Bond Strength Behavior for Deformed Steel Rebar Embedded in Recycled Aggregate Concrete

This study investigated the bond strength behavior of a deformed steel bar embedded in RAC through an experimental program and numerical analysis. In the experimental work, eighteen push-out specimens were tested. The compressive strength of RAC, the recycled aggregate replacement ratio, the embedded length of the reinforcing bar, the size of the rebar, the concrete cover, and the yield stress of the reinforcing steel bar were the main parameters investigated. The effect of these parameters on bond strength, bond-slip behavior, and modes of failure are discussed. Analysis of the test results indicate that the bond strength in concrete is reduced by 13% when using a specimen constructed from recycled aggregate compared with conventional concrete. The failure modes in a reinforcing bar embedded in RAC representing splitting failure and push-out failure, were similar to those in conventional concrete. The finite element analysis presented in this study was used to analyze forty-four push-out specimens. Through numerical analysis, the bond strength of RAC was related to the 0.57 power function of compressive strength. A design equation for bond strength of reinforcing bars embedded in RAC is proposed. The proposed equation was calibrated through the numerical and experimental results.

Effect of Rootstock, Soil and Foliar Nutrition in Some Vegetative Characteristics Growth of Local Lemon Seedlings Citrus Limon L.

نفذت التجربة في الظلة الخشبية التابعة للكلية التقنية المسيب خلال الفترة من بداية شهر آذار ولغاية نهاية كانون الاول2017 على شتلات الليمون الحامض المحلي بعمر سبعة أشهر المطعمة على الأصلين البذريين النارنج والليمون الحلو لدراسة تأثير الأصلين والتغذية الأرضية بالسماد العضويTARASOIL CALCIO بتركيز(100 ,50 ,0مل.لتر-1) والتغذية الورقية بـDECSON بتركيز(0, 10, 20مل.لتر-1) لدراسة صفات النمو الخضري. تم التسميد الأرضي في 11/4 /2017 و 11 /5 /2017 و 11/9/2017  و 11/10/2017  والرش الورقي في 7/4/2017 و 7/5/2017 و 7/9/2017 و7/10/2017، طبقت التجربة بإتباع التصميم التام التعشية(C.R.D) بوصفة تجربة عاملية بثلاثة عوامل(2×3×3) وبثلاث مكررات وبثلاث شتلات لكل وحدة تجريبية و162 شتلة  في المجموع الكلي، حللت النتائج باستخدام برنامج التحليل الإحصائيExcel وقورنت المتوسطات وفق اختبار اقل فرق معنوي (L.S.D)عند مستوى احتمال0.05، كان لنوع الأصل تأثير معنوي في بعض صفات النمو الخضري لشتلات الليمون حامض المحلي إذ تفوق أصل الليمون الحلو بارتفاع النبات وعدد الأوراق ومساحة الورقة الواحدة في حين تفوق أصل النارنج معنويا بقطر الأصل وقطر الطعم. كما تفوق أصل الليمون الحلو+ 100مل.لتر-1سماد ارضي معنويا بارتفاع النبات، عدد الأوراق في حين تفوق أصل النارنج معنويا بقطر الساق، قطر الطعم، مساحة الورقة الواحدة وتفوق أصل الليمون الحلو+ 20مل.لتر-1 رش ورقي معنويا في ارتفاع النبات، عدد الأوراق، مساحة الورقة، في حين تفوق أصل النارنج معنويا في قطر الساق، قطر الطعم. واظهر التداخل(100مل.لتر-1TARASOIL CALCIO+20مل.لتر-1DECSON)تفوقا معنويا في جميع صفات  النمو الخضري وأظهرت معاملة التداخل الثلاثي(الأصل+100مل. لتر-1 سماد ارضي+ 20مل.لتر-1رش ورقي) تفوقاً معنوياً في ارتفاع النبات وقطر الطعم وعدد الأوراق ومساحة الورقة في حين تفوق أصل النارنج معنوياً بقطر الساق.      An experiment was conducted in the wooden canopy affiliated to the Technical College AL-Musaib during the period from the beginning of March until the end of December, 2017 on local lemon citron seedlings aged seven months and grafted on the two seed roots Sour orange and Sweet lemon to study the effect spray and soil fertilizers feeding of organic TARASOIL CALCIO with concentration(0, 50, 100)ml.L-1and sprays of DECSON with concentration of (0, 10, 20) ml. L-1to study the characteristics of vegetative, The soil fertilization in 11/4/2017, 11/5/2017, 11/9/2017 and  11/10/2017, foliar spray in 74//2017, 7/5/2017, 7/9/2017 and 7/10/2017, the experiment was applied by Completely Randomized Design(C.R.D)as factorial experiment(2×3×3) with three replicates and three seedling  and 162 seedlings as a total group, The results were analyzed using the statistical analysis program(Excel). The averages were compared according to the least significant difference(L.S.D)at a probability level of (0.05), The type of rootstock have a significant effect on vegetative, The rootstock of sweet lemon increased plant height, leaves the number, leaf area, while rootstock sour orange increased in the stem, Scion. Stalk of sweet lemon +100ml.L-1TARASOIL CALCIO had a suppressive  effect in plant height,  leaves number while rootstock sour orange suppressive in stock stem, Scion, leaf area, Stalk of sweet lemon +20 ml.L-1 DECSON had a suppressive effect in plant height, leaf number, leaf area while Sour crease stalk a suppressive in  main stem, Scion. sweet lemon stalk+100ml.L-1TARASOIL CALCIO+20 ml.L-1 DECSON had a suppressed in plant height, Scion, leaf number, leaf area, while stalk the orange had a suppressive effect in a stock stem

Compression Splices of Reinforcing Bars in Reactive Powder Concrete

Compression splices are widely used in compression members such as columns in multi- story buildings. There are efficient design equations for compression splice of reinforcement embedded in conventional concrete proposed by design codes of practice. However, there is no design equation for compression splice in compression members made of reactive powder concrete (RPC). So, it is required to introduce a design equation to calculate the steel bars lap splice length of RPC compression members. In this study, an experimental work was conducted to investigate the effect of different variables on compression splices strength. These variables were compressive strength of concrete, transverse reinforcement amount, splice length, yield stress of reinforcement and spliced rebar diameter. The experimental results showed that; Increase in the yield stress of reinforcing bars, length of spliced bars and compressive strength of concrete result in increasing in splice strength. Meanwhile, increase in diameter of reinforcing bars result in decreasing in compression splice strength. The increase in the amount of transverse reinforcement has insignificant effect on compression spliced strength of rebar. Finite element analysis was used to analyze the tested specimens and compared between numerical and experimental result was carried out. The numerical and experimental ultimate load and load-deflection behavior is very close to each other. Finite element method was used to investigate a wide range of experimental variables values through a parametric analysis. A new proposing equation for compression splicing of rebar in RPC column is presented in this research

Optical and structure Characteristics of diamond like-carbon thin films produced by PLD.

تم استخدام ليزرND: YAG الطول الموجي ١٠٦٤ نانومتر  في الترسيب بالليزر النبضي  PLD لتكوين غشاء الماس شبيه الكاربون DLC على اساس زجاجي في درجة حرارة الغرفة. التركيب ومورفولوجيا السطح بالفحص بمجهر القوى الذرية  AFM لدراسة الغشاء  وتحويل فورييه لأطياف الأشعة تحت الحمراء FTIR للماس شبيه الكاربون DLC المستخدمة لمعرفة وجود الروابط وكذلك خصائص المجهر الالكتروني الماسح SEM وتشتيت الطاقة بالأشعة السينية EDX . يحتوي غشاء الماس شبيه الكاربون DLC المرسب على بنية مدمجة من الحبيبات المتراصة ويحتوي الغشاء على جسيمات غير منتظمة الشكل ( عناقيد) منDLC واكدت أطياف FTIR ان غشاء DLCيحتوي على ذرات كاربون مع تهجينsp3  وتم التحقيق في الخواص البصرية مع النتائج المتعلقة مثل النفاذية ومعامل الامتصاص وفجوة الطاقة البصرية والانعكاس R ومعامل الخمودKومعامل الانكسارn .     The utilizing of Nd: YAG laser (wave length-1064 nm) in the pulsed laser-deposition-PLD for placing diamond-like carbon DLC-film on glass substratum at the normal temperature of room. The composition and morphology of the surface for the atomic force microscopy (AFM), synthesized film and Fourier transform infrared FTIR-spectra for DLC utilized to know the presence of bonding were characterized by scanning electron microscopy-SEM and energy dispersive x-ray -EDX. Deposited DLC-film has a compact structure of dense grains, and the film contained irregular shape particles (clusters) of DLC. FTIR-spectra confirmed that the DLC-film contains carbon atoms with sp3-hybridization.Were investigated in optical properties with the results concerning the transmittance, absorption coefficient-(α), optical energy-gap, reflectance-R, extinction coefficient-k and refractive index-n

Improvement of Mechanical Welding Properties by using Induced Harmonic Vibration.

The enhancement of the welding mechanical properties and the quality of the fusion metal is considered recently by using vibration during welding. In this study, the effect of induced harmonic vibration during welding is employed to improve the welding mechanical properties and to reach the best shape of welding line on the surface. The harmonic vibration method is examined experimentally by using four values of mechanical frequency during welding on the ductility, tensile strength and the homogeneity of the welding line. The frequencies were specified according to the natural frequency of the plate. Five simply supported rectangular plates are supported on the supporting stand and welded using a manual arc-welding machine. The experimental results show that the vibration applied during welding generally improved the bend property of the welding line, as well as the tensile strength has been improved distinctively at the resonance case when compared with that one welded without vibration. The morphology of the fillet metal after welding and for each value of frequency show an enhancement in the distribution of the fusion fillet metal, with gradually disappearing of the micro crack that may shown inside the metal with increasing the mechanical frequency. A comparison between the properties of welding without vibration and welding with vibration is discussed

Prediction of Sediment Accumulation Model for Trunk Sewer Using Multiple Linear Regression and Neural Network Techniques

Sewer sediment deposition is an important aspect as it relates to several operational and environmental problems. It concerns municipalities as it affects the sewer system and contributes to sewer failure which has a catastrophic effect if happened in trunks or interceptors. Sewer rehabilitation is a costly process and complex in terms of choosing the method of rehabilitation and individual sewers to be rehabilitated.  For such a complex process, inspection techniques assist in the decision-making process; though, it may add to the total expenditure of the project as it requires special tools and trained personnel. For developing countries, Inspection could prohibit the rehabilitation proceeds. In this study, the researchers proposed an alternative method for sewer sediment accumulation calculation using predictive models harnessing multiple linear regression model (MLRM) and artificial neural network (ANN). AL-Thawra trunk sewer in Baghdad city is selected as a case study area; data from a survey done on this trunk is used in the modeling process. Results showed that MLRM is acceptable, with an adjusted coefficient of determination (adj. R2) in order of 89.55%. ANN model found to be practical with R2 of 82.3% and fit the data better throughout its range. Sensitivity analysis showed that the flow is the most influential parameter on the depth of sediment deposition

Once Upon a Microscopic Slide: The Story of Histology

For centuries, histology has maintained its remarkable place in the medical curriculum. However, its teaching has been influenced by the new technological advancement that has reshaped medicine teaching into a more modern student-friendly form. Since its inception in the 18th century, the discipline of histology has progressed hand in hand with the advancements in microscopy and microscopic technologies, including immunohistochemistry. In the traditional curriculum of USA medical schools, especially after the first Flexner’s report of 1910, histology was considered as very essential topic for a physician studying the “Art and Science” of medicine. In this era, the teaching relied more on the light microscope and to some extent on the electron microscope. However, the field nowadays, after the second Flexner’s report, which stressed the importance of integrating clinical topics in the curriculum, is shifting towards the use of more electronic resources for teaching. Such new resources rely on information technology and electronic imaging modalities which are considered to be more student-friendly, time efficient, consistent in conveying the images, promote self-learning and are less costly. In fact, in the last 25 years, most universities started relying on virtual microscopy with limited use of the light microscopy by the students. Such an approach facilitated curricular integration of histology into histopathology and provided the opportunity to promote self-learning and clinical relevance. In the era of competency-based curriculum, histology remains an essential and indispensable basic science in the integrated module

Seroprevalence study of IgG and IgM Antibodies to Toxoplasma, Rubella, Cytomegalovirus, Chlamydia trachomatis and Herpes simplex II in Pregnancy women in Babylon Province

In this work 180 blood samples was collected from pregnant women in Babylon province, Babylon maternity and children hospital from October/2008 to April/2009. It revealed that TORCH infections was; Cytomegalovirus formed (CMV) 57.2% followed by Toxoplasma gondii 55.5% Rubella 53.9%, Herpes simplex II 28.9% and Chlamydia trachomatis 24.4%. Seroprevalence of Toxoplasma, Rubella, CMV, Chlamydia trachomatis and Herpes IgM Antibodies according to various obstetric losses showed that Abortions happened in all causes with high percentage (Over than 30%) except Herpes infections (less than 6%), while congenital anomalies and premature delivery formed high ratio with some different in some cases. Neonatal deaths are very low under 1% except in CMV infections which formed 4.9%. Distribution of age with type of infection according IgM Antibodies to Toxoplasma, Rubella, CMV, Chlamydia trachomatis and Herpes simplex revealed that major age group for infection was between <20 to 40 years which formed more than two third of all infection cases. Residential distribution with type of infection according IgM Antibodies shows that most infection occurred in rural area (over than 50% in all agents) except in Herpes simplex infections which formed 82.7% in urban area. TORCH (Toxoplasma gondii, Rubella, Cytomegalovirus and Herpes simplex) infections with incidence of abortion in pregnant women in this study revealed that First trimester was the highest ratio of infection than other two trimesters

Nano-architecture of gustatory chemosensory bristles and trachea in Drosophila wings

International audienceIn the Drosophila wing anterior margin, the dendrites of gustatory neurons occupy the interior of thin and long bristles that present tiny pores at their extremities. Many attempts to measure ligand-evoked currents in insect wing gustatory neurons have been unsuccessful for technical reasons. The functions of this gustatory activity therefore remain elusive and controversial. To advance our knowledge on this understudied tissue, we investigated the architecture of the wing chemosensory bristles and wing trachea using Raman spectroscopy and fluorescence microscopy. We hypothesized that the wing gustatory hair, an open-ended capillary tube, and the wing trachea constitute biological systems similar to nano-porous materials. We present evidence that argues in favour of the existence of a layer or a bubble of air beneath the pore inside the gustatory hair. We demonstrate that these hollow hairs and wing tracheal tubes fulfil conditions for which the physics of fluids applied to open-ended capillaries and porous materials are relevant. We also document that the wing gustatory hair and tracheal architectures are capable of trapping volatile molecules from the environment, which might increase the efficiency of their spatial detection by way of wing vibrations or during flight

Investigation of transdermal permeation of atorvastatinloaded microemulsions

Purpose: To develop microemulsions containing atorvastatin for transdermal application, which will improve the bioavailability and reduce the side effects associated with the oral administration of atorvastatin.Methods: Atorvastatin-loaded microemulsions (MEs) were developed using tween 80 as a nonionic surfactant, isopropyl myristate, polyethylene glycol 400 and dimethyl sulfoxide. Their droplets’ size, and rheological properties were estimated, with the diffusion through the rat’s skin being evaluated using Franz diffusion cells. Furthermore, the in vivo transdermal and oral bioavailability, as well as the toxicity of formulation, were assessed in rats.Results: The results showed that the MEs have a droplet size lower than 100 nm and low Newtonian viscosity. In addition, a flux rate of atorvastatin as high as 10.078 μg/cm2.h was achieved after the loading of the MEs. The in vivo transdermal application maintained a steady state concentration of 1.02μg/mL for 48 h, in comparison to a maximum concentration of 7.7 μg/mL after 2.74 h following oral administration at the same dosing level. Moreover, the transdermally treated rats did not elicit skin irritation.Conclusion: The developed atorvastatin MEs for transdermal application delivers the drug to achieve a controlled plasma level, as well as reduce dosing frequency and toxicity in rats when compared to oral administration. Therefore, the formulation has a potential for development for use in humans