bluuebunny/crossref_metadata_2025 huggingface dataset:
Study of the reinforcement of structure members by polypropylene fibres waste
Authors: Bendjillali Khadra , Chemrouk Mohamed
Published: February 2018

The valorisation of industrial waste in the field of construction became a very interesting axis of research from scientific, economic and environmental point of view. We have conducted this work to study the effect of the addition of polypropylene fibres waste on the mechanical behaviour of reinforced concrete beams subjected to a simple flexural loading, with and without transversal reinforcement. The used fibres are coming from the waste of the fabrication of domestic brushes and sweeps; they have an average diameter of 0.47 mm and a length between 40 and 60 mm. Two weight dosages of fibres are used, 0.25 and 0.5 %. The experimental results showed that the incorporation of polypropylene fibres waste into the concrete affects negatively its workability, but its flexural and compressive strength are improved. The fibers have presented a significant contribution on the shear behavior and the cracking of beams, particularly in absence of transversal bars. The waste used in this work as fibrous reinforcement has not only increased the ductility of reinforced concrete beams, but it have also provided a perfect cracking distribution on the concrete surface and it has participated in a considerable way in the reduction of cracks number and dimensions, which allows to ensure the material durability and then the structure longevity. The reinforcement of concrete beams with 0.5 % of polypropylene fibers waste with a minimal steel bars can ensure an excellent mechanical behavior in shear, as in flexion.
Hybrid Latex Particles: Preparation with Miniemulsion Polymerization
Authors: Bouanani F.
Published: February 2018

This research developed a novel poly(trifluoropropylmethylsiloxane) (PTMS)/montmorillonite nanoparticles, for technologic applications. PTMS /MMT nanoparticles were prepared by the miniemulsion polymerization method. Montmorillonite clay was encapsulated within a fluorinated cyclosiloxane (1,3,5-tris(trifluoropropylmethyl)cyclotrisiloxane) to give stable water based nanocomposite latex, using miniemulsion polymerization technique. The resulting composite latex was characterized by transmission electron microscopy (TEM), dynamic light scattering (DLS) and RX diffraction. The particles stability was investigated by sedimentation and surface tension measurements. An efficient cationic/nonionic surfactant mixture was used in order to achieve the best compatibility with the monomer. TEM and RX data revealed the partial embedding of montmorillonite in the spherical polymer based nanoparticles. According to DLS measurements, the encapsulated clay particles conserve their size throughout the polymerization process. The melt processing of poly(trifluoropropylmethylsiloxane) matrix to encapsulate the montmorillonite clay was also carried out for comparison purposes.
Development of new baked bricks based on clay and sawdust
Authors: Benjeddou Omrane , Soussi Chokri , Khadimallah Mohamed Amine , Alyousef Rayed , Jedidi Malek
Published: February 2018

Current research in the field of building materials is oriented towards the recovery of waste to ensure the lightening of certain building elements and energy saving. The objective of this study is to produce a new bricks by adding sawdust to clay mixtures. The first part of this experimental work consists on detremining the proper manufacturing process and cooking diagram for these new bricks. In the second part, the effect of the maximum cooking temperature, the firing phase time's of the bricks and the sawdust prportion on the physical and mechanical properties of the new bricks have been studied. The studied properties are the absorption ratio, the unit weight and the compressive strength. The results showed that the addition of an increasing amount of sawdust tends to modify the physical and mechanical properties of the cooked samples. The presence of sawdust reduces the number of connections between the clay grains and produces a lighter, more absorbent and less resistant material. Finally, the results showed that the manufacture of bricks based on sawdust is possible.
Dynamic buckling of laminated composite stringer stiffened CFRP panels under axial compression
Authors: Ouadia Mouhat , Abdellatif Khamlichi , Boubel Hasnae , Elmrabet Oumnia , Rougui Mohamed , Echebba El Mehdi , Bouhmidi Ahmed El
Published: February 2018

In this work, the dynamic buckling of stiffened panels is evolved numerically through a nonlinear incremental expression through making use of a specific time integration procedure via the finite element software program. the buckling and post-buckling behaviours of hat-stringer-stiffened composite curved panel under axial compression load .Dynamic buckling is extracted from the curve abandoning the very last shortening as a characteristic of time while the shape is subjected with the aid of a square compression pulse movement carried out inside the axial direction. The duration of the heart beat and the amplitude of curvature of decreasing of the cloth inside the band tormented by the warmth, the dynamic buckling motion, are constant. The method approach was proposed to predict the dynamic buckling load of curved panel. Finite element analysis was used to investigate these tests and the FE models were performed by ABAQUS.Approach to determine the reliability of the stiffened panel in dynamic buckling state.
Contribution to the damage modelling of reinforced concrete structures
Authors: KHEBIZI Mourad , GUENFOUD Hamza , GUENNFOUD Mohamed
Published: February 2018

A two-dimensional multi-layered finite elements modeling of reinforced concrete structures at nonlinear behaviour under monotonic and cyclical loading is presented. The non-linearity material is characterized by several phenomena such as: the physical non-linearity of the concrete and steels materials, the behaviour of cracked concrete and the interaction effect between materials represented by the post-cracking field. These parameters are taken into consideration in this paper to examine the response of the reinforced concrete structures at the non-linear behaviour. Two examples of application are presented. The numerical results obtained, are in a very good agreement with available experimental data and other numerical models of the literature.
Contribution to the requalification of Alkali-Silica reaction damaged concrete: particular respect to the slag effect
Authors: Douaissia Zineb , Merzoud Mouloud
Published: February 2018

A significant concern when designing durable concretes structures is the risk of alkali silkai reaction (ASR). The cracks formed by ASR increase the permeability of concrete, reduce the strength and lower the economic lifetime of concrete. The use of mineral and chemical admixtures to prevent expansion due to the alkali-silica reaction (ASR) was first reported 40 to 50 years ago. In this paper, a comprehensive experimental research was carried out to prevent the damages and to be able to improve in concrete structures with the reactive aggregates by using the ground granulated blast-furnace slag (GGBFS) in the mixtures. Furthermore, the engineering properties of blast-furnace slag and the test methodology used in the research were presented and the research findings were also discussed.
Effect of mineral admixtures on the rheological and mechanical properties of mortars
Authors: Douaissia Zineb , Merzoud Mouloud
Published: February 2018

We propose in this study to determine the role of mineral admixtures on the properties of cementitious materials in order to define a formulation method allowing an optimization of their use and the improvement of the rheological and mechanical properties of the mortars. In order to meet the objectives of this study, and to evaluate the effects that mineral admixtures may have on the properties of mortars in the fresh and hardened state, we have proposed to use a specific method based on progressive volume substitution of cement by the mineral admixtures, in order to preserve the absolute volume of all the solid constituents and the consistency for all the mixtures. The use of the mineral admixtures in the mortars also has for objective to valorize a category of natural materials or coproducts available in Algeria. As a result, the mineral admixtures chosen for this study are Blast furnace Slag, natural pozzolan and silica fume. Then the effect of the mineral admixtures on the rheological and mechanical properties of the mortars was evaluated according to the substitution rate of the cement. We applied to the studied mortars the notion of equivalent binder in order to calculate the coefficient of activity (K) defined by the two theoretical formulas Féret and Bolomey. The specific chemical action of each mixture was evaluated by analysing the variation of the coefficient of activity K as a function of the rate of substitution of the cement.
Experimental Study on Ready-Mix Concrete: Case Study
Authors: Ellouze Dorra , Ghammouri Aida , Ben Amar Rahma
Published: February 2018

Ready-mix concrete (RMC) in Tunisia is becoming more and more in demand in the civil engineering sector thanks to its qualities of handling in the fresh state and resistance in the hardened state, this composite material must respect the quality-price ratio. A RMC with a minimal cost is the object of our work. This research is part of the opening of higher education on professional life, where we optimized the formulation of a RMC. This work has 3 axes. In the first place the resources in building materials were characterized, namely various samples of sand, gravel, cement and water. Subsequently, the adjuvant-cement ratio (A/C) was optimized. Finally, the workability of the concrete as well as its mechanical aptitude at various ages 7, 14 and 28 days were characterized. These examinations have resulted in an appropriate formulation for any type of resource that varies according to the provenance of the quarries (gravel and sand), the effect of the plasticizer-water reducer is found for a very interesting A/C ratio, the mechanical tests for different ages are also conclusive.
Synthesis and characterization of innovative insulation materials
Authors: Skaropoulou Aggeliki , Ntziouni Afroditi , Kioupis Dimitris , Tsivilis Sotiris , Kakali Glikeria
Published: February 2018

Insulation elements are distinguished in inorganic fibrous and organic foamed materials. Foamed insulation materials are of great acceptance and use, but their major disadvantage is their flammability. In case of fire, they tend to transmit the flame producing toxic gases. In this paper, the synthesis and characterization of innovative inorganic insulation materials with properties competitive to commercial is presented. Their synthesis involves the mixing of inorganic raw material and water with reinforcing agent or/and foaming agent leading to the formation of a gel. Depending on raw materials nature, the insulation material is produced by freeze drying or ambient drying techniques of the gel. The raw material used are chemically benign and abundantly available materials, or industrial by-products and the final products are non-toxic and, in some cases, non-flammable. Their density and thermal conductivity was measured and found 0.02-0.06 g/cm3 and 0.03-0.04 W/mK, respectively.
Characterization of clay deposits in the Adrar region, with a view to their valorization in the building materials industry
Authors: Mohammed Abbou , Hassan Moulay Omar , Abdélaziz Semcha , Fatiha Kazi-Aoual
Published: February 2018

In the context of sustainable local development of the Adrar region, one of the largest regions in the Algerian Sahara. The search for local useful substances has been initiated by the Algerian state to cover the need for building materials in the construction industry. However, from a geological point of view, the Adrar zone is located in the extension of the primary chain of the Ougarta which separates two sedimentary basins of Reggane and Timimoun, as well as the basin of Sbâa. In this context, an experimental study is focused on the characterization of clay deposits, with a view to their valorization in the construction materials industry (ceramics) sector, with the aim of contributing to the use of local materials.
Study of the mechanical and chemical properties of potassium manganese phosphate glasses
Authors: Ahmina W. , El Moudane M. , Zriouil M. , Cherraj M. , Taibi M.
Published: February 2018

Homogeneous phosphate glasses having the general formula 20K2O-xMnO-(80-x)P2O5 were synthesized using a melt-quenching method. The amorphous nature of the samples was asserted by X–ray diffraction. The glasses are studied in order to evaluate the influence of MnO addition on the chemical and mechanical properties, such as, dissolution rate, average compressive strength (Rc), Young’s modulus (E) and limit strain (εlim). Some studies show that the addition of MnO significantly reduces the degradation rate (DR) of soluble phosphate glasses and enhanced chemical stability of both alkali-resistance and acid-resistance. MnO interfere with the chemical structure of the glass, and consequently improve their mechanical properties. Indeed, the mechanical measurements showed that the glass structure was modified by the addition of MnO oxide, becoming more rigid, and as a result, increasing the compressive strength (Rc), Young’s modulus (E). These new materials could be an important opportunity for applications in the fields of building, construction, civil engineering, etc…
Effect of bio-loading on polyvinyl chlorides morphology
Authors: Jammoukh M. , Mansouri K. , Salhi B.
Published: February 2018

To integrate the consideration of environmental issues in the design phase of a product eco-design is an ecological quality improvement and preventive approach of it while verifying that the resulting environmental gain is not at the expense of other environmental aspects and focusing on the preservation of its quality of use of its features or certain stages of its life cycle without losing the own global vision of eco-design. Following this vision, the use of bio-laden animal based polymers derived from a mode of production by implementing optimization practices respectful of natural resources sustainably, has become changing way of thinking largely replace the use of non-renewable resources for human activities, the depletion of fossil resources deposits and to fight against the impact of climate change generated by this practice. Our paper attempts to analyze first the mechanical behavior of a bio-load and then incorporated into a polymer material to test improved mechanical and thermal characteristics made to it after adding and optimizing subsequently, its use. This is a load in the form of powder or chips extracted from an animal sheath. Tensile tests are performed in a first step, in order to mechanically characterize the virgin material and eco-composite obtained after the combination, i.e. the maximum tensile strength, the relative deformation and the modulus of the elasticity, etc
Numerical Derivation of Iso-Damaged Curve for a Reinforced Concrete Beam Subjected to Blast Loading
Authors: Temsah Yehya , Jahami Ali , Khatib Jamal , Sonebi M
Published: February 2018

Many engineering facilities are severely damaged by blast loading. Therefore, many manufacturers of sensitive, breakable, and deformed structures (such as facades of glass buildings) carry out studies and set standards for these installations to withstand shock waves caused by explosions. Structural engineers also use these standards in their designs for various structural elements by following the ISO Damage Carve, which links pressure and Impulse. As all the points below this curve means that the structure is safe and will not exceed the degree of damage based on the various assumptions made. This research aims to derive the Iso-Damage curve of a reinforced concrete beam exposed to blast wave. An advanced volumetric finite element program (ABAQUS) will be used to perform the derivation.
Study of the degradation of the geometry of the railway between the pk 80 and 105 at the plateau of Settat (Morocco)
Authors: Ben Ouakkass Mohamed , Ouadif Latifa , Akhssas Ahmed , Bahi Lahcen
Published: February 2018

The plateau of Settat is formed by Paleozoic age formations surmounted by a subhorizontal
cover made up mainly of Cretaceous sedimentary rocks formed of limestones, sandstones and clays with alternating marly limestones and marls. The study area is characterized by a dry to semi-dry climate, an endorheic hydrographic network that flows into the plain, and is affected by a hydraulic fracturing network of WNW-ESE and NE-SW directions. These factors cause repetitive and cyclical disturbances and disorders recorded on the railway section between Settat and Machraa Ben Abbou and are due to the shrinkage-swelling of the clay formations. The statistical and critical analysis of the defects identified by the device of measuring the geometric parameters of the railway, coupled with an exploitation of the Optical and Radar satellite images, made it possible to refine the geological, hydrological and structural study of the plain studied. These approaches have shown that this hazard has been favored by the existence of recent clayey and swelling formations under the influence by the climatic, hydrological and geological contrasts marked by intense hydraulic fracturing of the zone.
Validation and Verification of Semi-Empirical Methods for Evaluating Liquefaction Using Finite Element Method
Authors: Touijrate Soukaina , Baba Khadija , Ahatri Mohamed , Bahi Lahcen
Published: February 2018

Liquefaction is a hazardous and temporary phenomenon by which a soil saturated with water loses some or all of its resistance. The undrained conditions and a cyclic load increase the pores water pressure inside the soil and therefore a reduction of the effective stress.

Nowadays many semi-empirical methods are used to introduce a proposition to evaluate the liquefaction's potential using the in-situ test results. The objective of this paper is to study their ability to correctly predict the liquefaction potential by modelling our case using finite element methods.

The study is based on the data of Cone Penetration Tests experimental results of the Casablanca-Tangier High-Speed Line exactly between PK 116 + 450 and PK 116 + 950 and near of Moulay-Bousselham city. It belongs to the Drader-Soueir basin region which is located in the North-West of Morocco.

This region had a specific soil’s formation, the first 50 meters are characterised by the existence of sand layers alternating with layers of clay. These formations are very loose and saturated which suggests the possibility of soil liquefaction.

We present and discuss the results of applying the Olsen method [1], the Juang method [2] and the Robertson method [3], in the evaluation of liquefaction susceptibility.

Apart from the previous empirical analysis to evaluate the liquefaction potential, numerical modelling is performed in this study.
Time rate of swelling of compacted highly plastic clay soil from Sudan
Authors: Elsharief A M , Sufian Mai
Published: February 2018

This paper investigates the development of swelling with time for a highly plastic and potentially expansive clay from Sudan. Soil samples were prepared in the laboratory at different moisture content values. The prepared samples were placed in the oedometer ring at three density levels and then placed in an oedometer cell which allows one dimensional swelling. Swelling was observed at different time intervals to 48 hours. The data was analyzed to determine the development of swelling with time. The data analysis clearly demonstrated three stages of swelling, initial, preliminary and secondary for all tested samples except the quasi-saturated ones. The swell percent and primary swelling were very sensitive to the initial moisture content and dry density of the tested samples. Most of the swelling took place during the first 24 hours for all the tested specimens. The hyperbolic model was assessed for prediction of the percent swell. The 12 hours data was found to be very successful in predicting the percentage swell.
Influence of relative density on the cyclic shear strength of sands
Authors: Arab A. , Sadek Marwan , SHAHROUR I.
Published: February 2018

This paper presents a laboratory study of the influence of relative density on the liquefaction potential of a soil. The study is based on undrained triaxial tests that were performed on samples with relative density Id = 0.15, 0.5 and 0.65. The article is composed of three parts. First, we present the materials and characteristics of the studied sands. the second part deals with the procedure and the device used. The third part studies the influence of the relative density on the liquefaction potential of the three sands (Hostun Rf, Chlef and Rass). This study also makes it possible to explore the influence of granulometry on the liquefaction potential. The results of the tests show that concordant results have been obtained which clearly show that the increase of the relative density leads to a significant improvement in the resistance to liquefaction of the sands. This effect is very significant when the initial relative density Id = 0.50 to Id = 0.65.
Weights of evidence method for landslide susceptibility mapping in Tangier, Morocco
Authors: Bousta Mahfoud , Ait Brahim Lahsen
Published: February 2018

Tangier region is known by a high density of mass movements which cause several human and economic losses. The goal of this paper is to assess the landslide susceptibility of Tangier using the Weight of Evidence method (WofE). The method is founded on the principle that an event (landslide) is more likely to occur based on the relationship between the presence or absence of a predictive variable (predisposing factors) and the occurrence of this event. The inventory, description and analysis of mass movements were prepared. Then the main factors governing their occurrence (lithology, fault, slope, elevation, exposure, drainage and land use) were mapped before applying WofE. Finally, the ROC curves were established and the areas under curves (AUC) were calculated to evaluate the degree of fit of the model and to choose the best landslide susceptibility zonation. The prediction accuracy was found to be 70%. Obtained susceptibility map shows that 60% of inventoried landslides are in the high to very high susceptibility zones, which is very satisfactory for the validation of the adopted model and the obtained results. These zones are mainly located in the N-E and E part of the Tangier region in the soft and fragile facies of the marls and clays of the Tangier unit, where landuse is characterized by dominance of arable and agricultural land (lack of forest cover). From a purely spatial point of view, the localization of these two classes of susceptibility is completely corresponding to the ground truth data, that is to say that all the environmental and anthropogenic conditions are in place for making this area prone to landslide hazards. The obtained map is a decision-making tool for presenting, comparing and discussing development and urban scenarios in Tangier. These results fall within the context of sustainable development and will help to mitigate the socio-economic impacts usually observed when landslides are triggered.
Effect of spatial variability of ground motion on non-linear dynamic behavior of cable stayed bridges
Authors: Ouanani Mouloud , Tiliouine Boualem , Hammoutene Malek
Published: February 2018

This present paper summarizes the main results of incoherence of Spatial Variability of Ground Motion (SVGM) component on the non-linear dynamic behavior of a Mila cable stayed bridge. The Hindy and Novack coherence model is developed for the present study in order to examine the SVGM on bridge responses, Nonlinear bridge responses are investigated in terms of transverse displacements and bending moments along the superstructure and substructure of the study bridge, as well as temporal variations of rotational ductility demands at the bridge piers ends under the incoherence SVGM component. The results are systematically compared with those obtained assuming uniform ground motion. As a general trend, it may be concluded that incoherence component of SVGM should be considered for the earthquake response assessments of cable-stayed bridges.
Extraction of the predisposition parameters for mapping the susceptibility of slides lands, in the region of EL Quola, province of Larache (Nothern Rif)
Authors: El hamdouni Ikram , Aitbrahim Lahcen
Published: February 2018

Slide lands (Lands mass movements) are among the natural risks that Morocco faces in the Rifaines regions in particular. They generally constitute small-scale, punctual phenomena. But their diversity and frequency are nevertheless responsible for significant and costly damages and injuries. To deal with this problem, the study of field instabilities must take into account that: ithe ground movements must be taken in a context of the overall dynamics of the watershed, ii-the choice of more objective methods, which is not based on the very subjective opinion of the expert; iii-the choice of an adapted approach to the scale of work. In this article, we used the evidence theory "WofE" to evaluate the sensibility of landslide in the El Quola area. This method is based on the analysis of the relationships between landslides that occurred in the past (the so-called modelable variable Vm) and the spatial distribution of some predictive parameters of instability (Vp). The result obtained is a landslide susceptibility map that is the result of multi-disciplinary and multi-temporal data. This method has been described as one of the most performing by several authors; however, it requires a conditional independence between the different predictive factors. The quality of the performances was evaluated with success curves.
Numerical analysis of a reinforced concrete beam under blast loading
Authors: Temsah Yehya , Jahami Ali , Khatib Jamal , Sonebi M
Published: February 2018

The types of Dynamic loads that might face an engineer during any design procedure vary. One of these loads is the explosion's pressure on buildings which is in other words the blast load. This research has examined the possibility of using a finite element method as a tool for predicting the dynamic response of blast loaded reinforced concrete beams. In this study, the advanced software, ABAQUS is used in order to model materials and consider the material nonlinearity, stiffness degradation and strain rate effects. Experimental results for several beams under explosion are chosen to be modeled and verified using ABAQUS. These experiments were carried out at the National University of Defense Technology in China. The results show that the material properties of concrete under impact loads (high strain rates) can be well defined in ABAQUS. Also the built in model CONWEP for blast load in ABAQUS can be used in the simulation process with an acceptable error.
Effect of quick lime on physicochemical properties of clay soil
Authors: Bessaim Mohammed Mustapha , Bessaim Aicha , Missoum Hanifi , Bendani Karim
Published: February 2018

Clay soils are known for their water sensitivity, which causes irreparable damage to any structure built on this type of soil. In order to avoid such problem, it is necessary to use various improvement and stabilization methods such as treatment with lime. This process has been used successfully in the field for decades. The addition of lime generates various physicochemical reactions within the soil such as cation exchange and pozzolanic reactions which are largely responsible for the improvement of the soil in question. This paper presents a study concerning the variation of physicochemical properties of clayey soil with the addition of quicklime at different percentages. Experiments were performed on two clayey soils (CL type) in order to investigate the influence of quicklime on Atterberg limits and pH. These tests were carried out in an attempt to study and follow the development and progression of various reactions occurred within the soil with various lime percentages. The results show that the addition of quicklime causes a significant improvement in soil properties by reducing plasticity and thereby improves the soil workability. It can also be found that the addition of lime increase pH of soil, which allow activating pozzolanic reactions who tend to stabilize the soil in question by formation of cementitious compounds. Finally, the pH can be considered as a relevant parameter who allows a better understanding of the reactions that occur in the soil matrix.
Study and monitoring of the stability of a rock mass at the Dar-El-Oued
tunnel, wilaya of Jijel – Algeria
Authors: Yellas Chahra , Benzaid Riad , Tekkouk Mustapha
Published: February 2018

The construction of a civil engineering work requires many preliminary studies as well as various calculation methods to give an assessment or a forecast of the state of the rock in place and the behavior of the structure in its real environment and under various conditions (construction phase, service and operating phase). The present work concerns the access zone of the Dar-El-Oued tunnel, located on the national road n°43 about 40 km West of the city of Jijel (northeastern Algeria). The geotechnical study of this tunnel was carried out following the classification methods relating to underground structures. Through the results of this study we have determined the influence of land pressures on the mechanical behavior of the ground, which allowed us to measure the state of stress in the rock and to make a comparison between the results of the measurements of convergence and that of numerical modeling. On the other hand, the influence of the velocity of vibration induced by explosive shots has been discussed in order to check the stability of the face as the digging progresses. From the results obtained, it can be said that the surface displacements of the soil are relatively small compared to those determined by the numerical model at the level of the vault and the slab. Note the good agreement between the results provided by our numerical model and those obtained in-situ.
Application Of Logistic Regression Method To Produce Landslide Susceptibility Map: A Case Study Of Tetouan Mazari, Morocco
Authors: Brahim L. Ait , Elmoulat M.
Published: February 2018

The main purpose of this study is to use logistic regression (RL) model to map landslide susceptibility in and around the area of Tetouan Mazari in the Northern Morocco. Parameters, such as lithology, slope gradient, slope aspect, faults, drainage lines, and hillshade, were considered. Landslide susceptibility map was produced using RL method and then compared and validated. Before the modeling and validation, the observed landslides were separated into two groups. The first group was for training, and the other group was for validation steps. The accuracy of the model was measured by fitting them to a validation set of observed landslides. For validation process, the half landslides remaining was used. The final map was classified into five classes: Very High (32%), High (40%), Medium (7%), Low (7%) and Nil (15%). According to these values logistic regression was determined to be one of the most accurate method to generate landslide susceptibility map. Last but not least, logistic regression model can be used to manage and mitigate hazards related to landslides and to aid in land-use planning for the city of Tetouan‥
Study of indoor performances of a building using Rammed earth
Authors: Cheikhi Wiçal , Baba Khadija , Lamrani Sidi Mohamed , Nounah Abderrahmane , Khalfaoui Mohamed , Bahi Lahcen
Published: February 2018

Nowadays, many assumptions hold that returning to rammed earth construction could be a solution to the energy challenges of the time. These assumptions are based on the ability of the material to maintain a comfortable indoor temperature regardless of the outdoor climatic variations. However, its influence on the energy performance of buildings remains little explored so far. This paper comes in this order of ideas. It is devoted to study and evaluate the energy efficiency of rammed earth buildings compared to those in concrete structure and masonry envelope. It takes as case study two buildings: one is traditional, entirely built with the technique of rammed earth; the other is constructed of concrete. In order to compare between their performances, we have performed a simulation of the thermal behavior of each by the dynamic thermal simulation software Design Builder.
Parametric study of the thermal performance of a typical administrative building in the six thermal zones according to the RTCM, using TRNSYS
Authors: Abdelghafour LAMRANI , Said SAFAR , Mohamed ROUGUI
Published: February 2018

In this work, we present a parametric study of a new administrative building, located in El-Ksar El Kebir region (Morocco). In order to have a building that complies with the RTCM in a technically and economically sound manner, we have carried out a number of interventions to insulate the components of the building, namely external walls, exposed roofs and openings. In this perspective, we have modelled the building envelope as a multi-zone building in TRNSYS and we have adopted an occupation scenario for this type of building. After determining the optimal insulation solutions, we simulated the administrative building in the five other thermal zones, to determine its feasibility in the latter.
Introduction of inclined open channels for the control of surface runoff of slopes in road structures
Authors: Hniad O. , Bahi L. , Amgaad S.
Published: February 2018

The phenomenon of water erosion induced by runoff speeds at the surface of the embankments causes their instability. Particularly in road environments, gullying on the slope's surface due to runoffs causes landslides, which in turn cause considerable damage and consequent disorders to the road network. The aim of this research is to put in place a new technology for superficial water drainage on slope surfaces. Our study has developed a methodology involving the change of the geometric configuration of the water flow, aiming at velocity control of the flows by choosing slanting waterways with small slopes coupled to vertical drains. A modelling of the proposed solution will evaluate its effectiveness as to prevent the erosive factor and to identify other factors that are responsible for slope disorders.
Metal-Free Oxidative C(sp3)–N Coupling by HBr and DMSO: A Novel Synthesis of 2,3-Dihydroquinazolin-4(1H)-ones
Authors: Ranjbar Parviz , Rezaei Narjes , Sheikhi Ehsan
Published: February 2018

A metal-free oxidative C(sp3)–N coupling process has been developed for the synthesis of 2,3-dihydroquinazolin-4(1H)-ones. The reaction between primary amines, isatoic anhydride, and benzylic alcohols in the presence of HBr in DMSO at 80 °C affords 2,3-dihydroquinazolin-4(1H)-ones in excellent yields. Under these reaction conditions, benzylic alcohols react with in situ generated bromodimethylsulfonium bromide to form alkoxysulfonium intermediates. These intermediates undergo an oxidative cyclization reaction with primary amines and isatoic anhydride to produce the title products.
Studies on Iron-Catalyzed Aerobic Oxidation of Benzylic Alcohols to Carboxylic Acids
Authors: Ma Shengming , Jiang Xingguo
Published: February 2018

A comprehensive study on aerobic oxidation of benzylic alcohols­ to carboxylic acids with a catalytic amount each of Fe(NO3)3·9H2O, TEMPO, and KCl is conducted. Various synthetically useful functional groups are well tolerated in the reaction. Distinct electronic and steric effects are observed in the reaction: electron-withdrawing groups accelerate the reaction while electron-donating groups make the reaction slower, and ortho-substituted substrates react slower than meta-substituted substrates. Several large-scale reactions (100 mmol) are conducted using a slow air flow of 30 mL/min to demonstrate the practicality of this method in an academic laboratory.
Anticoagulant Preferences and Concerns among Venous Thromboembolism Patients
Authors: Lutsey Pamela , Horvath Keith , Fullam Lisa , Moll Stephan , Rooney Mary , Cushman Mary , Zakai Neil
Published: February 2018

Background Warfarin and direct oral anticoagulants (DOACs) are used for the initial treatment and secondary prevention of venous thromboembolism (VTE), and have similar efficacy. Patient concerns and preferences are important considerations when selecting an anticoagulant, yet these are not well studied.

Methods VTE patients (n = 519) were surveyed from online sources (clotconnect.org, stoptheclot.org and National Blood Clot Alliance Facebook followers [n = 495]) and a haematology clinic in Vermont (n = 24).

Results Patients were 83% females and on average (±standard deviation [SD]) 45.7 ± 13.1 years; 65% self-reported warfarin as their initial VTE treatment and 35% a DOAC. Proportions reporting being extremely concerned about the following outcomes were as follows: recurrent VTE 33%, major bleeding 21%, moderate bleeding 16% and all-cause death 29%. When asked about oral anticoagulant characteristics, patients strongly preferred anticoagulants that are reversible (53%), and for which blood drug levels can be monitored (30%). Lower proportions agreed with statements that regular blood testing is inconvenient (18%), that they are comfortable using the newest drug versus an established drug (15%) and that it is difficult to change their diet to accommodate their anticoagulant (17%). In multivariable-adjusted models, patients tended to have had as their initial treatment, and to currently be taking, the oral anticoagulant option they personally preferred.

Discussion Patients held the greatest concern for recurrent VTE and mortality, regardless of which treatment they were prescribed. Potential weaknesses of warfarin (e.g., dietary restrictions, regular monitoring) were generally not considered onerous, while warfarin's advantages (e.g., ability to monitor) were viewed favourably.
Evaluation der Faktorenstruktur und Konstruktvalidität der 12-Item Kurzversion des OPD-Strukturfragebogens (OPD-SFK) an psychosomatischen Patienten
Authors: Obbarius Alexander , Obbarius Nina , Fischer Felix , Liegl Gregor , Rose Matthias
Published: February 2018

Einleitung Das Screening struktureller Einschränkungen der Persönlichkeit gilt zunehmend als wichtig für die Planung der stationären Behandlung, da hierdurch frühzeitig spezifische Behandlungspfade festgelegt werden können. Kürzlich wurde zu diesem Zweck der 12-Item Screening-Fragebogen zur OPD-Strukturachse (OPD-SFK) entwickelt und erste Ergebnisse zur Faktorenstruktur und Validität veröffentlicht. Das Ziel der aktuellen Studie bestand darin, den OPD-SFK außerhalb des Entwicklerteams an weiteren Stichproben zu validieren und Referenzwerte zur Verfügung zu stellen.

Material und Methoden Die Datenerhebung erfolgte zwischen 2012 und 2016 in der psychosomatischen Ambulanz (N=565) und auf der psychosomatischen Station (N=670) der Charité – Universitätsmedizin Berlin. Um die Faktorenstruktur des OPD-SFK zu überprüfen wurden für beide Stichproben konfirmatorische Faktorenanalysen (CFA) durchgeführt. Zur Überprüfung der Konstruktvalidität wurde bei N=105 Patienten ein SKID-II-Interview durchgeführt und N=160 Patienten füllten die 90-Item Version des Narzissmusinventars (NI-90) aus. Zusätzlich wurde die psychische, soziale und körperliche Gesundheit anhand weiterer Instrumente erhoben. Bivariate Korrelationen wurden berechnet, um die Zusammenhänge zwischen diesen Instrumenten und dem OPD-SFK zu untersuchen.

Ergebnisse Die CFAs ergaben eine gute bis zufriedenstellende Modellgüte für das vorgeschlagene Dreifaktorenmodell und sehr gute Werte für ein Bi-Faktor-Modell. Die Analysen zur Konstruktvalidität ergaben hohe positive Korrelationen zwischen dem OPD-SFK und dem dimensionalen Score des SKID-II-Interviews, den SKID-II-Interviews und dem NI-90 und bestätigten somit die konvergente Validität. Für die diskriminante Validität zeigten sich heterogene Ergebnisse: Mit einer Reihe von Instrumenten zeigten sich mittlere bis hohe Zusammenhänge, bspw. mit dem D-CAT (Depression), A-CAT (Angst), S-CAT (Stress) und PHQ-15 (somatische Symptome). Folgeanalysen zeigten, dass der OPD-SF Faktor Selbstwirksamkeit möglicherweise besonders von aktueller Depressivität und Angst beeinflusst wird. Die Unterschiede der einzelnen Korrelationen der Subskalen des OPD-SFK mit den anderen Instrumenten waren gering.

Schlussfolgerung Der OPD-SFK scheint zum Screening struktureller Defizite geeignet. Allerdings werden auch andere Aspekte der Psychopathologie miterfasst, sodass während der klinischen Behandlung eine weitere Diagnostik der Persönlichkeitsstruktur, z. B. durch ein OPD-Interview zusätzlich sinnvoll scheint.
Risikofaktoren und Zielwerte in der kardiovaskulären Primär- und Sekundärprävention: Bedeutung für das Glaukom
Authors: Hacke Claudia , Erb Carl , Weisser Burkhard
Published: February 2018

Bluthochdruck, Diabetes mellitus und Fettstoffwechselstörungen gehören zu den wichtigsten kardiovaskulären Risikofaktoren. Gleichzeitig besteht auch ein Zusammenhang mit der Entwicklung und Progression des Glaukoms. In den letzten Jahren wurde eine intensive Diskussion über die optimalen Zielwerte für diese Risikofaktoren geführt. Vor kurzer Zeit haben die amerikanischen Fachgesellschaften 130/80 mmHg als neue Grenze zum Bluthochdruck definiert und auch europäische Richtlinien werden folgen. Die strengeren Grenzwerte erhöhen die Gefahr, dass unter Umständen ein zu starker Blutdruckabfall in der Nacht beim Glaukompatienten erfolgen könnte. Im Gegensatz dazu sollte das LDL-Cholesterin so niedrig wie möglich eingestellt werden („the lower the better“). Differenzierter sind die Zielbereiche beim Diabetes mellitus zu sehen. Für Ältere, also die Hauptgruppe der Glaukompatienten, wird inzwischen eine eher moderate Blutzuckereinstellung mit einem HbA1c-Wert von über 7% empfohlen, um stärkere Unterzuckerungen zu vermeiden. In der vorliegenden Zusammenfassung werden die Bedeutung kardiovaskulärer Risikofaktoren und deren therapeutische Zielbereiche für die Ophthalmologie bei der Therapie von Glaukompatienten dargestellt.
Stellenwert vom Homocystein beim Glaukom
Authors: Jünemann Anselm , Rejdak Robert , Hohberger Bettina
Published: February 2018

In der multifaktoriellen Pathogenese der glaukomatösen Optikusatrophie spielen endotheliale Dysfunktion und vaskuläre Dysregulation eine Rolle. Eine Hyperhomocysteinämie als Risikofaktor für die endotheliale Dysfunktion ist sowohl mit dem primären Offenwinkelglaukom als auch mit dem sekundären Offenwinkelglaukom bei Pseudoexfoliationssyndrom assoziiert. In dieser Übersichtsarbeit wird die aktuelle Datenlage zur Assoziation zwischen Homocysteinmetabolismus und Glaukomerkrankung dargelegt sowie eine mögliche Rolle der Hyperhomocysteinämie in der Pathogenese und Progression der Glaukomerkrankung erläutert. Die Bedeutung von Homocystein für die Regulationsstörung der extrazellulären Matrix, der Vasotoxizität, der Neurodegeneration sowie der Epigenetik wird dargelegt. Die Prävention und Therapie der Glaukomerkrankung durch Beeinflussung des Homocysteinspiegels wird diskutiert.
Parametric study on the vortex-induced motions of semi-submersibles: Effect of rounded ratios of the column and pontoon
Authors: Liu Mingyue , Xiao Longfei , Yang Jianmin , Tian Xinliang
Published: February 2018

The vortex-induced motions (VIMs) of semi-submersibles have emerged as an important issue in offshore engineering, as they pose a threat to safe and reliable operations and severely affect the fatigue lives of risers and mooring systems. The VIM response depends on the shape of the submerged structure and thus is significantly influenced by the design parameters related to the columns and pontoons. Numerical simulations by the detached Eddy simulation method are validated by experimental data and then used for parametric analysis of the VIM performance of various semi-submersibles with different column rounded ratios (Rc/L) and pontoon rounded ratios (Rp/Lp). The results show that the transverse amplitudes of a semi-submersible with circular columns at a 0° current heading are twice as large as those at a 45° current heading. However, the semi-submersible with rounded square columns shows more significant transverse motions at a 45° current heading than at a 0° current heading. Furthermore, at the 45° current heading, the transverse amplitudes of the semi-submersibles show a rapid increase as the column radius increases in the range of Rc/L<0.1. The peak values remain roughly the same for 0.1≤Rc/L≤0.2 and then decrease as the column radius increases (Rc/L≥0.3). In addition, the effect of the pontoon shape on the transverse response is negligible for semi-submersibles with sharp square columns, while for semi-submersibles with rounded square columns or circular columns, the sharp rectangular pontoons greatly mitigate the VIM response.
On the macroscopic modeling of dilute emulsions under flow in the presence of particle inertia
Authors: Mwasame Paul M. , Wagner Norman J. , Beris Antony N.
Published: February 2018

Recently, Mwasame et al. [“On the macroscopic modeling of dilute emulsions under flow,” J. Fluid Mech. 831, 433 (2017)] developed a macroscopic model for the dynamics and rheology of a dilute emulsion with droplet morphology in the limit of negligible particle inertia using the bracket formulation of non-equilibrium thermodynamics of Beris and Edwards [Thermodynamics of Flowing Systems: With Internal Microstructure (Oxford University Press on Demand, 1994)]. Here, we improve upon that work to also account for particle inertia effects. This advance is facilitated by using the bracket formalism in its inertial form that allows for the natural incorporation of particle inertia effects into macroscopic level constitutive equations, while preserving consistency to the previous inertialess approximation in the limit of zero inertia. The parameters in the resultant Particle Inertia Thermodynamically Consistent Ellipsoidal Emulsion (PITCEE) model are selected by utilizing literature-available mesoscopic theory for the rheology at small capillary and particle Reynolds numbers. At steady state, the lowest level particle inertia effects can be described by including an additional non-affine inertial term into the evolution equation for the conformation tensor, thereby generalizing the Gordon-Schowalter time derivative. This additional term couples the conformation and vorticity tensors and is a function of the Ohnesorge number. The rheological and microstructural predictions arising from the PITCEE model are compared against steady-shear simulation results from the literature. They show a change in the signs of the normal stress differences that is accompanied by a change in the orientation of the major axis of the emulsion droplet toward the velocity gradient direction with increasing Reynolds number, capturing the two main signatures of particle inertia reported in simulations.