Cultivation of rapeseed plant is expanding and larger volume of residues from its stalk is produced which necessitate its proper utilization. Therefore, properties of APMP PULPs from rapeseed stalks are investigated. A combination of 2, 3 and 4% NaOH and 3, 4, 5, and 6% H2O2 is used for chemical pretreatment of stalks. Pretreatment time and temperature as well as DTPA and sodium silicate were kept constant at 35 minutes , 75oC, 0.5% and 3% (O.D. basis ) respectively. Treated stalks were defiberated using 25 cm laboratory disk refiner and total yield range was measured between 61.24 – 69.56%. Since both NaOH and H2O2 charge did not significantly affect the total yield, based on visual indication of PULP brightness, Then PULP samples produced using 3% NaOH and 3-6% H2O2 were selected for further analysis. All PULPs were refined to 400 ml CSF and then 60 g/m2 handsheets were made. Tear index and tensile index of handsheets varied between 4.48-6.02 mN.m2/g and 12.53-22.71 N.m/g respectively. The influence of H2O2 addition on these properties was significant at 99% level. Optical properties of handsheets including brightness, opacity, yellowness, color factors L*, a* and b* were measured at 66.1-68.44%, 87.20–89.55%, 14.53-17.65, 90.01-90.045, 1.02-1.34 and 8-9.68 respectively. The effect of H2O2 addition on measured properties was significant at 99%. Overall the results indicate that the newsprint paper could be produced from APMP of rapeseed stalks.

This study was conducted to investigate the properties of APMP PULP. Prepared from chipped cotton stalks. The PULPs were prepared separately from debarked and bark containing stalks using three two-stage treatments. Sodium hydroxide charge as a constant level of 4% and hydrogen peroxide at three levels of 0, 1 and 2% were used in to two-stages, sodium hydroxide as a constant level of 2% and hydrogen peroxide at three levels of  2, 3, 4% were applied. Other conditions of PULPing was time's of 20 min for first stage and 100 min for second stage, temperature 70oC and l/w:6:1 as fixed factors considered. PULP yield determined after neutralization and defiberation. All the PULPs were refined up to 300 (ml, CSF) freeness and handsheets were made, then and properties of papers measured using TAPPI standards. Results showed that the PULP yield and brightness was higher in free-bark compared to bark-containing conditions. Also paper produced in free-bark condition with cotton stalks core, resulted the higher tensile and burst indexes and higher breaking length compared to whole cotton stalk. While tear index didn’t show significant difference. Generally, caliper and bulk rates were high in total treatments (free-bark and bark-containing conditions) from cotton stalk APMP process.

The present study was fulfilled with the aim of investigating the effects of process variables on APMP (alkaline peroxide mechanical PULPing) PULP brightness and yields of P.alba to produce high yield PULPs suitable for making writing and printing papers. The wood samples have been prepared from the poplar plantation fields in the area of Maragheh Paper Company and converted to acceptable chips by MWPI industrial chipper. Based on the results obtained in the preliminary experiments (1), chips prostrating time of 20 minutes, impregnation times of 20 minutes for first stage and 90 and 105 minutes for second stage, total caustic soda charge of 6 and 7 % with usage rations of 40, 50 and 60% of total caustic in first impregnation stage, total hydrogen peroxide charge of 5% with usage ratio of 25% in first impregnation stage, PULP consistency of 32-34 and 23% in first and second impregnation stages, respectively, were selected and studied as effective process variables to achieve high yield APMP PULPs with PULP brightness of about 80%. The results have shown that; at caustic soda charge level of 6% with usage ratio of 60% of total caustic in first impregnation stage and treatment time of 105 minutes at second impregnation stage, it would be possible to produce APMP PULP with 81.9% brightness and relatively high PULP yield of about 88%. At total caustic charge of 7% with similar usage ratio, APMP PULP of 79.9% brightness at PULP yield of 86.8% in treatment time of 90 minutes, and APMP PULP of 80.2% brightness at relatively low PULP yield of 85.3% can be produced in treatment time of 105 minutes at second impregnation stage. By reducing the treatment time at second impregnation stage and using lower usage ratio of total caustic in the first impregnation stage, APMP PULPs have higher yields but at lower brightness.

The Effects of some process variables on P. nigra APMP PULP yield and brightness were investigated. Wood samples were prepared from poplar plantation fields in the vicinity of Maragheh Paper Company. Fiber dimentions such as average fiber length, diameter cell cavity and fiber wall thickness were assessed as 853, 22.66, 15.16 and 3.74 microns, respectively. For making APMP PULP, different chemicals namely sodium hydroxide (6 and 7%), hydrogen proxide (5 and 6%) diethylene triamine pentaacetic acid (0.5%) and sodium silicate (3.5%) (based on O.D chips) were used. Based on the preliminary chemical treatment results, chips treated with preheating of 20 minutes, impregnation times of 20 and 75-105 minutes in first and second stages, PULP conssistency of 34-36 % and 23-25 % in the first and second stages of impregnation, respectively, percentages of caustic charge in 3 levels of 40, 50 and 60% in the first impregnation stage, percentages of proxide charge in 3 levels of 20, 25 and 44% in the first impregnation stage, percentages of diethylene triamine pentaacetic acid in 2 levels of 60 and 75% as well as percentages of sodium silicate of 50% in each stage of chemical impregnation, were selected as the process conditions. The APMP PULP brightness and yield obtained in the 24 treatments, were in the ranges of 71.7 -78.6 % and 84.17 -93.46 %, respectively. The final results indicated that by using optimum process variables such as total caustic and proxide charges of 7 and 6% respectively, percentages of caustic, proxide and diethylene triamine pentaacetic acid in the first impregnation stage of 60, 20 and 75%, consistency of 34 and 23% in the first and second stages respectively, It is possible to produce APMP PULP of high brightness in an acceptable yield range.

The present study was carried out aiming to investigate the effect of using Deinked Mixed Office Waste PULP (MOW) on the properties of Alkaline Peroxide Mechanical PULP (APMP) from cotton stalk. APMP PULPs was prepared using chelating agents such as Na2SiO3 and DTPA (control sample) and without these agents in two-stage PULPing with L/W ratio 6: 1 (ml/g), 20 minutes impregnation time at 70 oC for first stage, 60 minutes impregnation at 75 oC for second stage. Also, PULP was prepared from mixed office waste paper, which were deinked with conventional flotation and then each PULP was separately refined up to about 300 ml CSF. The handsheets were made from control sample PULPs, APMP without chelating agents, MOW deinked PULP and mixing with 10%, 20% deinked PULP with control APMP. Physical and mechanical properties were determined using TAPPI standard methods. Deinked MOW PULP had the maximum values of density, brightness, strength properties and APMP PULP without chelating agents had the minimum values. Among mixed PULPs, APMP PULP containing 20% deinked MOW PULP showed the maximum value of density, brightness, burst index and tear index.

Back ground & Aim: Preservation of tooth vitality is one of the most important tasks for clinicians dealing with exposed teeth. Several different materials have been used for PULP capping in recent years with calcium hydroxide being of the most Due to pathologic complication in the PULP following the are of Ca(OH)2, this investigation was designed to evaluate the effect of MTA on PULP reaction following PULP capping procedure. Method & Material: Calcium Hydroxide (Dycal) was used for direct PULP cap ping of II human maxillary third molar teeth with intentional exposure as control group. The same number of teeth was capped using MTA using the same condition. Results: Results showed that the dentinal bridge was thicker in cases treated with MTA with a clearly milder inflammation in PULP of the teeth treated by MTA. Conclusion: MTA could be used as an acceptable material for PULP capping of exposed permanent teeth.

Mixed Office Waste DIP produced at Latif Paper Company was used as reinforcement PULP to substitute part of imported long fiber PULP in White Poplar APMP furnish produced at Maraghe Paper Company. Each PULP was separately refined to about 250 CSF and then, handsheets were made applying 0(control sample), 5, 10, 15, 20 and 25 percent DIP mixed with APMP and LF PULPs. The control sample contained 30 percent LF and 70 percent APMP PULPs. Mechanical and optical properties of the handsheets, including tensile, tear and burst strengths, brightness and opacity were determined according to relevant TAPPI standard test methods. Comparison of the data was done using ANOVA and the best treatment, was determined using scoring method based on normalization equation. The results showed that 5 to 15 percent Mixed Office Waste DIP can be properly used in mixtures with 15 to 25 percent LF and 70 percent White Poplar APMP PULPs to produce writing and printing paper with suitable mechanical and optical properties.

In this study, mechanical and optical properties of CMP, one stage APMP and two stage APMP PULPs ( from Tajan wheat straw Golestan province ) were investigated. wheat straw collected at research center of Agriculture and Natural resources of Golestan province. Fiber dimensions such as average fiber length , diameter cell , lumen and fiber wall thickness were assessed at 1.18mm, 18.156, 11.461 and 3.396 microns, respectively. chemical components such as cellulose , lignin , ash and extractives were assessed at 53.7, 21.1, 5.1 and 8.5 percent, respectively. Based on the preliminary experiment results, impregnation temperature was 95oC, impregnation times of 10, 20, 30, 40 minutes, caustic charge 10% and peroxide charge was 3% in CMP ,one stage APMP and two stages APMP PULPs. Considering PULP properties and treatment conditions, many treatments including 20 and 40 minutes treatments were selected for making of handsheet. The selected PULPs were refined up to 350 ml (CSF) freeness prior to making of hasndsheet. Final results indicated that two stages APMP PULP (impregnation in time 40 minutes) had the highest burst strength, breaking length and brightness. Also, the results of yield and tear strength showed that, there was no meaningful difference at the 5% level between three methods CMP, one and two stages of APMP PULPs.

CMP and APMP PULPing characteristics of corn stalk were investigated. Chemical composition of corn stalks including cellulose, lignin, extractives soluble in alcohol-actone and ash content were measured at %49.67, %21.88, %2.53 and %4.087 respectively. Fiber length, diameter, lumen and cell wall thickness were measured at 0.936mm, 18.463um, 11.59um, and 3.48 um respectively. CMP and APMP PULPs were prepared using two PULPing temperatures of 90-95 C, cooking times of 20,30,40 and 60 minutes, and NaOH charge at 5 and 10 percent based on oven dry weight of corn stalks. Liquor to corn stalk ratio was constant at 8/1. %3 H2O2 (based on oven dry weight of corn stalks) was used in APMP PULPing. The highest CMP yield was obtained with 20 minutes PULPing time and these PULPs as well as two PULPs obtained in 30 and 40 minutes are in group A. The yield of APMP PULP produced with 20 minutes PULPing time (PULP yield of %71.1) is in group A and the PULPs produced with 30 ,40 and 60 minutes PULPing times with average yields at % 70.27, %68.82 and %66.74 are in B,C and D groups respectively. The burst strength of hand sheets produced from these PULPs varied between 1.02-1.23 kPa. m²/gr , tear strength between 4.166-4.392 mNm²/gr and breaking length between 4.018- 4.144 Km. This investigation showed that due to limited availabilities of wood, corn stalks can be considered as a potential raw material for PULPing development in IRAN.

In this investigation, physical, chemical, fiber dimensions, PULP and papermaking characteristics of 4 years old Alnus glutinosa was researched. The average of oven dry and critical density, fiber length, fiber diameter, lumen diameter and cell wall thickness were measured at 0.396, 0.368, 0.875mm, 32.66um, 27.28 urn and 2.70 urn respectively. Chemical compositions were obtained 48.5% cellulose, 25.35% lignin, 0.31% ash and 2.36% extractives. CMP, one stage APMP and two stage APMP processes were used for cooking. After preliminary cooking, cooking temperature, cooking time, NaOH and H202 charges were applied at 95 degree of centigrade, 10, 20, 30 and 40 minutes 10%,3% and so on. In CMP process, the average of yield, burst index, breaking length, tear index opacity and brightness were obtained at %73.72-%82.57, Kpa m2/gr. 1.53, Km 3.81, mNm2/gr 3.34, %99.59 and %29.35 correspondingly.In one stage APMP process, the average of yield, burst index, breaking length, tear index opacity and brightness were obtained at %74.09-%81.57, Kpa m2/gr. 1.52, Km 3.5, mNm2/gr3.2, %99.80 and%28.21 respectively.In two stage APMP process, the average of yield, burst index, breaking length, tear index opacity and brightness were obtained at %73.99-%80.89, Kpa m2/gr. 1.92, Km 3.95, mNm2/gr 3.45, %99.85 and %32.41 in that order.Among yields of PULP in the three methods, there weren't significant difference at level 5%. In two stages APMP paper, the burst index, breaking length and brightness were more than other and changes of cooking methods hadn't significant differences at level 5% on tear index.