China
Africa
Explore chapters and articles related to this topic
Analytical Chemistry
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Analytical measurements and certifications often contain a statement of traceability. Traceability describes the "result or measurement whereby it can be related to appropriate standards, generally international or national standards, through an unbroken chain of comparisons (Ref. 9)." Traceability typically includes the application of a reference material (RM) or a standard reference material (SRM) for instrument calibration before standardization for the analytes of interest. The true value of a measured quantity () cannot typically be determined. The true value is defined as characterizing a quantity that is perfectly defined. It is an ideal value which could be arrived at only if all causes of measurement uncertainty were eliminated, and the entire population was sampled.
Optimization of Packet Scheduling Schemes
Published in Borko Furht, Syed Ahson, Handbook of Mobile Broadcasting, 2008
Hongfei Du, Linghang Fan, Barry G. Evans
To minimize the DTX insertion in downlink static rate matching (SRM), a novel rate-matching technology, namely, dynamic rate matching, has been proposed for delivering highly rate-variable MBMS service in the SDMB system.36 The objective of downlink DRM is to minimize the number of DTX bits required for the chosen TFC at a given TTI according to the available physical layer resources. Rather than per-session- and maximum-data-rate-based rate-matching calculation in SRM, in the DRM case, the rate-matching (RM) ratio is calculated in each TTI based on the instantaneous data rate of each TrCH. Therefore, the DRM employs a variable rate-matching ratio to prevent unnecessary DTX insertion. The scenario undertaken is applicable for the TrCHs featuring identical TTI scale. In each TTI, the following phases are performed in DRM: ■ Phase 1 (TFC reordering): All the TFCs within the TFCS list are reorganized according to their corresponding total data rate (i.e., based on the TFC size).■ Phase 2 (RM ratio calculation): The rate-matching ratio is calculated based on the instantaneous data rate (i.e., the TBS size) of each TrCH for each different TFC allowed for a given physical channel.■ Phase 3 (Bit matching): According to the selected TFC, a tentative value of repetition/ puncturing bits is calculated for each TrCH.
Performance investigation on ANFIS and FFNN assisted direct and indirect PV-fed switched reluctance motor water pumping system
Published in International Journal of Modelling and Simulation, 2022
Vijay Babu Koreboina, Narasimharaju B L, Vinod Kumar D M
Water resources play a major role in various sectors like agriculture, domestic needs, etc. Likewise, economic growth mainly depends on the agriculture sector. Most of the off-grid rural areas need portable alternative clean energy to drive the water pumps. Extending the grid to those remote areas would be capital-intensive and also inefficient due to transmission and distribution losses. In addition, carbon emission and thermal fuel extinction call for clean alternative energy sources (AES) such as biomass, solar, wind, and hybrid. At present, these resources contribute to electricity generation by about 19% [1]. Therefore, small-scale AES are an ideal choice to reduce the burden on the grid, and to produce clean energy for water pumping systems. In the present scenario, conventional electrical motors (induction motors, synchronous motors, permanent magnet synchronous motors, and permanent magnet DC motors) are employed for PV-fed water pumping and household power generation. Switched reluctance motor (SRM) is an alternative candidate which is promising, cost-effective, and highly efficient in contrast to the conventional motors for small-scale applications. With its wider advantages, SRM has emerged in research importance for variable speed drive applications. With the absence of carbon brushes, slip rings, commutators, and cage bars, SRM has emerged in its suitability for wide applications such as hand fork, train air conditioner, and aerospace [2].
An inter-laboratory evaluation of new multi-element reference materials for atmospheric particulate matter measurements
Published in Aerosol Science and Technology, 2019
Nicole Pauly Hyslop, Krystyna Trzepla, Sinan Yatkin, Warren H. White, Travis Ancelet, Perry Davy, Owen Butler, Michel Gerboles, Steven Kohl, Andrea McWilliams, Laura Saucedo, Marco Van Der Haar, Armand Jonkers
Most ICP-MS measurements of atmospheric PM samples are calibrated using reference solutions produced by chemical manufacturers (Sigma, Pure Standards, etc.). ICP-MS labs check their digestion efficiency using certified dusts (e.g. NIST SRM 1648 and ERMCZ120 by European Union) instead of filter-based RM. The RM developed herein are highly soluble in dilute acid and while they do require the extraction step, they do not challenge the extraction efficiency (Yatkin et al. 2018).
Multi-objective optimization design of hydropneumatic suspension with gas–oil emulsion for ride comfort and handling stability of an articulated dumper truck
Published in Engineering Optimization, 2023
Lin Yang, Ruochen Wang, Zeyu Sun, Xiangpeng Meng, Zhihao Zhu
The vertical motion equation at the truck equivalent centre is as follows: where ms is the truck spring mass, zs is the sprung mass displacement, Klf is the suspension stiffness of the left front axle, Clf is the suspension damping coefficient of the left front axle, zulf is the unsprung mass displacement of the left front axle, and zslf is the sprung mass displacement of the left front axle; Krf is the suspension stiffness of the right front axle, Crf is the suspension damping coefficient of the right front axle, zurf is the unsprung mass displacement of the right front axle, and zsrf is the sprung mass displacement of the right front axle; Klm is the suspension stiffness of the left middle axle, Clm is the suspension damping coefficient of the left middle axle, zulm is the unsprung mass displacement of the left middle axle, and zslm is the sprung mass displacement of the left middle axle; Krm is the suspension stiffness of the right middle axle, Crm is the suspension damping coefficient of the right middle axle, zurm is the unsprung mass displacement of the right middle axle, and zsrm is the sprung mass displacement of the right middle axle; Klr is the suspension stiffness of the left rear axle, Clr is the suspension damping coefficient of the left rear axle, zulr is the unsprung mass displacement of the left rear axle, and zslr is the sprung mass displacement of the left rear axle; Krr is the suspension stiffness of the right rear axle, Crr is the suspension damping coefficient of the right rear axle, zurr is the unsprung mass displacement of the right rear axle, and zsrr is the sprung mass displacement of the right rear axle.