Effect of spherically converging shock waves on deformation and phase behavior of high-purity iron

Optical metallography, transmission electron microscopy, and microhardness measurements were used to perform a layer-by-layer study of the structure of a high-purity iron sphere 166 mm in diameter after loading by converging spherical shock waves. It has been found that the plastic deformation of ? iron under this loading proceeds by slip; in the middle and deep layers, it proceeds via the formation of localized deformation bands.     

Specifying, selecting, and testing quality cable

Medium-voltage power cables for modern petrochemical plants are considered. Test requirements, both at the factory and in the field, are considered to ensure that high-quality cable is manufactured and installed without damage. Cable technology changes and specifications are discussed. A new approach using life-cycle costs, which is making inroads in the petrochemical industry is described. The supplier partnership process for obtaining quality cable is discussed. Economic factors for the selection of power cables are detailed. It is argued that implementation of these programs will increase product performance and reliability, resulting in the lowest evaluated total cost of cable system ownership     

Cable with overall shield for protection from lightning and faults

A study was conducted to device means to prevent or control the effects of lightning on instrument and control systems. It is found that the best approach for lightning protection is to use instrument cables with an overall shield grounded at both ends. The overall shield functions as a magnetic shield. It is not a shield because of the mere presence of metal, but because it generates a counter, or opposition, current into the signal conductor. This counter current cancels out the interference current generated by a lightning stroke or other transients     

BK virus encephalitis in an immunocompetent patient

OBJECTIVES: To describe a previously healthy patient now suffering from monophasic encephalitis caused by a primary infection with BK virus and to discuss possible risk factors for developing BK virus encephalitis. DESIGN: Case report. SETTING: Referral hospital. PATIENT: The patient was examined on referral. MAIN OUTCOME MEASURES: The main diagnostic tests performed were serology, polymerase chain reaction on cerebrospinal fluid samples, and cranial magnetic resonance imaging. RESULTS: During the course of the patient's encephalitis, an IgM titer developed against polyomavirus, followed by anti-polyomavirus IgG. Wild-type BK virus was demonstrated in cerebrospinal fluid samples. Cranial magnetic resonance imaging showed diffuse reversible white matter changes most prominent on T2-weighted images. CONCLUSION: We conclude that diagnostic tests for BK, a human polyomavirus, should be included in the screening program for encephalitogenic pathogens.     

Comparing US and international power and control cable standards

Cables made to IEC and US standards, while having the same purpose, are of widely different designs. Cables made to one standard cannot be made to match the requirements of the other. The cable made to the US standards have been used in the US and throughout most of the world. The IEC standards have not been widely used in Europe where national and private industrial and utility standards have prevailed. IEC standards have been mainly used in countries where there have not been strong electrical codes. The European Union's adaptation of the IEC standards under the harmonized EN standards of CENELEC adds the force of law to the standards. This will promote a wider use of the IEC (CENELEC) standards on the European continent, although each country could still apply its national rules to the CENELEC standard. This is scheduled to change because all CENELEC European harmonized documents have already been withdrawn and replaced by European Norms. These are the same, word for word, in all European countries. CENELEC members are also members of the IEC and, therefore, do not operate a competitive policy with respect to the IEC. International harmonization of standards must be done at the IEC level. The addition of the CE mark to products meeting CENELEC is similar to the application of the UL mark to products meeting UL standards in the US Worldwide harmonization of standards looks to be a long process. North American and European electrical systems are based on different voltages or frequencies, different conductor sizes, and a different concept of what an electrical system should do     

Test Criteria and Methodology for Evaluation of Coal Mine Monitoring and Control Systems

Field evaluation of coal mine monitoring and control systems yields data on installation and maintenance, but does not provide a full evaluation of these systems under all possible conditions. Also, the differences in installations and configurations do not allow the performance of different systems to be measured and compared. Under contract of the United States Bureau of Mines (USBM), the West Virginia University (WVU) Department of Electrical Engineering has designed criteria for evaluation of monitoring systems, and a test facility for simulation of mine conditions. This facility provides evaluation of monitoring and control systems under both normal and abnormal conditions. This paper describes the test criteria chosen, the design of the test facility, and the experiences of tests performed on mine monitoring systems to date.     

Almost-sure convergence of adaptive algorithms by projections

A convergence proof is discussed for the normalized least-mean-square (LMS) algorithm for ergodic inputs. The approach is based on interpreting the algorithm as a sequence of relaxed projection operators by which the key contraction property is derived. The proof technique is strongly motivated by physical intuition, and provides additional insight into LMS-type algorithms under ergodic inputs. Embedded in the development is a slight generalization to a random time-varying gain parameter. This allows the incorporation of variations such as the LMS and signed LMS algorithms     

Chemical-moisture barrier cable-concept and practice

Cables with sheaths providing protection from chemicals and moisture have gained in popularity among many industrial and utility users in North America and Europe. These sheaths are used to protect low-, medium-, and high-voltage power cables as well as fiber-optic and instrumentation cables. This paper presents an overview of the theory, design, testing, and field experience for each type of cable as it pertains to chemical and moisture protection. Documentation is provided covering underground installations of chemical-moisture barrier cable in a large petrochemical manufacturing facility located on the Texas Gulf Coast     

A 2-year follow-up study of work ability among college educators

The aim of this study was to evaluate work ability among college educators before and after an intervention at the workplace. An administrative restructuring in the workplace started to be implemented in 2005. The work ability index (WAI) was administered to 154 educators before the restructure in 2004 and to 60 educators following the restructure in 2006. A t-test comparing the WAI score of the 60 educators who took part in both phases showed a trend of improving work ability (p=0.06; mean WAI in 2004 was 41.7 and 43.3 in 2006). The results suggest that the intervention led to an improvement in psychosocial factors, which in turn positively influenced work ability.