Investigations on nucleation thermodynamical parameters of NdBa2Cu3O7-δ (Nd123) crystallization by high temperature solution growth

Investigations on nucleation thermodynamical parameters are very essential for the successful growth of good quality single crystals from high temperature solution. A theoretical estimation of the nucleation thermodynamical parameters like interfacial energy between the solid Nd123 and its flux BaO-CuO, metastable zone-width, Gibbs free energy, critical energy barrier for nucleation and critical nucleation radius have been calculated from the knowledge of solubility data and by applying the classical nucleation theory. Results are discussed to understand the growth kinetics of Nd123 crystals. Paper presented at the 5th IUMRS ICA98, October 1998, Bangalore     

Stress oscillations in plane stress modelling of flexure—a field-consistency interpretation

Exactly integrated isoparametric plane stress elements behave poorly in flexure. The 4-noded element ‘locks’, with errors that progress indefinitely as element aspect ratio increases. Reduced integration of the shear strain energy eliminates this locking entirely. The 8-noded element does not lock, but improves in performance with reduced integration of shear strain energy. Both elements, with their original shape functions, show severe shear stress oscillations in flexure. In this paper we attribute these oscillations to the lack of ‘consistency’ of shear strain fields derived directly from independent field-variable interpolations. We derive error models for specific tractable examples which can confirm the accuracy of this conceptual scheme through digital computation using the finite element models. A field-consistent redistribution strategy for the shear strain field is offered as an elegant procedure to free the elements of spurious oscillations and give a ‘lock’-free performance.     

Leveraging resources in global software development

Leveraging global resources for software development is rapidly becoming the norm at Motorola, which has over 25 software development centers worldwide. Our project, called the 3G Trial (Third Generation Cellular System), was the first of its scope and significance developed by a global engineering team at Motorola. Staffing was the most significant issue we encountered in the 3G Trial. We had only about 20 percent of the required staff available at our division headquarters in Burlington Heights, Ill., US, and needed to find the other 80 percent to successfully complete the project. Early on, we concluded that our only means to staff the project was to rely on software development engineers from Motorola's worldwide software centers. We developed the system with staffing from six different countries. Next, we had to integrate the people into a team. While addressing this challenge, we identified key risk factors and developed approaches to reduce them. We separated the project risk factors into the five categories Carmel (1999) describes as the centrifugal forces that pull global projects apart. To pass on the lessons we learned from this project, this article sets out the global development issues we faced, our approaches to resolving them, and our findings compared to other research     

Carotid artery repair for radiation-associated atherosclerosis is a safe and durable procedure

OBJECTIVE: The development of carotid atherosclerosis after neck irradiation is well documented. There has been concern about the safety and durability of carotid artery repair through a radiated field. The objective of this report is to describe the immediate and long-term results of a series of cases collected in a 13-year interval. METHODS: From 1984 to 1997, 24 patients underwent 26 carotid artery operations. All the patients had undergone prior radiation therapy at a mean interval of 17 years, with an average radiation dose of 6300 rad. Severe scarring of the skin or radiation fibrosis were present in two thirds of the patients, with 4 patients having permanent tracheostomies. The indications for carotid surgery included cerebral or monocular transient ischemic attack (58%), asymptomatic high-grade stenosis (27%), prior stroke (12%), and tumor invasion of the carotid artery (4%). General anesthesia was used with selective shunting on the basis of carotid artery back pressure or electroencephalography monitoring. Patch angioplasty closure was used in 79% of the patients. The operations included standard carotid endarterectomy (n = 20), external carotid endarterectomy (n = 2), carotid patch angioplasty alone (n = 2), aortocarotid bypass grafting (n = 1), and carotid interposition grafting (n = 1). Four patients required skin grafting or myocutaneous flaps. RESULTS: No deaths or strokes occurred within 30 days of the operations. Six patients had transient cranial nerve palsy, and two had wound infections. The patients were followed from 1 to 156 months, with six patients being followed for longer than 18 months. No strokes were seen at late follow-up examination. Duplex scan examination documented one occlusion, in a patient with primary closure, and two restenoses, one of which necessitated reoperation. The remainder of the grafts were widely patent. CONCLUSIONS: Carotid surgery after neck irradiation is safe and durable. The long-term patency rates and the protection against subsequent neurologic events are similar to the results obtained in the absence of radiation therapy. Problems of wound healing were not found in this series.     

Joint trellis-coded quantisation/modulation

Joint trellis-coded quantisation (TCQ) and trellis-coded modulation (TCM) can achieve considerable signal-to-quantisation noise ratios with moderate complexity. TCM is replaced with turbo TCM (TTCM) and simulation results given which show that the new scheme can achieve the same performance as that possible using by trellis-coded scalar quantisation at an SNR slightly above the channel capacity bound     

Extraction and representation of facts from legal briefs

In knowledge-based consultation systems, the quality of the advice rendered depends on the techniques employed to represent the domain knowledge, the explanation generating capabilities, and the control strategies utilized during the consultative advice stage. The ability to understand the problem is more crucial in providing effective consultation. In this work, the emphasis is on understanding and the consequent formulation of a plausible internal representation of legal briefs. The system developed, SIFTER, reads the given input text from a legal practitioner's point of view and retrieves from it those facts that are relevant to the particular type of case on hand. In other words, it uses the domain specific knowledge to identify the type of case and to yank out the necessary information pertaining to the case. The SIFTER generates a noun-phrase processed form of the input which contains pseudo names for the proper-nouns, dates and time-intervals. The verbs in the processed input are used to check whether the case specific events have occurred or not and then the appropriate fact-containing noun-phrases are used to instantiate the relevant legal variables and, hence, to construct an internal representation of the given problem which can then be readily used by the consultative advice stage of a problem solver or analyzer. The implementation has been done in LISP culling the required domain knowledge from the Industrial Dispute Act of India.