In order to promote sustainable steel-concrete composite structures, special shear connectors that can facilitate deconstruction are needed. A lockbolt demountable shear connector (LB-DSC), including a grout-filled steel tube embedded in the concrete slab and fastened to a geometrically compatible partial-thread bolt, which is bolted on the steel section's top flange of a composite beam, was proposed. The main drawback of previous similar demountable bolts is the sudden slip of the bolt inside its hole. This bolt has a locked conical seat lug that is secured inside a predrilled compatible counter-sunk hole in the steel section's flange to provide a non-slip bolt-flange connection. Deconstruction is achieved by demounting the tube from the top of the slab by unfastening using a simple modified wrench. The mechanical behaviour of the proposed connector is assessed by four pushout tests that were conducted per Eurocode 4 recommendations. The tests showed high shear resistance, and high stiffness as compared to other DSCs, while the slip capacity results classified the LB-DSC as a ductile shear connector according to Eurocode 4. A refined nonlinear finite element model (FEM) was validated through the tests and reliably reproduced the experimental behaviour. Consequently, the calibrated FEM model was applied to carry out extensive parametric analyses to investigate the strength and geometry effects of concrete slab, infilled grout, tube, and bolt on the structural behaviour of the LB-DSC. On the basis of numerical and experimental results, a design equation is derived to predict the shear resistance of the LB-DSC.
In this research, the problem of multi- objective modal transport was formulated with mixed constraints to find the optimal solution. The foggy approach of the Multi-objective Transfer Model (MOTP) was applied. There are three objectives to reduce costs to the minimum cost of transportation, administrative cost and cost of the goods. The linear membership function, the Exponential membership function, and the Hyperbolic membership function. Where the proposed model was used in the General Company for the manufacture of grain to reduce the cost of transport to the minimum and to find the best plan to transfer the product according to the restrictions imposed on the model.
This study is the first investigation in Iraq dealing with genotyping of
Epstein-Barr Virus (EBV) infection is associated with broad spectrum of clinical manifestationsdepending on the immune status of the host, To analyze their possible role in the complication ofautoimmune hepatitis, we investigated (30) female patients with autoimmune hepatitis type-1 of(10-40)years and 25 healthy female of same ages(control groups). Both groups were carried outto measure the levels of EBV-CA IgM, IgG Ab, EBV-EA IgM, IgG Ab, and EBV-NA IgM, IgGAb using indirect immunoflourescent assay (IFAT).The prevalence of EBV-CA IgM, IgG Ab were(10%,20%) and EBV-EA IgM, IgG Ab were (10% and20%) respectively, while the prevalence ofEBV-NA IgG Ab was( 3.33%) and there are no prevalence of EBV-NA IgM Ab. There weresignificant differences (P
... Show MoreAn electrocoagulation process has been used to eliminate the chemical oxygen demand (COD) from wastewaters discharged from the Al-Muthanna petroleum refinery plant. In this process, a circular aluminum bar was used as a sacrificial anode, and hallow cylinder made from stainless steel was used as a cathode in a tubular batch electrochemical Reactor. Impacts of the operating factors like current density (5-25mAcm-2), NaCl addition at concentrations (0-2g/l), and pH at values (3-11) on the COD removal efficiency were studied.
Results revealed that the increase in current density increases the COD removal efficiency, whereas an increase
The present study addresses adopting the organic and nutritious materials in dairy wastewater as media for cultivation of microalgae, which represent an important source of renewable energy. This study was carried out through cultivation of three types of microalgae; Chlorella sp., Synechococcus, and Anabaena. The results shows the success the cultivation of the Synechococcus and Chlorella Sp, while the Anabaena microalgae were in low-growth level. The highest growth was in the Synechococcus farm, followed by Chlorella and Anabaena. However, the growth of Synechococcus required 10 days to achieve this increase that re
... Show MoreA total of (90) blood samples were collected from male patients infected with Toxoplasmosis who recovered from COVID- 19 and attended Kamal Alsamiraai Hospital from 15 January to 15 September 2021. We measured anti-Toxoplasma antibodies (IgG and IgM) detected by ELISA, whereas Anti-COVID-19 antibodies (IgG and IgM) were estimated using Elisa and Afilias. The semen characteristics were also studied among fertile, healthy individuals (control group) and sub-fertile patients. Results showed that the mean sperm count was high among the control group (40.5±1.3x 106/ml) compared with that of the sub-fertile patients (10.3±1.75 and 8.8±1.9 x 106/ml for oligozoospermia, and oligoasthenozoospermia respectively), and it was the highest (44.7±1.4
... Show MoreBackground: The prevention of the enamel demineralization at the periphery of the brackets is a significant challenge to orthodontic professionals. The aim of this clinical study was to compare the Streptococcus mutants count in the plaque surrounding two orthodontic adhesive types, Fuji Ortho LC and Enlight (Ormco). Materials and methods: A total of 13 patients (7 male and 6 female) needing fixed orthodontic appliance therapy were participated. A split mouth technique was followed with appliances bonded by two orthodontic adhesive types, Fuji Ortho LC and Enlight (Ormco). Saliva was collected before placement of appliances (T0) and again at three weeks (T1) and six weeks (T2) after placement of appliances. Plaque was collected from areas a
... Show MoreThis paper presents a method to organize memory chips when they are used to build memory systems that have word size wider than 8-bit. Most memory chips have 8-bit word size. When the memory system has to be built from several memory chips of various sizes, this method gives all possible organizations of these chips in the memory system. This paper also suggests a precise definition of the term “memory bank” that is usually used in memory systems. Finally, an illustrative design problem was taken to illustrate the presented method practically.