American National Standard ANSI Research Articles

Properties of Particleboard Manufactured from Commonly Used Bamboo (Bambusa vulgaris) Wastes in Bangladesh

Aims: This paper explores the properties of single layer particleboard produced from bamboo wastes and branches. Experimental: Three types of single layer particleboard i.e., branch-waste mixed particleboard (WBPB), bamboo branch particleboard (BPB) and bamboo wastes (shavings obtained during planning operation of bamboo) particleboard (WPB) were manufactured with 15% urea formaldehyde (UF) resin. Physical and mechanical properties of the manufactured particleboards were evaluated according to the ASTM D-1037 standard. Results: Results showed that the physical properties i.e., density, moisture content (MC), water absorption (WA), thickness swelling (TS), linear expansion (LE) and mechanical properties i.e. Original Research Article Alam et al.; AIR, 4(3): 203-211, 2015; Article no.AIR.2015.075 204 modulus of elasticity (MOE) and modulus of rupture (MOR) of bamboo branch-waste mixed particleboard (WBPB) was better than bamboo branch particle board (BPB) and bamboo wastes particle board (WPB). It was found that the density of BPB, WPB and WBPB were 742, 846 and 1024 kg/m, respectively. Thickness swellings of BPB, WPB and WBPB after 24 hours of immersion were 32.33, 19.6 and 16.3%, respectively. Water absorption rate of BPB, WPB and WBPB particleboards were 81, 64.3 and 39.8%, respectively. Modulus of rupture of BPB, WPB and WBPB were 16.8, 18 and 21.6 N/mm 2 , respectively. Conclusion: All these three types of particleboard followed the American National Standard ANSI A208.1 requirements for physical and mechanical properties of particleboard.

Comparison of three acoustics test fixtures for impulse peak insertion loss

Acoustic test fixtures (ATF) for testing the impulse peak insertion loss (IPIL) of a hearing protector are described by American National Standard ANSI S12.42-2010. The self-insertion loss, ear simulator design (canals, microphone, and temperature), hardness of the area surrounding the pinna, and the anthropometric shape of the head has been specified in the standard. The IPILs of four protector conditions were evaluated with three ATFs during an outdoor field study using firearm noise. The Etymotic Research ER20 musicians' earplug and electronic (EB1 earplugs), the Peltor Tactical Pro earmuffs, and a combination of the TacticalPro and ER20 protectors were tested at 130, 150, and 170 dB peak sound pressure level with the Institute de Saint Louis heated and unheated fixture and the GRAS 45CB heated ATF. IPILs exhibited good agreement across all three fixtures for earplugs. Significant differences were observed between the fixtures for the earmuff-only condition. These differences were more evident for the double-protection condition. [Portions of this work were supported by the U.S. EPA Interagency Agreement DW75921973-01-0.]

Calibration details for the impulse peak insertion loss measurement

The American National Standard ANSI S12.42-2010 specifies the measurement of hearing protector performance in the presence of impulse noise. A series of calibration impulses are recorded from an acoustic test fixture (ATF) and a field microphone for peak sound pressure levels of 130, 150, and 170 dB. The averaged acoustic transfer function between the ATF and field microphone is calculated as follows: H¯ATF¯−FF¯(f)=〈FFT¯(PATF,i(t))/FFT(PFF,i(t))〉.¯ The transfer function is computed for each of the ranges of impulse levels and is applied to the field microphone measurements to estimate the unoccluded fixture levels of the ATF when hearing protection is being tested. This method allows a comparison between occluded and unoccluded waveforms. The calibration transfer function is affected by the time-alignment of the field impulse peaks, time-windowing of the impulses, and compensation for any dc bias. Time-alignment significantly affected the accuracy of predicting individual calibration levels with H¯ATF¯−FF¯. The prediction error variance was less at 170 dB than at 130 dB impulses. The time-window was varied from 2.5 to 100 ms preceding the peak of the field impulse. [Portions of this work were supported by the U.S. EPA Interagency Agreement DW75921973-01-0.]

Assessment of the Proposed Draft American National Standard Method for Evaluating the Effectiveness of Hearing Conservation Programs

Using audiometric data, this study assessed the Draft American National Standard ANSI S12.13-1991 (DANS) method for evaluating the effectiveness of hearing conservation programs by comparing it against a standard epidemiologic method. Although the hearing conservation program of the study population was rated as "acceptable" (scale: acceptable, marginal, unacceptable) using the DANS method, the epidemiologic method found a 130% increased risk of hearing loss (relative risk = 2.3, 95% confidence interval = 0.8 to 6.5). In addition, study workers who were excluded from analyses for failing to comply with the DANS criteria were found to be at significantly increased risk of hearing loss (relative risk = 9.1, 95% confidence interval = 3.4 to 24.2). These data indicate that the DANS method may overestimate the effectiveness of hearing conservation programs and systematically exclude workers at high risk of hearing loss from analyses.

Alternate Path Analysis of Space Trusses for Progressive Collapse

Space trusses of the double‐layer grid type, because of their large degree of static indeterminacy, are often assumed to have sufficient redundancy such that the loss of one member would cause force redistributions that can be accommodated by the remaining structure. However, the results presented in this paper of the analyses performed on a hypothetical space truss and on a constructed space truss show that progressive collapse could occur following the loss of one of several potentially critical members when the structures are subject to full service loading. However, when the structures were evaluated using the American National Standard ANSI A58.1‐1982, the structures were found to survive with a small margin of safety. It is suggested that to improve resistance to progressive collapse the compression members and diagonal members along and adjacent to the column line should be designed with higher factors of safety than those currently used, particularly in the middle half of the span. Further researc...

The new ANSI standard for bandpass filters

The initial American standard for bandpass filters for analysis of sound or vibration was prepared by a Working Group of the Acoustical Society of America's Standards Committee S1 on Acoustics and was approved in 1966 as American National Standard ANSI S1.11‐1966. The 1966 standard was re‐affirmed in 1976 without technical changes. With advances in microelectronics and digital data‐processing techniques available in the 1980s, it was decided in 1981 that a thorough revision of the 1966 Standard was needed. In 1986, the new ANSI Standard was published as ANSI S1.11‐1986 with specifications for both analog and digital implementations of octave‐band and fractional‐octave‐band filters including devices that utilize discrete‐Fourier‐transform techniques to synthesize fractional‐octave‐band filters. This paper describes the principal technical features of the new standard including the specification of filter design Order Number, Type Number based on error in the analysis of a white noise signal, and a Subtype designation based on error in the analysis of signals having specified positive and negative slopes. Errors are determined relative to the equivalent power that would have been transmitted by an ideal filter having infinite rejection at frequencies outside the range of specified passband‐limiting frequencies. Examples are shown to demonstrate how various filter designs would conform to the specifications of the new Standard.

Measurements of stylus radii

Abstract In stylus measurements of surface texture the measured results for roughness depend on the stylus radius. Therefore it is important to determine the stylus radius. Since stylus tips are not perfectly spherical, the local radius of curvature varies significantly over the surface which makes the determination of an effective radius difficult. Both the techniques used to generate stylus profiles and the subsequent algorithms used to derive an effective radius are discussed. Comparisons are made between three techniques: sharp-edge traces, optical microscopy and scanning electron microscopy. Several algorithms, including that prescribed by the American National Standard ANSI B46-1, are discussed. It is concluded that the radius scale method is accurate, unambiguous and easy to use for routine measurements in the laboratory.

Qualifying the acoustic environment for in situ noise measurements

Much interest has centered in recent years in measurements of the noise of large machines as installed. Free‐field conditions above a reflecting plane are desired, and a means for evaluating conditions in situ are a necessary part of the measurement process. A current trend in drafting ISO and ANSI standards is to employ the method of enveloping surfaces. [G. Hubner, “Qualification procedures for free‐field conditions for sound power determination of sound sources,” in Internoise 73 Proceedings (Copenhagen, August 1973).] It has been found that spaces which fail to qualify by this method often pass a criterion like that of American National Standard ANSI S1.13‐1971, which requires only that the sound pressure level measured at one or more points in a direction away from the machine be at least 6 dB less than that at 1 m. It is argued that the latter criterion insures adequate accuracy for engineering measurements, and that the former one requires an unnecessary number of measurements.