Reduction Of Radius Research Articles

Self-focusing of an elliptic-Gaussian laser beam in relativistic ponderomotive plasma using a ramp density profile

The propagation characteristics of an elliptic-Gaussian beam in non-uniform plasma have been investigated by taking into account the combined effects of relativistic and ponderomotive types of nonlinearity. Self-trapping, self-phase modulation, and beam width variation with propagation distance are given particular attention in the study. It is observed that the plasma density function significantly affects the propagation behavior of the beam. The beam radius along the x axis and y axis is separately influenced due to the density function, which, as a result of the cross-focusing phenomenon, results in the reduction of the effective beam radius during propagation of the beam. The longitudinal phase shift increases in the present case in comparison to uniform plasma. Self-trapping is also observed, which is, however, not comparable with that of a cylindrically symmetrical Gaussian beam. We have used the variational approach to set up the coupled nonlinear differential equations for the beam width parameters along the x and y axes and the longitudinal phase of the beam.

Thermodynamic phase behaviour and miscibility of confined fluids in nanopores

In this paper, thermodynamic phase behaviour and miscibility of confined pure and mixing fluids in nanopores are studied. First, a semi-analytical equation of state (EOS) is developed, based on which two correlations are modified to predict the shifts of critical temperature and pressure. Second, the thermodynamic free energy of mixing and solubility parameter are derived, quantitatively calculated, and applied to study the conditions and characteristics of the fluid miscibility in nanopores. Third, an improved EOS model with the modified correlations is proposed and used to calculate the phase properties and miscibility-associated quantities of three mixing fluids. The critical temperature and pressure of confined fluids are always decreased by reducing the pore radius. The negative pressure state is validated for a confined liquid, whose upper temperature limit is quantitatively determined and found to be lowered with the reduction of pore radius. The liquid–gas miscibility is beneficial from the pore radius reduction and the intermediate hydrocarbons (e.g., C2, C3, i- and n-C4) perform more miscible with the liquid C8 in comparison with the lean gas (e.g., N2 and CH4). Moreover, the molecular diameter of single liquid molecule is determined to be the bottom limit, the pore radius above which is concluded as a necessary condition for the liquid–gas miscibility. The calculated phase behaviour and minimum miscibility pressures (MMPs) of the three mixing fluids agree well with the literature results, which reveals that the shifts of critical properties dominate the phase behaviour and miscibility changes of confined fluids from bulk phase to nanopores.

Utilization of remote sensing and GIS to identify radius of urban cool island for planning open green area in urban area (case study of Yogyakarta)

City is a center development of a region that has functions both social and economic. Yogyakarta City is the administrative center of Yogyakarta Special Region province and as educational centers in Indonesia. The complexity of activities that occurring has an impact on the microclimate situation in the region which is called as Urban Heat Island and it will affect the comfort of urban community so that urban area should be arranged especially about microclimate aspects. Open Green Area is one element that can lower the surface temperature. Radius reduction in surface temperature of Open Green Area became the main issue in this research as a basis for determining the location of Open Green Area spaces with an ideal distance interval among Open Green Areas in urban areas. The methods used Split Moving Window Analysis to obtain Land Surface Temperature, Normalized Difference Vegetation Index is transformation to obtain variation of vegetation density, statistic analysis to know LST correlation with NDVI, and buffer analysis to analyze changing of radius temperature. The results show that average surface temperature in Yogyakarta City ranges 25 to 35°C. The value of vegetation density is obtained 0-0,3. Based on the result of correlation between LST and NDVI show that they have correlation value with negative gradient. The higher value of NDVI give impact of LST value in the same location will tend to be low with average value of temperature rise of 0.122°C per 30 meters, then is obtained the ideal distance interval among Open Green Area ranged from 240-260 meters to maintain maximum temperature rise 1 degrees Celsius from the center of Open Green Area. The results of this study can be used as a suggestion to arrange of planning Open Green Area for the Yogyakarta Government.

Multi-Modal Pain Control in Ambulatory Hand Surgery.

We evaluated postoperative pain control and narcotic usage after thumb carpometacarpal (CMC) arthroplasty or open reduction and internal fixation (ORIF) of the distal radius in patients given opiates with or without other non-opiate medication using a specific dosing regimen. A prospective, randomized study of 79 patients undergoing elective CMC arthroplasty or ORIF of the distal radius evaluated postoperative pain in the first 5 postoperative days. Patients were divided into 4 groups: Group 1, oxycodone and acetaminophen PRN; Group 2, oxycodone and acetaminophen with specific dosing; Group 3, oxycodone, acetaminophen, and OxyContin with specific dosing; and Group 4, oxycodone, acetaminophen, and ketorolac with specific dosing. During the first 5 postoperative days, we recorded pain levels according to a numeric pain scale, opioid usage, and complications. Although differences in our data did not reach statistical significance, overall pain scores, opioid usage, and complication rates were less prevalent in the oxycodone, acetaminophen, and ketorolac group. Postoperative pain following ambulatory hand and wrist surgery under regional anesthesia was more effectively controlled with fewer complications using a combination of oxycodone, acetaminophen, and ketorolac with a specific dosing regimen.

Reduction of corner radius of cylindrical parts by magnetic force under various loading methods

To prevent small corner radius of cylindrical parts from cracking near the sheet bottom corner during deep drawing, a new method combining multidirection magnetic force electromagnetic forming and traditional stamping is proposed in this paper. First, a punch with an 8-mm corner radius is used to obtain a cylindrical part. Then, a coil-generated multidirection magnetic force is used to further deform the sheet corner radius and obtain a smaller corner radius. ANSYS/emag and ABAQUS/explicit software are used to calculate the multiphysical field coupling process in electromagnetic forming (EMF), and obtain accurate simulation data based on the experimental results. We found the following that the maximum thickness thinning ratio was 20% in the sheet corner region with an applied multidirection magnetic force in comparison to 33% if only a bulging coil was used.

Modeling and Implementing Nonlinear Equations in Solid-State Lasers for Studying their Performance

In this paper, the effect of radius variation of beam light on output efficacy of SFD Yttrium aluminium borate laser doped with Neodymium ion, which is simultaneously a non-linear and active laser crystal, is investigated in a double-pass cavity. This is done with a concave lens that concentrates (Reduction of optical radius within nonlinear material) as much optical laser as possible, resulting in increasing the laser efficiency, second harmonic and the population inversion difference. In this study, we first developed five discrete differential equations describing the interactions of 807 nm pump beam, 1060nm laser beam and 530nm second harmonic beam. Output efficiencies of laser and second harmonic beams at pumping power of Pp =20W and beam radius of 5μm have been presented. Meanwhile, in this paper, the first experiment for creating second harmonic in solid state lasers was fully described with a figure and its procedure was investigated and then the equations (second harmonic and laser and population inversion) were studied. Radius variation of beam light aims at increasing laser output efficacy and improving second harmonic and population inversion. The analytic methods which have been solved the discrete differential equations via Matlab.

Influence of liquid compressibility on the dynamics of single bubble sonoluminescence

The main effects of liquid compressibility on the dynamics of single bubble sonoluminescence are investigated via three different radial dynamics models. In order to precise description of the interior gas thermodynamics, a hydrochemical model is used. In the case of an argon gas bubble in water, the results obtained with the Gilmore model and the Lezzi and Prosperetti model are compared with those resulting from the Keller and Miksis model. It is shown that the variation of liquid density at bubble surface in a very short time interval around the end of the bubble collapse, which has been incorporated into the first two models, strongly influences the bubble cavitation dynamics at higher acoustic amplitudes. The simulation results denote an increase in the bubble temperature and pressure and a reduction in the bubble minimum radius, compared with those ones obtained with Keller and Miksis model. As the acoustic amplitude increases, the difference between the models becomes larger. Moreover, it is shown that increasing the bubble ambient radius leads to an improved match between the results of the models.

Fluid-Imbibition Coupled Interferometry Study of Surface Modifications in Nanoporous Anodic Alumina for Biosensing

Nanoporous anodic alumina (NAA) is a material with great perspectives in nanotechnology due to its cost-effective fabrication, its chemical stability and its versatility in applications such as biosensing or drug delivery[1]. Optical sensing with NAA has gained much attention in recent years[2,3]. Nano-optofluidic methods[4] based on a solid carrier matrix, a liquid carrying analytes and on the physico-chemical characteristics at their interfaces have been proven sensitive for substances as small as nanoparticles, viruses[5] and even ions[6]. Fluid imbibition-coupled laser interferometry (FICLI)[7] is an optofluidic technique that permits the investigation of the surface and geometrical properties of nanoporous structures by non-invasive optical methods. It consists of the measurement of interferometric light intensity fluctuations in a beam reflected in a nanoporous thin film membrane as it is being filled by a liquid. In FICLI, time-resolved interferograms are measured and then analyzed on the basis of mathematical models of the filling kinetics. With this the surface properties and the pore internal geometries can be estimated. Recently, we established for FICLI an accuracy better than 2 nm in determining changes in NAA pore radius after different modifications involving radius increase (by chemical wet etching) or decrease (by the deposition of layer-by-layer coatings). Such accuracy leads to consider NAA and FICLI as a platform to develop biosensing systems. Such application depends critically on the functionalization of the pore surface, as it is necessary to enable the selective immobilization of the desired biomolecules. In this work, we investigate the influence of three different NAA functionalization methods on the FICLI pore radius estimate: i) electrostatic binding of bovine serum albumin (BSA), ii) covalent binding for the attachment of streptavidin and biotin and iii) specific immune complexation of antibody-antigen pairs. The study was carried on NAA membranes produced in both oxalic and sulfuric acid electrolytes, and together a chemical wet etching step for a given amount of time (between 0 min. and 24 min.) permits to use a wide range of pore dimensions (between 15 nm and 44 nm). NAA inner pore surface was modified in different steps and the FICLI technique was applied to estimate the changes in filling dynamics and the consequent pore radius change after each step. For the electrostatic attachment of BSA, NAA membranes with different pore radius were used as-produced and measured before and after incubation in a BSA solution. For the covalent attachment of streptavidin, NAA samples with 40 nm initial pore radius were investigated after two steps: i) silanization with (3-aminopropyl)-triethoxysilane (APTES) with cross-linking activation with glutaraldehyde (GTA) and ii) incubation with streptavidin. Finally, immune complexation within NAA pores was tested on NAA samples with 40 nm initial pore radius attaching different kinds of immunoglobulin (IgG) to the inner pore surface. Several experiments were conducted, in all of them the first step was to attach electrostatically protein A, which has the ability to link with antibody or antigen portions. Then, samples were incubated following one of three possibilities: i) human IgG, ii) anti-human IgG and iii) anti-goat IgG from rabbit followed by incubation with goat IgG. Results show that for the case of the electrostatic attachment, FICLI is able to detect the formation of a BSA layer on the NAA pores, independently of the initial pore radius with slight differences observed for different electrolyte used in the preparation. For covalent immobilization of streptavidin, FICLI estimates a much bigger radius reduction than expected from the molecule size, what can be explained by a multi-layer deposition of streptavidin. Finally, FICLI is able to demonstrate that different IgG attach differently to the NAA pores with a determinant influence of the pore size. ACKNOWLEDGMENT This work was supported by the Spanish MINECO (TEC2015-71324-R), the Catalan authority AGAUR (2014SGR1344), and ICREA under the ICREA Academia Award. REFERENCES [1] J. Ferré-Borrull, E. Xifré-Pérez, J. Pallarès and L.F. Marsal in “Nanoporous Alumina: Fabrication, Structure, Properties and Applications”; Santos, A., Losic, D., Eds.; Springer-Verlag Berlin, 2015, p. 185. [2] G. Macias, J. Ferré-Borrull, J. Pallarès and L.F. Marsal, Analyst 140, 2015, p. 4848. [3] T. Kumeria, A. Santos, M.M. Rahman, J. Ferré-Borrull, L.F. Marsal, D. Losic, ACS Photonics 1, 2014, p. 1298. [4] D. Psaltis, S.R. Quake, C.H. Yang, Nature 442, 2006, p. 381. [5] A. Mitra, B. Deutsch, F. Ignatovich, C. Dykes, L. Novotny, ACS Nano 23, 2010, p. 1. [6] T. Kumeria, M.M. Rahman, A. Santos, J. Ferré-Borrull, L.F. Marsal, D. Losic, ACS applied materials & interfaces 6, 2014, p. 12971. [7] C. Eckstein, E. Xifré-Pérez, M. Porta-i-Batalla, J. Ferré-Borrull, L.F. Marsal, Langmuir 32, 2016, p. 10467.

Evaluating the hydraulic and transport properties of peat soil using pore network modeling and X-ray micro computed tomography

Micro-scale properties of peat pore space and their influence on hydraulic and transport properties of peat soils have been given little attention so far. Characterizing the variation of these properties in a peat profile can increase our knowledge on the processes controlling contaminant transport through peatlands. As opposed to the common macro-scale (or bulk) representation of groundwater flow and transport processes, a pore network model (PNM) simulates flow and transport processes within individual pores. Here, a pore network modeling code capable of simulating advective and diffusive transport processes through a 3D unstructured pore network was developed; its predictive performance was evaluated by comparing its results to empirical values and to the results of computational fluid dynamics (CFD) simulations. This is the first time that peat pore networks have been extracted from X-ray micro-computed tomography (µCT) images of peat deposits and peat pore characteristics evaluated in a 3D approach. Water flow and solute transport were modeled in the unstructured pore networks mapped directly from µCT images. The modeling results were processed to determine the bulk properties of peat deposits. Results portray the commonly observed decrease in hydraulic conductivity with depth, which was attributed to the reduction of pore radius and increase in pore tortuosity. The increase in pore tortuosity with depth was associated with more decomposed peat soil and decreasing pore coordination number with depth, which extended the flow path of fluid particles. Results also revealed that hydraulic conductivity is isotropic locally, but becomes anisotropic after upscaling to core-scale; this suggests the anisotropy of peat hydraulic conductivity observed in core-scale and field-scale is due to the strong heterogeneity in the vertical dimension that is imposed by the layered structure of peat soils. Transport simulations revealed that for a given solute, the effective diffusion coefficient decreases with depth due to the corresponding increase of diffusional tortuosity. Longitudinal dispersivity of peat also was computed by analyzing advective-dominant transport simulations that showed peat dispersivity is similar to the empirical values reported in the same peat soil; it is not sensitive to soil depth and does not vary much along the soil profile.

The impact of a passive tuned mass damper on offshore single-blade installation

Single-blade installation is a method suitable for the installation of blades on large wind turbines. For single-blade installations on offshore monopile-type wind turbines, a jack-up vessel is often involved, and each blade is mated with the hub at the tower top. Prior to the alignment phase, the blade root and the nacelle at the tower top experience relative motions. The blade-root motions are induced by the wind loads, and the nacelle motions are due to the resonant vibrations of the monopile support structure under wave loading. To alleviate the relative motions and to facilitate the alignment process, external passive tuned mass dampers can be installed on the monopile support structures. This work investigates the application potential of tuned mass dampers in single-blade installation. Multibody simulations were conducted under collinear wind and waves conditions, and the relative motions between the blade-root and the hub were analysed. It was found that when an optimally tuned passive damper is considered for the monopile structure, the reduction in the critical motion radius can reach up to 30%.

A simulation of atomic force microscope microcantilever in the tapping mode utilizing couple stress theory

The nonlinear vibration behavior of a Tapping mode atomic force microscopy (TM-AFM) microcantilever under acoustic excitation force has been modeled and investigated. In dynamic AFM, the tip–surface interactions are strongly nonlinear, rapidly changing and hysteretic. First, the governing differential equation of motion and boundary conditions for dynamic analysis are obtained using the modified couple stress theory. Afterwards, closed-form expressions for nonlinear frequency and effective nonlinear damping ratio are derived utilizing perturbation method. The effect of tip connection position on the vibration behavior of the microcantilever are also analyzed. The results show that nonlinear frequency is size dependent. According to the results, an increase in the equilibrium separation between the tip and the sample surface reduces the overall effect of van der Waals forces on the nonlinear frequency, but its effect on the effective nonlinear damping ratio is negligible. The results also indicate that both the change in the distance between tip and cantilever free end and the reduction of tip radius have significant effects on the accuracy and sensitivity of the TM-AFM in the measurement of surface forces. The hysteretic behavior has been observed in the near resonance frequency response due to softening and hardening of the forced vibration response.

Impact of floodplain gravel mining on landforms and processes: a study case in Orlat gravel pit (Romania)

Understanding gravel mining, a very common but aggressive activity, as a morphogenetic action is fundamental for analyzing and assessing the impact on floodplain morphology and the dynamic of riverbeds, on sediments budget and water balance assessment, but also for floodplain planning and resources management. Field observations and GIS analysis were performed in a gravel pit area from central Romania to assess the impact of gravel harvesting during the last decade (2005–2015) on floodplain landscape, landforms dynamic and fluvial processes. Field measurements, diachronic analysis on maps, channel sinuosity coefficient and braided coefficient were carried out to assess the riverbed pattern. The results indicate that the intensive harvesting of gravels and sands in floodplain area leads to doubling of pit and pit ponds surfaces, changes in floodplain morphology and landscape degradation and radical changes in land use/land cover. The channel analysis indicates that the natural conditions and gravel harvesting had an important role in riverbed mobility and reveals different patterns along the Cibin River: meandered, disentangling and sinuous. The main changes of the riverbed consist of meanders radius reduction, meander loops migration northward and downstream, increased sinuosity and decreased braided coefficient. This study facilitates a better understanding of the geomorphologic consequences of off-stream gravel harvesting, the fluvial processes variability linked to flow and bedload and point to human action as morphogenetic and morphodynamic factors. Moreover, this study may enhance the environmental significance in sustainable management of floodplain being a useful tool in applied ecology, river remediation studies and territorial planning.

Symmetry analysis of a 3D printed model of distal radius

Objective To investigate whether a 3D printed model of the contrlateral healthy distal radius, especially its articular accuracy, helps anatomical reduction and precise reconstruction of the fractured distal radius. Methods The CT data of bilateral radii were collected from 15 normal volunteers (11 males and 4 females with an average age of 22.8 years) between November and December 2016. After 3D reconstruction of the bilateral distal 1/3 radii, solid 3D models of left radius were mirrored and generated by 3D printing. The data of right radii (reference group) were compared with the data of the solid 3D models of left radius acquired through a 3D scanner (test group) using deviation analysis. Results The maximum volume difference between the 3D printed model and the contralateral radius was 6.86%. The average volume of the reference group was 19,165.82±3,250.50 mm3 and that of the test group 19,310.65±3,305.15 mm3, showing no statistically significant difference between the 2 groups (t=-0.941, P=0.363). The maximum surface area difference was 3.84% between the 2 groups. The average surface area of the reference group was 5,075.80±549.34 mm2 and that of the test group 5,139.43±572.48 mm2, showing a significant difference (t=-2.451, P=0.028). The 3D deviation analysis showed a mean positive deviation of 0.37±0.10 mm and a mean negative deviation of 0.30±0.07 mm. The maximum mean square root was 0.65. The 3D deviation was distributed mainly within 1 mm interval, with a distribution frequency of 96.27%. Conclusions A 3D printed model prepared by high precision equipment is accurate enough to guide reconstruction of distal radius fractures in adults. In the treatment of complex fractures of the distal radius, a 3D printed model of the contralateral healthy distal radius can be used as a reference to achieve anatomical reduction and precise reconstruction of the fractured distal radius. Key words: Radial fractures; Wrist joint; 3D printing technology; Imaging, three-dimensional; Deviation analysis

Outcome analysis of hybrid fixation technique (radius nailing and ulna plating) in closed proximal radius and ulna fractures in adults

Background: The aim of the study was to evaluate results of hybrid fixation technique (radius nailing and ulna plating) in closed proximal radius and ulna fractures in adults. The hypothesis behind hybrid fixation is to provide rigid fixation and restoration of forearm length, by ulna plating and large diameter square nail in radius gives rotational stability without any posterior interosseous nerve palsy in proximal radius and ulna fractures. Closed nailing of proximal radius avoid posterior interosseous nerve palsy which has high probability in open surgical approach.Materials and method: We prospectively evaluated 25 patients with closed proximal radius and ulna fractures. 20 males and 5 females with mean age of 30.7 years underwent closed reduction and intramedullary nail fixation in radius and open reduction internal fixation in ulna with plating. The fractures were classified according to the AO/OTA system. The average follow up was 1 year (range 6 months – 18 months). Results: The average time to union was 12.77 weeks (10-14 weeks). Union was achieved in all 25 patients in both radius and ulna. Using the Grace and Eversmann rating system7 patients were excellent, 16 good, 1 acceptable and 1 unacceptable results. Using Andersons scale 23 patients had an excellent, 2 unsatisfactory, 0 failure. None of the patients had intraoperative as well as postoperative complications and no posterior interosseous nerve palsy occurred in any of case. Conclusion: Closed reduction internal fixation with use of Hybrid fixation modality in closed proximal radius and ulna fractures has good results. Rigid fixation by ulna plating and rotational stability in radius by large diameter square nail provides almost the same construct as with dual plating with minimal invasive approach. Complication rates are lower as compared to plate osteosynthesis especially with similar union rates in terms of posterior interosseous nerve palsy.

Teaching the Basics: development and Validation of a Distal Radius Reduction & Casting Model

Teaching the Basics: development and Validation of a Distal Radius Reduction & Casting Model

Coupling optimization of urban spatial structure and neighborhood-scale distributed energy systems

When planning a neighborhood-scale distributed energy system (NDES), enough attention should be paid to the urban spatial structure, which may affect not only the system configuration on the supply side but also the load profiles on the demand side as well as their interactions. In this study, a novel nonlinear optimization model is developed for the determination of neighborhood design and NDES arrangement in terms of energy-saving aspect. By executing the optimization model, besides the configuration of energy supply technology, optimal building mix within the neighborhood can be also deduced. As an illustrative example, a mixed-use neighborhood located in Shanghai, China has been assumed for analysis. According to the simulation results, the introduction of NDES may achieve satisfied energy-saving benefits. Although additional energy consumption including heat loss and pump power may be encountered in the NDES, it can be offset through rational plan of the urban spatial structure and its cooperation with the supply side. For a fixed building mix, the reduction of supply radius may lead to better energy performance. Moreover, there exists the maximum supply radius over which, the NDES will not be recommended from the energy-saving viewpoint.

STAGES OF DEVELOPMENT OF THE PLANET EARTH IN THE FRAMEWORK OF ANALYTICAL GEOLOGY

Based on the known geophysical data on the structure of the inner and outer core, mantle, oceanic and continental crust, within the framework of the concept of self-development and self-organization of protoplanetary matter underthe influence of the cosmic pressure, against the background of a pulsating reduction in the earth's radius, a possible mechanism for the formation of the planet's geospheres and its surface shell. Attention is drawn to the morphology of geo-textures and morphostructures of the ocean floor - as an information system that gives an idea of the course of deep processes. The prism blocks of increased stiffness (BCG) of the primary oceanic crust are located in deep-water basins, marginal and inland seas of the continents and their lowered areas. The assumption is that the BPZ ensembles, moving in expansion-contraction regimes under the influence of radial and rotational dynamics forces, formed sigmoid structures of the planet's surface and formed Procrustean beds for the development of icebergs of continents. The symmetry and antipodality of the surface structures of the Earth is explained by the superposition of two energy sources - external and internal: the internal energy substance, according to the rule of the borer, is more dynamic in the southern hemisphere, and the waves of the external energy of the universe are rolling on the Pacific Ocean.Key words: globule of the right-hand plane, high-energy substance, cosmic pressure, the wave field of the universe, sources-ooids, rheons, pulsation, expansion-contraction regimes.

Janus modes of Hasegawa plasma waves in a streaming and tempestuous plasma pillar

Janus modes of the damping and growing of Hasegawa plasma waves are studied in a plasma pillar containing the dissipation and the beam energy deposition caused by tempestuous electrons and streaming ions. We find that the Janus modes split into the upper- and the lower-modes. For the upper-mode, the imaginary part of the wave frequency is negative for any parameters so that the corresponding Hasegawa space-charge plasma wave is always damped away. We found that the damping rate of the upper-mode decreases with a reduction of the pillar radius and a raising of the degree of the harmonic-roots. However, for the lower-mode, called lower-Janus mode, the wave can be either damped away or growing, depending on the wave number, streaming velocity, and geometric factor. The lower-Janus mode can be a pure growing wave with a reduction of the pillar radius. Interestingly, this growing mode turns to damping as the wave number decreases.

A novel index for damage detection of deck and dynamic behavior of horizontally curved bridges under moving load

The purpose of this paper is to evaluate the responses of horizontally curved bridges that are affected by vehicles load. The effect of vehicles dynamic loads on bridges is influenced by factors such as geometric characteristics of structures and moving loads specifications. To consider the effect of dynamic loads in design of bridges, static load increases with a coefficient which is called “impact factor” in Design Codes. In this paper, by examining the effect of curvature of deck and the speed of vehicles which are passing along the bridge on the dynamic response of bridge, set of new equations for DAF is presented. For this purpose, dynamic analysis is performed for seven bridges with different radius of curvature under the influence of AASHTO truck. In the case study models, it can be seen that the separation of impact factor into two different coefficients; support reaction and displacement responses make bridge design more economical and safer. Reduction of the curvature radius decreases dynamic amplification factor (both coefficients). To identify the possible damages of the examined bridges in the early stages of the advent a new index is presented. This index can predict the damages due to moving vehicles.

Efficiency analysis of utilizing phase change materials as grout for a vertical U-tube heat exchanger coupled ground source heat pump system

To study the effects of using phase change materials (PCMs) as grout on the efficiency of a ground source heat pump (GSHP) system, a numerical GSHP system model was established in this study, considering both the site conditions and dynamically changing loads regulated by the heat pump. First, system efficiencies of using an ordinary grout and two other PCM grouts were investigated and compared. Second, the applicability of PCM grouts to different soil environments was investigated by analyzing the effects of subsurface characteristics on the heat exchanger efficiency. Finally, the appropriate operation mode for PCM-backfilled GSHP system was determined by comparing the effects of daily running modes with various intermittent ratios on the system performance. The results show that it is necessary to consider the effect of heat pump, especially for poor heat transfer conditions. PCM grouts with a low thermal conductivity will significantly reduce the system efficiency, whereas PCM grouts with a thermal conductivity comparable to that of an ordinary grout will improve the efficiency and operational stability of a GSHP system. A higher soil thermal conductivity and Darcy velocity improve the heat exchanger efficiency, and PCM grouts with a high thermal conductivity are more suitable for areas where the groundwater is not rich. Sufficient recovery time is necessary and important for a PCM-backfilled GSHP system to ensure operational stability and sustainability and the effectiveness of thermal radius reduction.