On the continuity of the protoplasm through the walls of vegetable cells

By Walter Gardiner

The Polish Jews behind the Nazi ghetto walls

S. Mendelsohn

Rammed earth walls in Serón de Nágima castle (Soria, Spain): Constructive lecture

The Raya or frontier between the kingdoms of Castile and Aragón was fortified with a system of castles and walled-cities that were useful during the several conflicts that took place in the Late Medieval Age. The Serón de Nágima castle defended the communication road between the axis of the Jalón river valley, which flows into the Ebro, and Duero valley. Its uniqueness stems from the fact that it is one of the few fortifications in the area where rammed earth is the only building system used. In this paper, the castle building fundaments are exposed mainly focusing on the techniques and building processes developed from the interpretation of the legible constructive signs in its walls.

Suppression of the intrinsic stochastic pinning of domain walls in magnetic nanostripes

Nanofabrication has allowed the development of new concepts such as magnetic logic and race-track memory, both of which are based on the displacement of magnetic domain walls on magnetic nanostripes. One of the issues that has to be solved before devices can meet the market demands is the stochastic behaviour of the domain wall movement in magnetic nanostripes. Here we show that the stochastic nature of the domain wall motion in permalloy nanostripes can be suppressed at very low fields (0.6-2.7 Oe). We also find different field regimes for this stochastic motion that match well with the domain wall propagation modes. The highest pinning probability is found around the precessional mode and, interestingly, it does not depend on the external field in this regime. These results constitute an experimental evidence of the intrinsic nature of the stochastic pinning of domain walls in soft magnetic nanostripes

Failure and impact behavior of facade panels made of glass fiber reinforced cement(GRC)

GRC is a cementitious composite material made up of a cement mortar matrix and chopped glass fibers. Due to its outstanding mechanical properties, GRC has been widely used to produce cladding panels and some civil engineering elements. Impact failure of cladding panels made of GRC may occur during production if some tool falls onto the panel, due to stone or other objects impacting at low velocities or caused by debris projected after a blast. Impact failure of a front panel of a building may have not only an important economic value but also human lives may be at risk if broken pieces of the panel fall from the building to the pavement. Therefore, knowing GRC impact strength is necessary to prevent economic costs and putting human lives at risk. One-stage light gas gun is an impact test machine capable of testing different materials subjected to impact loads. An experimental program was carried out, testing GRC samples of five different formulations, commonly used in building industry. Steel spheres were shot at different velocities on square GRC samples. The residual velocity of the projectiles was obtained both using a high speed camera with multiframe exposure and measuring the projectile’s penetration depth in molding clay blocks. Tests were performed on young and artificially aged GRC samples to compare GRC’s behavior when subjected to high strain rates. Numerical simulations using a hydrocode were made to analyze which parameters are most important during an impact event. GRC impact strength was obtained from test results. Also, GRC’s embrittlement, caused by GRC aging, has no influence on GRC impact behavior due to the small size of the projectile. Also, glass fibers used in GRC production only maintain GRC panels’ integrity but have no influence on GRC’s impact strength. Numerical models have reproduced accurately impact tests.

Softening-up mannan-rich cell walls

The softening and degradation of the cell wall (CW), often mannan enriched, is involved in several processes during development of higher plants, such as meristematic growth, fruit ripening, programmed cell death, and endosperm rupture upon germination. Mannans are also the predominant hemicellulosic CW polymers in many genera of green algae. The endosperm CWs of dry seeds often contain mannan polymers, sometimes in the form of galactomannans (Gal-mannans). The endo-beta-mannanases (MANs) that catalyse the random hydrolysis of the beta-linkage in the mannan backbone are one of the main hydrolytic enzymes involved in the loosening and remodelling of CWs. In germinating seeds, the softening of the endosperm seed CWs facilitates the emergence of the elongating radicle. Hydrolysis and mobilization of endosperm Gal-mannans by MANs also provides a source of nutrients for early seedling growth, since Gal-mannan, besides its structural role, serves as a storage polysaccharide. Therefore, the role of mannans and of their hydrolytic enzymes is decisive in the life cycle of seeds. This review updates and discusses the significance of mannans and MANs in seeds and explores the increasing biotechnological potential of MAN enzymes.

Failure mechanism of reinforced concrete structural walls with and without confinement

This paper presents the results of cyclic loading tests on two large-scale reinforced concrete structural walls that were conducted at Purdue University. One of the walls had confinement reinforcement meeting ACI-318-11 requirements while the other wall did not have any confinement reinforcement. The walls were tested as part of a larger study aimed at indentifying parameters affecting failure modes observed to limit the drift capacity of structural walls in Chile during the Maule Earthquake of 2010. These failure modes include out-of-plane buckling (of the wall rather tan individual reinforcing bars), compression failure, and bond failure. This paper discusses the effects of confinement on failure mode. Distributions of unit strain and curvature obtained with a dense array of non-contact coordinate-tracking targets are also presented.

Rammed earth walls in the late middle age castles in the actual province of Soria, Spain

This paper analyzed the building techniques based in the use of rammed earth in the Late Medieval fortifications in the province of Soria, Spain. The manorial castles of Serón de Nágima and Yanguas were built completely with rammed earth. However, these techinques are different. Through the study of the constructive signals, we can reconstruct the constructive process and made an hypothesis of the auxiliary scaffolding necessary for the construction. After, other four cases in which there is presence of rammed earth are described: Ágreda, Arcos de Jalón, Caracena and the tower of Martín González or castle of La Raya (the Border). Rammed earth is used in some secondary architectural elements and also as a filling of the masonry walls, but somtimes there are ancient rammed earth walls overlaid with stone masonry.

Facade typologies as a tool for selecting refurbishment measures for the Spanish residential building stock

Today, the building sector alone accounts for 40% of the total energy consumption in the European Union (EU). In most EU member states, about 70–90% of the buildings were constructed at least 20 years ago. Due to this, these buildings have a worse energy efficiency behavior than the new ones that comply with current regulations. As a consequence, acting on the existing building stock is needed, developing special methods on assessment and advice in order to reduce the total energy consumption. This article addresses a procedure allowing the classification and characterization of existing buildings facades. It can help researchers to achieve in-depth knowledge of the facades construction and therefore knowing their thermal behavior. Once knowing that, the most appropriate upgrading strategies can be established with the purpose of reducing the energy demand. Furthermore, the classified facade typologies have been verified, complying with current and future Spanish regulations and according to the results obtained, a series of upgrading strategies based on the opaque part and those in the translucent part, have been proposed. As a conclusion, this procedure helps us to select the most appropriate improvement measures for each type of facade in order to comply with current and future Spanish regulations. This proposed method has been tested in a specific neighborhood of Madrid, in a selected period of time, between 1950 and 1980, but it could be applicable to any other city.

On the use of trenches and walls on the control of ground transmitted railway vibrations

An actual case of an underground railway in the neighbourhood of habitation buildings has been analyzed. The study has been based on a twodimensional BEM model including a tunnel and a typical building. The soil properties were obtained using geophysical techniques. After a sensitivity study, the model has been simplyfied and validated by comparison with "in situ" measurements. Using this simplyfied model, a parametric study has been done including trenches and walls of different materials and different depths at two different distances from the tunnel. The reductions obtained with the different solutions can then be compared.

Testing the performance of a green wall system on an experimental building in the summer

It is known that a green wall brings some advantages to a building. It constitutes a barrier against solar radiation, thus decreasing and delaying the incoming heat flux. The aim of this study is to quantify such advantages through analytical comparison between two facades, a vegetal facade and a conventional facade. Both were highly insulated (U-value = 0.3 W/m2K) and installed facing south on the same building in the central territory of Spain. In order to compare their thermal trend, a series of sensors were used to register superficial and indoor air temperature. The work was carried out between 17th August 2012 and 1st October 2012, with a temperature range of 12°C-36°C and a maximum horizontal radiation of 1020 W/m2. Results show that the indoor temperature of the green wall module was lower than the other. Besides, comparing superficial outdoor and indoor temperatures of the two walls to outdoor air temperatures, it was noticed that, due to the shading plants, the green wall superficial temperature was 5 °C lower on the facade, while the bare wall temperature was 15 °C higher. The living wall module temperature was 1.6 °C lower than the outdoor, while the values of the conventional one were similar to the outdoor air temperature.

Performance of buildings with masonry infill walls during the 2011 Lorca earthquake

On Wednesday 11th May 2011 at 6:47 pm (local time) a magnitude 5.1 Mw earthquake occurred 6 km northeast of Lorca with a depth of around 5 km. As a consequence of the shallow depth and the small epicentral distance, important damage was produced in several masonry constructions and even led to the collapse of one of them. Pieces of the facades of several buildings fell down onto the sidewalk, being one of the reasons for the killing of a total of 9 people. The objective of this paper is to describe and analyze the failure patterns observed in reinforced concrete frame buildings with masonry infill walls ranging from 3 to 8 floors in height. Structural as well as non-structural masonry walls suffered important damage that led to redistributions of forces causing in some cases the failure of columns. The importance of the interaction between the structural frames and the infill panels is analyzed by means of non-linear Finite Element Models. The resulting load levels are compared with the member capacities and the changes of the mechanical properties during the seismic event are described and discussed. In the light of the results obtained the observed failure patterns are explained. Some comments are stated concerning the adequacy of the numerical models that are usually used during the design phase for the seismic analysis.