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41.
F. S. Qureshi A. S. Sheikh Z. Khan M. Ahmad 《Journal of Materials Engineering and Performance》1999,8(3):347-352
In this work, a statistical evaluation of the crack-growth process in high-density polyethylene (HDPE) was carried out. The
specimens were compression molded from virgin, molding-grade HDPE. Edgenotched specimens for replicate fatigue testing were
prepared from compression-molded sheets. Fatigue test results were then analyzed, and it is shown that if the crack-growth
process can be characterized as a random process following a power-law-type behavior, then the time to reach a critical crack
length will be distributed according to an inverted lognormal model. 相似文献
42.
A new approach for the template image matching is being presented. The method first converts the image into edges, then, the
vital information of these edges has been presented as a set of vectors in a four dimensional hyper-space. A modified Radon
Transform has been proposed to facilitate this vectorization process. All the above processing is being done offline for the
main image of the area. The template image has also been vectorized in a same fashion in real time which is to be matched
with the main image. A vector matching algorithm has been proposed to deliver match location with a very low computational
cost. It works for a wide range of template scaling and noise conditions which were not there in the previous algorithms found
in the literature. 相似文献
43.
44.
A case is reported of a woman with an ischemic arm as a result of damage to the subclavian artery by the clavicular anomaly associated with cleidocranial dysostasis. Only one similar case has been reported previously. 相似文献
45.
Systems modems intended for use in relatively large private networks are characterized by high performance, reliability and flexibility to support network management, and multiple modes of operation and user features. This paper describes a programmable digital signal processor which is teamed with a 16-bit microprocessor in a dual processor architecture satisfying the requirements of high-speed voiceband systems modems. The architecture of the two custom integrated circuits which form the basis of the signal processor is presented. This processor has novel arithmetic, data structure address generation, and program flow-control capabilities, which result in a high utilization of the arithmetic unit and a low program overhead for housekeeping tasks. Some of these features are illustrated by programming examples. 相似文献
46.
Kinetic study of crude oil-to-chemicals via steam-enhanced catalytic cracking in a fixed-bed reactor
Qi Xu Aaron C. Akah Mansour AlHerz Abdullah Aitani Ziyauddin S. Qureshi M. Abdul Bari Siddiqui Nabeel Abo-Ghander 《加拿大化工杂志》2023,101(7):4042-4053
This study presents new experimental results on the direct conversion of crude oil to chemicals via steam-enhanced catalytic cracking. We have organized the experimental results with a kinetics model using crude oil and steam co-feed in a fixed-bed flow reactor at reaction temperatures of 625, 650, and 675°C over the Ce-Fe/ZSM-5 catalyst. The model let us find optimum conditions for crude oil conversion, and the order of the steam cracking reaction was 2.0 for heavy oil fractions and 1.0 for light oil fractions. The estimated activation energies for the steam cracking reactions ranged between 20 and 200 kJ/mol. Interestingly, the results from kinetic modelling helped in identifying a maximum yield of light olefins at an optimized residence time in the reactor at each temperature level. An equal propylene and ethylene yield was observed between 650 and 670°C, indicating a transition from dominating catalytic cracking at a lower temperature to a dominating thermal cracking at a higher temperature. The results illustrate that steam-enhanced catalytic cracking can be utilized to effectively convert crude oil into basic chemicals (52.1% C2-C4 light olefins and naphtha) at a moderate severity (650°C) as compared to the conventional high-temperature steam cracking process. 相似文献
47.
48.
AI Qureshi JI Suarez A Bhardwaj M Mirski MS Schnitzer DF Hanley JA Ulatowski 《Canadian Metallurgical Quarterly》1998,26(3):440-446
OBJECTIVE: To determine the effect of continuous hypertonic (3%) saline/acetate infusion on intracranial pressure (ICP) and lateral displacement of the brain in patients with cerebral edema. DESIGN: Retrospective chart review. SETTINGS: Neurocritical care unit of a university hospital. PATIENTS: Twenty-seven consecutive patients with cerebral edema (30 episodes), including patients with head trauma (n = 8), postoperative edema (n = 5), nontraumatic intracranial hemorrhage (n = 8), and cerebral infarction (n = 6). INTERVENTION: Intravenous infusion of 3% saline/acetate to increase serum sodium concentrations to 145 to 155 mmol/L. MEASUREMENTS AND MAIN RESULTS: A reduction in mean ICP within the first 12 hrs correlating with an increase in the serum sodium concentration was observed in patients with head trauma (r2 = .91, p = .03), and postoperative edema (r2 = .82, p = .06), but not in patients with nontraumatic intracranial hemorrhage or cerebral infarction. In patients with head trauma, the beneficial effect of hypertonic saline on ICP was short-lasting, and after 72 hrs of infusion, four patients required intravenous pentobarbital due to poor ICP control. Among the 21 patients who had a repeat computed tomographic scan within 72 hrs of initiating hypertonic saline, lateral displacement of the brain was reduced in patients with head trauma (2.8 +/- 1.4 to 1.1 +/- 0.9 [SEM]) and in patients with postoperative edema (3.1 +/- 1.6 to 1.1 +/- 0.7). This effect was not observed in patients with nontraumatic intracranial bleeding or cerebral infarction. The treatment was terminated in three patients due to the development of pulmonary edema, and was terminated in another three patients due to development of diabetes insipidus. CONCLUSIONS: Hypertonic saline administration as a 3% infusion appears to be a promising therapy for cerebral edema in patients with head trauma or postoperative edema. Further studies are required to determine the optimal duration of benefit and the specific patient population that is most likely to benefit from this treatment. 相似文献
49.
Qureshi Ziyauddin S. Ellouh Mohammed Aitani Abdullah Akhtar Muhammad Naseem Jin Yaming Koseoglu Omer Alasiri Hassan 《Journal of Porous Materials》2022,29(3):683-692
Journal of Porous Materials - The transformation of light naphtha to value-added aromatic compounds is gaining momentum in the petrochemical industry. In this work, a series of metal modified... 相似文献
50.
Mercer Eric Slind Konrad Amundson Isaac Cofer Darren Babar Junaid Hardin David 《Software and Systems Modeling》2023,22(5):1451-1471
Software and Systems Modeling - Safety-critical systems such as avionics need to be engineered to be cyber resilient meaning that systems are able to detect and recover from attacks or safely... 相似文献