The Design of the Pallet Program

This paper describes the procedures underlying the development of the Pallet program which has been produced to design regular pallet racks according to the FEM code. The program determines the buckling load of the equivalent free sway structure and, using stability functions, calculates the axial and shear forces and the bending moments within the structure including the non-linear P - Δ effects. Twelve different combinations of load are analysed and design checks given in the FEM code applied. The paper discusses the different modes of operation of the program. Finally the accuracy of the program is discussed together with future developments

Rotational Stiffnesses of Semi-rigid Baseplates

The paper describes a test procedure to determine the rotational stiffnesses and moment-curvature relationships of semi-rigid baseplates of cold-formed structures. The influence of the modulus of the foundation subgrade on baseplate performance is determined. Increasing the axial load applied to a baseplate is shown to increase the ultimate moment-rotation capacity of a baseplate

Experimental Procedures for Stub Column Tests

In this paper a total of 36 stub columns was tested by two different experimental procedures, namely the FEM and AISI procedures, to investigate the difference in the ultimate load between these procedures. Of these 26 were carried out in the pin-ended condition according to FEM, the rest were in the fixed-end condition according to AlSI specification. It is shown that the failure loads obtained by the two experimental procedures were very close to each other. Both procedures worked well. The AISI procedure is recommended as the standard procedure

Shear Stiffness of Pallet Rack Upright Frames

PaIIet racks, often fabricated using cold-formed steel, are used for the storage of goods. Uprights of these racks are braced in the cross-aisle direction forming a frame, which behaves like a built-up column. Evaluation of the shear stiffness of this frame is needed to determine the buckling load. Currently two approaches prevail in the rack industry to determine the shear stiffness. The RMI code uses a theoretical formula and the FEM code requires testing. There is a considerable difference in the stiffness values determined by two approaches. The present paper describes experimental and numerical studies conducted at Oxford Brookes University to evaluate shear stiffness in an ongoing research project

Cross-aisle Stiffness Tests on Rack Upright Frames

The US Rack Manufacturers Institution (RMI) code uses a theoretical formula derived by Timoshenko and the new Eurocode EN15512 requires testing. There is a considerable difference in the stiffn ess values determined by two approaches. This paper describes the experiments conducted on 80 full sized upright frames at Oxford Brookes University varying upright size, number of panels in the frame, aspect ratio of the panel (panel length/depth), restraints at the intermediate nodes of the frame, loading pattern, lacing pattern (channels back to back or front to front) and bolt tightness. The experimental data reported can be used in proposing revised design procedures

Transition Matrix Monte Carlo Reweighting and Dynamics

We study an induced dynamics in the space of energy of single-spin-flip Monte Carlo algorithm. The method gives an efficient reweighting technique. This dynamics is shown to have relaxation times proportional to the specific heat. Thus, it is plausible for a logarithmic factor in the correlation time of the standard 2D Ising local dynamics.Comment: RevTeX, 5 pages, 3 figure

Human Erythroid Progenitors Are Directly Infected by SARS-CoV-2: Implications for Emerging Erythropoiesis in Severe COVID-19 Patients

We document here that intensive care COVID-19 patients suffer a profound decline in hemoglobin levels but show an increase of circulating nucleated red cells, suggesting that SARS-CoV-2 infection either directly or indirectly induces stress erythropoiesis. We show that ACE2 expression peaks during erythropoiesis and renders erythroid progenitors vulnerable to infection by SARS-CoV-2. Early erythroid progenitors, defined as CD34-CD117+CD71+CD235a-, show the highest levels of ACE2 and constitute the primary target cell to be infected during erythropoiesis. SARS-CoV-2 causes the expansion of colony formation by erythroid progenitors and can be detected in these cells after 2 weeks of the initial infection. Our findings constitute the first report of SARS-CoV-2 infectivity in erythroid progenitor cells and can contribute to understanding both the clinical symptoms of severe COVID-19 patients and how the virus can spread through the circulation to produce local inflammation in tissues, including the bone marrow

Probability-Changing Cluster Algorithm: Study of Three-Dimensional Ising Model and Percolation Problem

We present a detailed description of the idea and procedure for the newly proposed Monte Carlo algorithm of tuning the critical point automatically, which is called the probability-changing cluster (PCC) algorithm [Y. Tomita and Y. Okabe, Phys. Rev. Lett. {\bf 86} (2001) 572]. Using the PCC algorithm, we investigate the three-dimensional Ising model and the bond percolation problem. We employ a refined finite-size scaling analysis to make estimates of critical point and exponents. With much less efforts, we obtain the results which are consistent with the previous calculations. We argue several directions for the application of the PCC algorithm.Comment: 6 pages including 8 eps figures, to appear in J. Phys. Soc. Jp

Evidence for a singularity in ideal magnetohydrodynamics: implications for fast reconnection

Numerical evidence for a finite-time singularity in ideal 3D magnetohydrodynamics (MHD) is presented. The simulations start from two interlocking magnetic flux rings with no initial velocity. The magnetic curvature force causes the flux rings to shrink until they come into contact. This produces a current sheet between them. In the ideal compressible calculations, the evidence for a singularity in a finite time $t_c$ is that the peak current density behaves like $|J|_\infty \sim 1/(t_c-t)$ for a range of sound speeds (or plasma betas). For the incompressible calculations consistency with the compressible calculations is noted and evidence is presented that there is convergence to a self-similar state. In the resistive reconnection calculations the magnetic helicity is nearly conserved and energy is dissipated.Comment: 4 pages, 4 figure

Is council tax valuation band a predictor of mortality?

BACKGROUND: All current UK indices of socio-economic status have inherent problems, especially those used to govern resource allocation to the health sphere. The search for improved markers continues: this study proposes and tests the possibility that Council Tax Valuation Band (CTVB) might match requirements. PRESENTATION OF THE HYPOTHESIS: To determine if there is an association between CTVB of final residence and mortality risk using the death registers of a UK general practice. TESTING THE HYPOTHESIS: Standardised death rates and odds ratios (ORs) for groups defined by CTVB of dwelling (A – H) were calculated using one in four denominator samples from the practice lists. Analyses were repeated three times – between number of deaths and CTVB of residence of deceased 1992 – 1994 inclusive, 1995 – 1997 inc., 1998 – 2000 inc. In 856 deaths there were consistent and significant differences in death rates between CTVBs: above average for bands A and B residents; below average for other band residents. There were significantly higher ORs for A, B residents who were female and who died prematurely (before average group life expectancy). IMPLICATIONS OF THE HYPOTHESIS: CTVB of final residence appears to be a proxy marker of mortality risk and could be a valuable indicator of health needs resource at household level. It is worthy of further exploration