Buckling of Nonprismatic Column on Varying Elastic Foundation with Arbitrary Boundary Conditions

Citation: Ahmad A. Ghadban, Ahmed H. Al-Rahmani, Hayder A. Rasheed, and Mohammed T. Albahttiti, “Buckling of Nonprismatic Column on Varying Elastic Foundation with Arbitrary Boundary Conditions,” Mathematical Problems in Engineering, vol. 2017, Article ID 5976098, 14 pages, 2017. doi:10.1155/2017/5976098Buckling of nonprismatic single columns with arbitrary boundary conditions resting on a nonuniform elastic foundation may be considered as the most generalized treatment of the subject. The buckling differential equation for such columns is extremely difficult to solve analytically. Thus, the authors propose a numerical approach by discretizing the column into a finite number of segments. Each segment has constants  (modulus of elasticity),  (moment of inertia), and  (subgrade stiffness). Next, an exact analytical solution is derived for each prismatic segment resting on uniform elastic foundation. These segments are then assembled in a matrix from which the critical buckling load is obtained. The derived formulation accounts for different end boundary conditions. Validation is performed by benchmarking the present results against analytical solutions found in the literature, showing excellent agreement. After validation, more examples are solved to illustrate the power and flexibility of the proposed method. Overall, the proposed method provides reasonable results, and the examples solved demonstrate the versatility of the developed approach and some of its many possible applications

The role of citizenship values and civic education for the development of social skills at secondary schools

This paper seeks to empirically investigate the question of citizenship values and civic education in Moroccan secondary schools. It undertakes a comparative study based on an interdisciplinary approach in order to measure the presence of these values in Physics and English educational practices. The study is realized via a questionnaire administered to and interviews conducted with practicing teachers of Physics and English throughout different schools in Morocco. Data collection and analysis were performed by adopting a statistical descriptive method. The study is accomplished by targeting a number that reached 84 teachers in both disciplines. Our results demonstrate that teachers have different conceptions concerning values and they show less interest in implementing those values in the teaching/learning operation. Physics teachers believe that Physics as a purely scientific discipline cannot lead itself to integrating citizenship values and they can be integrated only in Humanities disciplines. Furthermore, we find that teachers not only never benefited from a basic or in-service training but also professional interaction among them about those values is very lacking. Besides, a considerable number of respondents agree that citizenship values are decreasing among learners. In this sense, majority of respondents suggest that training, motivation and well-prepared institutional strategies are fundamental prerequisites to overcome those difficulties.

Shear-flexure-axial load interaction in rectangular concrete bridge piers with or without FRP wrapping

Doctor of PhilosophyDepartment of Civil EngineeringHayder RasheedRecent applications in reinforced concrete columns, including strengthening and extreme loading events, necessitate the development of specialized nonlinear analysis methods to predict the confined interaction domain of axial force, shear, and bending moment in square and slightly rectangular concrete columns. Fiber-reinforced polymer (FRP) materials are commonly used in strengthening applications due to their superior properties such as high strength-to-weight ratio, high energy absorption and excellent corrosion resistance. FRP wrapping of concrete columns is done to enhance the ultimate strength due to the confinement effect, which is normally induced by steel ties. The existence of the two confinement systems changes the nature of the problem. Existing research focused on a single confinement system. Also, very limited research on rectangular sections was found in the literature. In this research, a model to estimate the combined behavior of the two systems in rectangular columns is proposed. The calculation of the effective lateral pressure is based on Lam and Teng model and Mander model for FRP wraps and steel ties, respectively. The proposed model introduces load eccentricity as a parameter that affects the compression zone size, and in turn the level of confinement engagement. Full confinement corresponds to zero eccentricity, while unconfined behavior corresponds to infinite eccentricity. The model then generates curves for eccentricities within these boundaries. The numerical approach developed has then been extended to account for shear interaction using the simplified modified compression field theory adopted by AASHTO LRFD Bridge Design Specifications 2014. Comparisons were then performed against experimental data and Response-2000, an analytical analysis tool based on AASHTO 1999 in order to validate the interaction domain generated. Finally, the developed models were implemented in the confined analysis software “KDOT Column Expert” to add FRP confinement effect and shear interaction

Studija helminta u ovaca u Laghouat regiji u južnom Alžiru

The objective of this study was to detect helminths in sheep on farms in three different zones of the Laghouat region, and to examine relationships between the prevalence of these parasites and the factors of age, sex, and area. The study was carried out over a period of four months (March to June 2019) on 77 faecal samples taken from 77 sheep. For this purpose, we used both a qualitative technique (flotation) and a quantitative technique (Mac Master). These two techniques allowed us to isolate helminths and determine the degree of infestation of sheep in the steppe region, specifically the Laghouat region. The results showed that the sheep flock studied overall was negative, with the exception of eight subjects infected with Nematodirus or Strongyloides at a rate of 7.49% each. The helminth parasite prevalence was 10.40%. Statistical analysis of the influence of specific factors revealed no significant effect (P˃0.05) for sex, though the effects of age and area were significant (P<0.05). This parasite prevalence must be taken seriously to avoid its detrimental effect on animal health and the zootechnical performance of sheep flocks.Cilj ovoga rada je bio istražiti helminte na farmama ovaca u tri različite zone Laghouat regije, kao i proučiti vezu između prevalencije tih parazita i određenih čimbenika poput dobi, spola i područja. Naša studija provedena je tijekom razdoblja od 4 mjeseca (od ožujka do lipnja 2019. godine) na 77 uzoraka fecesa uzetih od 77 ovaca. U ove smo svrhe rabili kvalitativnu tehniku flotacije i drugu, kvantitativnu tehniku - Mac Master. Ove dvije tehnike omogućile su nam izdvojiti helminte i odrediti stupanj infestacije ovaca u stepskoj regiji, ili preciznije u regiji Laghouat. Podatci su pokazali da je proučavano stado ovaca pretežito bilo negativno uz izuzetak 8 jedinki u kojih je otkrivena prisutnost parazita Nematodirus i Strongyloides u postotku od 7,49 % za svaku vrstu. Prevalencija parazita helminta bila je 10,40 %. Statistička analiza utjecaja određenih čimbenika otkrila je da spol nije imao značajnijeg učinka (P˃0,05). Međutim, učinak dobi i područja uzorkovanja bio je značajan (P<0,05). Zaključno, zabilježenu prevalenciju parazita potrebno je ozbiljno razmotriti da bi se izbjegao negativni učinak na zdravlje životinja i zootehničke pokazatelje stada ovaca

Development of an Effective Procedure Writer’s Guide using a Human Factors and Regulatory Compliance Approach

PresentationWell-written procedures are an integral part of any industrial organization for safe operation, managing risks, and continuous improvement. Regulatory bodies around the world require industries to have current, accurate, and appropriate procedures for most processes. Although the importance of procedures is recognized by all industries in general, significant incidents have occurred in the past due to procedural breakdowns. Some of the procedural breakdowns come from obvious problems such as the procedure not being available or the procedure being wrong. However, some incidents have occurred when correct procedures were available and the operator used those procedures. In these instances, the reason why operators do not follow procedures correctly may be attributable to many factors, one of them being that the procedure is presented or designed in a manner that does not sufficiently communicate to the operators the information that is needed in a manner that is easily and quickly understood. The work presented here is focused on the latter circumstance and is part of a program of research that will ultimately lead to the development of a writer’s guide for procedures that supports operators’ comprehension and compliance with all types of industrial procedures. The writer’s guide is based on empirical findings from human factors and human performance studies and provides writers with information on how to present procedures in a manner that is clear, thorough, and (if necessary) implementable with short notice. For the first phase of the project, a sample of the regulations and standards from several industries were used to identify procedure writing practices necessary for ensure regulatory compliance. Regulations and industrial standards from around the world were organized to reflect common ideas and the implications in terms of human factors needs were identified with regard to procedure design. Any human factors (HF) that had implications for the writer’s guide that had empirical support, were included in the writer’s guide (with the reference) with an explanation of the HF implication and empirical support. The writer’s guide developed is structured to allow procedure writers access to guidance on various types of procedures they are writing, the type of information they are trying to communicate, and methods for maintaining accurate and current procedures. As mentioned, the current project is the beginning of a program of research and then next phase will include feedback from operators regarding the challenges they face when using procedures

Studying the ShcD and ERK interaction under acute oxidative stress conditions in melanoma cells.

The newly identified melanoma-associated adaptor ShcD was found to translocate to the nucleus upon hydrogen peroxide treatment. Therefore, the aim of this study was to identify the ShcD network in melanoma cells under oxidative stress. LC-MS/MS and GFP-trap were performed to study the ShcD phosphorylation status during acute severe oxidative stress. ShcD was found to be phosphorylated at threonine-159 (Thr159) in response to 5 mM H2O2 treatment. The GPS 2.1 phosphorylation prediction program predicted that the Thr159Pro motif, housed in the N-terminus of the ShcD-CH2 domain, is a potential phosphorylation site for MAPKs (ERK, JNK or p38). Co-immunoprecipitation experiments revealed that ShcD mainly interacts with ERK in B16 and MM138 melanoma cells under both hydrogen peroxide-untreated and -treated conditions. Moreover, ShcD interacts with both phosphorylated and un-phosphorylated ERK, although the interaction between ShcD and phospho-ERK was primarily observed after H2O2 treatment. A MEK inhibitor (U0126) enhanced the interaction between ShcD and unphosphorylated ERK under oxidative stress conditions. Furthermore, Thr159 was mutated to either alanine (A) or glutamic acid (E) to study whether the threonine phosphorylation state influences the ShcD/ERK interaction. Introducing the T159E mutation obliterated the ShcD/ERK interaction. To identify the functional impact of the ShcD/ERK interaction on cell survival signalling under oxidative stress conditions, caspase 3/7 assays and 7AAD cell death assays were used. The ShcD/ERK interaction promoted anti-survival signalling upon exposure to hydrogen peroxide, while U0126 treatment reduced death signalling. Our data also showed that the death signalling initiated by the ShcD/ERK interaction was accompanied by p21 phosphorylation. In summary, these data identified ShcD, via its interaction with ERK, as a proapoptotic protein under oxidative stress conditions