Effects of sewage sludge on heavy metal accumulation in soil and plants and on crop productivity in Aleppo governorate

Sewage sludgeHeavy metalsCrop productionCropsOrganic matterSoil

USE OF DRILL CUTTINGS ASH AS STABILISING AGENT FOR SELECTED NIGER DELTA SOILS FOR ROAD CONSTRUCTION

his study investigated potential of the use of Drill Cuttings Ash (DCA) in the stabilisation of Niger Delta soils for road construction. Most of the in-situ soils encountered in the region are fine-grained and highly plastic that would require special treatment. Four soil samples were obtained and the following tests were carried out: classification, compaction, California Bearing Ratio (CBR), and Unconfined Compressive strength (UCS). Dry DCA quantities ranging 2 – 8 percentages by weight of the soil was added to the air-dried soils for the stabilisation process. They were classified as A-6 (clayey soil), A-2-6 (clayey sand), A-3 (silty fine sand), and A-4 (silty clay soil). Generically, the unstabilised soils were fine-grained having low to medium plasticity, with low shear strength. Other results showed that 6% DCA content caused improvement in the texture, plasticity, and dry density of the clayey soil, while its CBR and UCS parameters compared favourably well with the unstabilised soil values. Also, there was increase in CBR value of the clayey soil after soaking for 24 hours. DCA increased the plasticity of the clayey sand, silty fine sand, and silty clay soil, and there was no substantial improvement in their strength properties. These results showed that DCA would be useful in improving clayey soilswhich are known to be prone to excessive swelling and difficult to handle during construction especially after heavy rainfall.     &nbsp

Deformation and mechanical properties of the expansive cements produced by inter-grinding cement clinker and MgOs with various reactivities

Magnesia (MgO) either intrinsically contained in cement clinker or prepared separately as expansive additive has been used to compensate for the shrinkage of cementitious materials. In this study, for improving the homogenous distribution of MgOs, the cement clinker was inter-ground with MgO expansive additives with various reactivities ranging from 50 to 400 s to prepare series of expansive Portland cements and blended cements with incorporation of slag and fly ash. The deformations and mechanical properties of the expansive cements were investigated. Results showed that the expansive cements containing more reactive MgOs produced more rapid expansion under sealed condition or water curing, leading to effective autogenous shrinkage compensations at early age. The reactivities of MgOs caused insignificant influences on the mechanical strengths of expansive cements. The blended cements had lower strengths at early age but higher strengths than that of the corresponding Portland cements at late age due to the pozzolanic reaction.The financial support from the Royal Academy of Engineering UK/China, India Exchange, The National Key Technology R&D Program (2011BAE27B01-1), Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and National Natural Science Foundation of China (51461135003) are acknowledged.This is the accepted manuscript. The final version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0950061815000914#

Improving discrete particle packing models for the microstructural formation simulation of Portland cement

Improving discrete particle packing models for the microstructural formation simulation of Portland cemen

Comparative Analysis of Cement and Lateralite on the Engineering Properties of Niger Delta Soils for Pavement Construction

This is the final published version. It first appeared at http://sciencedomain.org/abstract/9224.This study investigated the effect of cement and lateralite in improving some engineering properties of Niger Delta soils, classified as clayey soil, silty/clayey sand, and fine sand. Cement had very good effect in reducing the plasticity of the clayey soil and the silty/clayey sand but increased the plasticity of the fine sand, and all the samples had increased soaked CBR and UCS at 28 days especially with 6% and 8% cement contents. 14% lateralite content had the best effect on the silty/clayey sand in reducing the plasticity and increasing both the CBR and UCS. However, no positive effect on the plasticity indices was noticed for the clayey soil and the fine sand, but appreciable increases in their unsoaked and soaked CBR and UCS at 28 days curing. The applications of cement (6% and 8%) and 14% lateralite would make the stabilized soils applicable as sub-base and base materials.The sponsorship of the PhD program of the first author by Schlumberger Faculty for the Future Foundation at the University of Cambridge, United Kingdom and the funding by Cambridge- Africa Alborada Scheme of this study which formed part of the PhD research are acknowledged

Deformation and mechanical properties of quaternary blended cements containing ground granulated blast furnace slag, fly ash and magnesia

Shrinkages of cementitious materials may lead to cracking under restrained conditions. This study was motivated to develop non-shrinkage quaternary blended cements through blending slag and fly ash with Portland cement containing reactive MgO. The hydration process, autogenous shrinkage at early age, long-term volume deformation, mechanical properties, and microstructure of cement specimens were investigated. Results showed that the autogenous shrinkage of the cement pastes was effectively mitigated due to the compensation of the MgO present and the reduction of cement content owing to the partial replacements with slag and fly ash. The mechanical strengths of the blended cement mortars were lower than that of the corresponding plain Portland cement mortars at early age of 3 d, but increased significantly to be similar or higher at late ages of 28 d and 90 d. This is attributed to the microstructure densification and the interface microstructure enhancement due to the reaction of SCMs with clinker phases.The financial support from the Royal Academy of Engineering UK/China Exchange (12/13RECI013), the National Key Technology R&D Program (2011BAE27B01-1), the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and the National Natural Science Foundation of China (51461135003) is acknowledged.This is the accepted manuscript. The final published version is available from Elsevier at http://www.sciencedirect.com/science/article/pii/S0008884615000319

Positive Design: Using Design Thinking as a Creative Process for Enhancing Project Outcomes

This PDW brings together scholars and practitioners working on creativity, design thinking and strategy to explore, debate, and illustrate the ways in which design thinking is being used as a creative process to positively impact people as the beneficiaries and stakeholders of projects. The PDW is the first of a series of PDWs to be proposed at AOM over the next three years seeking to bring the design thinking and positive organizational scholarship communities together to advance knowledge, theorizing and research on how design thinking can impact projects to improve society and have a positive and sustainable impact on people, planet and profit. The workshop will be an interactive, design thinking led session and will produce micro-projects to advance the ‘positive design’ cause within the academy. This session will also be supported by the Project Management Institute (PMI) and will seek to broaden and build networks across AOM, SMS and PMI to advance creative approaches to project design with a focus on beneficiaries and stakeholders

Sequential group trial to determine gastrointestinal site of absorption and systemic exposure of azathioprine

Azathioprine (AZA) is used in the treatment of patients with refractory inflammatory bowel disease; however, its use is limited because of systemic toxicity associated with long-term use. Ileocecal delivery of AZA might be advantageous if local intestinal therapeutic effects could be provided with decreased systemic side effects. Decreased cecal systemic absorption would allow higher dosages of AZA to be administered. A two-phase study was performed to compare the systemic exposure of AZA and 6-mercaptopurine (6-MP) following administration of AZA into the stomach, jejunum, and cecum and to compare the systemic exposure to AZA and 6-MP following administration of three different dosages of AZA into the cecum. In phase I, six healthy male volunteers received three 50 mg sequential doses of AZA via an oral tube directly placed into the stomach, jejunum, and cecum, respectively. In phase II, six healthy male volunteers received three different dosages (50, 300, 600 mg of AZA) into the cecum. Plasma concentrations of AZA and 6-MP at various times were quantified and area under the plasma concentration-time curve (AUC) and mean residence time (MRT) were determined. No significant differences in the AUC of AZA were seen at the different sites. The AUC of 6-MP following administration of AZA into the jejunum (67.0 ± 30.1 ng × hr/ml) was higher compared to the stomach (39.9 ± 38.1 ng/hr/ml) and cecum (29.2 ± 10.9 ng × hr/ml). Jejunal absorption was 68% higher than absorption from the stomach and 129% higher than that of the cecum. Gastric absorption was 27% higher than that of the cecum. Increased dosages given into the cecum resulted in increased AUCs of AZA and 6-MP. The AUCs of AZA following 50, 300, and 600 mg dosages were 16.9 ± 7.4, 52.3 ± 67.2, and 132 ± 151 ng × hr/ml, respectively, and the AUCs of 6-MP were 22.2 ± 14.9, 63.4 ± 50.6, and 104 ± 115 ng × hr/ml, respectively. Systemic exposure to 6-MP is reduced following administration of AZA into the cecum, most likely secondary to reduced absorption of 6-MP from the colon. Higher dosages of AZA presented to the cecum do result in increased systemic absorption, but may still allow more drug to be administered with less toxicity than the same dose received orally

A statistical investigation of the rheological properties of magnesium phosphate cement

Magnesium phosphate cement (MPC) is a promising material applied for rapid patch repairing in civil engineering and waste immobilisation in nuclear industry. However, the rheological properties of this new binder material which highly affects its engineering application, is to be explored. The current work aims at investigating the rheological properties of MPC along 98 with determining the optimum conditions to obtain MPC materials with desirable rheological performances. The Response Surface Methodology (RSM) accompanied by Central Composite Design (CCD) were adopted to establish mathematical model describing the rheological characteristics of MPC in terms of yield stress (Pa) and plastic viscosity (Pa.s), as a function of three independent variables namely W/S ratio, M/P ratio and Borax dosage. The analysis of variance (ANOVA) was also conducted to assess the significance and adequacy of the regression models attained. The results showed that the M/P ratio and Borax dosage could affect significantly the yield stress of MPC, while W/S ratio was the significant coefficient influencing the plastic viscosity. The numerical optimised values of the W/S ratio, M/P ratio and Borax dosage were 0.25, 8.97 and 0.17 respectively, and a MPC paste with desirable rheological characteristics (yield stress of 0.40 Pa and plastic viscosity of 0.93 Pa.s) can be obtained. Further experiments will be carried out to verify the predicted optimum conditions and study the interactions between the factors in relation to the responses

Analysis of genetic diversity and differentiation of sheep populations in Jordan

Background: Genetic diversity of sheep in Jordan was investigated using microsatellite markers (MS). Six ovine and bovine MS located on chromosomes 2 and 6 of sheep genome were genotyped on 294 individual from ten geographical regions. Results: The number of alleles per locus (A), the expected heterozygosity (He) and observed heterozygosity (Ho) were measured. Overall A, He and Ho were 12.67, 0.820 and 0.684, respectively. On the other hand, genetic distances undoubtedly revealed the expected degree of differentiation among the studied populations. The finding showed closeness of three populations fromsouth (Maan, Showbak and Tafeilah) to each other. Populations from themiddle regions of Jordan (Karak, Madaba, Amman, AzZarqa and Mafraq) were found to be in one cluster. Only two populations of the middle region were an exception: AlSalt and Dead Sea. Finally, sheep populations from Irbid were located in separated cluster. It was clear that the studied predefined populations were subdivided from four populations and would be most probably accounted as ancestral populations. These results indicate that number of population is less than the predefined population as ten based on geographical sampling areas. Conclusions: The possible inference might be that geographical location, genetic migration, similar selection forces, and common ancestor account for population admixture and subdivision of Awassi sheep breed in Jordan. Finally, the present study sheds new light on themolecular and population genetics of Awassi sheep fromdifferent regions of Jordan and to utilize the possible findings for future management of genetic conservation under conditions of climate changes and crossbreeding policy