Strength determination for band-loaded thin cylinders

Cylindrical shells are often subjected to local inward loads normal to the shell that arise over restricted zones. A simple axisymmetric example is that of the ring-loaded cylinder, in which an inward line load around the circumference causes either plasticity or buckling. The ring-loaded cylinder problem is highly relevant to shell junctions in silos, tanks and similar assemblies of shell segments. The band load is similar to the ring load in that a band of inward axisymmetric pressure is applied over a finite height: when the height is very small, the situation approaches the ring loaded case: when the height is very large, it approaches the uniformly pressurised case. This paper first thoroughly explores the two limiting cases of plastic collapse and linear bifurcation buckling, which must both be fully defined before a complete description of the non-linear and imperfection sensitive strengths of such shells can be described within the framework of the European standard for shells EN 1993-1-6 (2007). Finally, the application of the Reference Resistance Design (RRD) over the complete range of geometries for the perfect structure is shown using the outcome of the limiting cases. (EN1993-1-6, 2007; Rotter, 2016a; 2016b; Sadowski et al., 2017)

Silos and tanks in research and practice: state of the art and current challenges

p. 65-76Silos and tanks are probably the commonest form of large engineering shell structure in service, but their placement on industrial sites and out of the public eye often leads them to be neglected by researchers and the public alike. The high rate of structural failure in these structures is a strong indication of the extensive range of issues that must be understood by the designer and the complexity of their behavior. This paper outlines some of the most critical aspects of the loading, structural behavior and failure modes of silos and tanks, and points in many places towards the need for additional research to permit better regulation of these very varied and complex structures.Rotter, JM. (2009). Silos and tanks in research and practice: state of the art and current challenges. Editorial Universitat Politècnica de València. http://hdl.handle.net/10251/646

BaT2As2 Single Crystals (T = Fe, Co, Ni) and Superconductivity upon Co-doping

The crystal structure and physical properties of BaFe2As2, BaCo2As2, and BaNi2As2 single crystals are surveyed. BaFe2As2 gives a magnetic and structural transition at TN = 132(1) K, BaCo2As2 is a paramagnetic metal, while BaNi2As2 has a structural phase transition at T0 = 131 K, followed by superconductivity below Tc = 0.69 K. The bulk superconductivity in Co-doped BaFe2As2 below Tc = 22 K is demonstrated by resistivity, magnetic susceptibility, and specific heat data. In contrast to the cuprates, the Fe-based system appears to tolerate considerable disorder in the transition metal layers. First principles calculations for BaFe1.84Co0.16As2 indicate the inter-band scattering due to Co is weak.Comment: Accepted to Physica

Heritability patterns in hand osteoarthritis: the role of osteophytes

Abstract Introduction The objective of the present study was to assess heritability of clinical and radiographic features of hand osteoarthritis (OA) in affected patients and their siblings. Methods A convenience sample of patients with clinical and radiographic hand OA and their siblings were evaluated by examination and radiography. Radiographs were scored for hand OA features by radiographic atlas. The heritability of hand OA phenotypes was assessed for clinical and radiographic measures based on anatomic locations and radiographic characteristics. Phenotypic data were transformed to reduce non-normality, if necessary. A variance components approach was used to calculate heritability. Results One hundred and thirty-six probands with hand OA and their sibling(s) were enrolled. By anatomic location, the highest heritability was seen with involvement of the first interphalangeal joint (h 2 = 0.63, P = 0.00004), the first carpometacarpal joint (h 2 = 0.38, P = 0.01), the distal interphalangeal joints (h 2 = 0.36, P = 0.02), and the proximal interphalangeal joints (h 2 = 0.30, P = 0.03) with osteophytes. The number and severity of joints with osteophyte involvement was heritable overall (h 2 = 0.38, P = 0.008 for number and h 2 = 0.35, P = 0.01 for severity) and for all interphalangeal joints (h 2 = 0.42, P = 0.004 and h 2 = 0.33, P = 0.02). The severity of carpometacarpal joint involvement was also heritable (h 2 = 0.53, P = 0.0006). Similar results were obtained when the analysis was limited to the Caucasian sample. Conclusions In a population with clinical and radiographic hand OA and their siblings, the presence of osteophytes was the most sensitive biomarker for hand OA heritability. Significant heritability was detected for anatomic phenotypes by joint location, severity of joint involvement with osteophytes as well as for overall number and degree of hand OA involvement. These findings are in agreement with the strong genetic predisposition for hand OA reported by others. The results support phenotyping based on severity of osteophytes and a joint-specific approach. More specific phenotypes may hold greater promise in the study of genetics in hand OA

Trapped ions in optical lattices for probing oscillator chain models

We show that a chain of trapped ions embedded in microtraps generated by an optical lattice can be used to study oscillator models related to dry friction and energy transport. Numerical calculations with realistic experimental parameters demonstrate that both static and dynamic properties of the ion chain change significantly as the optical lattice power is varied. Finally, we lay out an experimental scheme to use the spin degree of freedom to probe the phase space structure and quantum critical behavior of the ion chain

Attitudes and Performance: An Analysis of Russian Workers

This paper investigates the relationship between locus of control and performance among Russian employees, using survey data collected at 28 workplaces in 2002 in Taganrog and at 47 workplaces in 2003 in Ekaterinburg. We develop a measure that allows us to categorize the Russian employees participating in our survey as exhibiting an internal or external locus of control. We then assess the extent to which there are significant differences between “internals” and “externals” in work-related attitudes that may affect performance. In particular, we focus on (1) attitudes about outcomes associated with hard work, (2) level of job satisfaction, (3) expectation of receiving a desired reward, and (4) loyalty to and involvement with one’s organization. In each case we identify where gender and generational differences emerge. Our main objective is to determine whether Russian employees who exhibit an internal locus of control perform better than employees with an external locus of control. Our performance measures include earnings, expected promotions, and assessments of the quantity and quality of work in comparison to others at the same organization doing a similar job. Controlling for a variety of worker characteristics, we find that (1) individuals who exhibit an internal locus of control perform better, but this result is not always statistically significant; (2) even among “internals,” women earn significantly less than men and have a much lower expectation of promotion; (3) even among “internals,” experience with unemployment has a negative influence on performance.http://deepblue.lib.umich.edu/bitstream/2027.42/40144/3/wp758.pd