Dynamic structure selection and instabilities of driven Josephson lattice in high-temperature superconductors

We investigate the dynamics of the Josephson vortex lattice in layered high-T$_{c}$ superconductors at high magnetic fields. Starting from coupled equations for superconducting phases and magnetic field we derive equations for the relative displacements [phase shifts] between the planar Josephson arrays in the layers. These equations reveal two families of steady-state solutions: lattices with constant phase shifts between neighboring layers, starting from zero for a rectangular configuration to $\pi$ for a triangular configuration, and double-periodic lattices. We find that the excess Josephson current is resonantly enhanced when the Josephson frequency matches the frequency of the plasma mode at the wave vector selected by the lattice structure. The regular lattices exhibit several kinds of instabilities. We find stability regions of the moving lattice in the plane lattice structure - Josephson frequency. A specific lattice structure at given velocity is selected uniquely by boundary conditions, which are determined by the reflection properties of electromagnetic waves generated by the moving lattice. With increase of velocity the moving configuration experiences several qualitative transformations. At small velocities the regular lattice is stable and the phase shift between neighboring layers smoothly decreases with increase of velocity, starting from $\pi$ for a static lattice. At the critical velocity the lattice becomes unstable. At even higher velocity a regular lattice is restored again with the phase shift smaller than $\pi/2$. With increase of velocity, the structure evolves towards a rectangular configuration.Comment: 28 pages, 12 figures, submitted to Phys. Rev.

Recommended Practices: Protecting Temporary Workers

[Excerpt] Workers employed through staffing agencies are generally called temporary or supplied workers. For the purposes of these recommended practices, “temporary workers” are those supplied to a host employer and paid by a staffing agency, whether or not the job is actually temporary. Whether temporary or permanent, all workers always have a right to a safe and healthy workplace. The staffing agency and the staffing agency’s client (the host employer) are joint employers of temporary workers and, therefore, both are responsible for providing and maintaining a safe work environment for those workers. The staffing agency and the host employer must work together to ensure that the Occupational Safety and Health Act of 1970 (the OSH Act) requirements are fully met. See 29 U.S.C. § 651. The extent of the obligations of each employer will vary depending on workplace conditions and should therefore be described in the agreement or contract between the employers. Their safety and health responsibilities will sometimes overlap. Either the staffing agency or the host employer may be better suited to ensure compliance with a particular requirement, and may assume primary responsibility for it. The joint employment structure requires effective communication and a common understanding of the division of responsibilities for safety and health. Ideally, these will be set forth in a written contract. OSHA and NIOSH recommend the following practices to staffing agencies and host employers so that they may better protect temporary workers through mutual cooperation and collaboration. Unless otherwise legally required, these recommendations are for the purpose of guidance and in some cases represent best practices

Safety culture maturity in several latin America mining activities

Health and safety is a crucial issue in the mining industry because of the implication of fatalities in this sector. A study of safety culture maturity in several Latin America countries has been done based on the model from Filho et al. [1]. The questionnaire includes 28 items regarding the type of activity, number of employees and safety culture characteristics of the activity: Information of accidents and misses, organizational structure to deal with the information, involvement of the company in health and safety issues, the way it communicates accidents and misses and commitment of the company towards health and safety. The questionnaire was completed by 58 mining company managers from Bolivia, Peru, Colombia and Mexico. Results show different behaviours depending on the type of company, cooperative or private company. When private companies are analysed, it is seen a level of maturity according to the size of the company, whereas cooperatives does not have a clear trend in terms of size apart from very small cooperatives, less than 10 employees. However, there is a remarkable difference between cooperatives that have implemented continuous improvement systems and the others. In particular, cooperatives with a continuous improvement system have been analysed, displaying much higher safety culture levels. Therefore, it can be concluded that private companies improve their level of safety culture as the size of the company increase, because procedures and control systems are implemented. When cooperative or small companies introduce similar systems they also achieve substantial gains, but their approach is different. Managers from cooperatives have to see economic reasons to implement it, such as the Fairmined certificate.Peer ReviewedPostprint (published version

Accident Rate as a Measure of Safety Assessment in Polish Civil Engineering

Civil engineering is characterised by high volatility with respect to working conditions, which are the source of many threats to worker life and health and contribute to high accident rates. The purpose of this paper is to analyse and evaluate the phenomenon of accidents in Polish civil engineering and define the direction of changes that should occur in the safety area. The studies included in this research covered the years 2004–2018. The following indicators were used to assess the accident rates: (1) The total number of persons injured in workplace accidents and this total divided into fatal, severe, and minor accidents; (2) indicators of frequency of accidents in total and this total divided into minor, severe, and fatal accidents; (3) and an indicator of the severity of accidents. From the analysis of statistical data for the years 200–2018, the changes in accident rate parameters demonstrate the continuous improvement of workplace safety in the Polish civil engineering sector. From the analysed data from the 15 years, a clear decrease in the value of the applied indicators is apparent, including both the number of people involved in accidents and the frequency and severity of accidents

Determination of Safety Indicators in the Developed Muffins with Non-traditional Raw Materials

The aim of research is studying the effect of unconventional raw materials (buckwheat, oatmeal, rye, corn, milk whey, skimmed milk powder, propolis, flower pollen, bean powder, sesame oil, pumpkin seed oil, walnut oil, walnut kernels, candied fruit mixes (apple-cherry fruits of bilberries, natural honey with floral pollen, natural honey with propolis) for the quality and safety of new muffins. The article analyzes the results of the study of the quality and safety indicators of muffins of improved composition, manufactured using non-traditional raw materials. For the preparation of new types of muffins, part of the wheat flour was replaced with buckwheat, corn, oat, milk whey, skimmed milk powder and additives of vegetable origin. Margarine has been replaced by vegetable oils. It has been established that flour confectionery products have high organoleptic properties. From the physico-chemical parameters, the mass fraction of total sugar was determined, which ranged from 28.17 % to 33.07 %, the mass fraction of fat – 16.2–20.66 %, the mass fraction of moisture – 18.0–22.0, mass fraction of ash – 0.03–1.3 %, alkalinity – 0.03–1.8°, the content of toxic elements (copper, zinc, lead, cadmium, arsenic, mercury) and microbiological indicators were also determined. Based on the data obtained as a research result, the expediency of using non-traditional raw materials to expand the range of flour confectionery products, in particular muffins is substantiated

Integrated Road Safety Approach Towards Safer Road in Indonesia

Safer road is a global issue in the world. Regarding road conditions, traffic conditions, and accident rate in developing countries, including Indonesia, safer road is crucial. Furthermore, the problem is worse because of a number of reasons i.e. data of road geometric, road pavement surface, road furniture conditions, and traffic accident are not well recorded, difference available recorded data among institutions, and beginning level of intelligent transportation systems implementation. Moreover, to reach safer road, all stakeholders involved (road authorities, industries, experts, road users) should work together. In order to reach integrated road safety approach, the aims of this study are to determine steps to decrease number and severity of traffic accident before, during, and after accident occur, and then to recommend road safety scheme towards safer road in Indonesia. Sustainable and consistent implementation of steps and road safety scheme leads to significant improvement of safer road in Indonesia. Keywords: safer road, accident rate, traffic accident, traffic condition Jalan berkeselamatan merupakan isu global di dunia. Terkait dengan kondisi jalan, kondisi lalu lintas, dan tingkat kecelakaan di negara-negara berkembang, termasuk di Indonesia, jalan yang lebih aman sangat penting. Selain itu permasalahan lebih diperburuk oleh beberapa alasan, yaitu data geometrik jalan, kondisi permukaan perkerasan jalan, kondisi perlengkapan jalan, data kecelakaan lalulintas yang tidak tercatat dengan baik, perbedaan data yang tercatat di institusi-institusi terkait, dan implementasi sistem transportasi cerdas baru pada tahap awal. Untuk mencapai jalan yang berkeselamatan semua pemangku kepentingan yang terlibat (otoritas jalan, industri, ahli, pengguna jalan) harus bekerja sama. Dengan memperhatikan pendekatan keselamatan jalan terpadu, tujuan penelitian ini adalah menentukan langkah-langkah untuk mengurangi jumlah dan tingkat keparahan kecelakaan sebelum, selama, dan setelah kecelakaan terjadi serta merekomendasikan skema keselamatan jalan menuju jalan yang lebih aman di Indonesia. Keberkelanjutan dan penerapan yang konsisten langkah-langkah dan skema keselamatan jalan akan menghasilkan perbaikan yang signifikan akan jalan berkeselamatan di Indonesia. Kata