Проблемы локации источников акустической эмиссии

The accuracy of the location of acoustic emission (AE) sources in the concentrator zones (central holes 5 mm in diameter) located at a distance of 40 mm from the receiving transducers during tensile tests of steel, aluminum alloy and composite flat specimens with dimensions of 550x50x4 mm was evaluated. Calculated speed dependence of propagation of pulses on the level of their amplitude and the partial energy of the high-frequency components of the spectrum is studied. With the threshold method of signal registration, the error in the location of AE event sources arising in the near zone of the receiving transducers at a distance 𝛥L<0.1 m can significantly exceed 10% relative to the base size (B) of the location area, when B<0.5 m. Moreover, with a decrease in the distance 𝛥L<0.05 m, the level of possible error will increase, reaching 20-30% relative to the basic size of the antenna array, when recording pulses with an amplitude level um<60 dB and a fraction of the energy of high-frequency spectrum components not exceeding 10%.

Actuation-Coordinated Mobile Parallel Robots With Hybrid Mobile and Manipulation Function

Mobile robots with manipulation capability are a key technology that enables flexible robotic interactions, large area covering and remote exploration. This paper presents a novel class of actuation-coordinated mobile parallel robots (ACMPRs) that utilize parallel mechanism configurations and perform hybrid moving and manipulation functions through coordinated wheel actuators. The ACMPRs differ with existing mobile manipulators by their unique combination of the mobile wheel actuators and the parallel mechanism topology through prismatic joint connections. The common motion of the wheels will provide the mobile function while their differentiation will actuate the parallel manipulator function. This new concept reduces the actuation requirement and increases the manipulation accuracy and mobile motion stability through the coordinated and connected wheel actuators comparing with existing mobile parallel manipulators. The relative wheel location on the base frame also enables a reconfigurable base size with variable moving stability on the ground. The basic concept and general type synthesis are introduced and followed by the kinematics and inverse dynamics analysis of a selected three limb ACMPR. A numerical simulation also illustrates the dynamics model and the motion property of the new mobile parallel robot. The work provides a basis for introducing this new class of robots for potential applications in surveillance, industrial automation, construction, transportation, human assistance, medical applications and other operations in extreme environment such as nuclear plants, Mars, etc.

Ultrasonographic Evaluation of the Pyramidal Lobe of the Thyroid Gland in Infants and Children in Western Turkey Between 2018 and 2020

Background: The pyramidal lobe (PL) is a common anatomic variation of the thyroid gland with a reported prevalence of over 50% in adult series, but to the best of our knowledge, there are no data in the literature regarding its characteristics in the pediatric population. Objectives: The aim of this study was to evaluate the prevalence, anatomic, and morphological features of the PL in pediatric participants on thyroid ultrasonography (US). Methods: The descriptive cross-sectional study design was used. Between November 2018 and January 2020, the US images obtained from 325 participants with normal thyroid glands were retrospectively evaluated. The presence, location, size, volume, the morphology of the base, and continuity or separation from the thyroid gland were noted for each PL. Results: The PL was present in 34.1% (110/325) of the pediatric participants. It was more frequent in girls than in boys. In all, 56.4% were found to originate from the left of the midline of the isthmus. One patient had double PL. The mean anteroposterior, transverse, and longitudinal diameters were 2.5 ± 1.4, 2.7 ± 1.3, and 5.6 ± 2.5 mm, respectively. The median volume of the PL was 15.11 mm3. PL was longer in girls compared to boys; however, these changes were not significant (5.8 vs. 5.1, P = 0.406, respectively). A total of 63.6% of the PLs were with a wide base and narrow apex, and 36.4% were with a thin base size the same as the apex size. A separation of the PL from the thyroid was not observed. Conclusion: The present study showed, for the first time, that the age of the children is positively correlated with the size and volume of the PL. The prevalence and location of the PL were consistent with those reported in the adult population.

Bounds for finite semiprimitive permutation groups: order, base size, and minimal degree

In this paper, we study finite semiprimitive permutation groups, that is, groups in which each normal subgroup is transitive or semiregular. These groups have recently been investigated in terms of their abstract structure, in a similar way to the O'Nan–Scott Theorem for primitive groups. Our goal here is to explore aspects of such groups which may be useful in place of precise structural information. We give bounds on the order, base size, minimal degree, fixed point ratio, and chief length of an arbitrary finite semiprimitive group in terms of its degree. To establish these bounds, we study the structure of a finite semiprimitive group that induces the alternating or symmetric group on the set of orbits of an intransitive minimal normal subgroup.

Does Disruptive Event Affect Supply Base Size: Evidence from an Emerging Economy

This article examines the effect of disruptive event, namely recession, on supply base management (measured by supply base size) by using a large and longitudinal dataset on Indian manufacturing firms. It is found that the buyer firms have increased their supply base size at the annual rate of 8.23 suppliers per year per manufacturer during the pre-recession (2004–2007) period. The strategy of having a larger supply base is viable, specifically, in an emerging economy (e.g., India) as the probability of disruptions is high due to the inadequacy of basic inputs such as physical infrastructure, logistics services, technology, etc. Therefore, manufacturers tend to have a number of suppliers for the same product group to reduce supplier dependence. Further, we find that buying firms preferred to have a larger supply base even after a recession (2010–2013). However, they have increased their supply base size at the annual rate of just 0.2 (compared to 8.3 during the pre-recession period) suppliers per year per manufacturer during the post-recession. This study highlights the importance of a disruptive event (proxied by recession), by examining its association with supply base size in the emerging economy perspective. JEL Codes: C1, C5, C8

Strategic sustainable purchasing, environmental collaboration, and organizational sustainability performance: the moderating role of supply base size

Purpose This paper aims to examines the moderating effect of small vs large supply base size on the relationship between strategic sustainable purchasing (SSP) and organizational sustainability performance (OSP). SSP is conceptualized as a dynamic capability consisting of strategic purchasing and environmental purchasing. Environmental collaboration is conceptualized as a mediator between SSP and OSP. Extant research has not examined the effect of the size of the supply base on the relationship between SSP and OSP. Design/methodology/approach The hypothesized relationships are tested using a two-step multi-group analysis in partial least squares-structural equation modeling (PLS-SEM). Findings A small supply base size positively moderates the relationship between SSP and environmental collaboration, thus achieving OSP. In contrast, when the supply base is large, strategic purchasing is positively associated with environmental collaboration, while environmental purchasing is negatively related to environmental collaboration. A large supply base has a positive relationship to environmental collaboration and economic sustainability, while the relationship between environmental collaboration and environmental and social performance is not significant. Practical implications This research argues that despite the nuances in the moderating effects of small versus large supply base size, managers need to invest in both dynamic and relational capabilities to achieve organizational sustainability. Originality/value Scant research is available in supply chain management research that has examined the important effect of the supply base size on the relationship between SSP and OSP. This research aims to fill this gap. The study helps practitioners understand the effects of supply base sizes for their organizations, increase interrelationships among suppliers, reduce the level of differentiation among them, and, thereby, reduce costs and increase revenues.

Food and Drink: Thoughts on Base Size in Sensory and Consumer Research

In the applied world of product testing the appropriate number of panelists (base size) involves technical and business considerations. Base sizes range from very low (around six; used in expert panelist profiling) to high (hundreds; used in product tests by marketing researchers). Often base sizes are dictated by the requirement that the project identify statistical differences between or among samples. The probabilistic analysis of differences (significance vs. insignificance) derives from statistical theory, with base size used as a method to influence the sampling error (variability). This paper looks at base sizes another way-from the viewpoint of psychophysical scaling. The issue then can be re-stated as ‘what is the necessary base size at which the average rating stabilizes?’ Empirical data suggest that base sizes of 40-50 panelists generate stable averages and that beyond the 80 panelists the average is not particularly affected by the base size. These results hold for actual data for a variety of products, and for different types of attributes, specifically sensory (amount of a characteristic), and hedonic (liking of a characteristic).

A SURVEY STUDY OF SIZE FACTOR IMPACT ON TQM SUCCESS AND SUSTAINABILITY

Total Quality Management (TQM) is a management approach to long–term success through customer satisfaction. There have been numerous studies devoted to TQM success and failures but relatively few took into account size factors. The objective of this study was to determine if size factors impacted TQM success and sustainability. In this study, the authors looked at three areas where size may impact TQM success: size of an organization, size of customer base, and size of the core TQM team. The authors developed a survey and measured the responses of 101 industry professionals with varying degrees of expertise in TQM to understand if size factors impacted the success and sustainability of TQM. The findings suggest that responses varied widely based on TQM expertise. General trends were evident with responses from select subgroups. The study concluded that size factors play a contributor role but are not root causes to success or failure. This research is unique because it looks at customer base size and core TQM team size to determine if these factors impact TQM implementation and sustainability.

Random bases for coprime linear groups

The minimal base size {b(G)} for a permutation group G is a widely studied topic in permutation group theory. Z. Halasi and K. Podoski [Every coprime linear group admits a base of size two, Trans. Amer. Math. Soc. 368 2016, 8, 5857–5887] proved that {b(G)\leq 2} for coprime linear groups. Motivated by this result and the probabilistic method used by T. Burness, M. W. Liebeck and A. Shalev, it was asked by L. Pyber [Personal communication, Bielefeld, 2017] whether or not, for coprime linear groups {G\leq GL(V)}, there exists a constant c such that the probability that a random c-tuple is a base for G tends to 1 as {\lvert V\rvert\to\infty}. While the answer to this question is negative in general, it is positive under the additional assumption that G is primitive as a linear group. In this paper, we show that almost all 11-tuples are bases for coprime primitive linear groups.