Dynamic response analysis of Euler–Bernoulli beam on spatially random transversely isotropic viscoelastic soil

A novel dynamic soil-structure interaction model is developed for analysis for Euler–Bernoulli beam rests on a spatially random transversely isotropic viscoelastic foundation subjected to moving and oscillating loads. The dynamic equilibrium equation of beam-soil system is established using the extended Hamilton's principle, and the corresponding partial differential equations describing the displacement of beam and soil and boundary conditions are further obtained by the variational principles. These partial differential equations are discretized in spatial and time domains and solved by the finite difference (FD) method. After the differential equations of beam and soil are discretized in the spatial domain, the implicit iterative scheme is used to solve the equations in the time domain. The solving result shows the FD method is effective and convenient for solving the differential equations of beam-soil system. The spring foundation model adopted the modified Vlasov model, which is a two-parameter model considering the compression and shear of soil. The advantage of the present foundation model is avoided estimating input parameters of the modified Vlasov model using prior knowledge. The present solution is verified by publishing solution and equivalent three-dimensional FE analysis. The present model produced an accurate, faster, and effective displacement response. A few examples are carried out to analyze the parameter variation influence for beam on spatially random transversely isotropic viscoelastic soil under moving loads.

Undrained Elastoplastic Solution for Cylindrical Cavity Expansion in Structured Cam Clay Soil Considering the Destructuration Effects

Soil structure has significant influences on the mechanical behaviors of natural soils, although it is rarely considered in previous cavity expansion analyses. This paper presents an undrained elastoplastic solution for cylindrical cavity expansion in structured soils, considering the destructuration effects. Firstly, a structural ratio was defined to denote the degree of the initial structure, and the Structured Cam Clay (SCC) model was employed to describe the subsequent stress-induced destructuration, including the structure degradation and crushing. Secondly, combined with the large strain theory, the considered problem was formulated as a system of first-order differential equations, which can be solved in a simplified procedure with the introduced auxiliary variable. Finally, the significance and efficiency of the present solution was demonstrated by comparing with the previous solutions, and parametric studies were also conducted to investigate the effects of soil structure and destructuration on the cavity expansion process. The results show that the soil structure has pronounced effects on the mechanical behavior of structured soils around the cavity. For structured soils, a cavity pressure that is larger than the corresponding reconstituted soils when the cavity expands to the same radius is required, and the effective stresses first increase to a peak value before decreasing rapidly with soil structure degradation and crushing. The same final critical state is reached for soils with different degrees of the initial structure, which indicates that the soil structure is completely destroyed during the cavity expansion. With the increase of the destructuring index, the soil structure was destroyed more rapidly, and the stress release during the plastic deformation became more significant. Moreover, the present solution was applied in the jacking of a casing during the sand compact pile installation and in situ self-boring pressuremeter (SBPM) tests, which indicates that the present solution provides an effective theoretical tool for predicting the behavior of natural structured soils around the cavity.

Humidification–Dehumidification (HDH) Desalination and Other Volume Reduction Techniques for Produced Water Treatment

Volume reduction has been suggested as a novel method to tackle the various challenges associated with produced water. The present solution offers an economical and environmentally friendly solution to treat a large bulk of produced water that may overwhelm conventional water treatment methods. The current study provides a review of the various volume reduction technologies including freeze concentration, reverse osmosis, and humidification and dehumidification desalination systems. Focus is concentrated on the general HDH technologies in addition to its integration with refrigeration cycles for conditioned air production, and the power cycles for power generation. The GOR, freshwater yield, and efficiencies of the integrated HDH systems were reviewed. Lastly, innovation in the HDH desalination technology is discussed with emphasis on its incorporation with the MVC process.

Torsional Vibration of a Pile in Transversely Isotropic Saturated Soil Considering Its Construction Disturbance Effect

The torsional dynamic response of a pile embedded in transversely isotropic saturated soil is investigated while allowing for the construction of disturbance effect. The dynamic governing equations of soil are established based on Biot’s poroelastic theory. By virtue of the continuous conditions of stress and displacement of adjacent disturbance circle and the boundary conditions of pile-soil coupling system, the circumferential displacement of soil and the shear stress on pile-soil contact surface are derived. Subsequently, a closed-form solution for the torsional dynamic response of a pile is derived in the frequency domain. By using inverse Fourier transform and the convolution theorem, a quasi-analytical solution for the velocity response of the pile head subjected to a semi-sine excitation torque is derived in the time domain. The proposed analytical solution is verified by comparing with the two existing solutions available in literature. Following the present solution, a parameter study is undertaken to portray the influence on the complex impedance, twist angle and torque of pile.

استخدام التخطيط و البحوث العلمية في المؤسسات الإعلامية : دراسة وصفية تحليلية على عينة من المؤسسات الإعلامية الاتحادية بولاية الخرطوم في الفترة من أول يناير 2009م إلى 31 ديسمبر 2010م

استخدام التخطيط و البحوث العلمية في المؤسسات الإعلامية : دراسة وصفية تحليلية على عينة من المؤسسات الإعلامية الاتحادية بولاية الخرطوم في الفترة من أول يناير 2009م إلى 31 ديسمبر 2010م The study deals with the use of planning scientific research in some information institutes at Khartoum state in the period 2009- 2010. The study concentrated on the use of planning in this institutes and do the information instates use the scientific concept of planning , in adition to the institutes information how to use the planning to collect information , data on the scientific research. For their more the difficulties which face the planning and scientific research in the information in states. The study summarizes that planning used by these institution sometimes is bsed on scientific research. These institutions do not use planning continuously, with planner in their general policies, and the use of scientific in bases in their researches one reflected. The study suggested the necessity of using planning in information institution through scientific principles. The researches implemented by the information institution must present solution the problems and difficulties they faced , and which are assist and facilitate in using the planning process , in addition to the existence of scientific research assessment and valuation for researches of communication used by these information institution

An analytical model for mountain wave in stratified atmosphere

An analytical, two-dimensional computer model has been developed for real time prediction of 'mountain wave due to Principal mountains over Kashmir valley. Simulation of the L2 profile has been made with realistic, non-zero values at higher levels and exponentially decreasing values at lower levels. Unlike Doos (1961), present solution has no restriction on the value of wave number (k). Validity of the model has been tested with the satellite observed waves in seven cases and actual aircraft report in one case.

Stretchable Textile Yarn Based on UHF RFID Helical Tag

In the context of wearable technology, several techniques have been used for the fabrication of radio frequency identification (RFID) tags such as 3D printing, inkjet printing, and even embroidery. In contrast to these methods where the tag is attached to the object by using sewing or simple sticking, the E-Thread® technology is a novel assembling method allowing for the integration of the RFID tag into a textile yarn and thus makes it embeddable into the object at the fabrication stage. The current E-Thread® yarn uses a RFID tag in which the antenna is a straight half-wave dipole that makes the solution vulnerable to mechanical strains (i.e., elongation). In this paper, we propose an alternative to the current RFID yarn solution with the use of an antenna having a helical geometry that answers to the mechanical issues and keeps quite similar electrical and radiative properties with respect to the present solution. The RFID helical tag was designed and simulated taking into consideration the constraints of the manufacturing process. The helical RFID tag was then fabricated using the E-Thread® technology and experimental characterization showed that the obtained structure exhibited good performance with 10.6 m of read range in the ultra high frequency (UHF) RFID band and 10% of tolerance in terms of elongation.

Hot Spots in the Weak Detonation Problem and Special Relativity

Problem statement: The initiation of a detonation in an explosive gaseous mixture in the high activation energy regime, in three space dimensions, typically leads to the formation of a singularity at one point, the “hot spot”. It would be suitable to have a description of the physical quantities in a full neighborhood of the hot spot. Results of this paper: (1) To achieve this, it is necessary to replace the blow-up time, or time when the hot spot first occurs, by the blow-up surface in four dimensions, which is the set of all hot spots for a class of observers related to one another by a Lorentz transformation. (2) A local general solution of the nonlinear system of PDE modeling fluid flow and chemistry, with a given blow-up surface, is obtained by the method of Fuchsian reduction. Advantages of this solution: (i) Earlier approximate solutions are contained in it, but the domain of validity of the present solution is larger; (ii) it provides a signature for this type of ignition mechanism; (iii) quantities that remain bounded at the hot spot may be determined, so that, in principle, this model may be tested against measurements; (iv) solutions with any number of hot spots may be constructed. The impact on numerical computation is also discussed.

Functional Restoration of a Midforearm Level Amputation using the Second Toe Transfer

Unilateral midforearm level amputation is a severely debilitating situation. The present solution for this problem is either restoration of function using a prosthetic hand, or a vascularized composite allotransplant (VCA) in some very selected cases. In cases of distal forearm level amputations, even vascularized second toe transfer could be done on the radial side of the hand to achieve good functional restoration. We present a case of midforearm level amputation in which the second toe transfer has been done above the level of insertion of pronator teres muscle to achieve meaningful function. This report highlights the fact that a single toe transfer could be helpful in achieving meaningful prehension, even at this proximal.

A modified Fourier series-based solution with improved rate of convergence for two-dimensional rectangular isotropic linear elastic solids

This paper presents a new displacement solution based on a Modified Fourier Series (MFS) for isotropic linear elastic solids under plane strain or plane stress states subject to continuous displacement and traction boundary conditions in a two-dimensional rectangular domain. In contrast with existing approaches that are restricted to Fourier series with a rate of convergence of second order O(m-2), the MFS allows increasing the rate of convergence of the solution. The governing Partial Differential Equations (PDEs) are satisfied exactly by two displacement solutions while the boundary conditions are approximated after solving a finite system of algebraic equations. Numerical results for a solution with an MFS with rate of convergence O(m-3) are compared with results from existing numerical and analytical methods, showing the enhanced behavior of the present solution.