1,485 research outputs found
Efficient Method of Pitch Estimation for Speech Signal Using MATLAB
In this paper, we are estimating the pitch of telephone speech signal. We use different types of methods such us, Burg, Covariance, Fast Fourier transform, Modified Covariance, Multiple Signal Classification (MUSIC) algorithm or Eigen vector, Multi Taper method (MTM), Welch, and Yule Auto Regressive (Yule AR) , to estimate the PSD using signal processing tool box of MATLAB. The spectrum was constructed and the pitch ,amplitude , and slope of the speech signal were calculated and their performance were analyzed
A High Efficient High Input Power Factor Interleaved Boost Converter
In this paper an improved ZVT interleaved boost PFC topology is introduced. The proposed ZVT interleaved boost converter is composed of two cell boost conversion units and an active auxiliary circuit. The proposed converter has two important advantages over the similar soft switching converters. The first one is that parallel to the main switches of the converter the auxiliary switch also operates under soft switching condition. Providing soft switching conditions for interleaved boost converters with more than one cells using only one auxiliary switch is another advantage of this topology. The prototype for the proposed converter was developed with an input of 110V-220V ac power supply feeding a resistive output load of 600 watts. In addition, the proposed converter has the advantages of fewer structure complications, lower cost and ease of control.DOI:http://dx.doi.org/10.11591/ijece.v2i3.25
Durability Map for The Friction Stir Welding Tools with Flat Faced Pins
In friction stir welding, tools made with flat faced pins deliver comparatively higher strength joints than circular pins. However, its non-axisymmetric cross section about the rotational axis results in fluctuating stress along its surface that leads to premature tool failure. This requires a systematic definition for process parameter selection domain based on the number of flat faces in the pin to improve tool life. Temperature dependent strength of the material to be joined in the stir zone is the only source of opposing force for the tool movement. To predict opposing force, temperature gradient developed by the different levels of process parameters in the stir zone is numerically quantified with an experimentally validated model. Based on the estimated temperature, maximum stress acting on the tool pin is quantified with a remodified temperature dependent analytical model. The effect of increase in process temperature on the strength of the weld joint is experimentally analysed through the investigation of change in hardness value in heat affected zone. Obtained results are used to develop tool durability maps for tools with flat faced pin in a domain on which higher and lower limits are fixed by considering satisfactory level of joint strength and tool life respectively. These maps provide flexibility in the parameter selection with an acceptable level of compromise in joint strength or in tool life based on the quality requirement of weld joint
Cage Farming of Cobia Rachycentron canadum
Cobia has gained popularity as a good
candidate for mariculture due to its rapid
growth and white meat of versatile use. It
is considered as one of the most promising
candidates for warm-water marine fish
aquaculture in the world. Being the only
member of the family Rachycentridae, it is
found in the warm, temperate to tropical
waters of the West and East Atlantic,
throughout the Caribbean and in the
Indo-Pacific off India, Australia and Japan.
To date, research and development of
cobia aquaculture has been initiated in
over 23 countries and territories
Farming of Silver Pompano Trachinotus blochii in coastal aquaculture ponds
The Central Marine Fisheries Research Institute has
initiated aquaculture research on pompano from 2008
and the first successful broodstock development,
induced breeding and larval production was achieved in
2011. Following the successful seed production of silver
pompano, demonstration of farming in brackishwater
ponds was initiated by the CMFRI to popularize among
the farmers about its suitability for aquaculture. The first
farming demonstration from the hatchery produced seed
was carried out in a coastal aquaculture pond at Anthervedi
Village, East Godavari District, Andhra Pradesh. It has
been proven that silver pompano can be cultured in the
brackishwater shrimp culture ponds as an alternative
species with high survival rate, appreciable FCR and meat
quality. These fishes have attained an average weight of
450 grams in 240 days (8 months).
Based on the experience gained on the brackishwater
farming of silver pompano, the practices to be adopted
for pompano farming are narrated
A Pragmatic Approach Towards the Manufacture of Wet-White Leathers Using a Bio-Polymeric Tanning System
Content:
Different tanning materials endow leather with varying colors observable in undyed leathers. Periodateoxidized starch tanned leathers have a yellow tinge or light brown color and get darker with age. The color change in situ is ascribable to iodate ions that are byproducts of periodate oxidation. Iodate ions undergo reduction to form iodine molecules that are yellow or brown in low or at higher concentrations. This study focuses on the removal of iodate ions from Dialdehyde Tapioca Starch (DTS) using a simple precipitation method. Preparation of DTS is by periodate oxidation and precipitation of iodate ions using an inorganic precipitant. The experiments for manufacturing wet-white leathers used pickled goatskins and DTS (unmodified and modified) tanning agents at various percentages based on pelt weight. Glutaraldehyde (GTA) tanning was the control. The percentage removal of iodate ions in modified DTS was 98%. Both unmodified and modified DTS had an aldehyde content of 70%. FT-IR and 1H-NMR confirmed the aldehyde groups. GTA, unmodified, and modified DTS tanned leathers had shrinkage temperatures of 80, 87, and 89°C, respectively. The physico-mechanical properties of the control and experimental leathers are comparable. GTA tanned leather had the typical brown color associated with GTA tannages. The ‘b’ color value of unmodified DTS tanned leather was high confirming yellowing of leathers upon ageing. Wet-white leather tanned with modified DTS had no discernible color change. Analysis of the spent tan liquor shows a reduction in the BOD, COD, TS, and TDS load when compared to GTA tanning system evincing the biodegradability of DTS. This study has overcome the drawback associated with periodate-oxidized starch tanning agents, viz. leather darkening over time, considering the chemical and physico-mechanical properties of the resultant leathers. The novel iodate free DTS can be scaled-up for commercial availability.
Take-Away:
Removal of iodate ions from periodate-oxidized starch before its use as a tanning agent is imperative to avoid leather color change over time.
This study reports the successful removal of iodate ions from Dialdehyde Tapioca Starch (DTS).
Wet-white leather tanned with the modified DTS had no observable color change upon ageing
Pressure Ulcer Risk and Prevention: Examining the Inter-Rater Reliability of the National Database of Nursing Quality Indicators® (NDNQI)
ABSTRACT Measuring and reporting performance have become the norm. The purpose of this descriptive multi-site (N = 36 NDNQI-participating hospitals) study was to examine the reliability of the National Database of Nursing Quality Indicators® (NDNQI®) pressure ulcer (PrU) risk and prevention measures. This is the first known study to examine the inter-rater reliability of these measures. Data for Part 1 of this two-part study were extracted from 1,637 patient records by 120 raters. One rater at each hospital was considered the "expert". Agreement between the expert and non-expert raters was calculated for the risk measures. Among the patients, 530 were "at risk" for PrU, and included in calculations of agreement for the prevention measures. In Part 2, raters completed an online survey about the methods they use to collect these data. Cohen's kappa values varied widely within and across hospitals. Because most patients were assessed for PrU risk, and those at risk received prevention, the prevalence of a "Yes" response was high suggesting prevalence-adjusted kappa (PAK) may be a better estimate of inter-rater reliability than Cohen's kappa. PAK values for: Skin assessment, PAK = .977, 95% CI [.966 - .989]; Risk assessment, PAK = .978, 95% CI [.964 -.993]; Time since last risk assessment, PAK = .790, 95% CI [.729 - .852]; Risk assessment scale, PAK = .997, 95% CI [.991 - 1.0]; Risk status, PAK = .877, 95% CI [.838 - .917]; Any prevention, PAK = .856, 95% [.769 - .943]; Skin assessment documented, PAK = .956, 95% CI [.904 - 1.0]; and Pressure-redistribution surface use, PAK = .839, 95% CI [.763 - .916] indicated substantial to near perfect agreement. PAK values for: Routine repositioning, PAK = .577, 95% CI [.494 - .661]; Nutritional support, PAK = .500, 95% CI [.418 - .581]; and Moisture management, PAK = .556, 95% CI [.469 - .643] indicated moderate agreement. Results provide support for the reliability of all (5) PrU risk measures, and three of six prevention measures. Areas of disagreement between the expert and non-expert raters should direct education to improve reliability. Results of the online survey suggest raters need further training on the NDNQI guidelines for PrU data collection
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