect on stress carrying capacity. There was no significant difference between the species. The maximum stress carrying capacity was obtained of joints that were reinforced with poplar corner block with 10 mm groove depth (30.3 MPa) and the minimum stress carrying capacity was obtained of control sample (6.06 Mpa). Results of numerical analysis have shown that maximum stress of reinforced joints with corner block are in the groove zone of joint members and corner block glue line which this stress concentration caused the failure of members in these zones.

Due to the lack of forest resources, the use of fast-growing wood species has been considered by designers and engineers. Low density and mechanical strength are the main challenges of using some of these wood species, especially in the manufacturing of construction products and their final properties. Using different methods such as hydrothermal and hygrothermal treatments combined with compaction techniques can be a solution to this problem. This study aimed to investigate the effect of pretreatment type and densification conditions on the physical and mechanical properties of paulownia (Paulownia fortune) and poplar (Populus deltoides) wood. For this purpose, pretreatment with water at 25˚C and compression in hot press at 160˚C, and also pretreatment with steam at 160˚C and compression in cold press at 60C˚ were used. Compression was performed at two levels of 25 and 50 percent for 20 minutes in a press with a pressure of 5MPa to reach a final thickness of 2cm. Then, the equilibration of the samples in the cold press was performed to reduce the spring back and reach the temperature and equilibrium moisture content. To investigate the physical and mechanical properties of the samples, tests including density, water absorption, and thickness swelling (after 96 hours of immersion in water), modulus of rupture, modulus of elasticity, impact strength, and hardness were performed. The results showed that the poplar wood has better physical and mechanical properties than the paulownia wood due to its higher density. Except for thickness swelling, desirable physical properties and higher mechanical strengths were obtained in wood samples modified by the steam-cold pressing method. The greater impact of the wood modification process by steam-cold pressing on the properties was well observed. Water absorption and thickness swelling values of wood samples increased with increasing compaction percentage. The mechanical properties of wood had shown a decreasing trend, with increasing compaction and consequently increasing the density of wood samples, except for impact resistance

This study aimed at the evaluation of wood machining parameters and surface quality upon using a water jet without abrasive material. Hence, wood species (beech, oak, and poplar), cutting velocity (200, 400 and, 600 m/s), and cutting direction (parallel and perpendicular to the grain) were chosen as variables. After cutting samples with water jet, the samples were scanned from edge and surface using a 1200 dpi scanner. For analyzing the depth of cut and kerf width, Image J software was used. The Surface quality was evaluated using a stylus profilometer, and the surface roughness parameters including Ra and, Rz were measured. The highest and lowest values of depth of cut and kerf width were measured for poplar and beech woods, respectively. According to the results, it can be stated that the cutting direction has a significant effect on the machining parameters so that the maximum depth of cut and the lowest kerf width was observed in the direction parallel to the grain. Also, the results showed that with increasing cutting velocity, the depth of cut increases, and kerf width decreases. The highest and lowest values of surface roughness parameters were observed in poplar (Rz=136/8µ), and beech (Rz=115/62µ) woods, respectively. Based on the results, it can be concluded that high-speed machining in woods with dense texture and parallel to grain can improve the surface quality in water jet cutting.

A well-designed desk and chair, in addition to proper learning, can prevent changes in the userchr('39')s physical form. Therefore, this study aimed to determine the anthropometric characteristics of students in the College of Agriculture and Natural Resources located at the University of Tehran to design an ergonomic table and chair.

In this research, 18 anthropometric characteristics including the popliteal height, knee height, shoulder height, eye height, sitting height, elbow support height, elbow height, knotted elbow length, hip-popliteal length, hip-knee length, thigh thickness, abdominal depth, chest depth, hip width, shoulder width, the transverse width of the elbows, height, and as well as weight for 260 students (130 girls and 130 boys) aged 18 to 35 years were investigated. To collect data, an anthropometric chamber and chair were used. Finally, according to the measured physical dimensions of the students, the Dimensions of ergonomic table and chair were calculated and designed according to the INSO 9697-1 standard.

Anthropometric dimensions of students were obtained through mean, minimum, maximum, standard deviation, mean, and the percentile value of 2.5 to 97.5 using SPSS version 20 software. The results showed that the age of the user does not have a significant effect on the size of the table and the chair. Also, the results showed that there was a significant difference in popliteal height between girls and boys.

Considering the difference in dimensions between female and male students, it was found that the popliteal height in the percentile of 5 for boys is 4 cm more than girls. Therefore, using measured anthropometric characteristics, the dimensions of the chair and table ergonomics were designed in two sizes.

Pollution from airborne particles is one of the most important threats to human and environmental health in the world. Today, industrial air filters use synthetic polymers based on oil and chemicals, these materials are incompatible with the environment and lead to secondary pollution. Therefore, the development of the use of new materials in the fabrication of air filters, which is not only environmentally friendly but also renewable, is a vital need. For this reason, in recent years, many researches and studies have been done to replace cellulose nanofiber (CNF) with synthetic fibers such as glass nanofibers, activated carbon, and plastic polymersnanofibers in the manufacture of air filters. CNF has many advantages such as biodegradability, cheapness, low density, and network structure that can compete with synthetic nanofibers. Therefore, this review study aims to investigate the general use of CNF for the adsorption of particulate matter (PM) and carbon dioxide (CO2) in the air. The results showed that CNF increase the adsorption efficiency of CO2 and PM due to the presence of active hydroxyl groups on the surface as well as high specific surface area. In addition, the nanofilters made of CNF have a lower pressure drop than filters on the market due to their small pore diameter.

One application of hydrogels is to use them as dressings (wounds and burns). Biocompatibility and cytotoxicity are of particular significance for hydrogels used in the medical field. Cellulosic materials can load and relief drugs at temperatures or pH levels of the body as a result of contrary processes such as diffusion. The aim of this study was to investigate the mechanism of release of silver nitrate in nano-cellulose-based biodegradable hydrogel film for burn repair. To prepare a hydrogel in the form of film, cellulose nanofibers and hydroxyethyl cellulose were used with the weight ratio (3:1), and also, the citric acid was used as a crosslinker in different amounts of 10 and 20 wt% matrix. Later on, the loading silver nitrate as a disinfectant drug into selected hydrogels was performed. Drug release results illustrated that there was a direct relationship between absorption rate and drug concentration. In the initial times of the testing, 70 to 90% of the drug release was detected and then for 24 h, the drug was gradually released from the hydrogel. Investigation of modeling drug-releasing selected kinetic diffusion as the dominant mechanism in drug delivery. MTT non-toxicity test displayed high efficacy of nanocellulose cationization and confirmed the non-toxicity of biocompatible hydrogels. It can be concluded that biodegradable nanocellulose based hydrogel containing silver nitrate can be used as an appropriate and relevant product for burn repair.

Nowadays, using of fiber reinforced plastic (FRP) rods in composites structures has been increased due to their light weight and high specific strength. In this research, the behavior of steel and glass-FRP rods with different surface patterns (plain, ribbed) were experimentally investigated in the points of bonding length (200, 300 mm) and adhesive type (unsaturated polyester, epoxy) view, parallel to poplar (Populus alba) wood grain. In this regards, after specimens preparation based on the above mentioned situations, tensile pull-out strength, shear stress, as well as failure modes in wood-adhesive and rod-adhesive interfaces were investigated. The maximum value for poll-out strength, i.e. 82.5 kN was achieved for ribbed glass-FRP rods, and 300 mm anchorage length. In addition, while pull-out load carrying capacity increased with increasing bonding length, nominal shear stresses were decreased from 6.8 to 3.8 MPa, and 8.9 to 4.7 MPa, respectively for wood-adhesive, and rod-adhesive interfaces. Worth noting, the most common failure mode was pull-out of rods with attached wood, due to shear failure parallel to the wood grains.

Forest harvesting operations as heavy and dangerous work requires abnormal, uncomfortable working conditions, exposure to noise and vibration, which has adverse health consequences and may lead to illness and injury. Vascular abnormalities, such as the Rhinoceros or White Hand phenomenon (VWF), are known to be the most important, most dangerous, and most common effects of vibration. The purpose of this study was to determine the permissible time limit for vibration exposure during operator exposure to echomotor vibrations in evacuation of evergreen, poplar and alder trees (VWF) in Kheyrud Nowshahr training and research forest in Mazandaran province. Measurement of the time limit index of the governor indicated that the maximum exposure time (hour) for the operator during vibration was 2.59 hours for the whole tree. Therefore, maximal timing workers can partially prevent diseases and injuries caused by vibration motors. According to the results, since the amount of clock exposure the vibrator worker has in the bibliographic mode is higher and the prediction time of the white-handed disease in the rotor worker is greater, therefore, if one is in the binary phase Working two hours a day, evangelical worker has to work with saw for a maximum of 9.61 hours during the week, which is 14/34 hours for poplar and 18/01 for alder. Accordingly, the more hours an ohmicor worker was exposed to in one day and the more the ohmicorum's total vibration increased, the operator had to wait less time than the saw during the week to prevent white-handed disease (VWF).

Wood is a natural material used in the construction of various wooden structures. Due to the presence of wooden structures in the outdoor, wooden structures are weathering and surface degradation. Regarding the use of wood as outdoor furniture, flooring, parquet and wooden houses, some properties such as hardness, scratch resistance and abrasion are important. In this study, the effect of accelerated weathering on the abrasion resistance of Populus nigra, Fagus orientalis and Quercus castaneifolia was studied.

For this purpose, wood samples were cut to standard dimensions of 2×10×15 cm (L × R × T) and the surfaces of wood samples coated with linseed oil (100 mlm3) and for 2 weeks were kept in accelerated weathering. Then, by Taber test and Confocal laser microscope, the abrasion resistance and topography of the wood surfaces before and after weathering were investigated.

The results of this study showed that, due to weathering, the wear resistance of all wooden species decreased and the more resistance among them was related to oak with the weight loss of 1.7 grams. Also, the results showed that the amount of abrasion index reduced by 28, 38 and 18 percent for poplar, beech and oak, respectively. The lowest and highest abrasion resistance after weathering was related to the poplar and oak and the results of the laser microscopy showed that, in the poplar, beech and oak the abrasion depth was 201, 183, and 136 (μ), respectively. The results also showed that, there was a significant difference between coated and uncoated samples.

The increase in oak wear resistance to other species can be due to higher specific gravity. In addition, the use of linseed oil coating reduces water absorption and, on the other hand, reduces friction and makes the surface of the wood lubricate. Also, the increase in weight loss after weathering is due to the higher absorption of uncoated samples than the coated samples, which causes faster and easier destruction of the wood structure. Based on the results of the laser microscope, the coating with linseed oil has been able to reduce the wear depth and reduce wear resistance. According to the results of this study, linseed oil can be used to increase the resistance of wood structures to abrasion.Based on the results of the laser microscope, the coating with linseed oil has been able to reduce the wear depth and reduce wear resistance. According to the results of this study, linseed oil can be used to increase the resistance of wood structures to abrasion.

chitin and chitosan, as the most abundant amino-polysaccharide in nature, have characteristics such as biocompatibility, low toxicity, and biodegradability. These unique specifications have resulted in chitin and chitosan attracting a lot of attention because of the high potential for producing valuable products. Chitosan has many uses in the agricultural industry and wood preservation, such as pesticides and insecticides, as well as in biomedical applications, including the use in the pharmaceutical industry as a drug release, and can also be used as drug carriers. The purpose of this article is to extract highly purified chitosan with high de-acetylation degree from shrimp shells.

In this study, the extraction and characterization of chitosan from the shrimp shell (Litopenaeus vannamei) was investigated. For this purpose, chitosan was extracted by chemical method including mineralization (with 4% HCl concentration), protein degradation (with 4% NaOH concentration), and deacetylation (with 60% NaOH concentration). Also, nano-chitosan was prepared by ionic gelation method. A series of parameters were studied, which included the degree of deacetylation, molecular weight, pH and solubility. Also, FTIR spectroscopy, FESEM scanning electron microscopy, Zeta potential, X-ray diffraction spectroscopy (EDX) and X-ray diffraction (XRD) were used.

The results of FTIR test on chitin and chitosan extracted from shrimp shell showed that the removal of protein and mineral materials was appropriate with the use of hydrochloric acid, sodium hydroxide. The high degree of deacetylation of chitosan in this study (87%) had a significant effect on the proper solubility and low viscosity of chitosan. The solubility of chitosan in acetic acid was 86%. The molecular weight of the chitosan extracted was 110 kDa. With this molecular weight, chitosan can be used well in the pharmaceutical industry. According to chitosan XRD patterns in previous studies, the peaks obtained in XRD patterns in this study confirmed the semi-crystalline structure of chitosan. Due to the change in the level of chitosan seen in FESEM images, it can be due to the purification of chitosan. The FESEM test confirms nano-chitosan with diameter range of 100 to 150 nm.

From the results of this study, it can be concluded that using the chitosan extraction method in this research, highly purified chitosan with high de-acetylation degree can be obtained. With increasing degree of deacetylation, the solubility of chitosan has increased, and this degree of deacetylation has had a significant effect on improving molecular weight (Low molecular weight). As a result of the study of the role of solubility of chitosan in the vicinity of acetic acid, it becomes obvious that the solubility of the chitosan and the size of the nano-chitosan particles depend on the solution pH. The produced chitosan can be used in wide variety of application mainly in pharmaceutical industry.

Occupational vibration is considered as one of the most important occupational problems in chainsaw work in a forestry environment. The aim of this study was to measure the hand-arm vibration of the chainsaw operator in the bucking operation of Persian ironwood, popular, and alder logs in the Kheyrud Educational and Research Forest. In this study, bucking operation of two trees of Persian ironwood, popular, and alder species with different wood density was measured in a transverse section. Vibration measurement was carried out using a SVANTEK vibration device at the same time in X, Y and Z directions. The averaged vibrational intensity indices (aeq), total ahv chainsaw vibration, vibration transmission coefficient (Tr and daily exposure period) (A8) was used to assess the vibration of the chainsaw. The results of this study showed that the mean averaged vibration ratio of the averaged jet propulsion (aeq) in all three axes ((X, Y, Z more) Is a species of poplar and alder, and in Persian ironwood species, there is a significant increase in direction X and direction Z is the least amount of vibration (P

In this study, fracture toughness and internal bonding of OSB made from Poplar (Populus nigra) was studied. For this aim, ratio of UF to MF (20; 80, 40:60, 60:40 and 80:20), mat moisture (11 and 13), press time (5 and 7 min) and the panel thickness (12 and 16 mm) were chosen as variables. Specimens based on Taguchi design of experiments with the array of L8 (4^1 2^3) were produced and fracture toughness and internal bonding were determined following ASTM E399 and 319 EN respectively. Fracture toughness was determined using stress intensity factor and fracture energy. The result of percentage contribution and the variables ranking showed that the most determining factor on fracture toughness is the ratio of UF to MF. The effect of press time on stress intensity and internal bonding and the effect of panel thickness on fracture energy had the least importance. The highest fracture toughness was belong to OSBs made with UF to MF ratio of 60:40, mat moisture of 11%, press time of 7min and the panel thickness of 12 mm. The highest fracture energy and stress intensity factor was 2944 J/m2 and 0.19 MPa respectively. The optimum treatment was UF to MF ratio of 80:20, mat moisture of 13%, press time of 7min and the panel thickness of 12 mm in light of gaining the highest internal bonding (0.95 MPa).

The aim of this study was to determine stress carrying capacity of doweled corner joints in wood members made with modified resin (polyvinyl acetate) and its comparison with unmodified ones. Joint members were out of European silver Fir (Abies alba) and dowels were made from Beech and poplar woods as variables in this study. Diameter of dowel had three levels in size, namely 6, 8 and 10 mm. The experimental joints were tested under diagonal compression loads. Results have shown that stress carrying capacity of tested joints made with modified glue is more than unmodified ones. Maximum stress capacity was observed in the joints of beech which with 10 mm in diameter dowels. Based on the results, the highest strength was belonging to those joints made with beech wood glued with modified resin containing 10 mm dowel. Furthermore, the lowest strength was belonging to poplar joints made with unmodified resins and 6 mm dowels. The improvement can be due to increased viscosity and controlled penetration of the resin into the wood structure and hence better bonding. Concerning the wood species, beech had the highest stress carrying capacity that it can attributed to its higher density.

The purpose of this study was to extract pure cellulose from the waste spirulina alga (Spirulina platensis) using a method of chemical treatment and then isolation of cellulose nanofibers by applying a mechanical process. For this purpose, purification of spirulina algae (separation of fat and protein) was carried out during three stages of chemical treatment using a 2% solution, followed by 3% sodium chloride solution, which was buffered by acetic acid. The extracted cellulose fibers were then subjected to 1% dry weight suspension and passed through a high pressure homogenizer in order to isolate the cellulose nanofibers. Before and after chemical treatment, the infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and X-ray diffraction (XRD) were used to study the chemical and structural properties of the samples. Also, the diameter and length of the prepared cellulose nanofibers were measured by atomic force microscopy (AFM). The FTIR results showed that the chemical and mechanical treatment could successfully isolated cellulose and nanocellulose fibers which are totally compatible with previously studies. The analysis of SEM images showed that pure cellulose fibers were extracted from spirulina algae. In addition, the XRD analysis illustrated that the cellulose and nanocellulose fibers had similar diffractogram to the cellulose I. AFM images demonstrated that the nanofibers had average diameter of 37 nm while their length was several microns. It can be concluded that the isolation of cellulose nanofibers by using the high pressure homogenizer could be possible from the chemically treated cellulose fibers.

The banknotes is one of the most important ways to transfer of the many of microbes to human and also human diseases. These banknotes have several contaminants such as fungi, bacteria, and microbes which can transfer different diseases to human and also make huge problems for health as we as environment. Therefore, the use of proper techniques especially if they were friendly environment and biobased can introduce as suitable suggestion for decreasing the environment contaminants and also healthy concern. So, in this study, the anti-fungal effect of cellulose nanocrystal alone and with chitosan nanofiber on the common paper banknotes has been examined.
Cellulose nanocrystals have been prepared using acid hydrolysis by H2SO4 from cotton linter. Shortly, the cellulose nanocrystal preparation was consist of acid hydrolysis (by using sulfuric acid), centrifuging technique at 16000 rpm, and dialysis process by using cellulose acetate membrane, and naturalizing with distilled water. The diameter of the prepared cellulose nanocrystals and chitosan nanofibers was characterized by transmission electron microscopy (TEM). Firstly, the fungal contamination of the banknotes from four centers (bakery, butchery, passenger terminal and hospital) was evaluated. Then, in order to consider the antifungal activity of cellulose nanocrystals and chitosan nanofiber compound, stable emulsions with 1%, 2%, 4% and 6% concentrations have been prepared and then coated to the surface of banknotes using rolling coating method.
According to the TEM images, the diameter for cellulose nanocrystals and chitosan nanofiber was 5-20 nm and 45 nm, respectively. It can be concluded that the cellulose nanocrystals have been successfully prepared from cotton linter. The results showed most fungal spices found in banknotes from bakery, butchery, passenger terminal and hospital) are Aspergillus, Aspergillus niger and Penicillium respectively. Anti-fungal examination of paper banknotes covered with cellulose nanocrystals at concentration of 3% shows no significant anti-fungal activity on Penicillium fungi on paper banknotes from hospital. In addition, the results also show that adding chitosan nanofiber at 1%, 2% and 4% concentrations has no anti-fungal effect on the surface of banknotes from bakery, butchery, passenger terminal and hospital, but adding chitosan nanofibers at 6% concentration shows significant anti-fungal effect. The results show that cellulose nanocrystals had no antifungal effect alone effect alone on the banknote species, but in could improve the antifungal effect, adhesion, and stability of cellulose nanocrystals on the banknote surfaces.
This study suggested a new approach to decrease the infection spreads through banknotes.

In this study, twisting angle of wooden spiral stairs from beech wood (fagus orientals) on the scale of 1/6 and according to SMA-R311 has been calculated using trigonometry, and the effect of radius (in two levels as 11.5 and 42.5 cm), handrail width (in two levels as 4.5 and 8cm, and rake angle (in two levels as 15 º and 33º) on twisting angle was determined. The results showed that decreasing the diameter increases stair rake angle. While increasing the rake angle increases twisting angle of the handrail, an increase in the handrail width have not any significant effect on the twisting angle. The results also showed that there was a non-linear relationship between the rake angle and the twisting angle by radius of the circle.

In this study 3D stress-strain distribution of dowel and glue line on L-type joints made of plywood doweled was investigated. Members of joints made of 11-ply hardwood plywood (Hornbeam, Beech and Alder) that were 19 mm in thickness. In this study effect of beech dowels in three levels diameters (6, 8 and 10 mm) and penetration of depth (9, 13 and 17 mm) on bending moment capacity of L-type joints under compression loading was investigated as experimental test, then stress-strain distribution of wood dowel and glue line in specimens were simulated by means of ANSYS 15 software with finite element method (FEM).Results have shown that bending moment resistance increased with increasing dowel diameter from 6 to 8 mm, but downward trend was observed with increasing 8 to 10 mm in dowel diameter. Bending moment resistance increased with increasing penetration depth. Also, result obtained of simulation by means of ANSYS software have shown that stress-strain in dowel and glue line increased with increasing diameter of dowel and Increasing stress in joints made of diameter dowel 10 mm due to fracture in joints and decrease in resistance once. According to results obtained of model analysis, the ultimate stress of dowel and glue line occurred in the area that joints were contacted.