An evaluation of weld metal nitrogen retention and properties in 316NL austenitic stainless steel

A series of tests were conducted using varying levels of nitrogen and helium in a conventional argon shielding gas when welding 316LN austenitic stainless steel. The outcome was that a 15 per cent nitrogen addition to the argon shielding gas had the most significant effect on increasing the weld metal nitrogen. Subsequent additions of helium to the argon 15 per cent nitrogen shielding gas had very little overall benefit. Increasing the nitrogen content of the weld metal had the consequential effects of decreasing the ferrite content and the hardness. As a result of solid solution strengthening, the yield strength increased with increase in nitrogen content. There was an increase in impact toughness as the nitrogen content increased. This was related to the decreased ferrite content associated with the strong austenetizing potential of nitrogen. It was also shown that an almost fully austenitic weld metal could still have very good toughness. In combination with these effects there was no loss in corrosion resistance. The addition of nitrogen to a conventional argon shielding gas presents attractive cost and quality benefits over the established requirement to over alloy the weld filler material with expensive alloys such as nickel

The Accuracy of Accredited Glaucoma Optometrists in the Diagnosis and Treatment Recommendation for Glaucoma

Background/aims: To compare the diagnostic performance of accredited glaucoma optometrists (AGO) for both the diagnosis of, and decision to treat glaucoma with that of routine hospital eye care against a reference standard of expert opinion, i.e. consultant ophthalmologist with a special interest in glaucoma. Methods: A directly comparative, masked, performance study was performed in Grampian, Scotland. 165 people were invited to participate and, of those, 100 (61%) were examined. People suspected of having glaucoma underwent a full ophthalmic assessment both in a newly established, community optometry led, glaucoma management scheme and in a consultant led hospital eye service within a month. Results: The agreement between the AGO and the consultant ophthalmologist in the diagnosis of glaucoma was substantial (89%, kappa = 0.703, SE=0.083). The agreement regarding the need for treatment was also substantial (88%, kappa = 0.716, SE =0.076). The agreement between the trainee ophthalmologists and the consultant ophthalmologist in the diagnosis of glaucoma and treatment recommendation were moderate (83%, kappa = 0.541, SE = 0.098, SE = 0.98; and 81%, kappa = 0.553, SE = 0.90, respectively). The diagnostic accuracy of the optometrists in detecting glaucoma in this population was high for specificity (0.93 [95% CI 0.85 to 0.97]) but lower for sensitivity at 0.76 (95% CI 0.57 to 0.89). The performance was similar when accuracy was assessed for treatment recommendation (sensitivity, 0.73[95% CI 0.57 to 0.85]; specificity 0.96[95% CI 0.88 to 0.99]). The differences in sensitivity and specificity between AGO and junior ophthalmologist was not statistically significant.Conclusions: Community optometrists trained in glaucoma provided satisfactory decisions regarding diagnosis and initiation of treatment for glaucoma. With such additional training in glaucoma optometrists are at least as accurate as junior ophthalmologists but some cases of glaucoma missed.Chief Scientist Office of the Scottish Executive Health Departmen

MIG gas shielding : Economic savings without detriment to quality

Over the years a number of claims have been made related to potential savings of the shielding gas used in the MIG process. A number of work streams have been set up to consider such areas from a technical and economic standpoint. The use of small helium additions has particular benefits and despite an increase in unit cost, the overriding benefits are achieved in reduced manhour cost. A similar situation has been established when using a high frequency process to switch shielding gases during welding. The outcome from this was very similar to that already described. Overlaid on these has been the increasing use of a technique that visualises actual gas flow during welding by the use of laser backlighting. Some preliminary work in this area is described particularly related to the effect of drafts on the gas distribution. A recent development on the market place is a piece of equipment, which regulates the gas flow automatically and synchronously with the welding current. Gas savings in the region of 50-60% have been obtained. Data has been produced to illustrate these benefits. The potential benefit of developing a computational fluid dynamic model of the gas flow is also described, and early development stages of the model shown. However, there will always exist the very basic management need to minimise leaks from the gas delivery systems

Power analysis of local transmission technologies

With the number of Internet of Things (IoT) devices expected to explode to over 20 Billion devices by 2020, it is vital that efficient communication technologies are used. While ideally a single technology would emerge to simplify deployment, in practice the varying power and bandwidth requirements of different devices has led to an industry split over communication technologies, and while a number of new technologies have been designed with IoT in mind, commercial imperatives have meant that existing wireless protocols, in particular Wi-Fi and 433 MHz AM, remain the most prevelent. This article outlines the power usage of these two most common protocols, and considers power aspects of using each protocol in an IoT setting with experiments carried out with real world devices used in current products

OFFSET SKATING CHARACTERISTICS OF WORLD CUP LEVEL CROSS-COUNTRY SKIERS

The cross-country ski skating techniques have been evolving steadily over the past several years. Previous kinematic and temporal studies conducted by Smith, McNitt-Gray, & Nelson (1988); Smith & Nelson (1988); Smith, Nelson, Feldrnan, & Rankinen (1989); and McPherson (1991) have documented this evolution. A kinematic and temporal study was conducted during the 1994 Men's World Cup Cross-Country Ski Relay competition in Thunder Bay. The study was used to develop a current kinematic and temporal profile of the World Cup level competitors based on a multiple correlation and regression analysis of selected variables. The Peak 2D Motion Analysis System was used to digitize video footage of 24 competitors offset skating on a 9 degree slope. A significant positive relationship was found between the dependent variable cycle velocity and cycle length (ec.01,2-tailed). Further significant positive relationships (ec.05, 2-tailed) were found between the dependent variable race velocity and cycle velocity, and percentage of cycle time skating on the downhill leg. In addition there were other significant correlations found among the selected variables. Cycle length increased as the uphill pole angle at pole plant decreased (ec.05, 2-tailed), and the cycle velocity increased (ec.01, 2-tailed). Cycle time decreased as the percentage of the cycle time skating on the uphill leg and the cycle velocity increased (

Optimizing power consumption of Wi-Fi inbuild IoT device : an MSP430 processor and an ESP-03 chip provide a power-efficient solution

The Internet of Things (IoT) -- connection of small smart sensors, actuators and other devices to the Internet -- is a key concept within the smart home. To ease deployment, such devices are often wireless and battery powered. An important question is the wireless interface used. The ubiquity of Wi-Fi in homes today makes this an attractive option, but the relatively high power requirements of Wi-Fi conflict with the requirement for long battery life and low maintenance. Lower power alternatives, such as Bluetooth and Zigbee, have been proposed, but these have a much smaller installed base. In addition, many Smart Home products are currently available using 433MHz technology. This paper considers whether it is possible to reduce Wi-Fi power usage to the point where cheap Wi-Fi based products can be used instead of other protocols. The paper undertakes power analysis of a wireless sensor with an SoC Wi-Fi module, with and without a separate microcontroller optimised for low power usage which can be used to switch the Wi-Fi module on and off. This paper is an extension of previous work comparing Wi-Fi and 433MHz devices, and so we compare 433MHz to the optimised Wi-Fi sensor. Finally, the paper considers the energy usage of DHCP, demonstrating that further energy savings can be made if the application handles IP addressing and presents a static IP address to the Wi-Fi module

Use of drug therapy in the management of symptomatic ureteric stones in hospitalized adults (SUSPEND), a multicentre, placebo-controlled, randomized trial of a calcium-channel blocker (nifedipine) and an α-blocker (tamsulosin) : study protocol for a randomized controlled trial

Peer reviewedPublisher PD

Using primary care databases for addiction research:An introduction and overview of strengths and weaknesses

Primary care databases extract and combine routine data from the electronic patient records of various participating practices on a regular basis. These databases can be used for innovative and relevant addiction research, but such use requires a thorough understanding of how data were originally collected and how they need to be processed and statistically analysed to produce sound scientific evidence. The aims of this paper are therefore to (1) make a case for why primary care databases should be considered more frequently for addiction research; (2) provide an overview of how primary care databases are constructed; (3) highlight important methodological and statistical strengths and weaknesses of using primary care databases for research; and (4) give practical advice about how a researcher can get access to databases. Three major primary care databases from the UK serve as examples: Clinical Practice Research Datalink (CPRD), The Health Improvement Network (THIN), and QResearch

A computational fluid dynamic analysis of the effect of side draughts and nozzle diameter on shielding gas coverage during gas metal arc welding

Extensive experimental trials were conducted, emulating the conditions modelled, in order to validate the computational fluid dynamic results. Final results demonstrated that a more constricted nozzle was more effective at creating a stable gas column when subjected to side draughts. Higher shielding gas flow rates further reduce the gas column's vulnerability to side draughts and thus create a more stable coverage. The results have highlighted potential economic benefits for draught free environments, in which, the shielding gas flow rate can effectively be reduced