Electrostatic Risk Assessment for Combustible Dust Atmospheres

Since June 2003 new and modified plants in Europe must comply with the requirements of the European Directive ATEX 137, aimed at improving the safety and health protection of workers potentially at risk from explosive atmospheres. Of all possible sources of ignition that must be considered under this legislation, the ATEX Directive draws explicit attention to one: Static Electricity. Static is a common cause of fires and explosions, as it is present in a very wide range of industries, in some cases an inevitable outcome of the process being carried out. In others, unless specific measures have been taken, it may occur as a result of secondary actions such as movement of equipment and personnel. This paper shall firstly summarize the main characteristics of static electricity (charge generation, charge accumulation, types and modes of static discharges, such as sparks and propagating brush discharges). The paper shall then illustrate the methodology of an electrostatic risk assessment in a combustible dust environment, and the criteria to be adopted when assessing the effectiveness of the ignition. Lastly, the paper shall discuss prevention measures to reduce the electrostatic risk, such as solutions for avoiding charge generation and indications about proper grounding and bonding of conductive materials

Sinus Floor Elevation with Modified Crestal Approach and Single Loaded Short Implants: A Case Report with 4 Years of Follow-Up

Tooth extraction is usually followed by bone reduction. In the maxillary posterior region, this remodelling combined with sinus pneumatisation and periodontal defects may lead to a reduced basal bone height available for implant placement. Sinus floor elevation can be performed with different surgical techniques. Crestal approach has demonstrated to be effective, less invasive, and associated with a reduced morbidity. This article reports a modified sinus floor elevation by means of rotary, noncutting instruments, addition of xenograft, and 2 short-threaded implant placements. The aim of the study was to evaluate the implant’s success and intrasinus radiographical bone gain after 4 years of functional loading. The premolar implant site presented a starting basal bone height of 6 mm, while the molar site was of 2 mm. In the first surgical step, sinus floor elevation was performed mesially and the implant was inserted, and distally only sinus floor elevation was performed. After 6 months, the mesial implant was uncovered and the second implant was inserted; 4 months later, the second fixture was uncovered, and both fixtures were loaded with single provisional screw-retained crowns and later with single screw-retained porcelain fused to metal crowns. Implants integrated successfully, and crestal bone remodelling did not exceed the smooth collar. Bone gain was 3 mm for the mesial implant and more than 5 mm for the distal one

Intraoperative complications and early implant failure after transcrestal sinus floor elevation with residual bone height ≤5 mm: A retrospective multicenter study.

OBJECTIVE Clinical indications for maxillary sinus floor elevation with transcrestal techniques have increased in recent years even in sites with minimal residual bone height (RBH). Nevertheless, limited information is currently available on incidence of intraoperative complications and early implant failure in these cases. MATERIAL AND METHODS This retrospective multicenter study was performed on anonymized clinical and radiographic records of patients who underwent transcrestal sinus floor elevation in seven clinical centers. Influence of different factors related to patient, and sinus anatomy and surgical technique on the incidence of intraoperative complications and early implant failure rate after transcrestal sinus lift were investigated. RESULTS A total of 430 patients treated with transcrestal sinus floor elevation for single-implant insertion in sites with RBH ≤5 mm were included in the final analysis. After 1 year of loading, 418 implants of 430 were satisfactorily in function. Early implant failure was recorded in 12 cases (2.8%); results were significantly associated with the presence of large sinus cavities and with the occurrence of membrane perforation. The following adverse events were recorded: membrane perforation (7.2%), acute sinusitis (0.9%), implant displacement into the sinus cavity (0.7%), oro-antral fistula (0.2%), and benign paroxysmal positional vertigo (0.5% of osteotome cases). A strong direct correlation between sinus membrane perforation and bucco-palatal sinus width (p = .000) was demonstrated. CONCLUSIONS Early implant failure after transcrestal sinus elevation showed significant direct correlation with bucco-palatal maxillary sinus width and the presence of membrane perforation. Sinus membrane perforation was strongly associated with bucco-palatal sinus width (extremely low perforation rate in narrow and much higher incidence in wide sinuses)

Crestal Maxillary Sinus Lift with Rotating Instruments and Different Grafting Materials: Results at 4 Years Follow Up

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Developing tourism products in line with Islamic beliefs: some insights from Nabeul–Hammamet

In recent years, the interest of both the tourism industry and the academic world in Muslims as consumers with specific requirements has grown remarkably. Attracting Muslim tourists is considered a good business opportunity in an increasing number of Muslim and non-Muslim countries. Tunisia is one of the most important destinations for international tourism in the Middle East and North Africa. Despite being a Muslim-majority country, no significant effort has been made as yet to reach the growing demand for tourism products in line with Islamic beliefs. This study investigates the opinions of a group of 19 key informants in Nabeul–Hammamet concerning the possibility of developing such products. This research shows that tourism operators are becoming progressively more familiar with the global opening up to products designed for Muslim consumers. Opportunities offered by this segment have been recognised, and clear signs are emerging of a proactive attitude towards Muslim-oriented tourism as a differentiation to

The Creeping Attachment Induced Technique (CAIT) in Natural and Restored Teeth: Case Reports with 24 Months of Follow-Up

This article describes a nonsurgical approach for treating gingival recessions and increasing gingival thickness around the natural teeth. Two female patients, presenting gingival recessions at the maxillary frontal teeth, were treated. Patient #1 had a discrepancy among the central maxillary incisors’ gingival margin, and tooth UL1 needed to be restored. Patient #2 presented a buccal gingival recession at tooth UL3. In both cases, the sulcular gingival margin was gently disephitelized with a diamond bur leaving the soft tissue healing by itself. After 4 weeks, the procedure was reperformed. After 6 months, the gingival margins appeared thicker and a creeping attachment was achieved in both cases, obtaining gingival symmetry, related to the adjacent or contralateral teeth, and root coverage. Gingival asymmetry, gingival recessions, and gingival thickness may be improved by means of a guided gentle nonsurgical stimulation, providing creeping attachment in the natural and also restored teeth, with a healthy and stable tissue after 24 months of follow-up

An orientable solar panel system for nanospacecraft

An orientable deployed solar array system for 1-5 kg weight nanospacecraft is described, enhancing the achievable performance of these typically power-limited systems. The system is based on a deployable solar panel system, previously developed with cooperation between Laboratorio di Sistemi Aerospaziali of University of Roma "la Sapienza" and the company IMT (Ingegneria Marketing Tecnologia). The system proposed is a modular one, and suitable in principle for the 1U, 2U and 3U standard Cubesat bus, even if the need for three axis attitude stabilization makes it typically preferred for 3U Cubesats. The size of each solar panel is the size of a lateral Cubesat surface. A single degree of freedom maneuvering capability is given to the deployed solar array, in order to follow the apparent motion of the sun as close as possible, given the mission requirements on the spacecraft attitude. Considerable effort has been devoted to design the system compatible with the Cubesat standard, being mounted outside on the external spacecraft structure, without requiring modifications on the standard prescriptions. The small available volume is the major constraint, which forces to use miniaturized electric motor technology. The system design trade-off is discussed, leading to the selection of an architecture based on two independently steerable solar array wings. (C) 2014 IAA. Published by Elsevier Ltd. All rights reserved