Ground failure in Adapazari, Turkey during the 1999 Kocaeli earthquake was severe. Hundreds of structures settled, slid, tilted, and collapsed due in part to liquefaction and ground softening. Ground failure was more severe adjacent to and under buildings. The soils that led to severe building damage were generally low plasticity silts. In this paper, the results of a comprehensive investigation of the soils of Adapazari, which included cone penetration test (CPT) profiles followed by borings with standard penetration tests (SPTs) and soil index tests, are presented. The effects of subsurface conditions on the occurrence of ground failure and its resulting effect on building performance are explored through representative case histories. CPT- and SPT-based liquefaction triggering procedures adequately identified soils that liquefied if the clay-size criterion of the Chinese criteria was disregarded. The CPT was able to identify thin seams of loose liquefiable silt, and the SPT (with retrieved samples) allowed for reliable evaluation of the liquefaction susceptibility of fine-grained soils. A well-documented database of in situ and index testing is now available for incorporating in future CPT- and SPT-based liquefaction triggering correlations. 相似文献
The clinical and bacteriologic efficacy of topically applied ciprofloxacin was studied in 60 patients with chronic suppurative otitis media. Two hundred fifty and 125 microg/ml concentrations of ciprofloxacin solutions were given to two groups of patients. The duration of therapy was determined according to the clinical cure at follow-up. More than 21 days of therapy was not needed in any patient. The clinical cure rate with 250 microg/ml ciprofloxacin was 78.1% at 14 days and with 125 microg/ml it was 83.3%. However, a 100% clinical cure rate and complete bacteriologic eradication was obtained in 21 days in both groups. In each group only one patient had otomycosis by the fourteenth day of therapy, although ear discharge had ceased. It was concluded that 125 microg/ml ciprofloxacin could be applied as successfully as 250 microg/ml, and the duration of therapy had to be at least 14 days. This new dosage regimen can be adopted as an optimal dosage for ototopical application of ciprofloxacin in chronic suppurative otitis media. It will also obviously decrease the expense of therapy. 相似文献
WSNs (wireless sensor networks) consist of thousands of tiny nodes having the capability of sensing, computation, and wireless communications. Unfortunately these devices are limited energy devices, that is means we must save energy as much as possible, to increase network life time as long as possible. In this paper we introduce NEER--normalized energy efficient routing protocol that increases network life time through switching between AODV protocol that depends on request-reply routing, and MRPC that depends on residual battery in routing. 相似文献
Unmanned aerial vehicles have been widely used in many areas of life. They communicate with each other or infrastructure to provide ubiquitous coverage or assist cellular and sensor networks. They construct flying ad hoc networks. One of the most significant problems in such networks is communication among them over a shared medium. Using random channel access techniques is a useful solution. Another important problem is that the variations in the density of these networks impact the quality of service and introduce many challenges. This paper presents a novel density-aware technique for flying ad hoc networks. We propose Density-aware Slotted ALOHA Protocol that utilizes slotted ALOHA with a dynamic random access probability determined using network density in a distributed fashion. Compared to the literature, this paper concentrates on proposing a three-dimensional, easily traceable model and stabilize the channel utilization performance of slotted ALOHA with an optimized channel access probability to its maximum theoretical level, 1/e, where e is the Euler’s number. Monte-Carlo simulation results validate the proposed approach leveraging aggregate interference density estimator under the simple path-loss model. We compare our protocol with two existing protocols, which are Slotted ALOHA and Stabilized Slotted ALOHA. Comparison results show that the proposed protocol has 36.78% channel utilization performance; on the other hand, the other protocols have 24.74% and 30.32% channel utilization performances, respectively. Considering the stable results and accuracy, this model is practicable in highly dynamic networks even if the network is sparse or dense under higher mobility and reasonable non-uniform deployments.
Engineering design has great importance in the cost and safety of engineering structures. Rock mass rating (RMR) system has
become a reliable and widespread pre-design system for its ease of use and variety in engineering applications such as tunnels,
foundations, and slopes. In RMR system, six parameters are employed in classifying a rock mass: uniaxial compressive strength
of intact rock material (UCS), rock quality designation (RQD), spacing of discontinuities (SD), condition of discontinuities
(CD), condition of groundwater (CG), and orientation of discontinuities (OD). The ratings of the first three parameters UCS,
RQD, and SD are determined via graphic readings where the last three parameters CD, CG, and OD are estimated by the tables
that are composed of interval valued linguistic expressions. Because of these linguistic expresions, the estimated rating
values of the last three become fuzzy especially when the related conditions are close to border of any two classes. In such
cases, these fuzzy situations could lead up incorrect rock class estimations. In this study, an empirical database based on
the linguistic expressions for CD, CG, and OD is developed for training Artificial Neural Network (ANN) classifiers. The results
obtained from graphical readings and ANN classifiers are unified in a simulation model (USM). The data obtained from five
different tunnels, which were excavated for derivation purpose, are used to evaluate classification results of conventional
method and proposed model. Finally, it is noted that more accurate and realistic ratings are reached by means of proposed
model. 相似文献
1,2‐Dimethyl‐3‐(5‐methylisoxazol‐3‐yldiazenyl)‐1H‐indole was obtained by coupling 3‐amino‐5‐methylisoxazole with diazotised 1,2‐dimethylindole. It was characterised by proton and carbon nuclear magentic resonance, ultraviolet–visible, infrared and Raman spectra, and the X‐ray single crystal diffraction method. On the theoretical side, the molecular geometry, chemical shifts and the fundamental vibrational frequencies were evaluated using density functional theory. Time‐dependent density functional theory was used to evaluate the electronic excitation spectra. In addition, the scaled quantum mechanical approach was used to study the total energy distributions of the vibrational modes of the molecule. The results showed that the general agreement between experimental and calculated geometric parameters, chemical shifts and λmax values are good. Excellent agreement was found between the calculated and experimental vibrational frequencies. 相似文献
The aim of this paper is two fold. First we investigate the three different types of systems, namely cellular layout (CL), process layout (PL) and virtual cells (VCs). VCs are addressed by using family-based scheduling rule, developed by a part allocation algorithm in a PL. Simulation is used to compare three types of systems under the performance metrics such as mean flow time and mean tardiness. Results indicate that VCs have better responsiveness in terms of the performance metrics. Second we develop a new ant colony optimization-based metamodels fed by existing simulation runs to represent the prospective simulation runs, which require a lot of time and effort. Regression metamodels, which allow us to obtain much faster results, are seen to be promising to estimate the systems behaviors. 相似文献
UV-Visible (UVV) technique used to monitor powder coating and its dissolution processes from hard latex particles. Three sets
of latex coatings were prepared from poly(methyl methacrylate) (PMMA) particles. The first set of coatings was annealed at
elevated temperatures in various time intervals during which reflected photon intensity, Irf, was measured. The second set of coatings was annealed at various temperatures in 10 min time intervals during which transmitted
intensity, Itr, was measured. Irf first decreased and then increased as the annealing temperature was increased. Decrease in Irf was explained with the void closure mechanism due to viscous flow. Increase in Itr and Irf against time and temperature were attributed to an increase in crossing density at the junction surface. The activation energy
of viscous flow, ΔH, was measured and found to be around 8 kcal/mol and the back and forth activation energies (ΔErf and ΔEtr) were measured and found to be around 49 and 53 kcal/mol for a reptating polymer chain across the junction surface. Diffusion
of solvent molecules (chloroform) into the annealed latex coatings was followed by desorption of PMMA chains for the third
set of films. Desorption of pyrene, P, labeled PMMA chains was monitored in real-time by the absorbance change of pyrene in
the polymer-solvent mixture. A diffusion model with a moving boundary was employed to quantify real-time UVV data. Diffusion
coefficients of desorbed PMMA chains were measured and found to be between 2 and 0.6 × 10−11 cm2 s−1 in the 100 and 275°C temperature range.
Presented at the 2000 Spring Meeting of the PMSE Div. of the American Chemical Society, March 26–30, 2000, San Francisco,
CA.
Dept. of Physics, Maslak 80626 Istanbul, Turkey.
Dept. of Physics, 22030 Edirne, Turkey. 相似文献
This study focuses on the fabrication of poly(vinyl alcohol)/ poly(vinyl pyrrolidone)-Iodine nanofibers via electrospinning. Electrospun fibers were characterized by FT-IR, DSC and SEM techniques. DSC results indicated that the thermal stability of nanofibers were improved after the addition of chitosan and poloxamer 188. SEM images showed that the spongiform structure is much more compact and fibrous in the case of added chitosan, with an average fiber diameter of 374 nm, whereas the addition of poloxamer 188 resulted in a more porous and beaded composition, with average fiber diameter of 489 nm. 相似文献