Resistance to flow is an important and primary parameter in the determination of water surface elevation. A variety of bed forms, especially dunes, have a sensible effect on total roughness. Because of the complexity of bed form development, previous methods differ drastically from each other in predicting dune bed forms. In this paper, laboratory experiments were conducted to investigate the geometry of dunes in a sand-bed channel and its influence on total channel resistance. The experiments were performed in a flume in the hydraulic laboratory of Shiraz University using sand particles. Simple relations were sought for dune dimensions via some dimensional parameters, and previous methods were compared to each other in light of this new data.

Background Poor physical and chemical properties of sand dune soil are the main constrains in afforestation of sand dune in desertified area. The aim of this study is to improve the physical and chemical properties of dune soil in Elrawakeeb Dry Land Station using organic wastes as a fertilizer source and amendments, for sustainable sand dune stabilization program. Salvadora persica L. seedlings were transplanted in a 2 m ´ 2 m plots and treated with: sawdust (SW), chicken manure (CH), chicken manure with sawdust (CH+ SW), sawdust with inorganic fertilizer (SW+ IF), sewage sludge (SS), sewage sludge with sawdust (SS+ SW), and control (C). The treatments were arranged in a randomized complete block design with four replicates. The soil chemical properties were determined from soil samples collected from the fixed sand dune (0–20 cm depth) in the second year after application.Results Application of organic amendments significantly (P=0.001) increased soil organic carbon by 224 %, available P by 139.9 %, total nitrogen by 142.9 %, and mineral nitrogen by 83.5 % and decreased soil pH by 5.6 %.Conclusions Incorporation of organic waste in desertified sandy dune soils increased its nutrient content and hence sustained biological fixation of sand dunes.

A two-dimensional numerical model, based on solution of the Reynolds-averaged navier-stokes equations with k-e and EASM (explicit algebraic stress) turbulence models, is presented to describe' the free surface water flow over bed topography (dune) in open channels.The model application indicates insufficiency of k-e turbulence model for simulation of flow over dunes (because of separation and streamline curvature). In this case, algebraic stress model that is economic method for calculating stresses can do better. Therefore, an explicit version of it (Wallin and Johanson 2000) is used All of the differential equations are solved with a finite volume method in a nonstaggered grid. The geometric shape of sand dune is simulated by introducing a general non-orthogonal curvilinear coordinate system.The numerical results were compared with the available experimental data reported by Mierlo and Ruiter (1988) and general agreement was observed. Detailed calculations indicate improving prediction of turbulence characteristics and length of separation zone by EASM model.

Wind erosion is considered a major global environmental problem. Sands torms cause serious damages to municipal, industrial and agricultural areas. Mulch is one of the most common materials for soil stabilization, which mitigates wind erosion and dust formation. In this research different combinations of organic (waste press mud, beet vinasse dunder and compost) were used in combination with clay as a stabilizer. Sandy soil from the Dejgah plain, the Provice of Fars, was used as the erodible material. Experiments were carried out in a completely randomized desing (CRD) with 14 treatments (organic mulch type). The mulches were sprinkled on plots of 50×30×1 cm sand. The thickness and mechanical properties of the mulched layear, namely the: shear strength, penetration resistance, and wind erodibility of the treatments were measured. Based on the analysis of variance (ANOVA), the effects of mulch type on thickness, penetration resistance, and shear strength of surface soil were highly significant (p<0. 05). Based on comparison of means with the Duncan's multiple range test, the M1 treatment with 25g compost+100g vinasse+100g clay had the highest thickness, penetration resistance, shear strength and the lowest amount of wind erodibility. Due to the biodegradability and economic justification (lower operating cost than petroleum and polymeric mulches), the organic mulch was recognized as the best combination for stabilizing sandy soils.

A Study of Geometry in Islamic Architecture by Professor Golroo Najibaaghlou is a valuable work in the field of Islamic architecture. This book has a detailed preface, a brief introduction, and five main sections. As it is known from the introduction of the book, this book was originally written for a non-Iranian audience. The first purpose of writing this book is to try to moderate public belief about geometry and the stages of compilation and discussion in Islamic architecture. Another purpose is to correct the negative view of the geometric documentation of Islamic architecture in the West, because such a view has created a kind of reluctance to equate the works of Islamic architecture with the great works of classical Western architecture. In addition, Najibaaghlou wants to reject and respond to Western criticism that reduces Islamic architecture to the level of an unedited work. In the final chapter of the book, Najibaaghlou looks at the compiled documents of Islamic architecture from a Western perspective and highlights some of the missed points of geometric sciences, including clarifying conceptualization, recording, and transferring architectural design in the Islamic world.

The main purpose of the article, as the topic itself shows, is defining an eternal geometry(as a basic foundation and unavoidable structure)for the Islamic architecture. Therefore, as an abstract of this article, (giving a short but conclusive definition of the main subject),and in order to avoid from some possible misunderstandings in the mentioned subjects and meanings in the article, the following points seems to be useful:A. The referring meaning of the word "Geometry" (or its Arabic synonym "Hindiseh") by the author in this (article) is completely different from the common meaning of it in architecture (or the Euclidian Geometry) and its closed and limitful field of rules of some mathematical meanings and physical shapes and forms. But by the phrase "Hindiseh Jaavidan" or "Eternal Geometry" the author means the Unique, Wholistic and Comprehensive Truth, which according to the Quranic literature, is known by some Arabic terms such as "qadr", "taqdeer" and "muqaddir", "muqaddar", "qadeer", and so on. The meaning which points to the comprehensive and wholistic system of rules governing all various systems of measurement essential for the whole universe and its every individual parts's or thing's coming into existence (in their both physical being and meaningful identity).B. According to the above mentioned description, the referring meaning of the phrase "Natural Geometry" (or "Hindisi-yi Tabee 'at" or "Taqdeer") by the author in this article can be imagined as a symbolic light through which everything in the universe become visible, readable and understandable for every other thing in the whole cosmos of varieties and multiplicities (in both qualitative and quantitative groups of limits and measures). The limits and measures without which everything's essential mutual relation and harmonic suitable cooperative sharing life with every other thing in the world seems to become impossible.C. Then, in a similar symbolic structure, the other important meaning of "Geometry" or "Hindisih" to which the author is going to point to is "The Essential Geometry" or "Hindisik-yt Dhaatee". According to the Holy Quran, for every possible matter of being in the physical world, there is a limitless, unchangeable, eternal specific and determined Truth in The Presence of God which, as same as all other Truthful Meanings in such a Sacred Presence is free from all limits essential for the material world such as: matter, physical shape and form, length, width, thickness, color and other similar limits.D. And at last, the author's purposed meaning of the subject of "Islamic Architecture" in this article, is an orderly and unitary structure which in its both whole and parts, and in its both physical structure and meaningful identity obey the One Divine System of Rules named Islam. And, at last, by the word of "Islam" means the universal governing order of both physical and spiritual worlds.

Introduction: Gerbera is one of the most important cut flowers in the world and belongs to the Asteraceae family. Due to its diverse and adaptable species for growth with a wide range of climatic conditions, this flower has become a profitable cut flower for growers. Polyamines in plant tissues act as a potent factor in preventing the production of ethylene. Polyamines and ethylene have antagonistic effects (anti-aging and aging effects), so that the balance of these two hormonal groups in plants is very important for plant tissues. The balance between the two opposing regulators leads to a delay or acceleration in the aging process. Mycorrhizal fungi can be useful in hydroponic greenhouse systems, which increase the amount of CO2 in greenhouses by increasing photosynthesis in plants, as well as CO2 emissions in the control environment, which both optimally manage the environment and increase the yield and quality of plant products. Due to the economic importance of cut flowers, it seems necessary to provide treatments (such as the use of putrescine and mycorrhiza) to increase the quality and longevity of this plant. Materials and Methods: This study was conducted in the research and production greenhouses of Urmia University and the research laboratory of the Department of Horticultural Sciences of the Faculty of Agriculture in 2019-2020. This study was performed as a factorial experiment in a completely randomized design with three replications, each replication consistedd of three pots and each pot contained a plant. The factors of this experiment were Mycorrhizal fungi inoculation (with and without inoculation) during the transplanting process to the culture medium near the roots, and putrescine at four concentrations of 0 (control), 1, 2, and 4 mM, were applied two weeks after transplantation, every 15 day-interval for three months. In order to investigate the effects of putrescine and mycorrhizal fungi on some morphological and physiological characteristics of plants, two weeks after the end of treatments, leaf sampling was performed to measure physiological characteristics. Effects of putrescine and mycorrhizal fungi were assayed in some morphological characteristics including leaf number, leaf length and leaf area, fresh and dry weight of leaves and some physiological parameters including chlorophyll index, chlorophyll content (a, b and total) and soluble sugar as well as vase life and petal’s anthocyanin during postharvest time. The SAS software version 9. 1 was used to analyze the variance and compare the mean of the studied traits. Comparison of means was performed using the Tukey’s range test method at a probability level of 1 and 5%. Excel (2016) software was also used to draw the graph. Results and Discussion: According to the comparison of means, putrescine, along with mycorrhizal fungi, increased the number of leaves, leaf area, and the fresh and dry weight of the leaves as well as chlorophyll index, chlorophyll a, b and total and carotenoid content of leaves. In this study, inoculation with mycorrhiza reduced leaf length but increased leaf area resulted in that mycorrhiza could increase leaf blade because of increasing cytokinin in plant. Putrescine with mycorrhizal fungi, increased leaf growth, photosynthesis of plant and carbohydrates production. In the literatures, it is reported that, the vase life of cut flowers is a very important point in choosing them as great cut flowers. The results showed, putrescine and mycorrhiza had increased the vase life of gerbera flowers, therefore increased the quality of this plant. Putrescine and mycorrhiza also increased the amounts of anthocyanins in the petals, and by the sixth day, the highest levels of anthocyanins were observed in the petals. Probably, the reason for increasing the anthocyanins on the sixth day is the presence of carbohydrates stored in the flower, which due to the reduced respiration and carbohydrate consumption in this process. Conclusion: Based on the results of the present study, it can be concluded that putrescine, with mycorrhizae, improved growth characteristics as well as increasing the postharvest life and the quality of cut flowers of gerbera. It is also observed that among the different concentrations of putrescine, the concentration of 2 mM had the greatest effect on the growth and physiological parameters as well as vase life of gerbera.