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221.
The United States is in the middle of a large environmental restoration effort that is hampered by a lack of knowledge on how to measure the performance of the project delivery process. This study evaluates one environmental restoration program’s ability to deliver projects: the Environmental Management Program (EMP), a federally sponsored program managed by the U.S. Army Corps of Engineers. Project performance metrics are compiled and used to measure two types of program improvements made in project delivery: trend improvements over time, and the ability to reach established benchmarks. The benchmarks come from both agency guidance and construction industry benchmarks. The metrics measure the program’s ability to accurately estimate the required resources (time and money) to accomplish the project, estimate the cost to operate and maintain the project, and meet the customers’ design requirements. To build the metrics, estimates from the project planning documents are compared against the actual results. Currently, the Corps of Engineers has established some benchmarks and does evaluate projects for design success, but the benchmarks do not include all aspects of project delivery and are not universally applied. Analysis of the metrics shows that the Corps has made improvements in the delivery of projects, but some major components of the process should be improved. Establishing benchmarks would provide the Corps with information to improve the project delivery of the EMP and other environmental restoration programs across the country. This study provides an example of applying business principles to a governmental program. 相似文献
222.
Ilkay Orhan Murat Kartal Qamar Naz Asma Ejaz Gülderen Yilmaz Yüksel Kan Belma Konuklugil Bilge Şener M. Iqbal Choudhary 《Food chemistry》2007,103(4):1247-1254
Since Salvia species (Lamiaceae) have been recorded to be used against memory loss in European folk medicine, we herein examined in vitro anticholinesterase and antioxidant activities of 56 extracts prepared with petroleum ether, chloroform, ethyl acetate and methanol obtained from 14 Salvia species (Salvia albimaculata Hedge and Hub, Salvia aucheri Bentham var. canescens Boiss and Heldr, Salvia candidissima Vahl. ssp. occidentalis, Salvia ceratophylla L., Salvia cryptantha Montbret and Bentham, Salvia cyanescens Boiss and Bal., Salvia frigida Boiss, Salvia forskahlei L., Salvia halophilaHedge, Salvia migrostegia Boiss and Bal., Salvia multicaulis Vahl., Salvia sclarea L., Salvia syriaca L., Salvia verticillata L. ssp. amasiaca) growing in Turkey. The antioxidant activities were assessed by both chemical and enzymatic methods against 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging and xanthine/xanthine oxidase (XO) system generated superoxide anion radical inhibition. Anticholinesterase effect of the extracts was tested against both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) at concentrations of 0.2 and 1 mg/ml using a microplate-reader assay based on the Ellman method. Most of the extracts did not show any activity against AChE at 0.2 mg/ml, while the chloroform extracts had noticeable inhibition against BChE between 47.7% and 74.7%. The most active extracts at 1 mg/ml for AChE inhibition were observed to be petroleum ether extract of Salvia albimaculata (89.4%) and chloroform extract of Salvia cyanescens (80.2%), whereas ethyl acetate extracts of Salvia frigida and Salvia migrostegia, chloroform extracts of Salvia candidissima ssp. occidentalis and Salvia ceratophylla, as well as petroleum ether extract of Salvia cyanescens were found to inhibit potently BChE (92.2%, 89.6%, 91.1%, 91.3%, and 91.8%, respectively). Particularly, the ethyl acetate and methanol extracts were observed to be highly active against both DPPH and XO. Our data indicates that nonpolar extracts of Salvia species for anticholinesterase activity and the polar extracts for antioxidant activity are worth further phytochemical evaluation for identifying their active components. 相似文献
223.
M. Ahmad J. I. Akhter M. A. Shaikh M. Iqbal W. Ahmad 《Journal of Materials Engineering and Performance》2003,12(2):179-182
The Microstructure of two different lots of Zircaloy-4 was investigated by using a scanning electron microscope (SEM) attached
to an energy dispersive system (EDS). The alloy containing Ni higher than the ASTM specification shows parallel plate structure
with segregation of Ni, Fe, and Cr at the triple points of β-grains, and it failed during forging due to crack initiation. The second alloy having Ni content within the ASTM specification
has basketweave morphology with minute segregation of Fe and Cr and was forged successfully. The absorbed energy is higher
for the successfully forged alloy than for the alloy that failed during forging. It was also observed that the fracture started
from the segregated area rich in Ni, Fe, and Cr, and propagated along the plate. The alloy with parallel plate structure is
harder than the alloy with basketweave structure. 相似文献
224.
In this article, methods for force distribution control of power grasp are developed. A power grasp is characterized by multiple points of contact between the object grasped and the surfaces of the fingers and palm. The grasp is highly stable because of form closure. However, modeling power grasps is difficult because of the resulting closed kinematic structure and the complexity of multiple contacts. The first method used to obtain the desired force distribution is based on linear programming. In particular, a model of the DIGITS grasping system, under development at The Ohio State University, is used, and constraint equations are formulated for force balance and actuator torque limits. Supervisory control of the desired forces at the contacts is achieved by prescribing a desired clinch level. The objective function is designed to achieve the desired clinch level, except in cases where the specified force is inadequate to stably hold the object. Although this method yields the desired force distribution, a second method based on artificial neural networks (ANNs) is developed to achieve constant-time solutions. Linear programming solutions are used to generate training data for a set of ANNs. Two techniques, modular networks and adaptive slopes, are also developed and employed in the training to improve the training time and accuracy of the ANNs. The results show that the ANNs learn the appropriate nonlinear mapping for the force distribution and provide stable grasp over a wide range of object sizes and clinch levels. 相似文献
225.
Ruoli Sun Li Wang Haojie Yu Zain-ul-Abdin Yongsheng Chen Hamad Khalid Nasir Abbasi Muhammad Akram 《Journal of Inorganic and Organometallic Polymers and Materials》2014,24(6):1063-1069
A series of ferrocene-based hyperbranched polyethers (HBPE-Fc) with different ferrocene content were synthesized by esterification of ferrocenecarbonyl chloride and hyperbranched polyether (HBPE). 1H NMR and FT-IR were used to confirm the structure of HBPE and HBPE-Fc. GPC was used to calculate the molecular weights. The catalytic performance of the synthesized HBPE-Fc for thermal decomposition of ammonium perchlorate (AP) was investigated by TG and DTG techniques. The results showed that HBPE-Fc exhibited good catalytic activity on the thermal decomposition of AP. The influence factors on catalytic performances, such as substitution degree of ferrocene and mass ratio of AP/HBPE-Fc were discussed as well. 相似文献
226.
Mohammed Khalid Khan Muhammad Sohail Muhammad Aamir B. S. Chowdhry Syed Irfan Hyder 《Wireless Personal Communications》2014,76(3):535-548
Last decade belongs to business intelligence (BI) because it is one of the few concepts that have actually lived to the expectations. Not only the businesses have adopted it but also have reaped the fruits out of it. But the cost of BI solutions is very high and has restricted small and medium enterprises to use BI solutions. The human resource is also limited and resultantly expensive in this field. This research proposes a web support system for business intelligence which provides automated data mapping and loading from user application to BI framework and also validates it. The system also assists users in getting the outputs in terms of reports and dashboards. The implementation of the proposed framework demonstrates convenience of use and effective cost saving as it does not require any technical expertise. The beauty of this web support system is that all the steps are menu driven and any non-technical user can get hold of it easily. 相似文献
227.
Efficient PFD-Based Networking and Buffering Models for Improving Video Quality over Congested Links
Khalid A. Darabkh Abeer M. Awad Ala’ F. Khalifeh 《Wireless Personal Communications》2014,79(1):293-320
Video traffic over the Internet becomes increasingly popular and is expected to comprise the largest proportion of the traffic carried by wired and wireless networks. On the other hand, videos are usually compressed by exploiting spatial and temporal redundancy for the reason of increasing the number of video streams that can be simultaneously carried over links. Unfortunately, receiving high-quality video streaming over the Internet remains a challenge due to the packet loss encountered in the congested wired and wireless links. In addition, the problem is more apparent in wireless links due to not only employing limited system capacity, but also some of the major drawbacks of wireless networks, out of which the bandwidth limitations and link asymmetry which refers to the situation where the forward and reverse paths of a transmission have different channel capacities. Therefore, the wireless hops may be congested which result in dropping many video frames. Additionally, as a result of compressing videos, dependencies among frames and within a frame arise. Consequently, the overall video quality tends to be degraded dramatically. The main challenge is to support the growth of video traffic while keeping the perceived quality of the delivered videos high. In this paper, we extend our previous work concerning improving video traffic over wireless networks through professionally studying the dependencies between video frames and their implications on the overall network performance. In other words, we propose very efficient network and buffer models proportionately to novel algorithms that aim to minimize the cost of aforementioned possible losses by selectively discarding frames based on their contribution to picture quality, namely, partial and selective partial frame discarding policies considering the dependencies between video frames. The performance metrics that are employed to evaluate the performance of the proposed algorithms include the rate of non-decodable frames, peak signal-to-noise ratio, frameput, average buffer occupancy, average packet delay, as well as jitter. Our results are so promising and show significant improvements in the perceived video quality over what is relevant in the current literature. We do not end up to this extent, but rather the effect of producing different bit-stream rates by the FFMPEG codecs on aforementioned performance metrics has been extensively studied. 相似文献
228.
A. Zaman Y. Iqbal A. Hussain M. H. Kim R. A. Malik 《Journal of Materials Science》2014,49(8):3205-3214
Ta-doped 0.99Bi0.5(Na0.82K0.18)0.5TiO3–0.01LiSbO3 (BNKTT–LS) ceramics were prepared through a conventional mixed oxide solid-state sintering route. Partial substitution of Ta for Ti decreased the dielectric constant and depolarization temperature. The dielectric curves, polarization and strain hysteresis loops demonstrated that the incorporation of Ta stabilized the canonical relaxor phase of BNKT–LS ceramics leading to the degradation of piezoelectric and ferroelectric responses. The destabilization of field-induced ferroelectric order at x = 0.013 was accompanied by substantial enhancement in strain level. A unipolar field-induced strain of 0.39 % with a normalized strain (S max/E max = $ d_{33}^{*} $ ) of 650 pm/V was achieved at a driving field of 6 kV/mm. The observed large strain can be attributed to the non-ergodic relaxor phase at zero electric field that transformed into an ergodic relaxor phase under the influence of the applied electric field. 相似文献
229.
Internationalization of universities has become a worldwide phenomenon as global economic integration continues to make its way forcefully into the higher education. The objective of the study is to develop a model for internationalization of universities with the transformation of some promising macroeconomic variables i.e., educational reforms and economic growth in the seven largest regions of the world [namely, East Asia and Pacific (sample 25 countries); Europe and Central Asia (40 countries); Latin America and Caribbean (27 countries); Middle East and North Africa (17 countries); North America (22 countries); South Asia (7 countries) and Sub-Saharan Africa (21 countries)]. The data has been analyzed by panel fixed effect regression from the period of 1990–2011. In addition to transform inputs into output, the study employed eleven indicators of education and five indicators for growth, where the resulting vector is internationalization. The results show the dynamic linkages between educational indicators and economic factors in the selected regions of the World. In East Asia and Pacific region, tertiary and higher education expenditures per student increase the economic factors. Higher education is a powerful driver of long-term growth in Europe and Central Asia. Governments of the state should have to focus on higher education enrolment, as it does not have any significant contribution to increase GDP; gross capital formation and FDI in Latin America and Caribbean region. Higher education enrolment in MENA region significantly increases growth factors on the cost of increase gross national expenditures. Investment in general education and other generic human capital is of the utmost importance in creating an enabling environment for FDI in North America. It is imperative for South Asia to encourage the skill levels and education opportunities for females, in order to maximize the effects of FDI on the female human capital stock and therefore economic growth. Tertiary school enrolment and tertiary expenditures per student identified the importance of tertiary education in Sub-Saharan Africa. The results conclude that educational indicators improve the economic gains, which ultimately reap out the benefit of internationalization. 相似文献
230.
M Waqas Iqbal M Zahir Iqbal M Farooq Khan Xiaozhan Jin Chanyong Hwang 《Science and Technology of Advanced Materials》2014,15(5)
The properties of graphene are strongly affected by metal adsorbates and clusters on graphene. Here, we study the effect of a thin layer of platinum (Pt) metal on exfoliated single, bi- and trilayer graphene and on chemical vapor deposition-grown single-layer graphene by using Raman spectroscopy and transport measurements. The Raman spectra and transport measurements show that Pt affects the structure as well as the electronic properties of graphene. The shift of peak frequencies, intensities and widths of the Raman bands were analyzed after the deposition of Pt with different thicknesses (1, 3, 5 nm) on the graphene. The shifts in the G and 2D peak positions of the Raman spectra indicate the n-type doping effect by the Pt metal. The doping effect was also confirmed by gate-voltage dependent resistivity measurements. The doping effect by the Pt metal is stable under ambient conditions, and the doping intensity increases with the increasing Pt deposition without inducing a severe degradation of the charge carrier mobility. 相似文献