Consolidation Zone Research Articles

Experimental Approbation of Selective Laser Melting of Powders by the Use of Non-Gaussian Power Density Distributions

Experimental results on laser beam modulation at selective laser melting (SLM) are presented. The modulation is a possible way to improve the efficiency of the SLM process. The optical diagnostics shows the energy loss up to 30%. This could be a consequence of high thermal gradients in the melt pool resulted by the Gaussian power density distribution. The Gaussian distribution can be changed to the flat-top one or to the inverse-Gaussian (donut) one. An experimental stand with a 200W laser source was developed. Twenty single tracks for each of the three modes were obtained for a Co-Cr alloy. The samples were studied by scanning electronic microscopy (SEM) on irregularity. Optical diagnostics by high velocity camera (HVC) shows that the use of the non-Gaussian laser beam distributions can significantly reduce the width of the free-of-powder consolidation zone, which is considered as the main reason for irregularity of single tracks. A better metallurgical bonding of the single tracks with the substrate was obtained by the use of the flat-top laser beam. Both of these facts show a significant influence of the laser beam energy distribution on the energy loss at SLM, especially for high power laser sources. The observed escape of granules shows a possible influence of the dynamic factor. The use of the non-Gaussian distributions can enhance 3D parts, for example, improve the geometrical tolerance and decrease the residual porosity.

Idiopathic pulmonary hemorrhage: morphology and differential diagnosis. Case report

Idiopathic pulmonary hemorrhage (IPH) is a rare cause of alveolar hemorrhage (AH) with unknown etiology that primarily affects children. The process has a variable clinical progression, and its diagnosis is established after excluding all causes of AH. Herein, the authors report a case of IPH in an adult male patient referring cough and hemoptysis. The conventional radiography computed tomography imaging identified zones of consolidation and areas of ground-glass attenuation in the lower lobes and lingula. Forced spirometry, bronchoscopy, and laboratorial tests yielded normal results. Several alveolar hemosiderin-laden macrophages were identified on bronchoalveolar lavage and lung biopsy. Thus, the histopathological findings associated with clinical data were compatible with IPH.

Amiodarone-induced pulmonary toxicity mimicking malignancy at initial presentation.

An 81-year-old man with an extensive cardiac history was admitted to the cardiology department because of increasing shortness of breath. His medical history included melanoma and prostate adenocarcinoma 7 and 4 years ago respectively. His medication consisted of antihypertensive, anticoagulant and anti-arrhytmic drugs. Non-enhanced computed tomography (CT) of the chest revealed bilateral zones of consolidation (arrowheads) and multiple nodules of varying size (arrows) with predominant localization in the lower lobes (Fig. A). The lowest axial slices through the liver showed an increased attenuation of the liver parenchyma suggestive of amiodarone-induced liver disease (Fig. C(1), ROI: 78 HU). In view of his oncological history the multiple nodular lesions were primarily suspicious for metastasis. Combined pulmonary and liver imaging findings also raised the possibility of amiodarone induced pulmonary toxicity (AIPT). The patient – however – refused further diagnostic testing. Therefore await-and-see policy was implemented and amiodarone was withdrawn. Followup CT of the chest 4 months later showed marked regression of the lesions (Fig. B) and a decreased attenuation of the liver parenchyma confirming the diagnosis of AIPT (Fig. C(2), ROI: 56 HU).

Cavity in lung in a case of Cushing′s disease

Sir, A 32-year-old lady, known case of Cushing's disease, presented with persistent cough of 8 weeks duration. Cough was nonproductive without any postural or diurnal variation. Cough was not associated with any history of hemoptysis, fever, and night sweats. She gave history of tuberculosis lung for which she had received full course antitubercular therapy 6 months back. On examination, she had Cushingoid body habitus. On respiratory examination, bronchial breath sounds were heard at left supraclavicular, infraclavicular, and upper axillary areas. X-ray chest PA view showed two colocated thin-walled cavitatory lesions in right lung upper zone with a well-defined nodular shadows inside it which moved with change in position (Monad's sign) [Figure 1]. CECT chest was also indicative of thin-walled cavitatory lesions in right lung apex with soft tissue mass inside it [Figure 2]. Smear and culture results were negative for acid-fast bacilli. Smear and culture results were positive for Aspergillus fumigatus. The patient was treated with itraconazole. Saprophytic aspergillosis results from colonization of a preexisting pulmonary cavity and typically leads to the formation of a fungus ball, or mycetoma, within the cavity. Although pulmonary mycetoma may be asymptomatic, patients can present with life-threatening hemoptysis. Figure 1 Chest X-ray PA and lateral view showing cavity and movement of fungal ball Figure 2 CT scan of chest showing fungal ball in preexisting cavity Cavitatory lesion in lung is defined radiologically as “a lucency within a zone of pulmonary consolidation, a mass, or a nodule; hence, a lucent area within the lung that may or may not contain a fluid level and that is surrounded by a wall, usually of varied thickness.”[1] Cavitatory lesion in lung can be infectious or noninfectious and thick or thin walled. Cavities with wall thickness upto 4 mm are thin-walled, while cavities with wall thickness ≥ 5 mm are thick walled. Thin-walled cavities are usually nonmalignant; cavities with wall thickness between 5 and 15 mm are mixed and cavities with wall thickness more than 15 mm are mostly malignant. Thin-walled cavitatory lesions in lung can be caused by tuberculosis, congenital or acquired bullae, coccidioidomycosis, posttraumatic cysts, and few metastatic carcinomas. While fine cavitatory lesion in lung with fungal ball should make us consider diagnosis of aspergillosis; however, similar appearance may rarely also be seen with blood or fibrin in cavity.[2] Cushing's disease is an immune-compromised state characterized by excess cortisol levels secondary to pituitary adenoma. It is associated with impaired cell-mediated immunity, augmented by deficient neutrophil, and macrophage function.[3] Aspergilloma is most common form of lung involvement due to aspergillus. It most commonly occurs in already existing cavity which is most commonly caused by Mycobacterium tuberculosis in India. Aspergillous growth is facilitated by inadequate drainage in these cavities. It usually does not invade pulmonary parenchyma or blood vessels. Mostly it remains stable and may spontaneously regress in 10% of cases. Symptomatic aspergilloma can be treated by various modalities, varying from oral itraconazle to local instillation of antifungal drugs in cavity, to surgical resection and bronchial artery embolization in case of hemoptysis.[4]

Determination of Formation Strata and Groundwater Potential in Sapele Metropolis and Environ

This study was carried out in Sapele, Jesse and Oghara, Delta state to determine the groundwater potential by correlating results of seismic refraction survey and those of electrical resistivity studies. Fifteen vertical electrical sounding (VES) locations were sounded and nine seismic stations were shot to complement the study. The seismic results show that the area has generally three or four layer formations. The thin weathering layer with thickness of 1.0 - 3.5 m has velocity range of 250 – 350 m/s. while the velocities of second and third layers range from 900 -1400m/s to consolidated zone. The analysis of the VES data delineated 4 to 5 layers with HK and AKA curves types mainly and showed that the formation of the area is basically conducting which suggests the existence of heavy clay or clayey sand formations. Although the numbers of layers delineated differ, both methods indicate that viable aquifer at Sapele and Jesse is generally within 25m although false and contaminated aquifer may be intercepted at 10 -15 m. On the contrary, Oghara is more of sandy formation with aquifer above 35 m.

Density modeling of the basement of sedimentary sequences and prediction of oil-gas accumulation: Evidence from South SakhAlin and West Siberia

The zones of deconsolidation and consolidation in the lower parts of the sedimentary cover and in the basement are considered as an important exploration indicator of oil-gas accumulation zones. The described zones are mapped using geodensity modeling (in a gravity field) in the MZ-PZ basement and Cretaceous deposits of South Sakhalin, as well as in the pre-Jurassic basement and plate complex of the central part of West Siberia. It was found that the most promising zones are confined to the Central Sakhalin Fault and Krasnoleninsk arch in Sakhalin and to the Visim megaswell in the West Siberian plate. Recent prospecting drilling revealed that deconsolidation zones are correlated with hydrocarbon reservoirs. The presented technique of geodensity modeling can be applied for petroleum-geological explorations of structures formed in different geological and tectonic settings.

Drawing a powder through a conical die with mobile wall

Theoretical results are presented on the drawing of a powder through a conical die with mobile wall. Analytic formulas are derived for the state of stress and strain in the consolidation and extrusion zones, and for the normal and tangential stresses at the contact surface between the powder and the shell, with allowance for the inertial forces.

Modelling of long-term ground response to tunnelling under St James's Park, London

Following a tunnel excavation in low-permeability soil, it is commonly observed that the ground surface continues to settle and ground loading on the tunnel lining changes, as the pore pressures in the ground approach a new equilibrium condition. The monitored ground response following the tunnelling under St James's Park, London, shows that the mechanism of subsurface deformation is composed of three different zones: swelling, consolidation and rigid body movement. The swelling took place in a confined zone above the tunnel crown, extending vertically to approximately 5 m above it. On the sides of the tunnel, the consolidation of the soil occurred in the zone primarily within the tunnel horizon, from the shoulder to just beneath the invert, and extending laterally to a large offset from the tunnel centreline. Above these swelling and consolidation zones the soil moved downward as a rigid body. In this study, soil–fluid coupled three-dimensional finite element analyses were performed to simulate the mechanism of long-term ground response monitored at St James's Park. An advanced critical state soil model, which can simulate the behaviour of London Clay in both drained and undrained conditions, was adopted for the analyses. The analysis results are discussed and compared with the field monitoring data. It is found that the observed mechanism of long-term subsurface ground and tunnel lining response at St James's Park can be simulated accurately only when stiffness anisotropy, the variation of permeability between different units within the London Clay and non-uniform drainage conditions for the tunnel lining are considered. This has important implications for future prediction of the long-term behaviour of tunnels in clays.

Effects of smectite, salinity and water content on sedimentation and self-weight consolidation of thoroughly disturbed soft marine clay

Addition of a high-swelling smectite to low-activity-mineral-dominated Leda clay influenced the settling mode, settling/consolidation rates and the final sediment water contents attained when suspensions ranging in water content from 500 to 6000% were allowed to settle under salinity conditions ranging from 30 to 0.5 g/l, and to undergo self-weight consolidation for 14 days. The presence of high-swelling smectite extended the salinity and water content ranges over which consolidation settling and zone settling occurred and the final water content for any initial-water-content/salinity condition increased as the amount of high-swelling smectite increased. The settling and consolidation rate patterns change with time in a manner that is dependent on all of settling mode, water content and salinity. At high-swelling smectite content 10%, the lowest sediment water content is attained at high salinity and the lowest possible initial suspension water content.

Research Article: A GIS-embedded system to support land consolidation plans in Galicia

Land consolidation is a strategic instrument for rural planning and thus economic development in the Spanish region of Galicia. This paper describes an experimental system embedded in a GIS environment to aid rural engineers to develop land consolidation plans. The system supports all the stages of the plan and many functionalities are implemented as heuristic processes based on expert knowledge and advice. The overall aim is to overcome administrative and technical problems of traditional consolidation procedures. The system provides an integrated framework for the management of spatial and administrative consolidation information. It also includes optimization-based algorithms for the automated generation of multiple alternative parcel reallocations, as well as an environment to refine and objectively evaluate the proposed solutions. These key capabilities result in a powerful tool for decision making that dramatically reduces the time and cost of land consolidation plans. Pilot experiences in two consolidation zones of Galicia assess the feasibility and effectiveness of the system.

Relating arctic pack ice stress and deformation under winter conditions

Together, thermodynamic and dynamic processes determine the thickness distribution of the ice cover on polar oceans, which governs the exchange of energy between the atmosphere and the ocean. Key to the dynamic processes is the mechanical behavior of the ice cover. During the Surface Heat Budget of the Arctic Ocean (SHEBA) field experiment, we deployed sensors to measure the internal ice stress at several locations within a 15 × 15 km area. These measurements are combined with satellite‐derived ice motion and imagery products. The objective is to make a first step toward using these data sources for evaluating sea ice dynamics models by assessing whether the stress signal can be qualitatively linked to the regional‐scale (10–100 km) deformation activity. Four case studies are presented, each with distinguishing characteristics: consolidation of the seasonal ice zone against the Alaskan coast (5–7 December 1997); advancement of the consolidation zone into the perennial ice pack (11–13 December); extreme divergence (14–17 January); and consolidation of the pack against Wrangel Island and the Siberian coast (20–23 February). The results of this analysis (1) demonstrate that stress measurements are related to the regional deformation behavior of the ice cover, (2) confirm that regional‐scale ice dynamics is primarily a function of coastal geometry and sustained, large‐scale wind direction and magnitude, (3) provide continued evidence that the ice pack behaves as a granular hardening plastic, and (4) encourage pursuit of efforts to use direct measurements of ice stress and deformation in the formulation and development of sea ice dynamics models.

DEMOCRACY IN THE SADC REGION

The purpose of this overview is to compare the state of democracy among SADC states. This is a region where electoral democracies increased significantly since 1989, but regular elections are necessary, not sufficient, to consolidate democracies. Socio-economic conditions as well as levels of freedom may be the missing links in this regard. Per capita incomes and human development indexes are combined to constitute an appropriate socioeconomic development axis (quantified, then ranked) which is then juxtaposed with institutional criteria (autocracy, electoral democracy and consolidation zone), and then ranked according to surveys on political rights and civil liberties, constituting the liberty index (these measurements are ranked relatively). Factors such as electoral systems and deeply divided versus homogeneous societies are also taken account of. This makes for a model of development and democracy in the region with Mauritius at the most consolidated end, and the DRC the furthest away. This methodology can be repeated regularly, indicating comparative trends within the region, over periods of time.

Stabilizing Wellbores in Unconsolidated Formations for Fracture Stimulation

Summary A wellbore stabilization system incorporating fracture stimulation has been developed and modeled in the laboratory for unconsolidated and dilatant formations. The profile of resin leakoff and penetration depth into the formation is relatively dependent on the pattern of perforations. Use of soluble particulates as a fluid-loss control agent proved to be effective in diverting resin, resulting in a uniform distribution of resin over the highly varying permeability interval. A significant drop in permeability of the near-wellbore area occurred after the resin treatment, but high productivity was re-established by connecting the wellbore with the untreated formation through highly conductive fractures. During companion testing of the resin-consolidation technique, the unconsolidated sandpack became a competent formation with compressive strength in excess of 2,000 psi. This competent material will be affected less by high drawdown pressures and stress cycling during production/shut-in cycles. The injection pressure required to fracture the consolidated wellbore showed an increase when compared to that of the untreated wellbore. Stress levels existing in the formation were shown to control the number and direction of generated fractures by passing the consolidated zone.

Status of imported malaria in a control zone of the United Arab Emirates bordering an area of unstable malaria

A concerted malaria eradication programme in the United Arab Emirates has reduced local transmission to only a very few small foci in the country. The Al Ain district is now a consolidation zone. However, transmission across the undemarcated border with Oman continues. Malaria imported by the large immigrant work force from major disease endemic areas remains a large burden. An added threat is the appearance of chloroquine-resistant Plasmodium falciparum principally from Sudan and Pakistan but increasingly amongst Omani cases seen in the hospitals and clinics in Al Ain. The implications of re-introduction of malaria and the establishment of chloroquine resistance, particularly for non-immune residents and visitors, are emphasized.

Analysis of fiber motion during wet filament winding of composite cylinders with arbitrary thickness

A continuum consolidation model is proposed for macroscopic analysis of fiber motion during filament winding of thermoset composite cylinders with arbitrary thickness. The model takes account of the variation of both instantaneous stiffness and permeability of the mixture with fiber compaction. Due to resin filtration, structure of the resulting initial-boundary value problem is similar to that of a moving boundary problem. Based on this analogy, a finite difference scheme is devised for the solution of the problem. For the case of winding onto a rigid mandrel, the results point to the existence of an active and a passive zone of consolidation. The results further indicate the possibility that during hoop winding of relatively thick cylinders, the tension can be completely lost in the portion of the passive zone away from the mandrel.

Proteus mirabilis mutants defective in swarmer cell differentiation and multicellular behavior

Proteus mirabilis is a dimorphic bacterium which exists in liquid cultures as a 1.5- to 2.0-microns motile swimmer cell possessing 6 to 10 peritrichous flagella. When swimmer cells are placed on a surface, they differentiate by a combination of events that ultimately produce a swarmer cell. Unlike the swimmer cell, the polyploid swarmer cell is 60 to 80 microns long and possesses hundreds to thousands of surface-induced flagella. These features, combined with multicellular behavior, allow the swarmer cells to move over a surface in a process called swarming. Transposon Tn5 was used to produce P. mirabilis mutants defective in wild-type swarming motility. Two general classes of mutants were found to be defective in swarming. The first class was composed of null mutants that were completely devoid of swarming motility. The majority of nonswarming mutations were the result of defects in the synthesis of flagella or in the ability to rotate the flagella. The remaining nonswarming mutants produced flagella but were defective in surface-induced elongation. Strains in the second general class of mutants, which made up more than 65% of all defects in swarming were motile but were defective in the control and coordination of multicellular swarming. Analysis of consolidation zones produced by such crippled mutants suggested that this pleiotropic phenotype was caused by a defect in the regulation of multicellular behavior. A possible mechanism controlling the cyclic process of differentiation and dediferentiation involved in the swarming behavior of P. mirabilis is discussed.

Role of mechanical loading in the progressive ossification of a fracture callus.

The progressive ossification pattern in a fracture callus was predicted based on a theory that relates the local stimulus for ossification to the tissue mechanical loading history. Two-dimensional finite element analyses of a fracture callus were considered at three different stages of ossification. The sites of callus ossification represented in the initial model were predicted by previous analyses relating mechanical stress and vascularity to the differentiation of mesenchymal tissue in the early callus. The zones of further ossification, bone bridging, and bone consolidation predicted in the present study were found to be similar to the ossification patterns that have been documented by other researchers. The approach used to predict fracture healing is identical to that of previous studies predicting joint morphogenesis, with the exception that fracture healing requires continuous, attached skeletal elements, whereas joint morphogenesis requires discontinuous, articulating skeletal elements.

Experimental infection of lambs with an adenovirus followed by pasteurella haemolytica

Groups of caesarian-derived, colostrum-deprived lambs aged 10 to 11 weeks were inoculated with the adenovirus WV419/75 followed 4, 6 or 8 days later by Pasteurella haemolyttica type Al ( P.h.). Other groups of lambs were inoculated with the virus or P.h. alone. The majority of animals inoculated with P.h. 6 or 8 days after the virus developed an acute necrotizing bronchopneumonia and pleurisy, whereas, the bacteria were cleared rapidly from the lungs of the majority of animals inoculated with P.h. alone, and pneumonic lesions only rarely developed. Between groups, the development of bacterial superinfection and thus bronchopneumonia could not be related to virus titres in either the lung or nasal secretions. However, within individual animals that developed pneumonia, the distribution of virus paralleled the distribution of lesions. In animals inoculated with the virus alone (or the virus plus P.h. where bacterial superinfection did not develop) areas of epithelial cell proliferation and consolidation with basophilic intranuclear inclusion bodies in swollen epithelial cells were present. The consolidation and inclusion bodies had disappeared by 10 days after inoculation, together with the virus, but the proliferation of airway epithelium was still present 20 days after inoculation. On the other hand, when bacterial superinfection was present, areas of acute necrotizing bronchopneumonia were the predominant feature. These lesions were surrounded by a zone of consolidation with a massive neutrophil infiltration or, where bacterial numbers were high (usually ⩾ 10 3.0/g), a band where oat-cells predominated although, in animals killed on day 14, oat-cells were still present but bacterial numbers were lower.

Monoaminergic afferents to the neocortex: A developmental histofluorescence study in normal and reeler mouse embryos

The patterns of distribution of monoaminergic (MA) afferents during early histogenesis of the neocortex of normal and Reeler mice are studied by histofluorescence microscopy. Fluorescing fibers appear rostrally in the cortex of both genotypes on the 14th embryonic day (E14), which is within 24 h of the development of the cortical plate. They are distributed to all regions of the cortex by the time of birth. Although the patterns of intracortical deployment differ in the two genotypes, the fibers appear to have homologous target structures. These are: (1) the polymorphic cells of the subplate in the depths of the normal and in the superplate near the surface of the mutant cortex; and (2) the zones of consolidation of apical dendrites of pyramidal cells: the external plexiform zone of normal and a series of intracortical plexiform planes in the mutant cortex. By contrast, the axons of this system do not branch significantly among the compactly ordered somata of pyramidal cells within the cortical plate of either genotype.

Deformation of the rock foundation of the Bratsk hydroelectric station

Deformations of the rock foundation of the Bratsk dam occurred mainly during filling of the reservoir and primarily due to the weight of the water operation. During operation, settlements have increased insignificantly with a clear tendency toward their fading away. The maximum settlement, 74 mm, which had been predicted as early as 1966, was reached in 1970; in 1977 it amounted to 74.4 mm. Horizontal deformations have practically stabilized. At the base of the dam, if slight consolidation occurred at all during construction (which, apparently, caused mainly differential settlement of the sections), then it was hardly noted by observations. Despite the explicit stabilization of the processes, observations of settlements and horizontal displacements retain their importance, considering the essential character of the structures, the seismicity of the region, and the slowness of processes characteristic for hydraulic structures. The geodetic base of the Bratsk hydrostation has certain shortcomings: the bench marks are located on a diabase sheet and can settle along with it; the nearness of the diabase rock quarry to the right-bank bench marks; the rather long and complex traverse along the foreshores. Use of the geodetic base is also difficult: the traverses along the foreshores are difficult and dangerous owing to the adjacent high (up to 80 m) steep cliffs, the natural disintegration of which causes rock falls. We consider that it would be more convenient and reliable to embed bench marks with anchors in sandstones below the upper zone of consolidation (depth 100–120 m) in the bank tunnels of the inspection gallery at the 27-m level.