COMBUSTION CHARACTERISTICS AND EMISSION OF HAZARDOUS AIR POLLUTANTS IN COMMERCIAL FLUIDIZED BED COMBUSTORS FOR SEWAGE SLUDGE

Since the disposal of sewage sludge in ocean has been prohibited recently according to London Dumping Convention, technological need for treating sewage sludge safely and efficiently are getting increased in Korea. FBC (Fluidized Bed Combustor) technology has been selected and utilized as one of the alternatives because of combustible content in sludge, on-going process development to maintain the best combustion efficiency, and good heat recovery for energy utilization. In this paper, the process and combustion characteristics of commercially operating FBC incineration plants with the capacity ranging from 50 – 150 tons of sludge per day were investigated by comparing emission data from 4 different plants. Concentrations of hazardous gaseous pollutants (HAPs) such as fine particulate matter, heavy metals, and dioxin from sludge combustion before and after air pollution control devices were measured and analyzed at commercial operating conditions of one typical incinerator. Most of emission data at stack showed under the environmental regulatory limits. Mercury and some heavy metals emission have been reduced significantly as co-beneficial effect since the air pollution control configuration was well arranged and installed to control the regulatory gases such as NOx, SO2, particulates, and dioxin. Sludge, especially generated from industrial plants, contained measurable amounts of acidic materials and heavy metals including Hg. Therefore, such metal emission should receive an attention by monitoring them and further mass balance study for better understanding their fates in the process must proceed in future

Visual Function after Primary Posterior Chamber Intraocular Lens Implantation in Pediatric Unilateral Cataract: Stereopsis and Visual Acuity

PURPOSE: To investigate the association between binocular function and vision after cataract removal and primary posterior chamber intraocular lens (PC-IOL) implantation in children with unilateral cataract and to identify visual function differences according cataract type. METHODS: Clinical records of 2- to 6-year-old patients with unilateral cataract removal and primary PC-IOL implantation were reviewed retrospectively. Visual acuity and ocular alignment were measured. Sensory fusion was assessed with the Worth 4-dot test, and stereoacuity with the Titmus stereo test. Cataracts were classified according to cause, lens opacity location, age at onset, and presence of strabismus. Clinical characteristics of patients who obtained good visual function were identified. RESULTS: Forty-seven patients were included. Among 22 (46.8%) with good vision (20/40 or better), only 6 (27.3%) achieved good binocular function (the presence of fusion and 100 seconds of arc or better of stereoacuity). Visual acuity was better in eyes with good binocular function (p=0.002). No other variables were significant for achieving good binocular function. CONCLUSIONS: The removal of unilateral cataract in a visually immature child can result in a combination of good visual acuity and binocular function. Good binocular function is closely related to good visual acuity

Data-efficient active weighting algorithm for composite adaptive control systems

We propose an active weighting algorithm for composite adaptive control to reduce the state and estimate errors while maintaining the estimation quality. Unlike previous studies that construct the composite term by simply stacking, removing, and pausing observed data, the proposed method efficiently utilizes the data by providing a theoretical set of weights for observations that can actively manipulate the composite term to have desired characteristics. As an example, a convex optimization formulation is provided, which maximizes the minimum eigenvalue while keeping other constraints, and an illustrative numerical simulation is also presented

Rotational Resistance of Surface-Treated Mini-implants

Objective: To test the hypothesis that there is no difference in the stability and resistance to rotational moments of early loaded sandblasted and acid-etched (SLA) mini-implants and those of machined-surface implants of the same size and shape. Materials and Methods: A randomized complete block design was used in 12 skeletally mature male beagle dogs. Ninety-six orthodontic mini-implants were tested. Two types of implants were used: some had SLA surface treatment and some had machined surfaces without coating. After 3 weeks of healing, rotational moments of 150 g were applied. The success rates, maximum torque values, angular momentum, and total energy absorbed by the bone were compared. All values were subjected to mixed-model analysis to evaluate the influence of surface treatment, rotational force direction, and site of implantation. Results: The maximum insertion torque and angular momentum of SLA implants were significantly lower than those of machined implants (P = .034, P = .039). The SLA implants had a significantly higher value for total removal energy than the machined implants (P = .046). However, there were no significant differences in total insertion energy, maximum removal torque, and removal angular momentum between the 2 groups. There was no significant difference between clockwise and counterclockwise rotation in all measurements. Conclusion: SLA mini-implants showed relatively lower insertion torque value and angular momentum and higher total energy during removal than the machined implants, suggesting osseointegration of the SLA mini-implant after insertion

Computer-Aided Designing and Manufacturing of Lingual Fixed Orthodontic Appliance Using 2D/3D Registration Software and Rapid Prototyping

The availability of 3D dental model scanning technology, combined with the ability to register CBCT data with digital models, has enabled the fabrication of orthognathic surgical CAD/CAM designed splints, customized brackets, and indirect bonding systems. In this study, custom lingual orthodontic appliances were virtually designed by merging 3D model images with lateral and posterior-anterior cephalograms. By exporting design information to 3D CAD software, we have produced a stereolithographic prototype and converted it into a cobalt-chrome alloy appliance as a way of combining traditional prosthetic investment and cast techniques. While the bonding procedure of the appliance could be reinforced, CAD technology simplified the fabrication process by eliminating the soldering phase. This report describes CAD/CAM fabrication of the complex anteroposterior lingual bonded retraction appliance for intrusive retraction of the maxillary anterior dentition. Furthermore, the CAD/CAM method eliminates the extra step of determining the lever arm on the lateral cephalograms and subsequent design modifications on the study model

Unusual extraction treatment in Class II division 1 using C-orthodontic mini-implants.

AbstractThis paper describes the treatment of a female patient, aged 23 years and 5 months, with a Class II division 1 malocclusion, who showed severe anterior protrusion and lower anterior crowding. Specially-designed orthodontic mini-implants were placed bilaterally in the interdental space between both the upper and the lower posterior teeth. Both lower first molars showed severe apical lesions. Therefore, the treatment plan consisted of extraction of both upper first premolars and lower first molars, en masse retraction of the upper six anterior teeth, lower anterior alignment, and protraction of all the lower molars. C-implants® were used as substitutes for maxillary posterior anchorage teeth during anterior retraction and as hooks for mandibular molar protraction. The correct overbite and overjet were obtained by intruding and retracting the upper six anterior teeth into their proper positions. The dentition was detailed using conventional orthodontic appliances. The upper C-implants contributed to an improvement in facial balance, and the lower C-implants made it possible to protract the lower second and third molars with less effect on the axis of the lower anterior teeth. The active treatment period was 29 months and the patient's teeth continued to be stable 11 months after debonding

Environment and Its Influence on Health and Demographics in South Korea

As the prevalence of overweight and obesity has been increasing in South Korea, it is critical to better understand possible associations between environmental surroundings and general health status. We characterize key health test readings and basic demographic information from 10,816 South Koreans, obtained from two Ubiquitous Healthcare (U-Healthcare) centers that have distinct surrounding neighborhood characteristics. One is located in a rural area in Busan, the other is located in an urban area in Daegu surrounded by a highly crowded residential and commercial business area. We analyze comprehensive health data sets, including blood pressure, body mass index, pulse rate, and body fat percentage from December 2013 to December 2014 to study differences in overall health test measurements between users of rural and urban U-Healthcare centers. We conduct multiple regression analyses to evaluate differences in general health status between the two centers, adjusting for confounding factors. We report statistical evidence of differences in blood pressure at the two locations. As local residents are major users, the result indicates that the environmental surroundings of the centers can influence the demographics of the users, the type of health tests in demand, and the users’ health status. We further envision that U-Healthcare centers will provide public users with an opportunity for enhancing their current health, which could potentially be used to prevent them from developing chronic diseases, while providing surveillance healthcare data

Journey of a Swallowed Toothbrush to the Colon

Toothbrush swallowing is a rare event. Because no cases of spontaneous passage have been reported, prompt removal is recommended to prevent the development of complications. Most swallowed toothbrushes have been found in the esophagus or the stomach of affected patients, and there has been no previously reported case of a toothbrush in the colon. Here, we report a case of a swallowed toothbrush found in the ascending colon that caused a fistula between the right colon and the liver, with a complicating small hepatic abscess. This patient was successfully managed using exploratory laparotomy. To our knowledge, this is the first documented case of a swallowed toothbrush found in the colon