Beam-to-column end-plate joints can be classified as rigid (fully restrained), semi-rigid (partiallyrestrained) or pinned, depending on their type, configuration and the connector arrangement. Fullyrestrained joints are needed for rigid frames in which there is assumed that the frame joints havesufficient rigidity to maintain – under the service state – the angles between the intersecting mem-bers, ensuring the full moment transfer. In contrast in semi-continuous frames, partially restrainedjoints are characterized by relative rotations occurring between the intersecting members so thatthe bending moment can only be transferred partially. In recent years, the idea of using partiallyrestrained, unstiffened joints in building structures has gained momentum since this idea appearsto be more practical and economical. Semi-continuous frames can resist actions by the bendingmoment transfer in partially restrained joints, allowing in the same time for a certain degree ofrotation that enhances the overall ductile performance of these structures. One of the effective waysthat affects ductility of end-plate beam-to-column joints is to use thinner end-plates than those usednowadays in practical applications. In the current study, a certain class of steel-concrete compositejoints is examined in which the thickness of end-plates is to be equivalent to approximately 40-60% of the bolt diameter used in all the composite joints investigated in the considered joint class. Thispaper is an extension of the authors’ earlier investigation on numerical modelling of the behaviourof steel frame joints. The aim of current investigations is to develop as simple as possible andyet reliable three-dimensional (3D) FE model of the composite joint behaviour that is capable ofcapturing the important factors controlling the performance of steel-concrete end-plate joints inwhich the end-plate thickness is chosen to be lesser than that used nowadays in conventional jointdetailing. A 3D FE model constructed for composite joints of the considered joint class is reportedin this paper and numerical simulations using the ABAQUS computer code are validated againstexperimental investigations conducted at the Warsaw University of Technology. Comparison betwe-en the nonlinear FE analysis and full scale experimental results of the considered class of compositejoints is presented which conclusively allows for the accuracy assessment of the modelling tech-nique developed. Comparison between the FE results and test data shows a reasonable agreementbetween the numerical FE model developed and physical model of experimentally examined jointspecimens. Finally, practical conclusions for engineering applications are drawn.

Allelopathy is a complex phenomenon which depends on allelochemical concentrations. So, two pot experiments were carried out to investigate the allelopathic effect of alcoholic fresh shoot extract of Eruca sativa (foliar spray) and E. sativa shoot powder (mixed with soil) on Pisum sativum plants and two associated weeds, Phalaris minor and Beta vulgaris. The experiments were conducted in the greenhouse of the National Research Centre, Giza, Egypt during two successive winter seasons (2016–2017 and 2017–2018). Ten treatments were applied in this study. Four treatments were applied before sowing, that E. sativa shoot powder was mixed with the soil at rates of 15, 30, 45 and 60 g ⋅ pot–1. The other four treatments of E. sativa alcoholic fresh shoot extract were sprayed twice on both plants and weeds at 5, 10, 15 and 20% (w/v) concentrations. Additionally, two untreated treatments, healthy (P. sativum only) and unweeded (untreated infested P. sativum plants with weeds) were applied for comparison. The results indicated that both alcoholic extracts and powder reduced growth of both weeds. Moreover, there was a direct relationship between concentration and weed reduction. Eruca sativa alcoholic extracts increased yield parameters of P. sativum plants. The maximum yield attributes were recorded by spraying of E. sativa alcoholic extract at 20%. On the other hand, it was clearly noticed that the high powder rates affected negatively P. sativum yield parameters. But the lowest powder rate (15 g ⋅ pot–1) stimulated P. sativum yield parameters as compared to unweeded treatment. Chemical analysis of E. sativa shoot powder ensured that the abundant amount of glucosinolates (9.6 μmol ⋅ g–1) and phenolic compounds (46.5 mg ⋅ g–1) may be responsible for its allelopathic effect. In conclusion, spraying of alcoholic fresh shoot extract of E. sativa at 20% (w/v) and mixing E. sativa shoot powder at 15 g · pot–1can be applied as natural bioherbicides for controlling weeds.

Tetranychus urticae (Acari: Tetranychidae) infesting many plants but Mentha viridis L., and Mentha piperita L., were low in number of infestation. Therefore the objective of this study was to identify the resistance of M. viridis and M. piperita plants against T. urticae by studying the external shape and internal contents of those plants. For morphological studies, dried leaves were covered with gold utilizing an Edwards Scan coat six sputter-coater. For histological studies, arrangements of Soft Tissue technique were used. For phytochemical studies, the plants were cut, dried and then high performance liquid chromatography (HPLC) was used. While feeding the mites were collected from the area between oily glands, trichomes and respiratory stomata in both mint species. The most important leaf structures in aromatic plants are the oily glands found on the external part of the leaves (both upper and lower epidermis). The number of oil glands in M. viridis leaves was greater than in M. piperita; the trichomes on the epidermis of M. viridis were greater in number than in M. piperita; the spongy mesophyll in M. viridis was much thicker than in M. piperita. The essential oils in the leaves of both mint species contained 71 compounds representing 99.61% of the total oil constituents identified from M. viridis before infestation, and 90.95% after infestation, and about 99.65% from M. piperita before infestation, and 99.98% after infestation.

The effect of multiple Rushton impellers configurations on hydrodynamics and mixing performance in a stirred tank has been investigated. Three configurations defined by one, two and three Rushton impellers are compared. Results issued from our computational fluid dynamics (CFD) code are presented here concerning fields of velocity components and viscous dissipation rate. These results confirm that the multi-impellers systems are necessary to decrease the weaken zones in each stirred tanks. The experimental results developed in this work are compared with our numerical results. The good agreement validates the numerical method.