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991.
Layout planning plays a key role in the inherent safety performance of process plants since this design feature controls the possibility of accidental chain-events and the magnitude of possible consequences. A lack of suitable methods to promote the effective implementation of inherent safety in layout design calls for the development of new techniques and methods. In the present paper, a safety assessment approach suitable for layout design in the critical early phase is proposed. The concept of inherent safety is implemented within this safety assessment; the approach is based on an integrated assessment of inherent safety guideword applicability within the constraints typically present in layout design. Application of these guidewords is evaluated along with unit hazards and control devices to quantitatively map the safety performance of different layout options. Moreover, the economic aspects related to safety and inherent safety are evaluated by the method. Specific sub-indices are developed within the integrated safety assessment system to analyze and quantify the hazard related to domino effects. The proposed approach is quick in application, auditable and shares a common framework applicable in other phases of the design lifecycle (e.g. process design). The present work is divided in two parts: Part 1 (current paper) presents the application of inherent safety guidelines in layout design and the index method for safety assessment; Part 2 (accompanying paper) describes the domino hazard sub-index and demonstrates the proposed approach with a case study, thus evidencing the introduction of inherent safety features in layout design. 相似文献
992.
Hazardous impact of toxic metals on tobacco leaves grown in contaminated soil by ultrasonic assisted pseudo-digestion: multivariate study 总被引:1,自引:0,他引:1
Arain MB Kazi TG Jamali MK Jalbani N Afridi HI Kandhro GA Ansari R Sarfraz RA 《Journal of hazardous materials》2008,155(1-2):216-224
Tobacco leaves (Nicotiana tabacum L.), agricultural soil and pollute irrigated lake water samples were collected during 2005–2006 and analyzed for Cd and Ni by electrothermal atomic absorption spectrometry (ETAAS). A simple and efficient procedure was investigated for the complete decomposition of tobacco leaves using ultrasonic assisted acid pseudo-digestion method (UPDM). A Plackett–Burman experimental design was used as a multivariate strategy for the evaluation of seven factors/variables at once, while central composite were used to found optimum values of significant variables. The accuracy of the proposed methods was assessed by analyzing certified reference (CRM); Virginia tobacco leaves (CTA-VTL-2). The results being compared with those obtained by conventional wet acid digestion method. The result obtained by optimized method showed good agreement with the certified values and sufficiently high recovery 97.8 and 98.7% for Cd and Ni, respectively. Under optimal conditions, the detection limits (3σ) were evaluated to be 0.019 μg g−1 for Cd and 0.37 μg g−1 for Ni. The proposed method was successfully applied to the determination of Cd and Ni in raw, processed tobacco and different branded cigarettes samples. 相似文献
993.
M. S. Hossain R. Islam M. Shahjahan K. A. Khan 《Journal of Materials Science: Materials in Electronics》2008,19(11):1114-1121
The thermoelectric power of Zinc Telluride (ZnTe) thin films, prepared onto glass substrate by e-beam evaporation technique
in vacuum at ∼8 × 10−4 Pa, has been measured from room temperature up to 413 K with reference to pure copper. The deposition rate of the ZnTe thin
films was maintained at about 2.05 nm s−1. The thickness and temperature dependence of its related parameters have been studied. The Fermi-levels were determined using
a non-degenerate semiconducting model. The carrier scattering index, activation energy and temperature of coefficient of activation
energy have all been obtained at different ranges of thickness and temperature. All the samples were optically transparent
and amorphous in structure. 相似文献
994.
Nawazish A. Khan Faheem Ashraf M. Mumtaz Naghma Haider 《Journal of Superconductivity and Novel Magnetism》2008,21(5):279-287
The effect of self-doping and substitution of elements of higher and lower electronegativity, such as Bi, Hg, Nb, Pd, Li,
Na, K, on the superconducting properties of Cu0.5Tl0.5−x
M
x
Ba2Ca2Cu3O10−δ
with x=0.25 is investigated. These experiments demonstrated that the elements of lower electronegativity such as Li, Na, and K can
easily liberate their outer most s-electron that could be supplied to the conducting CuO2 planes of Cu0.5Tl0.5−x
M
x
Ba2Ca2Cu3O10−δ
superconductor, and as a result, we get enhanced superconducting properties. However, highly electro-negative elements hinder
the transfer of carriers from charge reservoir layer to the conducting CuO2 planes and promote inferior superconducting properties. In the present studies, we have investigated the effect of post-annealing
in nitrogen and oxygen atmospheres for optimizing the carriers in conducting CuO2 planes of Cu0.5Tl0.5−x
M
x
Ba2Ca2Cu3O10−δ
(M=Bi,Hg,Nb,Pd,Li,Na,K) superconductor. These studies are important since the density of carriers in the conducting CuO2 planes determines the Fermi-vector k
F and Fermi velocity v
F of the carriers, which ultimately brings about the final superconducting state of the system.
相似文献
995.
Z. H. Khan G. Cascante M. H. El Naggar C. G. Lai 《Canadian Metallurgical Quarterly》2008,134(9):1319-1326
Dynamic properties of soils are commonly evaluated at resonance; thus, their variation with frequency is difficult to measure. A nonresonance (NR) method has been recently used for testing soils at low frequencies and strain levels below the linear threshold shear strain. However, the NR method has not been validated with the standard resonant method for different shear strain levels. In this study, the NR method is used to measure the dynamic properties of soils at low and midstrain levels for a maximum frequency bandwidth between 5 and 100?Hz using the resonant-column device. A new transfer function (NTF) equation is introduced to compare the dynamic properties measured using the NR method and the conventional transfer function approach. Experimental results for two sands and a sand–bentonite–mud mixture are presented for different strain and stress confinement levels. Results from the NR method compare well with the standard resonant column method at the resonant frequency if the strain levels are the same. The NTF approach can be used to measure the dependence of phase velocity of shear waves with frequency. However, the NTF method cannot be used to measure the variation of material damping with frequency. On the other hand, the NR method can be used to measure the degradation curves of wave velocity and material damping ratio as a function of frequency. 相似文献
996.
A physical model study is conducted to investigate the flow field upstream of orifices. In particular, new experimental data for the upstream flow pattern resulting from multiple orifices, an orifice near a free surface, and a large orifice (where the pressure gradient across the orifice cannot be ignored) are collected and presented. A new potential flow solution for flow behind orifices is developed to include pressure gradient effects as well as to accurately superpose the solution due to multiple orifices and determine a solution close to orifices. The proposed solution compares well with the measured data for multiple orifices and for an orifice near a free surface. For a large orifice, the skew in the velocity profile in the vertical direction due to the pressure gradient is accurately predicted. 相似文献
997.
998.
Vertical Phase Separation in Small Molecule:Polymer Blend Organic Thin Film Transistors Can Be Dynamically Controlled
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Kui Zhao Olga Wodo Dingding Ren Hadayat Ullah Khan Muhammad Rizwan Niazi Hanlin Hu Maged Abdelsamie Ruipeng Li Er. Qiang Li Liyang Yu Buyi Yan Marcia M. Payne Jeremy Smith John E. Anthony Thomas D. Anthopoulos Sigurdur T. Thoroddsen Baskar Ganapathysubramanian Aram Amassian 《Advanced functional materials》2016,26(11):1737-1746
Blending of small‐molecule organic semiconductors (OSCs) with amorphous polymers is known to yield high performance organic thin film transistors (OTFTs). Vertical stratification of the OSC and polymer binder into well‐defined layers is crucial in such systems and their vertical order determines whether the coating is compatible with a top and/or a bottom gate OTFT configuration. Here, we investigate the formation of blends prepared via spin‐coating in conditions which yield bilayer and trilayer stratifications. We use a combination of in situ experimental and computational tools to study the competing effects of formulation thermodynamics and process kinetics in mediating the final vertical stratification. It is shown that trilayer stratification (OSC/polymer/OSC) is the thermodynamically favored configuration and that formation of the buried OSC layer can be kinetically inhibited in certain conditions of spin‐coating, resulting in a bilayer stack instead. The analysis reveals here that preferential loss of the OSC, combined with early aggregation of the polymer phase due to rapid drying, inhibit the formation of the buried OSC layer. The fluid dynamics and drying kinetics are then moderated during spin‐coating to promote trilayer stratification with a high quality buried OSC layer which yields unusually high mobility >2 cm2 V?1 s?1 in the bottom‐gate top‐contact configuration. 相似文献
999.
Anis Hamza Fakeeha Ahmed Aidid Ibrahim Wasim Ullah Khan Ahmed Elhag Abasaeed 《Petroleum Science and Technology》2016,34(19):1617-1623
Hydrogen is a chief source of energy. Catalytic decomposition produces hydrogen and carbon. In this work, x%M/Al2O3 (where M is Ni, Co and combined Ni-Co, and x is 10%, 15%, and 30%) has been successfully employed as a catalyst. The effect of activation temperature and active metal type and loading on catalyst perfomance was investigated. The catalysts were characterized with BET, XRD, TPO, TPR, TEM, XPS, and Raman. The results displayed that the 30%Co/Al2O3 catalyst activated at 500°C provided the greatest catalytic performance toward methane conversion. 30%Co/Al2O3 catalyst activated at 500°C formed amorphous carbon. 相似文献
1000.