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
Two germ-separation methods, dry-milling and density separation by flotation, were evaluated for recovering recombinant β-glucuronidase
(rGUS) that accumulated primarily in the germ of transgenic corn. The dry-milling process consisted of (i) seed tempering,
(ii) degerming with a horizontal-drum degermer/dehuller, (iii) particle size fractionation with standard sieves, (iv) germ
and endosperm separation by roller milling and sifting, and (v) removal of hulls by aspiration. Sieves nos. 5, 6, and 7 retained
the majority of germ, and subfractions from these sieves were pooled as a germ-rich fraction. Mass balances showed that the
germ-rich fraction, which constituted 17% of the total dry-milled corn weight, contained 49% of rGUS activity and 64% of the
total recoverable oil. Germ fractionation by flotation was tested as a proof-of-concept method aimed at separating corn fractions
based on their difference in specific gravity (sp gr). The process consisted of impact-grinding of corn kernels followed by
density separation using 1.15 or 1.3 specific gravity sodium nitrate solution. The oil-containing germ fraction floated, whereas
the heavier endosperm fraction sedimented. The flotation method was simpler and resulted in higher enzyme recovery, that is,
the germ-rich fraction was 20% (w/w) of the initial corn weight, and accounted for 80% of rGUS activity and 77% of total oil.
The sodium nitrate solution did not have an adverse effect on the enzyme activity. 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.
Due to a lot of robot manipulators application in industry, low noise degree is very important criteria for robot manipulator's joints. In this paper, joint noise problem of a robot manipulator with five joints is investigated both theoretically and experimentally. The investigation is consisted of two steps. First step is to analyze the noise of joints using a hardware and software. The hardware is a part of noise sensors. The second step; according to experimental results, some neural networks are employed for finding robust neural noise analyzer. Five types of neural networks are used to compare each other. From the results, it is noted that the proposed RBFNN gives the best results for analyzing joint noise of the robot manipulator. 相似文献
Approximate periodic solutions for the Helmholtz-Duffing oscillator are obtained in this paper. He’s Energy Balance Method (HEBM) and He’s Frequency Amplitude Formulation (HFAF) are adopted as the solution methods. Oscillation natural frequencies are analytically analyzed. Error analysis is carried out and accuracy of the solution methods is evaluated. 相似文献
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
The dielectric constant and the dielectric loss of tantalum pentoxide (Ta2O5) thin films, produced by sol-gel spin-coated process on Corning glass substrates, have been investigated in the frequency range of 20-105 Hz and the temperature range of 183-403 K, using ohmic Al electrodes. The frequency and temperature dependence of relaxation time has also been determined. The capacitance and loss factor were found to decrease with increasing frequency and increase with increasing temperature. The activation energy values were evaluated and a good agreement between the activation energy values obtained from capacitance and dielectric loss factor measurements were observed. 相似文献
This paper reports the presence of Al- O- Al linkages in an aluminosilicate glass where Si/Al = 1 by using 2D17O triple quantum MAS NMR technique (3Q MASNMR). The experiments were performed at external magnetic fields of 8.4 and 14.4T.
Despite17OMAS NMR spectra of the sample in both fields do not give much information about the different kinds of linkages in the sample,
3Q MAS NMR spectrum shows clear evidence that there are some amounts of Al-O-Al linkages in the sample giving two completely
resolved peaks. These two peaks were attributed to the Si-O-Al and Al-O-Al linkages on the basis of their chemical shifts
and, quadrupolar coupling constants which are quite sensitive to the local structure. 相似文献
The paper investigates the causality relationships among industrial production index, coal consumption and employment in industrial sector for the period of 1973:1–2011:10 in USA. After noticing that there are breaks in the regression model, the Hatemi-J test for cointegration is employed to the cases that take into account two possible regime shifts. It is concluded that there is a long run relationship between industrial production and industrial coal consumption with the breaks at 1983:4 and 1998:4. We found a negative relationship between coal consumption and industrial production for the period of 1973:1–1983:4 and positive relationship for 1983:5–1998:4 period. For the last period that covers 1983:5–2011:10, the cointegration relationship turned to negative. In addition, the results show that causal relationship between coal consumption and industrial production changes over time. 相似文献