Number Of Injection Points Research Articles

REDUCTION VIBRATIONS OF THE PILE FOUNDATIONS FOR MACHINES UNDER DYNAMIC LOADS BY HIGH-PRESSURE GROUP INJECTION METHOD

The vibration parameters of the foundations under dynamic loads or kinematic excitation directly depend on the stiffness and damping parameters of the base, the mass of the oscillating system consisting foundation, the machine and the «attached mass of soil». In the process of using pile foundations static load is transferred to the piles, the contact of the grillage with the ground is broken, and micro-gaps are formed. Micro-gaps impede the joint work of the soil mass of the inter-pile space with the foundation. An effective way to reduce the vibration parameters of foundations is the method of high-pressure group injection. The essence of the method lies in injection of a mobile cement-sand mortar into the soil base under the sole of the grillage under pressure exceeding the structural strength of the soil simultaneously through several injectors. The injection mixture eliminates micro-gaps and hardens the soil, which leads to an increase in the rigidity of the base and the involvement of an additional volume of soil mass in joint work with the foundation. The inclusion of inter-pile soil in joint work significantly increases the mass of the oscillating system and, as a result, reduces the parameters of horizontal and vertical vibrations of the pile foundation under dynamic loading and in the case of kinematic excitation. Injectors are immersed under the sole of the grillage through specially provided openings - injection conductors. The discharge points are usually located between piles and around the perimeter of the grillage. The parameters of the injection work (the number of injection points and their placement in the plan, the height of the injection horizons, the required volume of injected solution, the injection sequence, etc.) are assigned depending on the construction of the pile foundation, the engineering and geological conditions of the site, the dynamic operating mode of the equipment, and others factors. Strengthening pile foundations for machines under dynamic loads or vibration-sensitive equipment by high-pressure group injection can significantly reduce the amplitude of horizontal and vertical vibrations of foundations.

Erosion of dune sands stabilised by grouting with lime–silica fume mix

Dune sands are often an environmental hazard during strong winds and sand storms, particularly in the summer months. Wherever a granular soil surface is left unprotected, it can be subjected to wind erosion and dune formation. In this study, an attempt was made to stabilise sand dunes by grouting with a slurry of lime–silica fume (L–SF) material. Dune sand samples were collected from northern Iraq. In situ field density of the soil was determined by sand-cone tests for moisture content, classification, compaction, relative density, direct shear and chemical tests. Erosion tests were conducted using centrifugal fans, with wind applied to the soil at a speed of 90 km/h for 11 min. Silica fume (SF) and a L–SF mix were used for stabilisation and their effects on the dune sands were investigated. For grouting, a 1000 ml grout pump was used to stabilise a liquid tank of the L–SF mix; the maximum pumping pressure was about 25 kPa. It was found that when the dune sand was with a slurry of L–SF, there was a reduction in erosion by about 70% for a stabiliser grout of 33% (Lime to SF ratio, 3L : 4SF) with 67% water of the total mixture weight. The stabilisation effect increased with increases in the number and depth of grouting holes around the stabilised area. When wind was applied at a rate of about 90 km/h for 11 min, the eroded natural sand dune surface was about 66 mm, while for soil stabilised by grouting with L–SF, the erosion was 17–36 mm. An increase in the number of injection points and a reduction in the distances between them reduced the amount of soil erosion.

A Functional Approach to Posttraumatic Salivary Fistula Treatment: The Use of Botulinum Toxin.

This manuscript highlights key aspects regarding the practical use of botulinum toxin for the conservative nonsurgical treatment of a rarely encountered, but significant posttraumatic complication-the parotid salivary fistula. It adds information to the scarce existing literature on the subject. The authors outline the main differences between postoperative and trauma-related parotid injury regarding salivary fistula treatment. A total of 6 patients with trauma-related salivary fistulas have been treated by Abobotulinum toxin A injections over the course of 5 years. The technique is detailed, describing the doses used in the presence of parenchyma and duct injuries, the location and number of injection points in relation to the wound pattern. The results were favorable, leading to the healing of the salivary fistulas in all patients, with 1 injection session, without additional conservative treatment. In our experience, the use of botulinum toxin is of great benefit for treating salivary fistulas in a traumatic context.

Simulação geoestatística e numérica para previsão da eficiência da remediação por oxidação química in situ

A eficiência dos sistemas de remediação, como a oxidação química in situ (ISCO) é fortemente restringida pela presença de heterogeneidades nos valores de permeabilidade. As incertezas relacionadas à presença de heterogeneidades nos aquíferos em relação aos sucessos dos sistemas de remediação podem ser determinadas por intermédio de simulações estocásticas, embora tal metodologia não tenha sido empregada comumente para problemas envolvendo ISCO. Em decorrência deste cenário, foi objetivo deste trabalho desenvolver um procedimento metodológico para prever a eficiência da técnica de remediação por oxidação química in situ a partir do emprego de simulações estocásticas e simulações numéricas de fluxo e transporte. No caso hipotético simulado, foram gerados 30 campos randômicos tridimensionais equiprováveis de condutividade hidráulica e a eficiência da remediação foi testada em todos estes cenários. Os resultados indicam que o sistema de remediação proposto será ineficiente em 100% dos casos, invocando a necessidade de alterações no projeto inicial, tais como número de pontos e tempo de injeção. O elevado grau de incerteza identificado no cenário de contaminação admitido sugere ainda que novas investigações sejam realizadas para redução de incertezas e previsões mais realistas.

Variation of the Pole Length in Pole-Oriented Bonded Rings due to the Location and Number of Injection Points

Polymer bonded magnets are compounds consisting of a polymer matrix with embedded hard magnetic filler particles. These materials are mainly used in applications in actor or sensor technology. One example is the application as multipolar encoder wheel in magnetic sensors. Depending on the application different requirements have to be fulfilled, such as a high pole length accuracy and repeatability. This investigation deals with the production of multipolar rings in the injection molding process for sensor applications and influences of the design of the gating system on the pole length accuracy. It is shown that the number of injection points and developing weld lines, as well as the positioning of the injection points, has a major influence on the magnetization characteristics of the molded rings. In general, a positioning of injection points and weld lines in the pole pitch and higher number of injection points lead to rings with a high reproduction accuracy of the pole length of the mold.

Poster 306 Clinical Characteristics of Cervical Dystonia: Differences between Patients Previously Treated with Botulinum Neurotoxin Type A and Naïve Patients

Twenty-one muscles were selected for injection at Visit 1; of these the 5 most commonly injected were splenius capitis (93% of patients), sternocleidomastoid (SCM) (91%), trapezius (63%), levator scapulae (42%), and the semispinalis capitis (27%). Other muscles were injected with a frequency between 0.4e6%. The mean total injected volumes were 1.05 1.16 mL for splenius capitis, 0.68 0.78 mL for SCM, 0.67 0.58 mL for trapezius, 0.42 0.26 mL for levator scapulae and 0.56 0.33 mL for semispinalis capitis. Mean number of injection points were: splenius capitis (2.7 1.5), SCM (2.2 1.2), trapezius (2.7 1.6), levator scapulae (1.5 0.7), and semispinalis capitis (2.0 1.3). At Visit 2 the frequency of muscles injected, the injected volume, and injection points were similar to Visit 1. Injection guidance techniques were used in 37% (SCM) to 57% (levator scapulae) of Visit 1 injections, and this did not change at Visit 2. Analyses by study center revealed that when an injector uses guidance for one muscle, they generally use it for all muscles. Conclusion: In these interim analyses, 5 muscles were identified as being most frequently injected for CD, with other muscles being injected at much lower rates. The muscles and injection method (volume and number of injection points) are in line with recommendations in the literature and did not change between visits.

On the Concept of Grounding Impedance of Multipoint Grounding Systems

An N -port equivalent circuit approach is adopted to model a multipoint grounding system, N being the number of injection points. A methodology is proposed to determine the parameters of the N -port equivalent circuit from either numerical simulations or experimental measurements. For the case of a symmetrical grounding system, analytical closed-form expressions are derived for the equivalent parameters of the N -port circuit. We show that the concept of the equivalent input impedance (harmonic impedance) could be used in the case of a symmetrical multipoint grounding system. We show also that the experimental evaluation of the impedance of a grounding system using a single injection point is a conservative engineering practice, since the obtained impedance might be overestimated at high frequencies.

Hele-Shaw flows with time-dependent free boundaries involving a multiply-connected fluid region

Consider a Hele-Shaw cell that is initially empty, and inject fluid at a number of injection points into the gap. To begin with, the plan view of the region occupied by the fluid will consist of growing circular discs, but these will then coalesce and, in general, lead to a multiply-connected geometry. Assuming a constant pressure condition to be relevant at the free boundaries, we show that the entire motion can be explicitly described analytically. When the connectivity is greater than two, the geometry is characterized by a conformal map given by a function that is automorphic with respect to a Schottky group, and we show how to construct this as a ratio of Poincaré theta series. The efficacy of our solution procedure is demonstrated by a number of examples chosen to illustrate points of both physical and mathematical interest.

An Application of Vehicle-Routing Methodology to Large-Scale Larvicide Control Programs

Because black flies transmit disease-producing parasites, many countries try to control them by treating their breeding sites. We designed a strategy to minimize larvicide treatment costs. It involves the minimization of the larvicide used and the number of injection points, achieved by combining a mortality model of larvae, a model for the behavior of the larvicide in water-courses, and a shortest-path model. The strategy also involves the minimization of the flight time for the helicopters used to deploy larvicide, performed by a state-of-the-art heuristic. This method showed potential savings of $100,000 per year on a trial three-day circuit for one helicopter, issued by the onchocerciasis control program (OCP) aerial operations in Western Africa.

Some Hele Shaw flows with time-dependent free boundaries

We consider a blob of Newtonian fluid sandwiched in the narrow gap between two plane parallel surfaces. At some initial instant, its plan-view occupies a given, simply connected domain, and its growth as further fluid is injected at a number of injection points in its interior is to be determined. It is shown that certain functionals of the domain of a purely geometric character, infinite in number, evolve in a predictable manner, and that these may be exploited in some cases of interest to yield a complete description of the motion.By invoking images, these results may be used to solve certain problems involving the growth of a blob in a gap containing barriers. Injection at a point in a half-plane bounded by a straight line, with an initially empty gap, is shown to lead to a blob whose outline is part of an elliptic lemniscate of Booth for which there is a simple geometrical construction. Injection into a quarter-plane is also considered in some detail when conditions are such that the image domain involved is simply connected.

Isotope Studies on the Efficient Use of P-Fertilizers by Coffea arabica in Kenya I. Uptake And Distribution of P32 from labelled KH2PO4

SUMMARYUptake of P32 from labelled KH2PO4 solutions, injected in the top-soil at points distributed over 4000 cm.2 in the zone of high root activity, was measurable soon after application with accumulation of P32 in leaves increasing thereafter with time. The recently-acquired P32 was distributed uniformly in the tree canopies. Uptake of P32 reached a maximum when the number of injection points was increased from 15 to 30 per tree, with 45 and 60 injection points leading to little further change in P32 content of leaves. In the zone of high root activity, strip application of P32 was as efficient as application in a circle around each tree. The practical implications of these observations in relation to P-fertilization of coffee are discussed.