Search

Additive manufacturing (AM) is treated as a significant contributor to sustainability due to lower energy consumption, less material usage and reduced number of wastes generated when comparing with traditional manufacturing technologies. Currently there is a lot of commercial applications of such new technology in number of industry segments. However, such sector as high voltage engineering still struggles with number of challenges when considering additive manufacturing. In products working in high voltage environment, very often, in addition to mechanical loads there are demanding conditions, as elevated temperature and presence of insulation oil or gas. This requires a special approach to printing quality of the printed structures without internal voids and in case of metals, with improved electrical conductivity. In the paper, few examples of additive manufacturing applications in area of power products have been presented, including printed transformer insulation, printed copper, and application of AM for spare parts. For each case, the main challenges have been discussed.

Plastics are widely used materials, and their application increases considerably every year. Therefore, appropriate waste management policy should be used in relation to utilization/recycling of scrap plastic components. Currently, there are no clear utilization options for such scrap thermosetting materials, and landfill is the most commonly used method of their removal. However, it should be underlined that, in various products, especially from the electrotechnics industry, different metals are embedded in cured thermosets, and their recovery could be a very valuable recycling operation. Also, new environmental regulations are developing in this direction in that landfilling of organic wastes will be essentially limited. In this article, the results of the preliminary studies on pyrolytical degradation of thermosetting scrap have been presented, proving that this kind of waste treatment results in valuable pyrolysis products, and, as an additional benefit, recycling of the internal metallic parts can be successfully achieved. [ABSTRACT FROM AUTHOR]

The objective of the study was to determine if negative multidetector computed tomography (MDCT) and lateral radiography of the cervical spine effectively excludes patients with unstable cervical spine injuries. Over a period of 40 months, 6558 people were admitted to our trauma service with blunt injury and 447 (6.8%) were found to have cervical fractures. Fractures were identified by CT and/or lateral radiography. In order to rule out clinically significant instability in the absence of fracture, we identified nine patients who required any type of stabilization of the cervical spine including anterior fusion, posterior fusion and external orthosis. These patients also underwent MR of the cervical spine. Radiography, CT, and MR images and reports of these nine patients were reviewed. Nine patients without a fracture required cervical stabilization. These patients had the following abnormalities: disc herniation with canal stenosis in three, unilateral jumped facet in three, and various other soft tissue abnormalities in three, all of which were evident on CT or radiography. All nine patients had evidence for cervical spine injury or instability by MDCT. Normal MDCT and radiography appears adequate to 'clear' the cervical spine. We recommend that patients requiring cervical spine clearance undergo a complete MDCT and lateral radiograph of the cervical spine. If these studies are entirely normal, then the cervical spine may be cleared. If any abnormalities, including disc herniation, soft tissue swelling and bony malalignments are noted by radiography and/or MDCT, further studies, including MR, are indicated prior to clearance of the cervical spine. [ABSTRACT FROM AUTHOR]

Ventriculostomy is a common practice in neurosurgery, but the annual trend of this procedure in the United States has not been reported in the literature. This study evaluates the annual trend during a recent 5-year period. Between 1997 and 2001, a retrospective review was undertaken concerning all patients in the Nationwide Inpatient Sample (NIS) who had undergone ventriculostomy. The population sample represented approximately a 20% stratified sample of nonfederal hospitals in the United States. The annual number of patients who underwent ventriculostomy during the study period ranged from 20,586 to 25,634. Most patients were male (53.4%), with a mean age of 44.8 years, were commercially insured (46.0%) and had a median annual income above $25,000 (84.4%). Most frequent ICD-9-CM diagnoses were subarachnoid haemorrhage, intracerebral haemorrhage and obstructive hydrocephalus, respectively. The majority of ventriculostomies were performed in large, private, not-for-profit, metropolitan, teaching institutions. Mean length of hospital stay was 19.2 days. Regarding discharge status for patients who had undergone ventriculostomy, approximately one-quarter died in the hospital, one-third were discharged home and one-third were transferred to another institution. No demographic variables changed during the study with the exception of location of ventriculostomy in a teaching hospital, which increased from 64.4% in 1997 to 77.4% in 2001. Patient and hospital demographic characteristics were consistent during the study period. By extrapolation of the data, the prevalence of ventriculostomy in the United States averaged 24,380 per year. This study is the first to comprehensively document data concerning the epidemiology of this common procedure. [ABSTRACT FROM AUTHOR]

The paper presents application of newly developed three-dimensional (3-D) computer tool used for simulation of the automated pressure gelation process. The tool that is based on commercial CFD software-Fluent-enables the simulation of filling and curing stages and gives useful information helping to understand the phenomena occurring inside the mold. To simulate the complex rheology of the material, Macosko's model for viscosity and Kamal's model for curing kinetics were used and successfully applied in the software. First simulations were applied for arbitrary set parameters and formulated recommendations were later applied to approve the existing process. The simulation was performed for voltage transformer used in medium voltage applications and resulted in the optimization of the process parameters what allowed reduction of manufacturing time of the transformer considerably. Additionally the results of experimental verification of the simulation were presented in the paper showing very good agreement between simulation results and measured data. [ABSTRACT FROM PUBLISHER]

Although tethering of the spinal cord in the lumbosacral region, particularly following repair of congenital anomalies, such as myelomeningocele, is a well-known phenomenon, only sporadic reports of tethering along the rest of the neuraxis, including the hindbrain, cervical and thoracic spinal cord have been documented. In this report, we describe a woman who developed symptoms related to tethering of the cervical spinal cord 5 years after suboccipital decompressive surgery of the posterior fossa for Chiari I malformation. The authors discuss the diagnosis, treatment, and postoperative course of this entity. [ABSTRACT FROM AUTHOR]

Abstract Background Chiari I malformation (CMI) is diagnosed by rigid radiographic criteria along with appropriate clinical symptomatology. The aim of this study was to investigate the dimensions of the posterior cranial fossa in patients without significant tonsillar descent but with symptoms comparable to CMI. Methods Twenty-two patients with signs and symptoms comparable to CMI but without accepted radiographic criteria of tonsillar descent > 3–5 mm were referred to our clinic for evaluation. A history and physical examination were performed on all patients. In reviewing their MRI scans, nine morphometric measurements were recorded. The measurements were compared to measurements from a cohort of twenty-five individuals with cranial neuralgias from our practice. Results For patients with Chiari-like symptomatology, the following statistically significant abnormalities were identified: reduced length of the clivus, reduced length of basisphenoid, reduced length of basiocciput, and increased angle of the tentorium. Multiple morphometric studies have demonstrated similar findings in CMI. Conclusion The current classification of CMI is likely too restrictive. Preliminary morphologic data suggests that a subgroup of patients exists with tonsillar descent less than 3 mm below the foramen magnum but with congenitally hypoplastic posterior fossa causing symptomatology consistent with CMI.