Abstract: The current research has investigated the soil quality status under dryland vegetation of Yabello district, Southern Ethiopia in which we should identify the nature and extent of salinity problem of the area for further research bases. About 48 soil samples were taken from 0-30, 31-60, 61-90 and 91-120 cm soil depths by opening 12 representative soil profile pits at 1.5 m depth. Soil color, texture, bulk density, Soil Organic Carbon (SOC), Cation Exchange Capacity (CEC), Na, K, Mg, Ca, CaCO3, gypsum (CaSO4), pH, Sodium Adsorption Ratio (SAR), Exchangeable Sodium Percentage (ESP) were analyzed. The dominant soil texture was silty-clay-loam. Bulk density varied from 1.1 to 1.31 g/cm3. High SOC content was observed in 0-30 cm. The soil pH ranged from 7.1 to 8.6. The electrical conductivity shows indirect relationship with soil depth while CaCO3 and CaSO4 concentrations were observed in a direct relationship with depth. About 41% are non-saline, 38.31% saline, 15.23% saline-sodic and 5.46% sodic soils. Na concentration in saline soils was greater than Ca and Mg in all the soil depths. Ca and Mg contents were higher above 60 cm soil depth in non-saline soils. The concentrations of SO2-4 and HCO-3 were observed to be higher at the most lower depth than upper. SAR value tends to be higher at lower depths in saline and saline-sodic soils, but decreases at lower depth of the non-saline soils. The distribution of ESP above 60 cm depth was in an increasing order in saline and saline-sodic soils. The result of the research has shown the direction to which extent of salinity we should consider for the Commiphora plant species we want to grow on the area.
Abstract: Groundwater is main source of water supply in the Guanzhong Basin, China. To investigate the quality of groundwater for agricultural purposes in Jiaokou Irrigation District located in the east of the Guanzhong Basin, 141 groundwater samples were collected for analysis of major ions (K+, Na+, Mg2+, Ca2+, SO42-, Cl-, HCO3-, and CO32-), pH, and total dissolved solids (TDS). Sodium percentage (Na%), residual sodium carbonate (RSC), magnesium hazard (MH), and potential salinity (PS) were applied for irrigation water quality assessment. In addition, multivariate statistical techniques were used to identify the underlying hydrogeochemical processes. Results show that the content of TDS mainly depends on Cl-, Na+, Mg2+, and SO42-, and the HCO3- content is generally high except for the eastern sand area. These are responsible for complex hydrogeochemical processes, such as dissolution of carbonate minerals (dolomite and calcite), gypsum, halite, and silicate minerals, the cation exchange, as well as evaporation and concentration. The average evaluation levels of Na%, RSC, MH, and PS for irrigation water quality are doubtful, good, unsuitable, and injurious to unsatisfactory, respectively. Therefore, it is necessary for decision makers to comprehensively consider the indicators and thus reasonably evaluate the irrigation water quality.
Abstract: The work on indigenous binders in this paper focused on the following indigenous raw materials: red clay, red lava and pumice (as primary aluminosilicate precursors), wood ash and gypsum (as supplementary minerals), and sodium sulfate and lime (as alkali activators). The experimental methods used for evaluation of these indigenous raw materials included laser granulometry, x-ray fluorescence (XRF) spectroscopy, and chemical reactivity. Formulations were devised for transforming these raw materials into alkali aluminosilicate-based hydraulic cements. These formulations were processed into hydraulic cements via simple heating and milling actions to render thermal activation, mechanochemical and size reduction effects. The resulting hydraulic cements were subjected to laser granulometry, heat of hydration and reactivity tests. These cements were also used to prepare mortar mixtures, which were evaluated via performance of compressive strength tests. The measured values of strength were correlated with the reactivity, size distribution and microstructural features of raw materials. Some of the indigenous hydraulic cements produced in this reporting period yielded viable levels of compressive strength. The correlation trends established in this work are being evaluated for development of simple and thorough methods of qualifying indigenous raw materials for use in production of indigenous hydraulic cements.
Abstract: Many of thermosetting resins have application only in filled state, reinforced with different mineral fillers. The co-filling of polymers with mineral filler and gases creates a possibility for production of polymer composites materials with low density. This processing leads to forming of new materials – gas-filled plastics (polymer foams). The properties of these materials are determined mainly by the shape and size of internal structural elements (pores). The interactions on the phase boundaries have influence on the materials properties too. In the present work, the gas-filled urea-formaldehyde resins were reinforced by waste phosphogypsum. The waste phosphogypsum (CaSO4.2H2O) is a solid by-product in wet phosphoric acid production processes. The values of the interactions polymer-filler were increased by using two modifying agents: polyvinyl acetate for polymer matrix and sodium metasilicate for filler. Technological methods for gas-filling and recipes of urea-formaldehyde based materials with apparent density 20-120 kg/m3 were developed. The heat conductivity of the samples is between 0.024 and 0.029 W/moK. Tensile analyses were carried out at 10 and 50% deformation and show values 0.01-0.14 MPa and 0.01-0.09 MPa, respectively. The apparent density of obtained materials is between 20 and 92 kg/m3. The changes in the tensile properties and density of these materials according to sodium metasilicate content were studied too. The mechanism of phosphogypsum adsorption modification was studied using methods of FT-IR spectroscopy. The structure of the gas-filled urea-formaldehyde resins was described by results of electron scanning microscopy at three different magnification ratios – x50, x150 and x 500. The aim of present work is to study the possibility of the usage of phosphogypsum as mineral filler for urea-formaldehyde resins and development of a technology for the production of gas-filled reinforced polymer composite materials. The structure and the properties of obtained composite materials are suitable for thermal and sound insulation applications.
Abstract: With its arid climate, Qatar experiences low annual rainfall, intense storms, and high evaporation rates. However, the fast-paced rate of infrastructure development in the capital city of Doha has led to recurring instances of surface water flooding as well as rising groundwater levels. Public Work Authority (PWA/ASHGHAL) has implemented an approach to collect and discharge the flood water into a) positive gravity systems; b) Emergency Flooding Area (EFA) – Evaporation, Infiltration or Storage off-site using tankers; and c) Discharge to deep injection wells. As part of the flood prevention scheme, 21 deep injection wells have been constructed to discharge the collected surface and groundwater table in Doha city. These injection wells function as an alternative in localities that do not possess either positive gravity systems or downstream networks that can accommodate additional loads. These injection wells are 400-m deep and are constructed in a complex karstic subsurface condition with large cavities. The injection well system will discharge collected groundwater and storm surface runoff into the permeable Umm Er Radhuma Formation, which is an aquifer present throughout the Persian Gulf Region. The Umm Er Radhuma formation contains saline water that is not being used for water supply. The injection zone is separated by an impervious gypsum formation which acts as a barrier between upper and lower aquifer. State of the art drilling, grouting, and geophysical techniques have been implemented in construction of the wells to assure that the shallow aquifer would not be contaminated and impacted by injected water. Injection and pumping tests were performed to evaluate injection well functionality (injectability). The results of these tests indicated that majority of the wells can accept injection rate of 200 to 300 m3 /h (56 to 83 l/s) under gravity with average value of 250 m3 /h (70 l/s) compared to design value of 50 l/s. This paper presents design and construction process and issues associated with these injection wells, performing injection/pumping tests to determine capacity and effectiveness of the injection wells, the detailed design of collection system and conveying system into the injection wells, and the operation and maintenance process. This system is completed now and is under operation, and therefore, construction of injection wells is an effective option for flood control.
Abstract: Architecture in Iran has a continuous history from at least 5000 BC to the present, and numerous Iranian pre-Islamic elements have contributed significantly to the formation of Islamic art. At first, decoration was limited to small objects and containers and then progressed in the art of plaster and brickwork. They later applied in architecture as well. The art of gypsum and brickwork, which was prevalent in the form of motifs (animals and plants) in pre-Islam, was used in the aftermath of Islam with the art of calligraphy in decorations. The splendor and beauty of Iranian architecture, especially during the Islamic era, are related to decoration and design. After the invasion of Iran by the Arabs and the introduction of Islam to Iran, the arrival of the Iranian classical architecture significantly changed, and we saw the Arabic calligraphy decoration of the mosques in Iran. The principles of aesthetics in the art of calligraphy in Iran are based precisely on the principles of the beauty of ancient Iranian and Islamic art. On the other hand, after Islam, calligraphy was one of the most important sources of Islamic art in Islam and one of the important features of Islamic culture. First, the calligraphy had no cultural meaning and was only for decoration and beautification, it had the same meaning only in the inscriptions; however, over time, it became meaningful. This article provides a summary of the history of calligraphy in the mosques (from the entrance to Islam until the Safavid period), which cannot ignore the role of the calligraphy in their decorative ideas; and also, the important role that decorative elements play in creating a public space in terms of social and aesthetic performance. This study was conducted using library studies and field studies. The purpose of this study is to show the characteristics of architecture and art of decorations in Iran, especially in the mosque's architecture, which reaches the pinnacle of progress. We will see that religious beliefs and artistic practices are merging and trying to bring a single concept.
Abstract: In this study, the mechanical model of various anchors embedded in gypsum board subjected cyclic shear loading were investigated. Shear tests for anchors embedded in 200 mm square size gypsum board were conducted to measure the load - load displacement curves. The strength of the gypsum board was changed for three conditions and 12 kinds of anchors were selected which were ordinary used for gypsum board anchoring. The loading conditions were a monotonous loading and a cyclic loading controlled by a servo-controlled hydraulic loading system to achieve accurate measurement. The fracture energy for each of the anchors was estimated by the analysis of consumed energy calculated by the load - load displacement curve. The effect of the strength of gypsum board and the types of anchors on the shear properties of gypsum board anchors was cleared. A numerical model to predict the load-unload curve of shear deformation of gypsum board anchors caused by such as the earthquake load was proposed and the validity on the model was proved.
Abstract: The objective of this research is to study the physical and mechanical properties and durability of self-compacting mortars prepared by substituting a part of cement up to a percentage of 30% pozzolan according to different Blaine specific surface area (SSB1=7000 cm2/g and SSB=9000 cm2/g)). Order to evaluate durability, mortars were subjected to chemical attacks in various aggressive environments, a solution of a mixture of nitric acid and ammonium nitrate (HNO3 + NH4NO3) and a magnesium sulfate salt solution (MgSO4)) with a concentration of 10%, for a period of one month. This study is complemented by a comparative study of the durability of mortars elaborated with sulphate resistant cement (SRC). The results show that these mortars develop long-term, mechanical and chemical resistance better than mortars based Portland cement with 5% gypsum (CEM 1) and SRC. We found that the mass losses are lowest in mortars elaborated with pozzolanic cement (30% substitution with SSB2) in both of chemical attack solutions (3.28% in the solution acid and 1.16% in the salt solution) and the compressive strength gains of 14.68% and 8.5% respectively in the two media. This is due to the action of pozzolan which fixes portlandite to form hydrated calcium silicate (CSH) from the hydration of tricalcic silicate (C3S).
Abstract: This study investigated the differences in the objective parameters of sound depending on the changes in the lengths of the lateral surfaces of a space and on the replacement of the sound absorbers that are placed on these surfaces. To this end, three models of room were chosen. The widths and heights of these rooms were the same but the lengths of the rooms were changed. The smallest room was 8 m. wide and 10 m. long. The lengths of the other two rooms were 15 m. and 20 m. For each model, the differences in the objective parameters of sound were determined by keeping all the material in the space intact and by changing only the positions of the sound absorbers that were placed on the walls. The sound absorbers that were used on the walls were of two different sizes. The sound absorbers that were placed on the walls were 4 m and 8 m. long and story-height (3 m.). In all model room types, the sound absorbers were placed on the long walls in three different ways: at the end of the long walls where the long walls meet the front wall; at the end of the long walls where the long walls meet the back wall; and in the middle part of the long walls. Except for the specially placed sound absorbers, the ground, wall and ceiling surfaces were covered with three different materials. There were no constructional elements such as doors and windows on the walls. On the surfaces, the materials specified in the Odeon 10 material library were used as coating material. Linoleum was used as flooring material, painted plaster as wall coating material and gypsum boards as ceiling covering (2 layers with a total of 32 mm. thickness). These were preferred due to the fact that they are the commonly used materials for these purposes. This study investigated the differences in the objective parameters of sound depending on the changes in the lengths of the lateral surfaces of a space and on the replacement of the sound absorbers that are placed on these surfaces. To this end, three models of room were chosen. The widths and heights of these rooms were the same but the lengths of the rooms were changed. The smallest room was 8 m. wide and 10 m. long. The lengths of the other two rooms were 15 m. and 20 m. For each model, the differences in the objective parameters of sound were determined by keeping all the material in the space intact and by changing only the positions of the sound absorbers that were placed on the walls. The sound absorbers that were used on the walls were of two different sizes. The sound absorbers that were placed on the walls were 4 m and 8 m. long and story-height (3 m.). In all model room types, the sound absorbers were placed on the long walls in three different ways: at the end of the long walls where the long walls meet the front wall; at the end of the long walls where the long walls meet the back wall; and in the middle part of the long walls. Except for the specially placed sound absorbers, the ground, wall and ceiling surfaces were covered with three different materials. There were no constructional elements such as doors and windows on the walls. On the surfaces, the materials specified in the Odeon 10 material library were used as coating material. Linoleum was used as flooring material, painted plaster as wall coating material and gypsum boards as ceiling covering (2 layers with a total of 32 mm. thickness). These were preferred due to the fact that they are the commonly used materials for these purposes.
Abstract: Flue gas desulfurization gypsum (FGD) is a waste
material arouse from coal power plants. Hydroxyapatite (HAP) is a
biomaterial with porous structure. In this study, FGD gypsum which
retrieved from coal power plant in Turkey was characterized and
HAP particles which can be used as an adsorbent in wastewater
treatment application were synthesized from the FGD gypsum. The
raw materials are characterized by using X Ray Diffraction (XRD)
and Fourier transform infrared spectroscopy (FT-IR) techniques and
produced HAP are characterized by using XRD. As a result, HAP
particles were synthesized at the molar ratio of 5:10, 5:15, 5:20, 5:24,
at room temperature, in alkaline medium (pH=11) and in 1 hour-reaction
time. Among these conditions, 5:20 had the best result.
Abstract: A number of studies have been conducted recently to
investigate the influence of randomly oriented fibers on some
engineering properties of cohesive and cohesionless soils. However,
few studies have been carried out on freezing-thawing behavior of
fine-grained soils modified with discrete fiber inclusions and additive
materials. This experimental study was performed to investigate the
effect of randomly distributed polypropylene fibers (PP) and some
additive materials [e.g.., borogypsum (BG), fly ash (FA) and cement
(C)] on freezing-thawing durability (mass losses) of a fine-grained
soil for 6, 12, and 18 cycles. The Taguchi method was applied to the
experiments and a standard L9 orthogonal array (OA) with four
factors and three levels were chosen. A series of freezing-thawing
tests were conducted on each specimen. 0-20% BG, 0-20% FA, 0-
0.25% PP and 0-3% of C by total dry weight of mixture were used in
the preparation of specimens. Experimental results showed that the
most effective materials for the freezing-thawing durability (mass
losses) of the samples were borogypsum and fly ash. The values of
mass losses for 6, 12 and 18 cycles in optimum conditions were
16.1%, 5.1% and 3.6%, respectively.
Abstract: In this study, the feasibility of incorporating ceramic
waste from bricks (perforated brick and double hollow brick) and
extruded polystyrene (XPS) waste, is analysed.
Results show that it is possible to incorporate up to 25% of
ceramic waste and 4% of XPS waste over the weight of gypsum in a
gypsum matrix. Furthermore, with the addition of ceramic waste an
8% of surface hardness increase and a 25% of capillary water
absorption reduction can be obtained. On the other hand, with the
addition of XPS, a 26% reduction of density and a 37% improvement
of thermal conductivity can be obtained.
The obtained results are favorable to use these materials in order to
produce prefabricated gypsum and also as material for interior
cladding walls.
Abstract: An innovative flooring underlayment was produced
and tested. The composite system is made of common OSB boards
and a layer of eco-friendly non-cement gypsum based material
(GeoGypTM). It was found that the shear bond between the two
materials is sufficient to secure the composite interaction between the
two. The very high compressive strength and relatively high tensile
strength of the non-cement based component together with its high
modulus of elasticity provides enough strength and stiffness for the
composite product to cover wider spacing between the joists. The
initial findings of this study indicate that with joist spacing as wide as
800 mm, the flooring system provides enough strength without
compromising the serviceability requirements of the building codes.
Abstract: Gypsum (CaSO4.2H2O) is a mineral that is found in
large quantities in the Turkey and in the World. In this study, the
dissolution of this mineral in the diammonium hydrogen phosphate
solutions has been studied. The dissolution and dissolution kinetics of
gypsum in diammonium hydrogen phosphate solutions will be useful
for evaluating of solid wastes containing gypsum. Parameters such as
diammonium hydrogen phosphate concentration, temperature and
stirring speed affecting on the dissolution rate of the gypsum in
diammonium hydrogen phosphate solutions were investigated. In
experimental studies have researched effectiveness of the selected
parameters. The dissolution of gypsum were examined in two parts at
low and high temperatures. The experimental results were
successfully correlated by linear regression using Statistica program.
Dissolution curves were evaluated shrinking core models for solidfluid
systems. The activation energy was found to be 34.58 kJ/mol
and 44.45 kJ/mol for the low and the high temperatures. The
dissolution of gypsum was controlled by chemical reaction both low
temperatures and high temperatures.
Abstract: The thermal behavior of a large-scale, phase change material (PCM) enhanced building envelope system was studied in regard to the need for pre-fabricated construction in subtropical regions. The proposed large-scale envelope consists of a reinforced aluminum skin, insulation core, phase change material and reinforced gypsum board. The PCM impact on an energy efficiency of an enveloped room was resolved by validation of the EnergyPlus numerical scheme and optimization of a smart material location in the core. The PCM location was optimized by a minimization method of a cooling energy demand. It has been shown that there is good agreement between the test and simulation results. The optimal location of the PCM layer in Hong Kong summer conditions has been then recomputed for core thicknesses of 40, 60 and 80 mm. A non-dimensional value of the optimal PCM location was obtained to be same for all the studied cases and the considered external and internal conditions.
Abstract: This paper involved the performance of a hightemperature
X-Ray powder diffraction analysis (XRD) of a sample of
chemical gypsum generated in the production of titanium white; this
gypsum originates by neutralizing highly acidic water with limestone
suspension. Specifically, it was gypsum formed in the first stage of
neutralization when the resulting material contains, apart from
gypsum, a number of waste products resulting from the
decomposition of ilmenite by sulphuric acid. So it can be described as
red titanogypsum. By conducting the experiment using XRD
apparatus Bruker D8 Advance with a Cu anode (λkα=1.54184 Å)
equipped with high-temperature chamber Anton Paar HTK 16, it was
possible to identify clearly in the sample each phase transition in the
system of CaSO4·xH2O.
Abstract: Boron-gypsum is a waste which occurs in the boric
acid production process. In this study, the boron content of this waste
is evaluated for the use in synthesis of magnesium borates and such
evaluation of this kind of waste is useful more than storage or
disposal. Magnesium borates, which are a sub-class of boron
minerals, are useful additive materials for the industries due to their
remarkable thermal and mechanical properties. Magnesium borates
were obtained hydrothermally at different temperatures. Novelty of
this study is the search of the solution density effects to magnesium
borate synthesis process for the increasing the possibility of borongypsum
usage as a raw material. After the synthesis process, products
are subjected to XRD and FT-IR to identify and characterize their
crystal structure, respectively.
Abstract: Gypsum is being applied to ameliorate subsoil acidity and to overcome the problem of very slow lime movement from surface lime applications. Reduced Crude Conversion Spent Lime (RCCSL) containing anhydrite was evaluated for use as a liming material with specific consideration given to the movement of sulfate into the acid subsoil. Agricultural lime and RCCSL were applied at 0, 0.5, 1.0, and 1.5 times the lime requirement of 6.72 Mg ha-1 to an acid Trappist silt loam (TypicHapuldult). Corn [Zea mays (L.)]was grown following lime material application and soybean [Glycine max (L.) Merr.]was grown in the second year.Soil pH increased rapidly with the addition of the RCCSL material. Over time there was no difference in soil pH between the materials but there was with increasing rate. None of the observed changes in plant nutrient concentration had an impact on yield. Grain yield was higher for the RCCSL amended treatments in the first year but not in the second. There was a significant increase in soybean grain yield from the full lime requirement treatments over no lime.
Abstract: The protection of groundwater resources is the great
important many semiarid and arid environments. Baghan watershed
is located in the north of Kangan in the Boshehr province in Iran. The
groundwater resources have a vital role in supplying agricultural,
drinking, domestic and industrial water demand in Baghan
watershed. For our investigation into the water quality we collected
30 samples to chemical and physical analysis. The result showed the
marl and evaporation deposits that contain anhydrite and gypsum is
the main source of groundwater pollution, and one part of the
groundwater was polluted by oil and gas industrial. Another part of
the groundwater was contaminated by urban waste water. The
electrical conductivity and captions and anions increased around of
towns and gas refinery. Although the negative impact of untreated
domestic wastewater is relatively low but the results showed strongly
the negative impact of wastewater refinery is very considerable. This
negative impact increased in downstream due to shallow aquifer.
Additionally, the agents that adversely affect the quality of
groundwater come from a variety of sources, including geology,
domestic wastewater and the Jam refinery in Baghan watershed.
Abstract: In the present work the internal sulfate attack on
pastes made from pure clinker phases was studied. Two binders were
produced: (a) a binder with 2% C3A and 18% C4AF content; (b) a
binder with 10% C3A and C4AF content each. Gypsum was used as
the sulfate bearing compound, while calcium carbonate added to
differentiate the binders produced. The phases formed were identified
by XRD analysis. The results showed that ettringite was the
deterioration phase detected in the case of the low C3A content
binder. Carbonation occurred in the specimen without calcium
carbonate addition, while portlandite was observed in the one
containing calcium carbonate. In the case of the high C3A content
binder, traces of thaumasite were detected when calcium carbonate
was not incorporated in the binder. A solid solution of thaumasite and
ettringite was found when calcium carbonate was added. The amount
of C3A had not fully reacted with sulfates, since its corresponding
peaks were detected.