545,680 research outputs found
Indoor localization based on multiple LEDs position estimation
This paper describes the simulation results and hardware implementation of an inexpensive, low-complexity LED based indoor positioning system. Localization by multiple LEDs estimation model (MLEM) approximates position of a mobile receiver by the acquisition of positional information from LED transmitters. Multiple LED orientation can either be with or without overlap. Receivers in a no-overlap LED orientation experience only single access while multiple access receivers are designed for orientations with overlaps. Single and multiple access systems were developed and implemented by the use of low cost ATMEG 328 microcontroller. Since multiple LEDs transmit data at the same wavelength and are asynchronous, overlap in multiple access system causes interference. The possibility of this interference is reduced by packet based pulse duration multiplexing (PDM) and a low duty cycle transmission protocol. By the use of MLEM, root mean square error in position estimation is reduced to about 1 percent of the length an indoor location. Experimental results show that overlap increases positional accuracy over a wider coverage region and that the multiple access system allows for a more reliable positioning
Comparative Analysis on Roof Covering Materials Sustainability as Constructed by Bamboo and Corrugated Galvanized Iron Sheet in Rural Areas Around Wolkite, Ethiopia
One of the most important components of any building is the roof, which protects the interior of the building from environmental influences. It is sustainable to switch roofing materials from expensive roofing materials to inexpensive and environmentally friendly materials. Today's roofing materials have negative effects on the environment due to the manufacturing process. Therefore, this research has mainly focused on the development of sustainable roofing materials through life cycle cost analysis. Approximately ten bamboo samples from homeowners in the Wolkite area and one Adama corrugated galvanized sheet were taken to analyze the life cycle costs. Data on the ecological and socio-economic aspects of the selected roofing materials were collected with the help of interviews and questionnaires. The cost of galvanized corrugated iron sheet of 1.8m2 was 3.91; the researchers concluded that treated bamboo roofs have lower life cycle costs per 1.8 square meters (approximately 89.76% less than corrugated galvanized iron), more environmentally friendly. And also using bamboo as roofing material, create a good job opportunity for the society by cultivating and preparing bamboo to the construction input
Using Sensor-Based Demand Controlled Ventilation to Realize Energy Savings in Laboratories
The building sector in the United States accounted for 41% of domestic and 7% of global energy consumption in 2010, with heating, ventilating, and air-conditioning (HVAC) activities consuming approximately 41.4% of the total facility energy consumption. Within the HVAC system, the parasitic energy accounts for one-third of the total energy consumed while heating and cooling accounts for the balance. The fan energy is approximately 85% of the total parasitic energy in the HVAC system. In a laboratory, energy related to ventilation can account for nearly half of the electrical energy demand. A carbon dioxide (CO2)-based demand controlled ventilation (DCV) strategy can reduce the ventilation requirement by monitoring the indoor air quality (IAQ) of a space and modulating the ventilation based on the real-time occupancy. This research presents a tool for laboratory managers to quickly determine if employing a DCV system is potentially life-cycle cost effective. The tool presented is not to be used as sole justification for implementing a DCV system; instead, laboratory managers using this tool will be able to quickly determine if further investigation into DCV installation is warranted. The results show that a DCV system is life-cycle cost effective for many different HVAC system total pressure and square footage combinations
A BIM-based Detailed Electrical Load Estimation, Costing and Code Checking
Building Information Modeling (BIM) has established into a powerful solution for our construction requirements throughout its life cycle. Compared to conventional methods, BIM offers simple, faster and accurate methodology for modelling, estimation and analysis. In this paper, a novel Autodesk Revit add-in tool named as “Electrical System Estimation and Costing Tool”(ESECT) is proposed for the simultaneous estimation of electrical connected load, demand load, Volt Ampere per square meter, cost of electrical system construction and monthly bill from a residential building model and the add-in tool is developed by using Visual basic C# language. Research results indicate that wide range of BIM automated tools are possible for code-checking and estimation for design analysis at all stages of electrical system development and eventually leads to better design and cost reduction
Variations in visceral leishmaniasis burden, mortality and the pathway to care within Bihar, India
BACKGROUND: Visceral leishmaniasis (VL) has been targeted by the WHO for elimination as a public health problem (< 1 case/10,000 people/year) in the Indian sub-continent (ISC) by 2020. Bihar State in India, which accounts for the majority of cases in the ISC, remains a major target for this elimination effort. However, there is considerable spatial, temporal and sub-population variation in occurrence of the disease and the pathway to care, which is largely unexplored and a threat to achieving the target. METHODS: Data from 6081 suspected VL patients who reported being clinically diagnosed during 2012-2013 across eight districts in Bihar were analysed. Graphical comparisons and Chi-square tests were used to determine differences in the burden of identified cases by season, district, age and sex. Log-linear regression models were fitted to onset (of symptoms)-to-diagnosis and onset-to-treatment waiting times to estimate their associations with age, sex, district and various socio-economic factors (SEFs). Logistic regression models were used to identify factors associated with mortality. RESULTS: Comparisons of VL caseloads suggested an annual cycle peaking in January-March. A 17-fold variation in the burden of identified cases across districts and under-representation of young children (0-5 years) relative to age-specific populations in Bihar were observed. Women accounted for a significantly lower proportion of the reported cases than men (41 vs 59%, P < 0.0001). Age, district of residence, house wall materials, caste, treatment cost, travelling for diagnosis and the number of treatments for symptoms before diagnosis were identified as correlates of waiting times. Mortality was associated with age, district of residence, onset-to-treatment waiting time, treatment duration, cattle ownership and cost of diagnosis. CONCLUSIONS: The distribution of VL in Bihar is highly heterogeneous, and reported caseloads and associated mortality vary significantly across different districts, posing different challenges to the elimination campaign. Socio-economic factors are important correlates of these differences, suggesting that elimination will require tailoring to population and sub-population circumstances
Quantifying Fluid Shear Stress in a Rocking Culture Dish
Fluid shear stress (FSS) is an important stimulus for cell functions. Compared with the well established parallel-plate and cone-and-plate systems, a rocking “see-saw” system offers some advantages such as easy operation, low cost, and high throughput. However, the FSS spatiotemporal pattern in the system has not been quantified. In the present study, we developed a lubrication-based model to analyze the FSS distributions in a rocking rectangular culture dish. We identified an important parameter (the critical flip angle) that dictates the overall FSS behaviors and suggested the right conditions to achieving temporally oscillating and spatially relatively uniform FSS. If the maximal rocking angle is kept smaller than the critical flip angle, which is defined as the angle when the fluid free surface intersects the outer edge of the dish bottom, the dish bottom remains covered with a thin layer of culture medium. The spatial variations of the peak FSS within the central 84% and 50% dish bottom are limited to 41% and 17%, respectively. The magnitude of FSS was found to be proportional to the fluid viscosity and the maximal rocking angle, and inversely proportional to the square of the fluid depth-to-length ratio and the rocking period. For a commercial rectangular dish (length of 37.6 mm) filled with ∼2 mL culture medium, the FSS at the center of the dish bottom is expected to be on the order of 0.9 dyn/cm2 when the dish is rocked +5° at 1 cycle/s. Our analysis suggests that a rocking “see-saw” system, if controlled well, can be used as an alternative method to provide low-magnitude, dynamic FSS to cultured cells
Overcoming the Hurdle of First Cost: Action Research in Target Costing
Advocates of sustainable and evidence-based design initiatives argue that building owners can secure favorable internal rates of return when full life cycle building costs are considered. While the argument has merit, these decision-makers express concern about overcoming the hurdle of first cost. To reduce first cost, a number of lean construction practitioners are exploring a planning and design process called target costing. Target costing in construction is a collaborative cost management process that relies on business plan validation to determine what is to be delivered and what the client is willing and able to pay for a project--before establishing the allowable cost in order to spur innovation. Once a target cost has been established, the project is collaboratively designed to that target cost. This case study examines the target costing techniques used during the design of an 850,000 square foot (approximately 79,000 square meters) medical center. Qualitative and quantitative outcomes are explored, as well as implications for future projects
Fully Conjugated Phthalocyanine Copper Metal-Organic Frameworks for Sodium-Iodine Batteries with Long-Time-Cycling Durability
Rechargeable sodium-iodine (Na-I-2) batteries are attracting growing attention for grid-scale energy storage due to their abundant resources, low cost, environmental friendliness, high theoretical capacity (211 mAh g(-1)), and excellent electrochemical reversibility. Nevertheless, the practical application of Na-I-2 batteries is severely hindered by their poor cycle stability owing to the serious dissolution of polyiodide in the electrolyte during charge/discharge processes. Herein, the atomic modulation of metal-bis(dihydroxy) species in a fully conjugated phthalocyanine copper metal-organic framework (MOF) for suppression of polyiodide dissolution toward long-time cycling Na-I-2 batteries is demonstrated. The Fe-2[(2,3,9,10,16,17,23,24-octahydroxy phthalocyaninato)Cu] MOF composited with I-2 (Fe-2-O-8-PcCu/I-2) serves as a cathode for a Na-I-2 battery exhibiting a stable specific capacity of 150 mAh g(-1) after 3200 cycles and outperforming the state-of-the-art cathodes for Na-I-2 batteries. Operando spectroelectrochemical and electrochemical kinetics analyses together with density functional theory calculations reveal that the square planar iron-bis(dihydroxy) (Fe-O-4) species in Fe-2-O-8-PcCu are responsible for the binding of polyiodide to restrain its dissolution into electrolyte. Besides the monovalent Na-I-2 batteries in organic electrolytes, the Fe-2-O-8-PcCu/I-2 cathode also operates stably in other metal-I-2 batteries like aqueous multivalent Zn-I-2 batteries. Thus, this work offers a new strategy for designing stable cathode materials toward high-performance metal-iodine batteries
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