During the paper manufacturing process, especially when mechanical pulp or recycled pulp used, a large amount of soluble and colloidal substances (DCS) are comprised and dispersed or dissolved in the process water. Accumulation of DCS during the papermaking operation with the increasing closure process water systems, can have a variety of deleterious effects on papermaking process and paper products. In this study, The effect of anionic trash neutraliziation was investigated by using different catcher anionic tarsh and also pulp washing (removal of anionic trash) on the CMP pulp and paper properties. After the initial preparation chemi-mechanical pulp (CMP), bleached long fiber kraft pulp and mixing the pulps with each other, filler of precipitated calcium carbonate (PCC) was added. Then a cationic retention aid That in this research has been cationic polyacrylamide were added to the mix. To neutralization of and reduce the negative effects of anionic trash, different levels of poly DADMAC with molecular weight 100000-200000 (0.025, 0.05, 0.1, 0.15%) and poly aluminium chloride (PAC) (0.1, 0.25, 0.5%) was added before adding of retention aid. Results showed that the use of different neutralizers imprived of zeta potential and drainage time of pulp, and increase of total retention; but reduces burst index of paper that was not significant statistically. CMP pulp washing and drainage treatment caused reducing COD and on the other hand reduced the amount of anionic trash with organic origin. Washing treatment pulp improved drainage time from pulp, total retention; but reduced burst index. Based on these findings, using cationic polyelectrolyte can introduce as a good strategy to reduce the harmful effects anionic trash and more retention suspension components.

Various kinds of chemicals are used in papermaking to enhance paper properties and to improve efficiency of the production process. In the presence of cationic starch as an anionic charge catcher, effects of Nano silica/cationic Polyacrylamide complex on retention, drainage time, water volume drained by Dynamic Drainage Jar and properties of paper recycled from old corrugated container were investigated. The results revealed that individual addition of CPAM is more efficient than the individual addition of anionic nano silica, regarding to the investigated properties, increase all characteristics compared to the situation without these addition. Higher volume of drained water (up to 6%) and lesser time needed for the sheet formation (up to 10%) combined with retention increment (> 2%) have been achieved by flocculation and consolidation of fines and fibers via bridging and network flocculation of pulp ingredients and contributing to charge neutralization of anionic surfaces, more and more, resulted in bigger flocs which could be retained by papermaking wire. The mentioned mechanism contributed to better bonding of paper network resulted in tensile and burst indicates improvement up to > 45% and >50%, respectively. Influence of silica anionic nanoparticle on strengthening of the flocs formed by CPAM, made higher energy requirements (> 12%) for paper tearing. In addition to higher yield of production, application of CPAM/nano silica complex resulted in a paper with higher value from quality and application point of view.

In this study, the effect of alum- dispersed rosin sequence has been examined on different properties of papers made from recycled fibers. Therefore, reverse sizing recycled fibers with 0.5 consistency at pH6.5 was carried out by using 1 and 1.5 % alum, and 1, 1.5 and 2 % dispersed rosin, based on dry weight of pulp. Then, water absorption, optical and strength properties of papers with grammage (60±3 g/m2) were evaluated. Based on the results, to reduce the water absorption of papers, 1 % of both alum and dispersed rosin is required to achieve appropriate level of sizing. As a result, the water absorption of papers declined from 174±7.4 g/m2 to 36±0.4 g/m2, and the contact angle of water droplet with paper surface increased from 31.2 degree to 118.1 degree. Moreover, concurrent to the hydrophobicity of fibers surface formed by rosin molecules and its repellency impact of inter-fiber bonding, alum imparts an improvement of bonds in paper network owing to the neutralization of anionic trash and retention of cellulose fines. Paper opacity has been increased due to the development of filler retaining in fibrous web of paper.

Wind catchers in Yazd's traditional houses are the means to obtain optimal indoor climate against the heat in central plateau of Iran. It plays an effective role in modifying the temperature in the interior living spaces with regards to human thermal comfort. Wind-catchers are canals with the height of 3 meters mounted vertically on top of the roofs, resembling a chimney vent. The outlet openings in the upper end plays an effective role in modifying the heat and adjusting and regulating the temperature of the living space as appropriate for resident's comfort through convective wind flow using pure natural energy of nature. Relationship of the wind-catcher with the chamber and central yard has significant effect in its function. A chamber or a summer living quarter is directly and closely connected with a wind catcher. But in some instances this link is provided through the medium of an alternative space. In this research, a study of 24 houses in Yazd was conducted with an emphasis on the location and design of the wind-catchers. These houses were selected among Yazd's houses that have central yard and confirmed historical value.
The data was collected through fieldwork. The data was subsequently analyzed through logical Inference and classification in excel software. In this research the classification system was based on 3 factors: 1. orientation of wind catchers; 2. their position in the house and the connection with the summer living quarters; 3. Design of the wind-catcher for optimum reception of the dominant winds.
The canal of a wind catcher is usually divided into smaller sections by means of splitting blades. These blades rise 1.5-2 meters above the ground floor of the building and continue all the way up to the wind catcher's roof. The wind catcher's plan and the design of the splitting blades are different in each instance and seem to be in concordance with the general plan of the house and with the all the considerations needed for better performance. Moreover, the wind catchers sometimes have an added evaporative cooling function with a water pool positioned at the bottom. This study was initiated with a hypothesis that in all Yazd houses with wind-catchers, there is a water pool positioned underneath. A second hypothesis suggested that the area of the wind-catchers is related to the total area of the chamber to which it connects. A third hypothesis proposed that all wind-catchers face the dominant wind and that they have a Northeast-Southwest main orientation axis. All the hypotheses were rejected through this study. The relation between the chamber’s area and the relevant wind-catcher’s area were calculated with the correlation coefficient in excel software.

Aqda is one of the desert villages of Iran which is located in the hot and dry area with a distance of 26 kilometers far from Ardakan Yazd. Since ancient times, the architects of this village have benefited different methods to be compatible with the unfavorable conditions. One of these innovations which is the indication of Aqda village is its one-sided wind catchers. One-sided Wind catchers are considered as one of the engineering masterpieces of Iran which provide suitable ventilation for the building despite heavy dust storms. But by passing time, the capabilities of wind catcher have been gradually forgotten and it is regarded only as a decorative element. One-sided Wind catchers in Aqda are regarded as the main indication of the village and have the role of giving identification to it while being compatible with the hard conditions of the region. Although by passing time, the lifestyles have been changed and in the cities like Yazd, the people have gradually migrated from the traditional texture to the new city, but Aqda΄s traditional texture still exists and the people are living there with different lifestyles compared with the past and benefit from modern ways to have more convenient life. Wind catcher which is the inseparable element of traditional houses of Aqda has gradually lost its functionality and is regarded only as a symbol. Evaporative coolers for their easy usage and inexpensive cost have been substituted with the natural cooling by wind catchers. This article tries to investigate the wind catchers of Aqda from view point of their physical body and functionalities and introduce their unique structure to help their revival. The article focuses on four sectors subject to review: introducing the architectural features in Aqda, introduction of wind catchers, review and compare the physical body and function of one-sided wind catchers in Aqda with four-sided ones in Yazd and the solution of reviving them. Having introduced the structure, function and regional features, some proposals will be presented for improving the function of one-sided wind catchers in order to revive them. To prove the presented proposals, some samples of revived wind catchers have been introduced which have been made in use again based on proposals and are practically a proof of their functionality again. The research is based on field studies, using existing evidences and library sources. This article seeks to answer the following questions: -Do the wind catchers in Aqda supply cooling needs of the inhabitant? - How can one-sided wind catcher be revived? -How can the potential environment and local materials be used to improve one-sided wind catchers?

In the present study، the ventilation performance of a one-sided wind-catcher positioned in the wake of an upstream structure is experimentally investigated by measuring the induced airflow rates and employing smoke flow visualization techniques. Wind-catchers are usually used in places of high urban densities in Middle East regions; however، their potential to provide natural ventilation depends on the presence of upstream structures. The present study focuses on the ventilation performance evaluation of a one-sided wind-catcher located in the wake of an upstream structure model. The influence of the upstream structure height and its distance relative to the wind-catcher on the flow structure within and around the wind-catcher is investigated. Moreover، the ventilation performance is evaluated by measuring the ventilation flow rate using a hot wire anemometer for upstream air velocities of 10 and 15 m/s. The results show that the presence of an upstream object influences the rate and the direction of air flowing from the wind-catcher to the house. Placing a short upstream object increases the induced air flow rate. However، by increasing the height of upstream object، the airflow direction is reversed inside the wind-catcher and the air may flow backward from the ventilated space to the wind-catcher.

In many explored gas reservoirs in the word, which are considered as gas-gas condensate reservoirs, many surface facilities receive the gas as well as hydrocarbon condensates and water. Condensates cause slugs in a pipeline. The slugs, which are an aggregate of fluids, cause many problems in multiphase pipelines. Therefore, in order to separate condensates, slug catchers are normally used. A slug catcher is necessary equipment at the entry of a multi-phase flow processing factory. The specific performance of a slug catcher is the separation of gas and liquid phases and temporary storage of the liquids. In this paper, we recommend a method for designing finger type slug catchers, based on two phase flow in principles. Then, using the proposed method, we design a slug catcher for the two present phases in the South Pars gas field. At the end, by considering condensate recovery and economical investigation of the suggested slug catchers, we choose the optimum slug catcher for these two phases. Among the most important results of this investigation, we can mention an efficient pattern for designing finger type slug catchers and the selection of the optimum one. Using this pattern is recommended for a proper design and reduction of time and costs.

The purpose of this study is to investigate the role and importance of traditional Iranian architecture with emphasis on wind-catcher in reducing energy consumption in residential homes. Semnan province was selected as a study area and in the first step, suitable areas were identified for the establishment of wind-catcher in the province. In the second step, using two indices of Olgyay and effective temperature index (ET), the ted-cmperature of thermal comfort in the province was determined. Finally, the temperature difference was calculated by comparing the temperature in the residential houses adjacent to the wind-catcher and the internal temperature of the traditional buildings that had win-catchers. In the final step, the amount of energy consumption for heating or cooling in residential houses in Semnan province was estimated to determine the role and importance of wind-catchers. The results showed that April, May, June and October are in the zone of thermal comfort and there are times when wind-catchers will not be very useful in the province. On the other hand, July, August and September due to high temperatures and December, January, February and March due to high cold are good times to use wind-catchers. Also, the highest degree of conformity of the measured temperatures is observed in the cities of Semnan, Garmsar, Damghan and Shahrood, respectively. The amount of energy required to produce cooling is equal to 1700 kWh. However, if a wind-catcher is used, due to the reduction of coefficients and refrigeration losses, this amount will be equal to 1200 kWh.

Wind towers are historical Iranian vernacular architectural innovation and traditional wind towers are structured as static cooling ventilation system. The process is performed by using of renewable energy of wind.In this research, wind towers are studied in the context of vernacular architecture of hot dry climates of Iran and the city of Yazd in arid is selected. The different architectural forms of wind-towers have been seen in Yazd. This article indicates the fact that formal characteristics have played a major role in their functions.From the architecture point of view, learning about wind catchers of Yazd city in this study is done by the means of the field surveys. Research method for selection of the case is randomly chosen and based on explanation and analytical method. Wind catcher typology and knowledge of the relationship governing the wind catcher's architecture were those measures that are taken for the first time. The typology of the wind-catchers is done by the physical analyzing, patterns and common concepts as incorporated in the wind catchers. How the architecture of wind catcher can influence their operations or performances by analyzing thermal behavior are the archetypes of selected wind catchers. This study has used calculating fluids dynamics science, fluent software and numerical analysis as the most accurate analytical approach. 3 types were stimulated in soft ware and results show that they are different to each other and one of them has more improved operation.

Ancient wind catchers of Yazd city as net zero energy building components request the detailed numerical and experimental studies to renovate and reuse in old part of the city and for developing the new design strategies in future. In this ingenious natural ventilation strategy no other energy sources are required except wind and sun. In this research, the effect of both wind and sun on the flow and thermal behaviour of the solar-wind catchers of Yazd city - a city with very high solar radiation - in Iran, are investigated numerically and experimentally. This paper represents a systematic evaluation of isothermal 3D CFD modelling for predicting mean air velocity distributions over and through the wind catcher at three reference wind directions of 330°, 90° and 150°, using Open source CFD package (OpenFOAM). The evaluation is based on a grid-sensitivity analysis and on validation with full scaled long term measurement data set. The validated CFD simulation results show that steady RANS with Standard k−ɛ model, in spite of its limitations, can accurately predict the flow behaviour of wind catchers at wind direction of 90° with the average deviations of 19%, which is considered a good agreement against the long term experimental results. Moreover, the thermal behaviour of wind catcher during a summer day is discussed. The study reveals that the solar wind catchers of Yazd city, is quite effective in lowering air temperature and enhancing air circulation through the buildings. The result of this study will be useful for designing solar-wind catchers under hot and dry climate conditions.