Face Of Wall Research Articles

Suicide Death from Paraquat Auto-Inoculation: A Case Report

We examine a case involving a 34-year-old man who died of complications following the self-inoculation of Paraquat for suicidal purposes. During the crime scene investigation were seized all the paraphernalia were analyzed and were positive for Paraquat. At the autopsy were found an area of hemorrhagic infiltration on the inside face of the abdominal wall, in correspondence of the right peri-umbilical region, following the self-inoculation of the Paraquat performed. The aspects of greatest interest of the particular case under examination have been analyzed. In particular, we have taken into consideration the biochemical and toxicological aspects of Paraquat and the medico-legal problems related to the inoculation of the compound.

Recycling of Ceramic and Polymeric Wastes in the Production of Surfacing Composite Materials

Presents the results of research on the development of a method for joint utilization of polystyrene foam and brick waste with obtaining a polymer composite material for the production of wall cladding products. This method consists in grinding the waste polystyrene foam with their subsequent dissolution in carbon tetrachloride and cold mixing the resulting solution with a crushed brick. This method reduces the energy intensity of production, eliminates thermal decomposition of the polymer binder during processing and makes it possible to jointly dispose of two types of large-tonnage waste. Products that can be obtained from the developed material, according to the values of frost resistance and water absorption, meet the requirements for products for external facing of walls and sole plates of facades.

MINIMIZING BED SCOUR INDUCED BY SHIP BOW-THRUSTERS BY USING QUAY WALL FLOW DEFLECTOR

Recently, the combination of larger bow-thrusters installed with vessels have created higher levels of bed scour action affecting the berthing structure and its overall stability. Therefore, the bed near a quay wall structure must have sufficient strength by placing a bed protection which may cause the cost of the project to rise. This research is carried out to investigate experimentally the effect of modifying the geometry of the quay wall surface on minimizing bed scour. This is done by inserting flow deflectors within the longitudinal direction of the wall surface in order to deflect/minimize the water jet affecting the bed near the quay wall. Experimental tests had been carried out for single and triple deflectors. The results showed that the use of flow deflectors achieved a reduction in bed eroded area in front of quay wall face by about 63%, and causes the start point of erosion to move far away from it; this may improve the stability of quay walls. Therefore, the importance of the present study is testing a new possible measure to improve the stability of quay walls by minimizing the scour in front of the wall and to decrease the cost of bottom protection.

MINIMIZING BED SCOUR INDUCED BY SHIP BOW-THRUSTERS BY USING QUAY WALL FLOW DEFLECTOR

Recently, the combination of larger bow-thrusters installed with vessels have created higher levels of bed scour action affecting the berthing structure and its overall stability. Therefore, the bed near a quay wall structure must have sufficient strength by placing a bed protection which may cause the cost of the project to rise. This research is carried out to investigate experimentally the effect of modifying the geometry of the quay wall surface on minimizing bed scour. This is done by inserting flow deflectors within the longitudinal direction of the wall surface in order to deflect/minimize the water jet affecting the bed near the quay wall. Experimental tests had been carried out for single and triple deflectors. The results showed that the use of flow deflectors achieved a reduction in bed eroded area in front of quay wall face by about 63%, and causes the start point of erosion to move far away from it; this may improve the stability of quay walls. Therefore, the importance of the present study is testing a new possible measure to improve the stability of quay walls by minimizing the scour in front of the wall and to decrease the cost of bottom protection.

Axial Rotation and Lateral Torsional Buckling of Extruded Aluminium Mullions in Curtain Wall Facades

Large modern buildings frequently are enclosed by lightweight, panelised, aluminium-framed facades, known as unitised curtain walls. This study shows that, in such wall systems, the established procedures for analysing the stability of structural extrusions ignore two of the three greatest causes of lateral movement in the main member, or mullion. One of these overlooked influences is the force caused by the pressurisation of the mullion's interior cavity, and the other is the moment transferred to the mullion, through structural adhesive, from the wall's face material, which is usually glass.A new, closed-form, algebraic expression is proposed to describe the lateral movement of a unitised mullion's interior flanges, and predictions obtained in this way are compared with results from a finite element model. It is suggested that the novel analytical approach might obviate the need for conventional lateral torsional buckling calculations, which are not only time-consuming to produce, but which are also of questionable accuracy. This simplification of the structural design process will make it easier for facade engineers to design extrusions in which metal is used efficiently, and because the production of aluminium is energy-intensive, material savings achieved in this way will bring both commercial and environmental benefits.

Influence of toe restraint conditions on performance of geosynthetic-reinforced soil retaining walls using centrifuge model tests

Current design regulations most often require use of limit equilibrium methods for the internal stability analyses of geosynthetic-reinforced soil (GRS) walls. However, the limit-equilibrium based approaches generally over-predict reinforcement loads for GRS walls when comparing with measured data from full-scale instrumented walls under working stress conditions. Wall toe resistance has an important influence on the performance of GRS walls but is ignored in limit equilibrium-based methods of design. This paper reports centrifuge modelling of GRS walls which have different toe restraint conditions but are otherwise identical. The GRS wall models prepared in this study isolate the influence of wall toe resistance on the performance of walls. Based on measured data from four centrifuge wall model tests, a reduction in wall toe resistance (by reducing the interface shear resistance at the base of the wall facing or removing the soil passive resistance in front of the wall toe or both) induces larger maximum facing deformation and reinforcement strain and load. The results also demonstrate that the wall models with typical toe restraint conditions are most likely operated under working stress conditions while those with poor toe restraint conditions may experience (or be close to reach) a state of limit equilibrium.

Conjugate Nusselt Numbers for Simultaneously Developing Flow Through Rectangular Ducts

We consider conjugate forced-convection heat transfer in a rectangular duct. Heat is exchanged through the isothermal base of the duct, i.e., the area comprised of the wetted portion of its base and the roots of its two side walls, which are extended surfaces within which conduction is three-dimensional. The opposite side of the duct is covered by an adiabatic shroud, and the external faces of the side walls are adiabatic. The flow is steady, laminar, and simultaneously developing, and the fluid and extended surfaces have constant thermophysical properties. Prescribed are the width of the wetted portion of the base, the length of the duct, and the thickness of the extended surfaces, all three of them nondimensionalized by the hydraulic diameter of the duct, and, additionally, the Reynolds number of the flow, the Prandtl number of the fluid, and the fluid-to-extended surface thermal conductivity ratio. Our conjugate Nusselt number results provide the local one along the extended surfaces, the local transversely averaged one over the isothermal base of the duct, the average of the latter in the streamwise direction as a function of distance from the inlet of the domain, and the average one over the whole area of the isothermal base. The results show that for prescribed thermal conductivity ratio and Reynolds and Prandtl numbers, there exists an optimal combination of the dimensionless width of the wetted portion of the base, duct length, and extended surface thickness that maximize the heat transfer per unit area from the isothermal base.

Comparative Study of Anchored Wall Performance with Two Facing Designs

The present study compared the performance of soldier pile and concrete bearing pad anchored wall facings. Using Abaqus finite element software, two case studies have been precisely represented for the facing designs and effects of the parameters of soil type, spacing of anchors and facings, surcharge and facing sizes were investigated. The analysis results indicate that the soldier pile method can efficiently reduce anchored wall deformation, especially at the wall crest. The horizontal deformation at the top of the anchored soldier pile wall was about half of the wall anchored with concrete bearing pads. Soil arching between the anchors in the horizontal direction was more effective in the soldier pile wall and the bending moment of the laggings in the soldier pile wall was considerably less than that of the anchorage with bearing pads.

Analysis of resistance factors for LRFD of soil nail pullout limit state using default FHWA load and resistance models

Resistance factors for load and resistance factor design (LRFD) of pullout limit state of both permanent and temporary soil nails are calibrated against a wide design space using the current Federal Highway Administration (FHWA) nail load and resistance models. The calculated resistance factors were shown to scatter broadly among design scenarios that differ in wall face batter, soil friction angle, nail ultimate bond strength, and surcharge live load. An important lesson learned from the analysis results is that the current practice of using a single resistance factor for LRFD of nail pullout limit state could not result in uniform reliabilities across different design scenarios. Simple artificial neural network (ANN) models were developed for computation of resistance factors. Design examples demonstrated the ability of the ANN models in providing resistance factors that yield satisfactory and consistent reliabilities in different nail pullout designs.

Protection against Degradation of Contemporary Face Walls

The face wall is a construction element which is exploited in difficult environmental conditions. Its material solutions should effectively protect it against environment influences. But often the desired effect is not obtained – on most objects there is efflorescence along with damages appearing with various intensity, as a result of corrosion processes. Their dynamics depends on various factors. The most important ones include the environment quality and wall structural integrity. In case of face walls, the basic environmental factors are driving rain, long term snow cover, and changing temperatures oscillating about the level of 0 °C. The structural integrity of the wall depends mainly on mortar which aside from obvious supporting function should also protect against water penetration into the wall and thus creating subflorescence. The article systematizes activities related to ensuring correct moisture conditions of the wall and its maintenance in a proper technical state during exploitation.

Microstructure Ceramic Changes Resulting from Sodium Sulphate Subflorescence

In this article, the influence of sodium sulphate crystallization on microstructure changes in traditional ceramic was discussed. The tested elements in form of brick halves underwent capillary moistening in sodium sulphate solution with concentration of 5, 10, 15, 20, and 25%, and then their bottom walls were protected with polyethylene covers in order to ensure drying only through side walls. After drying, samples were taken from face walls (5mm) and 2 subsequent lower layers (each 10mm thick). Prepared samples were used for comparative analysis of ceramic microstructure changes caused by salt crystallization and material damage visible after salt extraction. In the tests, mercury porosimetry and confocal microscopy were used. Because of necessity to dry the samples to solid mass, the temperature of 80°±5°C was defined which enabled removing free water without damaging of crystallized salt structure. Based on the ceramic analysis, the initial salt concentration when macroscopic damage starts as a result of subflorescence (face layer delamination) was found. The analysis of pictures from a confocal microscope enabled to define the mechanism for ceramic material damage. A characteristic granular diffusion was observed which is the effect of pushing out ceramic by building out the sulphate crystals.

Long-Term Behavior of a Geosynthetic Reinforced Soil Integrated Bridge System in Hawaii

A 109.5-Ft-long Geosynthetic Reinforced Soil Integrated Bridge System (GRS-IBS) in Hawaii was instrumented to measure superstructure strains, vertical pressures below the footing, lateral pressures behind the end wall and modular block facing, and lateral displacements of the facing. Field surveys were also performed to measure the bridge footing settlement. The field data showed that: (1) with time the superstructure compressive concrete strains gradually increased and the end wall lateral pressures gradually decreased, evidence of superstructure concrete creep and shrinkage; (2) three years after construction, the total footing settlement was ≈ 1.2 in.; and (3) the bridge superstructure undergoes daily and seasonal thermal expansion and contraction cycles. Also seasonally, the vertical pressures beneath the footing, lateral pressures behind the end walls, and superstructure strains fluctuate cyclically. The vertical footing pressure closest to the stream experienced the greatest daily pressure fluctuation (≈ 2500−3000 psf), while the one nearest the end wall experienced the least. Based on the results of cyclic triaxial tests on a basalt aggregate similar to the GRS backfill to estimate permanent deformation of the abutment due to daily pressure fluctuations, it was estimated that the permanent strain ≈ 1%, comparable to what was observed in the bridge footing. After three years, the total settlement is about 1.6% of the GRS abutment height; ≈ 0.7% of this is due to the structure dead weight and the remaining 0.9% is due to cyclic loading, consistent with the 1% cyclic strain from laboratory permanent deformation tests.

Evolution of Salt Efflorescence on Clinker Face Walls

The lowering of building element aesthetics caused by salt efflorescences can have various characters. It depends mostly on types of wall component types, external environment conditions, and on-going physical and chemical processes. The active salts responsible for efflorescence appearance do not only worsen the wall look. They can also lead to lower durability because of microstructure destruction both in ceramic as well as in mortar. The type of mortar used for face clinker walls in essential way influences the limitation of efflorescences and discolorations which appear. Additionally, the way how wall is formed on the subsoil is a factor determining the character of salts appearing. In this work there is an analysis of the evolution of efflorescences appearing on two exemplary face walls made with various mortars. The walls were built with solid clinker bricks of traditional size 250x120x65mm in connection with two mortars: cement mortar based on portland cement CEM I 42.5, and cement-lime one. Additionally, during the research three different contacts of the wall with subsoil were tested: gravel layer, humus with lawn, and tight concrete band. The analysis lasted for ten years of wall exploitation in external environment. In the tested walls there were made chemical analyses for the quality and quantity of the appearing salts. There is also a raster picture of appearing efflorescence evolution made with AutoCad program during the research time period.

Inclined model experiment and discrete element method simulation of reinforced soil wall with leakage of backfill material

In this study, a series of inclined model experiments were conducted to investigate the behaviour of reinforced soil walls with leakage of backfill material. The experimental results were simulated by discrete element method (DEM). From the results of the inclined model experiments, it was confirmed that the tensile force in the reinforcement near the wall facing decreased due to the leakage of the backfill material, while decreasing the horizontal resistance of the reinforced soil wall remarkably. The leakage behaviour observed in the experiment was simulated using DEM. From the results of the DEM simulation, the calculated displacement pattern was found to be roughly similar to that obtained in the experiment. During leakage of the backfill material, an area without normal contact forces was generated at the lower end and this area developed toward the upper side. Such a change in normal contact forces affects the behaviour of a geogrid, in particular the disappearance of normal contact forces weakens the interlocking between the geogrid and the soil. This observation agrees with the experimental finding that the strain of the geogrid decreased in the area near the back of the wall facing.

Suicide Death from Paraquat Auto-Inoculation: A Case Report

We examine a case involving a 34-year-old man who died of complications following the self-inoculation of Paraquat for suicidal purposes. During the crime scene investigation were seized all the paraphernalia were analyzed and were positive for Paraquat. At the autopsy were found an area of hemorrhagic infiltration on the inside face of the abdominal wall, in correspondence of the right peri-umbilical region, following the self-inoculation of the Paraquat performed. The aspects of greatest interest of the particular case under examination have been analyzed. In particular, we have taken into consideration the biochemical and toxicological aspects of Paraquat and the medico-legal problems related to the inoculation of the compound.

Effect of Residual Stress on the Destruction of Field Joints of Gas Pipelines Operating in Conditions of the North

Welding residual stresses are determined by algebraic summation of stresses by the effect of external loading and can have a significant impact on the performance of welded joints. The present article examines the effect of residual welding stress on the destruction of circumferential butt welds of the gas pipeline sections. The features of the distribution of the welding residual stresses of annular welded pipe joints are considered. It has been established that thin-walled tubes are formed in the inner layers of the sealing elements with growing tension pins forming inside. Analysis of destruction of ring welded joints of the underground and underwater sections of the pipeline was carried out. The welding residual stresses were investigated with X-ray diffraction technique. It is shown that the initiation and growth of macrocracks in the field joints of thin-walled main gas pipelines occur in the heat-affected zone from the interior face of the pipe wall in the zone of high tensile residual welding stress. Analysis of the destruction of real welded joints of gas pipelines has proved that the residual welding stress is the main factor that influences the development of brittle and fatigue cracks in them.

Calculation of Natural Frequencies of Retaining Walls Using the Transfer Matrix Method

The dynamic response magnitudes of retaining walls under seismic loadings, such as earthquakes, are influenced by their natural frequencies. Resonances can occur when the natural frequency of a wall is close to the loading frequency, which could result in serious damage or collapse. Although field percussion tests are usually used to study the health state of retaining walls, they are complicated and time consuming. A natural frequency equation for retaining walls with tapered wall facings is established in this paper using the transfer matrix method (TMM). The proposed method is validated against the results of numerical simulations and field tests. Results show that fundamental frequencies decrease gradually with wall height; soil elastic modulus exerts a great influence on the fundamental frequency for walls with smaller facing stiffness; fundamental frequencies are smaller for a hinged toe than a fixed toe condition, and this difference is smaller in taller walls.

Feasibility of Employing a Heat Insulation Wall as the North Wall of a Chinese Solar Greenhouse in a Severely Cold Area of China

Abstract. The conventional north wall of a Chinese solar greenhouse (hereafter referred to as a “solar greenhouse”) can release heat inside and help maintain a high indoor air temperature (T) during winter nights. However, the construction of conversational walls face problems of high cost, low construction quality, environmental damage, etc. Based on this, heat insulation walls have aroused much interest. However, this kind of wall can barely store and release heat, putting the solar greenhouse at risk of low T. The purpose of this study is to investigate whether the impact of the heat insulation wall could be weakened by decreasing the heat loss through the greenhouse envelope. The thermal environment of a solar greenhouse located in a severe cold area of China (Mohe County, Heilongjiang Province) was examined during sunny days, of which the north wall was constructed from polystyrene boards and plastered with 10 mm-thick mortar. During the experiment, the outdoor air temperature (T) was -22.8±5.6°C during the night, reaching a low of -34.7°C. The amount of heat released from the north wall can be neglected, as it was 5.4% of the total heat obtained by the test solar greenhouse. In comparison with conventional solar greenhouses, both heat loss through the building envelope and the heat obtained from the test solar greenhouse during the night decreased. As a result, T was maintained at 10.6±2.9°C, with a low of 6.8°C, during the night, which was within the normal range of a conventional solar house located in northern China. Thus, the impact of the heat insulation wall on T in the sunny days was weakened by decreasing the heat loss through the greenhouse envelope. Nevertheless, more work on the performance of test solar greenhouse on cloudy days and summer days should be conducted to fully validate the proposed hypothesis. Keywords: Chinese solar greenhouse, Heat insulation wall, Heat loss, Indoor temperature.

Numerical simulation of infiltration into the fill of a wall reinforced with nonwoven geotextiles

This paper presents a numerical investigation of water infiltration into a fine-grained reinforced soil wall using nonwoven geotextiles. A large-scale reinforced soil wall was constructed in the laboratory and subjected to water irrigation to impose a controlled infiltration. The structure was fully instrumented to measure changes in the volumetric water content and matric suction during irrigation. The numerical investigation was performed to provide insight into the overall infiltration process, with a particular focus on the hydraulic behavior at soil-geosynthetic interfaces that was not properly captured in the laboratory model. The numerical study includes capillary effects, the location of breakthrough along the reinforcement length and the effect of the presence of a wrap-around anchorage. In general, the numerical analyses were found to agree with the experimental results. The results indicate that the use of nonwoven geotextiles to reinforce fine-grained backfill retarded water flow into the subsequent layers so that the water did not break through uniformly along the length of the geotextile but rather infiltrated progressively. The study also demonstrated the significant contribution of the presence of a wraparound anchorage on the change in the water flow path toward the wall facing. The capillary effects on fine-grained backfill reinforced with geotextiles were found to be significantly affected by the heterogeneity in the porosity expected for compacted soils.

TRACING THE ORIGIN OF JHAROKHA WINDOW USED IN INDIAN SUBCONTINENT

The Jharokha is a distinctive feature of the architecture of Indian Sub-continent of medieval times. The study of the built heritage features is a way to discover and know about the old culture and society. A Jharokha is an oriel window projecting from upper storeys of a building used in medieval Indian architecture. Jharokha window projecting from the wall face of the building in an upper storey overlooking a street, market or any other open space. This study aims to trace the origin of traditional Jharokha window used in Indian subcontinent. In order to do it, the available data and literature have been carefully reviewed and studied to draw inferences. This study shows that the trend of a protruding window similar to Jharokhas seems to be present in different regions with their regional architectural flavor. The Indian architecture has influenced by various empires, and a lot of external influences came to this region because of the trade route. The external and regional influences have been studied to investigate the Jharokha window origin and form. The 3rd century BC balconies in Mauriyan Empire seems to amalgamate with the windows of Islamic architecture and developed finally into a local window form in the shape of Jharokha. The style and features of Jharokha vary concerning the local material and techniques available. The different era and different regions adopted this window form according to their own needs and aesthetics.