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Using the ideas of variational differential quadrature (VDQ) technique and position transformation, an efficient numerical approach is developed herein in order to address the free vibration problem of compressible and nearly-incompressible solid bodies with arbitrary deformed shape within the framework of 3D hyperelasticity. The 3D hyperelasticity is first formulated by vector-matrix relations with the purpose of applying in coding process. An energy principle together with the Neo-Hookean strain energy function is also employed in the derivation of governing equations. The proposed numerical method is capable of addressing problems with irregular domains. Simple application, being free from the locking problem, and fast convergence rate are the key features of the approach. Hyperelastic rectangular/sector plates and cylindrical panel subjected to bending load are selected as test problems whose free vibrations are analyzed. The developed numerical method is found to be capable of yielding accurate solutions to the considered problems. Moreover, the effects of mode transition and geometrical properties are investigated in the numerical examples.

This paper presents an imaging system based on ultrawideband microwave radars for the detection of bleeding regions and strokes inside the human head. The proposed system is portable and focuses on revealing bleeding areas with unpredictable shapes using polarimetric data acquisition. A custom-designed dual-polarized bowtie patch antenna capable of pumping the UWB pulses inside the patient’s head is designed and presented as the biomedical sensor for the system. The antenna dimensions are 25 × 25 m m 2 . It mitigates the mismatch between the air and skin needles of any coupling liquid, resulting in safe SAR levels below 0.5 W/kg and wideband operating bandwidth that covers 1.2-4.5 GHz with unidirectional radiations. To collect the raw polarimetric data, an elliptical array of the proposed antenna is formed around the patient’s head model that includes 16 elements in direct contact with the phantom. The performance of the proposed method is validated through an imaging scenario with two nonuniform bleeding areas inside the patient head model. The whole structure is simulated with a Gaussian pulse as the excitation using CST Microwave Studio tools. To produce 2D images of the voxel model, the time-domain elliptical synthetic aperture radar (ESAR) imaging algorithm is applied. Accurately detecting the presence and shape of anomalies in reconstructed images using the proposed method demonstrates the efficiency of the proposed system and determines its advantages over single-polarization systems.

Based on Reddy’s third-order shear deformation theory and mixed formulation, a new numerical approach in the variational framework is developed to analyze the geometrically nonlinear free vibration behavior of cylindrical panels having cutouts with various shapes (e.g., square, circular, elliptical) under arbitrary boundary conditions. It is also assumed that the panel is made of functionally graded graphene platelet-reinforced composite with various patterns for the distribution of GPLs along the thickness direction whose effective properties are estimated using the modified Halpin–Tsai model in conjunction with the rule of mixture. The proposed approach can be named VDQFEM as it utilizes the VDQ and FE methods. Efficient matrix formulation, being free from the locking problem, computational efficiency and being able to solve problems with concave and polygon domains are the main features of VDQFEM. Selected numerical results are given to investigate the influences of geometrical parameters and weight fraction/distribution pattern of GPLs on the large-amplitude vibration response of panels with various cutouts and boundary conditions.

In this article, the vibrational behavior of conical panels in the nonlinear regime made of functionally graded graphene platelet–reinforced composite having a hole with various shapes is investigated in the context of higher-order shear deformation theory. To achieve this aim, a numerical approach is used based on the variational differential quadrature and finite element methods. The geometrical nonlinearity is captured using the von Karman hypothesis. Also, the modified Halpin–Tsai model and rule of mixture are applied to calculate the material properties of graphene platelet–reinforced composite for various functionally graded distribution patterns of graphene platelets. The governing equations are derived by a variational approach and represented in matrix-vector form for the computational purposes. Moreover, attributable to using higher-order shear deformation theory, a mixed formulation approach is presented to consider the continuity of first-order derivatives on the common boundaries of elements. In the numerical results, the nonlinear free vibration behaviors of functionally graded graphene platelet–reinforced composite conical panels including square/circular/elliptical hole and with crack are studied. The effects of boundary conditions, graphene platelet reinforcement, and other important parameters on the vibrational response of panels are comprehensively analyzed.

In this paper, a numerical solution strategy is proposed for studying the large deformations of rectangular plates made of hyperelastic materials in the compressible and nearly incompressible regimes. The plate is considered to be Mindlin-type, and material nonlinearities are captured based on the Neo-Hookean model. Based on the Euler–Lagrange description, the governing equations are derived using the minimum total potential energy principle. The tensor form of equations is replaced by a novel matrix–vector format for the computational aims. In the solution strategy, based on the variational differential quadrature technique, a new numerical approach is proposed by which the discretized governing equations are directly obtained through introducing differential and integral matrix operators. Fast convergence rate, computational efficiency and simple implementation are advantages of this approach. The results are first validated with available data in the literature. Selected numerical results are then presented to investigate the nonlinear bending behavior of hyperelastic plates under various types of boundary conditions in the compressible and nearly incompressible regimes. The results reveal that the developed approach has a good performance to address the large deformation problem of hyperelastic plates in both regimes.

The Eocene tectonic evolution of the easternmost Caribbean Plate (CP) boundary, i.e. the Lesser Antilles subduction zone (LASZ), is debated. Recents works shed light on a peculiar period of tectonic duality in the arc/back-arc regions. A compressive-to-transpressive regime occurred in the north, while rifting and seafloor spreading occurred in Grenada basin to the south. The mechanism for this strong spatial variation and its evolution through time has yet to be established. Here, using 3-D subduction mechanical models, we evaluate whether the change in the trench-curvature radius at the northeast corner of the CP could have modulated the duality. We assume asymmetrical CP boundaries at the north (from east to west: oblique subduction to strike-slip) and at the south (subduction-transform edge propagator-like behavior). Regardless of the imposed trench curvature, the southern half of our modeled CP always undergoes a NWto-W-oriented extension due to the tendency of the southernmost part of the South-America slab to rollback. In contrast, the tectonic regime in the northeast corner of the CP depends on the trench-curvature radius. A low radius promotes transtension-to-transpression, with a NE-oriented compressive component of the principal stress. A high trench-curvature largely reduces the compressive component and promotes an extensive regime similar to that in the south. We thus propose that an initially low-curvature radius of the NE-LASZ triggered the tectonic N-S duality in the Eocene and led to an ephemeral period of transpression/compression at the north, although an additional mechanism might have been required to locally enhance compression

In this article, a new solution approach is developed to numerically compute large deformations of 3D hyperelastic solids based on the compressible nonlinear elasticity. The governing equations are derived by the minimum total potential energy principle, and the Neo-Hookean model is used for the hyperelastic character of material. One of the key novelties of the work is its formulation in which the tensor form of equations is replaced by an efficient matrix–vector form that can be readily utilized in the coding process. Moreover, the variational differential quadrature technique is adopted to arrive at the discretized governing equations in a direct way. Simple implementation, fast convergence rate, and computational efficiency are the main advantages of present approach. Through some examples, the accuracy and effectiveness of the proposed numerical approach are revealed.

A numerical solution technique named as variational differential quadrature (VDQ) is adopted herein for the compressible nonlinear elasticity problems. The governing equations are obtained based on the virtual work principle by considering displacement as the unknown field. The neo-Hookean model is also considered for the hyperelastic behavior of material. In the solution method, an efficient vector–matrix formulation is developed from which the discretized governing equations are achieved from the weak form of equations in a direct approach. Simplicity in implementation and accuracy are among the features of the proposed approach. Moreover, it does not suffer from the locking problem and unphysical instabilities. Fast convergence rate and computational efficiency are other advantages of this method. A number of numerical examples are given to reveal the good performance of VDQ in the large deformation analysis of compressible and nearly-incompressible bodies.

Based on the ideas of variational differential quadrature (VDQ) method and position transformation, an efficient numerical variational strategy is proposed in this paper to analyze the large deformations of hyperelastic structures in the context of three-dimensional (3D) compressible and incompressible nonlinear elasticity theories. Based on the minimum total potential energy principle together with the Neo-Hookean model, the governing equations are derived. The relations of paper are presented in novel vector–matrix format. Replacing the tensor form of formulations with matricized ones is a novelty of present work since the matricized formulations can be readily employed for the programming in numerical approaches. Discretizing is also carried out via VDQ operators. For applying the VDQ technique, the irregular domain of elements is transformed into a regular one by the method of mapping of position field based on the finite element shape functions. This feature enables the proposed VDQ-transformed approach to solve problems with irregular domains. Moreover, the developed formulation is simple, compact and easy to implement. Considering structures with various shapes, several illustrative convergence and comparative investigations are given to assess the performance of the approach in both compressible and incompressible regimes. Good accuracy and computational efficiency can be reported as the features of developed VDQ-based approach.

Presented herein is a novel numerical approach for the vibrational analysis of conical panels with arbitrary-shaped holes made of functionally graded graphene platelet-reinforced composite (FG-GPLRC) within the framework of higher-order shear deformation theory (HSDT). The developed approach can be called variational differential quadrature finite element method (VDQFEM) as it is based on the ideas of VDQ and finite element methods. The governing equations are obtained by means of Hamilton’s principle. Also, the relations of paper are presented in a new matrix–vector form which can be efficiently utilized in the coding process of numerical techniques. By VDQFEM, the space domain of structure is first transformed into a number of finite elements. Then, the VDQ discretization technique is implemented within each element to derive the mass and stiffness matrices. Finally, the assemblage procedure is followed for obtaining total mass and stiffness matrices. Due to using HSDT, a novel mixed formulation approach is also proposed to accommodate the continuity of first-order derivatives on the common boundaries of elements. Conical panels with square/circular/elliptical cutout and with crack are selected to generate the numerical results. In the numerical examples, the effects of geometrical properties and reinforcement with GPL on the resonant frequencies of panels subject to various boundary conditions are investigated.

A computationally efficient numerical strategy called as variational differential quadrature-finite element method (VDQFEM) is developed herein for the nonlinear analysis of hyperelastic micromorphic continua. To this end, a novel formulation including microstructure effects is proposed in which high-order tensors are written in equivalent matrix or vector forms, and is then discretized in an efficient way. This feature is utilized in the coding process of numerical method. For the solution purpose, the domain is first transformed into a number of finite elements. Thereafter, a variational discretization technique called as VDQ is applied within each element. In order to employ the VDQ method, the irregular domain of the element is transformed into the regular one using the mapping technique. Finally, the assemblage procedure is performed. This approach can be used for the analysis of bodies with arbitrary geometries. By considering several numerical examples, it is revealed that the presented size-dependent formulation and numerical solution approach have a good performance to study the large deformations of hyperelastic micromorphic bodies with complex geometries.

The main objective of the present study is to analyze the thermal buckling of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) quadrilateral plates. Functionally graded patterns are introduced for the distribution of the carbon nanotubes (CNTs) through the thickness direction of the plate. The effective material properties of nanocomposite plate reinforced by CNTs are considered to be temperature-dependent (TD) and estimated using the micromechanical model. By the use of minimum total potential energy principle and based on the first-order shear deformation theory of plates, the stability equations are obtained. In order to use the generalized differential quadrature (GDQ) method and solve the stability equations, the irregular domain of quadrilateral plate is transformed into regular computational domain employing the mapping technique. The efficiency and accuracy of the proposed approach are first validated. Then, a comprehensive parametric study is presented to examine the effects of model parameters on the thermal buckling of FG-CNTRC quadrilateral plates. The results indicate that considering temperature dependency of the material properties plays an important role in the stability of the FG-CNTRC quadrilateral plates subjected to thermal loading.

The main objective of this paper is to analyze the free vibration of arbitrary shaped thick functionally graded carbon nanotube-reinforced composite (FG-CNTRC) plates based on the higher-order shear deformation theory (HSDT) using a variational differential quadrature approach. By means of the generalized differential quadrature (GDQ) numerical operators and Hamilton’s principle, the discretized equations of motion are obtained. In order to use the GDQ differential and integral operators appropriately, the coordinate transformation is considered through the conventional finite element approach for transforming the irregular domain of the plate into the regular computational one. Employing a unified numerical approach to analyze different shapes of thick FG-CNTRC plates based on HSDT is the main novel aspect of the present study. To imply the accuracy of the present model, a wide range of comparison studies are presented. The results indicate the efficiency of the developed numerical methodology to study the vibration of arbitrary shaped thick FG-CNTRC plates. Several results are also given to investigate the impacts of geometrical parameters and material properties on the vibrational behavior of FG-CNTRC plates.

In the present study, based on the higher-order shear deformation plate theory, the unified numerical formulation is developed in variational framework to investigate the thermal buckling of different shapes of functionally graded carbon nanotube reinforced composite (FG-CNTRC) plates. Since the thermal environment has considerable effects on the material properties of carbon nanotubes (CNTs), the temperature-dependent (TD) thermo-mechanical material properties are taken into account. In order to present the governing equations, the quadratic form of the energy functional of the plate structure is derived and its discretized counterparts are presented employing the variational differential quadrature (VDQ) approach. The discretized equations of motion are finally obtained based on Hamilton's principle. In order to convenient application of differential quadrature numerical operators in irregular physical domain, the mapping procedure is considered in accordance to the conventional finite element formulation. Some comparison and convergence studies are performed to show validity and efficiency of the proposed approach. A wide range of numerical results are also reported to analyze the thermal buckling behavior of different shaped FG-CNTRC plates.

The buckling analysis of thick composite annular sector plates reinforced with functionally graded carbon-nanotubes (CNTs) is presented under in-plane and shear loadings based on the higher-order shear deformation theory. It is considered that the plate is resting on the Pasternak-type elastic foundation. The overall material properties of functionally graded carbon nanotube-reinforced composites (FG-CNTRCs) are estimated through the micromechanical model. The governing equations are derived on the basis of the higher-order shear deformation plate theory, and the quadratic form of the energy functional of the system is presented. An efficient numerical method is presented in the context of variational formulation to obtain the discretized version of stability equations. The validation of the present study is demonstrated through comparisons with the results available in the literature and then comprehensive numerical results are given to investigate the impacts of model parameters on the stability of CNT-reinforced composite annular sector plates.

Based upon the third-order shear deformation theory (TSDT) and a variational mixed formation, the postbuckling response and free vibration around buckled configurations of variously-shaped plates made of functionally graded graphene platelet (FG-GPL)-reinforced nanocomposite are numerically investigated considering the effect of porosity. The proposed numerical strategy is formulated according to the ideas of variational differential quadrature (VDQ) and finite element method (FEM), and can be employed for plates with different shapes (e.g. rectangular, skew or quadrilateral and annular) including arbitrary-shaped hole. The material properties of nanocomposite are approximated based upon the Halpin–Tsai model together with the closed-cell Gaussian Random field scheme for various distribution patterns of porosity and GPLs along the thickness direction. The governing equations are obtained according to Hamilton’s principle by novel vector-matrix relations which can be readily used in numerical methods. One of the main novelties of developed numerical approach is proposing an efficient technique according to the mixed formulation to accommodate the continuity of first-order derivatives on the common boundaries of elements for the used TSDT model. A number of numerical examples are given to investigate the influences of porosity coefficient/distribution pattern, GPL weight fraction/dispersion pattern, cutout and edge conditions on the free vibrations of postbuckled FG-GPL-reinforced porous nanocomposite plates.

There are many two-dimensional (2D) structures of carbon allotropes which have been at the center of theoretical and experimental studies in recent years. α-, α2-, β- and γ-graphyne as the graphene allotropes with mixed sp1 and sp3 bonds are under study in the present work utilizing the molecular dynamics (MD) simulations. These thermodynamically stable forms of 2D carbon structure can also be rolled-up to generate novel nanotubes (NTs). Hence, the armchair (-A) and zigzag (-Z) NTs of the aforementioned one-atom-thick planar structures and their buckling behavior (critical force and strain) are considered. It is observed that γ-A- and γ-Z-graphyne NTs have the highest critical forces through the chosen range of aspect ratios (length/radius), whereas the α-graphyne NTs have the lowest critical forces. Also, α2- and β-graphyne NTs have the highest and lowest critical strains, respectively. Furthermore, the possible multi-walled (MW) NTs are simulated. In agreement with results of the single-walled (SW) NTs, the buckling analysis of MWNTs shows that γ-graphyne and α-graphyne MWNTs have the highest and the lowest mechanical stability under compression, correspondingly. In addition, the results of the critical strain for MWNTs are comparable with those of SWNTs.

Using the ideas of variational differential quadrature and finite element methods (VDQ and FEM), a novel numerical approach is developed in this paper to investigate the postbuckling behavior of plates with arbitrary shape under the action of thermal load within the framework of higher-order shear deformation theory (HSDT). It is considered that the plates are made of functionally graded carbon nanotube reinforced composite (FG-CNTRC). By the proposed approach, the thermal postbuckling behavior of plates with arbitrary-shaped cutout can be modeled. The rule of mixture is utilized to obtain the effective material properties of nanocomposite which are considered to be temperature-dependent. To implement the proposed method that can be named as VDQFEM, the variational temperature-dependent formulation of problem is first developed. This formulation is presented using novel vector-matrix relations with the aim of utilizing in programming in an efficient way. In the context of VDQFEM, the space domain of plate is first transformed into a number of finite elements. In the next step, the VDQ discretization technique is implemented within each element. Then, the assemblage procedure is performed to derive the set of matricized governing equations which is finally solved by means of the pseudo arc-length continuation algorithm. One of the main novelties of present approach is proposing an efficient way based on mixed-formulation to accommodate the continuity of first-order derivatives on the common boundaries of elements for the used higher-order shear deformable plate model. Quadrilateral plate, skew plate, annular plate, square plate with rectangular hole and rectangular plate with circular hole under different boundary conditions including CCCC, SSSS, CSCS and CCSS (S: simply-supported, C: clamped) are considered in the numerical example. First, validation studies are presented in terms of critical buckling temperature of CNTRC rectangular plates with various CNT distribution patterns. It is shown that the proposed method has the advantages of standard VDQ technique including fast convergence rate, being locking-free and simple implementation. Moreover, it is capable of considering polygon and concave domains. Also, the effects of geometrical properties, volume fraction and distribution pattern of CNTs and temperature-dependency of material properties on the thermal postbuckling of plates are studied.

In this paper, an efficient numerical strategy is used to study the geometrically nonlinear static bending of functionally graded graphene platelet-reinforced composite (FG-GPLRC) porous plates with arbitrary shape. Porous nanocomposite plates including cutout with various shapes can be modeled by the present approach. Four types of porous distribution scheme and four GPL dispersion patterns are selected, and the material properties are calculated based on the closed-cell Gaussian random field scheme, the Halpin–Tsai micromechanical model together with the rule of mixture. First, the variational statement of governing equations based on the virtual work principle and higher-order shear deformation theory (HSDT) is derived and presented in vector–matrix form for computational aims. Then, using the ideas of variational differential quadrature and finite element methods (VDQ and FEM), a numerical approach called as VDQ-FEM is used to address the considered problem. In VDQ-FEM, the domain of problem is first transformed into a number of finite elements. In the next step, the VDQ discretization technique is implemented within each element. Then, the assemblage procedure is performed to obtain the set of Studying effects of porosity and GPL distributions and porosity coefficient matricized governing equations which is finally solved by means of the pseudo arc-length continuation algorithm. One of the main novelties of the present work in implementing VDQ-FEM is proposing an efficient way based on mixed-formulation to guarantee the continuity condition of first-order derivatives in entire domain for the used HSDT model. A detailed parametric study is conducted to investigate the nonlinear bending of FG-GPLRC porous plates with different shapes. In the numerical results, the effects of porosity coefficient, porosity distribution pattern, GPL distribution pattern and boundary conditions on the nonlinear bending response of plates are analyzed.

The buckling behavior of a novel three-dimensional metallic carbon nanostructure known as T6 is investigated herein employing the molecular dynamics (MD) simulations. The models are prepared on the basis of two beam- and plate-like structures to study the effects of size and geometry on the critical buckling force and critical strain. It is observed that the range of critical force for the beam-like and plate-like T6 with different geometrical parameters is approximately identical. Moreover, it is demonstrated that the critical buckling force decreases and increases by increasing the length and the width of T6, respectively. Moreover, it is shown that critical strain of beam-like T6 decreases by increasing the length, whereas, in the case of plate-like T6, the critical strain only fluctuates around 2% by increasing the width. It is further found that the buckling parameters of T6 are not comparable with those of single-walled carbon nanotubes (SWCNTs) and graphene with a relatively similar dimension. The critical buckling force and critical strain of T6 are considerably smaller than those of SWCNT and larger than those of graphene.

In this study, palladium nanoparticles were synthesized and characterized by SEM, TEM, and BET analysis. The synthesized nanoparticles were loaded on activated carbon (Pd-NP-AC) and its adsorption efficiency was measured for methyl red (MR) removal from aqueous solution. To analyze the data, an experimental design was adopted considering three operating parameters viz. initial MR concentration, adsorbent mass, and contact time as input variables while the pH was optimized using one at a time method. Statistical analysis of data corresponded to MR holds in good agreement with predicted and experimental removal percentage. The equilibrium data followed Langmuir isotherm model, while pseudo-second-order and intraparticle diffusion models cooperatively represented experimental adsorption data at various time. High adsorption capacity was obtained because of high available surface area of the nanoparticle loaded adsorbent.

In the context of variational differential quadrature finite element method (VDQFEM), the vibration and buckling of functionally graded graphene platelet reinforced composite (FG-GPLRC) plates with cutout are investigated in this study. The modified Halpin-Tsai model is used to compute the effective mechanical properties of nanocomposite plate. The mixed-type formulation of the higher-order shear deformation plate theory (HSDPT) is developed based on the Lagrange multiplier to model the mechanical behavior of FG-GPLRC plates. The variational-based differential quadrature element is developed to numerically solve the problem. Various comparative results are provided to check the validity of the proposed approach. Additionally, multiple numerical results are represented to examine the vibration and buckling behaviors of FG-GPLRC plates.

Based on molecular dynamics (MD) simulations, the buckling analysis of a perfect carbon nanotorus is presented herein. First of all, the minimum length of single-walled carbon nanotubes (SWCNTs) with different radii is determined at which perfect toroidal CNTs can be formed without any ripple at the inner side of the rings. According to the results, by increasing the radius of SWCNT (r), the radius of its corresponding perfect nanotorus (R) increases. Also, for SWCNTs with various lengths, it is found that the buckling force and strain of related carbon nanotoruses increase by increasing R/r. In addition, as the perfect toroidal CNTs are arranged vertically in a column form in accordance with two different schemes, the effects of increasing the radius (R) and the number of carbon nanotoruses (the height of the column made by nanotoruses) on the buckling force and strain are investigated. Based on the results, as a fixed number of carbon nanotoruses with the same radius are arranged vertically in the column form, the buckling force and strain increase by increasing R/r. By contrast, increasing the height of the column made by carbon nanotoruses with similar radius leads to the reduction of buckling force and strain.

This paper presents off-line and on-line orientation results obtained with the new on line nuclear orientation device NICOLE in CERN. Magnetic moments of 187,185Pt g and 186Ir m, electric quadrupole moment ratios between Pt isotopes with mass number 185, 187 and 189, the spin of the 2 h isomer of 186Ir and a new decay scheme of 184Au involving a metastable state are established. The shape variation versus mass number of the Pt isotopes leads to sign change of the spectroscopic quadrupole moment between A=187 and 185. © 1990 J.C. Baltzer A.G., Scientific Publishing Company.

Nuclear orientation experiments on the system89Zr→89mY in iron are described. Incomplete relaxation in the 16.1 s yttrium isomer is fitted using the theory of Shaw and Stone, including effects of polarisation of the89Zr parent state. The value of the Korringa constant, CK=0.44 sK for89mYFe, is within a factor af two of the prediction of the empirical systematic CK(μBhf/I)2∼6×1016 Ks−1.

Nuclear orientation and nuclear magnetic resonance experiments were performed on185, 187, 189Pt isotopes oriented in Fe and single crystal Zn at temperatures down to about 6 mK. The hyperfine splitting frequencies of185Pt and187Pt in iron were determined to be 164.9(2) and 261.1(2) MHz, respectively. With the hyperfine field of -126.1(2.5) T, the g-factors are deduced to be |g(185Pt)|=0.172(3) and |g(187Pt)|=0.272(5). The spectroscopic quadrupole moment of187Pt was found to be negative with magnitude similar to that of189Pt, indicating a predominantly oblate ground state deformation for both isotopes. The spectroscopic quadrupole moment of185Pt was found to be positive, with the ratio Q(185Pt)/Q(189Pt)=-3.6(9), clearly indicating a change to prolate ground state deformation. © 1998 J.C. Baltzer A.G., Scientific Publishing Company.

In this paper, we study two different methods, called Legendre and LMS, to find the current distribution of an unequally spaced array structure. In both methods, we aim to find the most similar radiation pattern to a desired one toward an arbitrary angle and then show the ability of LMS method to provide the low SLL (Side Lobe Level) comparing to Legendre method due to its better performance for minimizing error.

A novel low profile wideband internal planar monopole (PM) antenna is proposed. It consists of a rectangular planar monopole, 10 × 20 mm2, loaded with a pair of parallel small thin plates, 8 × 12 mm2, placed on the two radiating sides of the PM antenna. The proposed antenna has two ground planes. A small horizontal ground, 9 × 20 mm2, that holds the PM antenna (making the overall volume of the antenna element 9 × 20 × 23 mm3) and the vertical ground, 50 × 80 mm2 that can be treated as the ground plane of the circuit board of a mobile phone. A prototype of the proposed antenna has been fabricated and tested. Its operating bandwidth with S 11 lower than −10 dB is 1.66–7.35 GHz, which covers the digital communication system (DCS 1.72–1.88 GHz), personal communication system (PCS 1.85–1.99 GHz), universal mobile telecommunication system (UMTS 1.92–2.17 GHz), wireless local area network (WLAN), which usually operate in the 2.4 GHz (2.4–2.484 GHz) and 5.2/5.8 GHz (5.15–5.35 GHz/5.725–5.825 GHz) and worldwide in...

Retropharyngeal abscess, a rare event in adults, is usually observed in immunodeficient persons or subsequent to foreign bodies. We report a case of retropharyngeal abscess which revealed diabetes mellitus. A 47-year-old woman with an uneventful history complained of fever, dysphagia and trismus. Clinical findings were swelling of the pharyngeal posterior wall. The CT scan showed an abscess in the retropharyngeal space. Puncture revealed the purulent nature of the collection. The bacteriological study identified a Gram-negative aerobic germ (Citrobacter freundii). Laboratory tests disclosed diabetes mellitus with ketosis. The treatment consisted in surgical drainage and lavage of the retropharyngeal space using a saline solution with gentamycin associated with infusion of appropriate antibiotics. Abscess formation in the retropharyngeal space is a rare event in adults. The immunological status of the patient should be carefully explored. Management requires drainage of the collection and infusion of active antibiotics.

The overall aim of this review was to evaluate the antihelminthics activity of browse forages containing secondary plant factors. Results from literature have shown the benefits of feeding browse foliage in terms of nutrient supply, supplementation supported animal growth and performance. It was found that supplementation with browse leaf meal reduced worm fecundity, also reduces the worm burdens and total fecal egg counts during feeding period. It is concluded that browse foliage can be used to reduce the adverse effects of intestinal parasite infections in ruminant, hence reducing the need for costly antihelminthics drugs and the development of resistance to these drugs. Keywords : Antihelminthics, browse foliage, intestinal parasite, tannins

Osteoarticular tuberculosis is the fourth leading extrapulmonary localization of tuberculosis. The disease has a progressive course and is often diagnosed in the stage of bone destruction, causing an important diagnostic problem in diabetics with nervous osteoarthropathy. We report the case of a 23-year-old patient with multicomplicated diabetes type 1, treated for pulmonary tuberculosis who consulted after a trauma distended the left ankle. Bone biopsy was performed because of the diagnostic doubt between diabetes and infectious osteoarthropathy. Pathology reported active tuberculosis. Osteoarticular tuberculosis is still a severe disease because of the functional prognosis that requires early diagnosis, a difficult task in some conditions particularly in the diabetic where the disease may mimic nervous osteoarthropathy. Bone biopsy should be performed if there is a doubt.