Probabilistic analysis of unreinforced brick masonry walls subjected to horizontal bending

Published online on April 11, 2017Unreinforced masonry walls subjected to out-of-plane horizontal bending can fail by two alternate modes: stepped failure along the brick-mortar bond, or line failure cutting directly through the bricks. Because of random variations in material properties throughout a panel and the tendency for failure to occur across the weaker elements, vertical cracks will generally exhibit a combination of the two modes. This paper develops a pair of analytical methodologies that treat this phenomenon using a stochastic approach. The first part deals with calculating the ultimate moment capacity by allowing for the weakening effect associated with the mixed (stepped and line) mode of failure. This effect is quantified in terms of strength-reduction factors for mean and characteristic (0.05 quantile) values of strength, which may be applied toward generic ultimate strength design. The second part deals with estimating the relative probability of each failure mode and the probability distribution for the relative proportions of each failure mode along a crack. This is of particular relevance to seismic performance because the two failure modes lead to significantly different postcracking behavior.Jaroslav Vaculik and Michael C. Griffit

Determination of the tension limit forces of a barley malt and a malt crush in correlation with a load size

ArticleThis article deals with determination of selected parameters of barley malt (whole grain and crushed grain). The barley malt is besides water, hops and brewer's yeast, one of the basic ingredients necessary for the production of traditional Czech pilsner type of beer. The aim of this research is to determine limit force and internal friction angle with depending on the size of the load. The assessed malt crush was produced using a 2-roller malt mill. The 2-roller malt mill is based on the principle of grinding the material in a milling gap between two milling rollers, which is a very commonly used production of the malt crush. By determining the tension limits of the barley malt and the malt crush in correlation with the load, we can obtain very important parameters that inform us of the bulk material behavior, particularly with respect to the storage method (storage shape, height of the stored material layer, and the removal method from the storage, etc.), and to the transport (route gradient, transport speed, etc.). The determination of the tension limits has a direct link with cohesion of the bulk material and thereby contributes to establishing of the basic parameters of the bulk material, such as - the friction angle. The measurement for the angle of internal friction determination were performed on a prototype device. The principle of measurement on a mobile prototype devices is, the upper square chamber slides down the lower square chamber. Barley malt (whole grain and crushed grain) were loaded from 100 g to 5,000 g. The results of measuring were statistically analyzed with software Statistica 12

Energy consumption of milking pump controlled by frequency convertor during milking cycle

ArticleThe article deals with selected parameters affecting the energy consumption of a vacuum pump in a milking system during the whole milking cycle in variants with and without regulation by a frequency convertor. When put into practice, the latest research of creation, control and stabilization of vacuum in milking devices allows dairy farmers to obtain a vacuum system that ensures maximum stability of milking pressure, which is a basic requirement affecting the health of dairy cows. The choice of vacuum system prioritizes in particular high performance, maximum operational reliability, minimum maintenance, long service life, environmental friendliness and economy. The vacuum pump was a Roots vacuum pump with a rotary piston which is typical for this use. Use of a frequency convertor significantly affected the efficiency of this pump for control of vacuum pressure level and pump performance by varying the rotation frequency according to the actual airflow requirement. Using this control system, only as much vacuum pressure is produced as necessary. By measurement of an experimental setup, it was found that the average power requirement of a setup with a control valve was 3.8 kW compared to 1.7 kW in the case of the variant with frequency convertor. Measurements and calculations have shown that this system is capable of saving more than 50% of electric energy

Out-of-plane load-displacement model for two-way spanning masonry walls

Abstract not availableJaroslav Vaculik, Michael C. Griffit

Bohdan Pavlu and His Activities in Russia (1915—1919)

The article is devoted to the study of the political activity of one of the prominent figures of the Czech and Slovak national movement Bohdan Pavlu, who played a significant role in the Civil War in Russia. The material was documents of personal origin and official documents containing information on the activities of sCzech-Slovak organizations in Russia. The author pays attention to the evolution of political views of B. Pavlu, his attitude to the tsarist government. It is shown how external circumstances influenced the support of the course of T. G. Masaryk. Particular attention is paid to the activities of B. Pavlu during the Civil War in Russia. The novelty of the research is due to the fact that for the first time the socio-political views of one of the leaders of the Czech national movement in Russia are comprehensively studied. The relevance of the study is due to the lack of consensus in Russian society on the role of foreign intervention in the events of 1917—1922. It is proved that B. Pavlu’s activities contributed to the consolidation of the Czech and Slovak national movement in Russia. It is emphasized that it was he who formulated the concept of “Czechoslovakia”, which formed the basis for the idea of creating a single state for the two peoples

Social perception on Science and Technology in the northeastern provinces of Argentina.

Se presentan datos de la percepción social  de  la  Ciencia  y  la  Tecnología  de  los habitantes  de  la  región  nordeste  de  Argentina  que  reflejan  una  sociedad  con moderada  cultura  científica  y  tecnológica. La  cuestión  "que  imagen  tiene  de  la  ciencia"   se  utilizó  para  realizar  una valoración general donde más de la mitad de  los  encuestados  tuvo  una  opinión positiva.  Sin  embargo,  solo  el  14%  de  la muestra  considera  que  la  Ciencia  y  la Tecnología  mejoran  la  calidad  de  la  vida  humana.  Se  propone  la  generación  de cultura  científica  a  través  de  la  participación  de  los  actores  sociales involucrados,  estimulados  por  los  organismos  públicos  responsables  del desarrollo  científico  y  tecnológico.  Los  resultados  pueden  ser  utilizados  para  la toma  de  decisiones  bien informadas en  el  desenvolvimiento  social  y  la  participación ciudadana;  además,  para  orientar  la  política científica y tecnológica.This paper presents data related to the social perception of science and technology to the people of the northeast of Argentina of the country that reflect a society with moderate scientific and technological culture. The question "what image has of science" was used to make a general assessment where more than half of surveyed had a positive opinion. However, only 14% of the sample believes that science and technology improve the quality of human life.We propose the generation of scientific culture through the participation of the social actors involved, stimulated by public agencies responsible for the scientific and technological development. The results can be used for making informed decisions in the social development and citizen participation, in addition to guide scientific and technological policy.Fil: Juarez, Rolando Pablo. Universidad Nacional del Nordeste. Facultad de Odontologia. Secretaria de Investigacion. Gabinete de Inv.interd.de Prevencion Salud y Epidemologia; Argentina;Fil: Martinez, Sandra Edda. Universidad Nacional del Nordeste. Facultad de Odontologia. Departamento de Clinicas Integradas;Fil: Dho, María Silvina. Universidad Nacional del Nordeste. Facultad de Odontologia. Secretaria de Investigacion. Gabinete de Inv.interd.de Prevencion Salud y Epidemologia;Fil: Vaculik, Patricia. Universidad Nacional del Nordeste. Facultad de Odontologia. Secretaria de Investigacion. Gabinete de Inv.interd.de Prevencion Salud y Epidemologia;Fil: Llarens, Adriana N.. Universidad Nacional del Nordeste. Facultad de Odontologia. Secretaria de Investigacion. Gabinete de Inv.interd.de Prevencion Salud y Epidemologia;Fil: Cúndom, Juan M.. Universidad Nacional del Nordeste. Facultad de Odontologia. Secretaria de Investigacion. Gabinete de Inv.interd.de Prevencion Salud y Epidemologia;Fil: Almirón, María. Universidad Nacional del Nordeste. Facultad de Odontologia. Secretaria de Investigacion. Gabinete de Inv.interd.de Prevencion Salud y Epidemologia

Focal osteoporosis defects play a key role in hip fracture

$\textbf{BACKGROUND}$: Hip fractures are mainly caused by accidental falls and trips, which magnify forces in well-defined areas of the proximal femur. Unfortunately, the same areas are at risk of rapid bone loss with ageing, since they are relatively stress-shielded during walking and sitting. Focal osteoporosis in those areas may contribute to fracture, and targeted 3D measurements might enhance hip fracture prediction. In the FEMCO case-control clinical study, Cortical Bone Mapping (CBM) was applied to clinical computed tomography (CT) scans to define 3D cortical and trabecular bone defects in patients with acute hip fracture compared to controls. Direct measurements of trabecular bone volume were then made in biopsies of target regions removed at operation. $\textbf{METHODS}$: The sample consisted of CT scans from 313 female and 40 male volunteers (158 with proximal femoral fracture, 145 age-matched controls and 50 fallers without hip fracture). Detailed Cortical Bone Maps (c.5580 measurement points on the unfractured hip) were created before registering each hip to an average femur shape to facilitate statistical parametric mapping (SPM). Areas where cortical and trabecular bone differed from controls were visualised in 3D for location, magnitude and statistical significance. Measures from the novel regions created by the SPM process were then tested for their ability to classify fracture versus control by comparison with traditional CT measures of areal Bone Mineral Density (aBMD). In women we used the surgical classification of fracture location ('femoral neck' or 'trochanteric') to discover whether focal osteoporosis was specific to fracture type. To explore whether the focal areas were osteoporotic by histological criteria, we used micro CT to measure trabecular bone parameters in targeted biopsies taken from the femoral heads of 14 cases. $\textbf{RESULTS}$: Hip fracture patients had distinct patterns of focal osteoporosis that determined fracture type, and CBM measures classified fracture type better than aBMD parameters. CBM measures however improved only minimally on aBMD for predicting any hip fracture and depended on the inclusion of trabecular bone measures alongside cortical regions. Focal osteoporosis was confirmed on biopsy as reduced sub-cortical trabecular bone volume. $\textbf{CONCLUSION}$: Using 3D imaging methods and targeted bone biopsy, we discovered focal osteoporosis affecting trabecular and cortical bone of the proximal femur, among men and women with hip fracture.Arthritis Research UK (grant no. ARC17822) and Cambridge National Institute for Health Research (NIHR) Biomedical Research Centre

IgM Promotes the Clearance of Small Particles and Apoptotic Microparticles by Macrophages

Background: Antibodies are often involved in enhancing particle clearance by macrophages. Although the mechanisms of antibody-dependent phagocytosis have been studied for IgG in greater detail, very little is known about IgM-mediated clearance. It has been generally considered that IgM does not support phagocytosis. Recent studies indicate that natural IgM is important to clear microbes and other bioparticles, and that shape is critical to particle uptake by macrophages; however, the relevance of IgM and particle size in their clearance remains unclear. Here we show that IgM has a sizedependent effect on clearance. Methodology/Principal Findings: We used antibody-opsonized sheep red blood cells, different size beads and apoptotic cells to determine the effect of human and mouse IgM on phagocytosis by mouse alveolar macrophages. Our microscopy (light, epifluorescence, confocal) and flow cytometry data show that IgM greatly enhances the clearance of small particles (about 1–2 micron) by these macrophages. There is an inverse relationship between IgM-mediated clearance by macrophages and the particle size; however, macrophages bind and internalize many different size particles coated with IgG. We also show that IgM avidly binds to small size late apoptotic cells or bodies (2–5 micron) and apoptotic microparticles (,2 mm) released from dying cells. IgM also promotes the binding and uptake of microparticle-coated beads. Conclusions/Significance: Therefore, while the shape of the particles is important for non-opsonized particle uptake, th