Conduit Channel Research Articles

Porphyry and Epithermal Au-Cu Systems of the Southern Caucasus and Northern Iran

This article presents tangible geological evidence for coexistence of porphyry copper and epithermal gold systems within single polygenic deposits and provides a paleothermophysical model for their origins. Brief metallogenic analysis of the Southern Caucasus and Northern Iran has shown that such deposits are confined to long-living calc-alkaline island arcs and were formed during their orogenesis. Examples of complex Sonajil (Iran), Gharta, and Merisi (Georgia) deposits are considered. Investigation has shown that for combined porphyry and epithermal ore formation some preconditions are suggested to exist: (i) Source of anomalous energy, which exceeds thermodynamics of the enclosing environment; (ii) Existence of temperature gradient, which determines conventional flows of fluids composed of endogenous and meteoric constituents (proven by rhythmical zoning of ore lodes); (iii) Stability of such conditions for a period of sulfide ore formation. However, such a process of sulfide ore formation cannot explain formation of high sulfidation gold deposits. Mass precipitation of free gold requires phreatic collapse in the ore conduit channel already after formation of hydrothermally altered rocks, and this event results in creation of either hydrothermal breccias, often with jigsaw-fit texture or brecciated vuggy silica where host rocks and hydrothermally altered rocks are cemented by a gold-bearing quartz matrix.

3D collagen porous scaffold carrying PLGA-PTX/SDF-1α recruits and promotes neural stem cell differentiation for spinal cord injury repair

Spinal Cord Injury (SCI), one of the major factors of disability, can cause irreversible motor and sensory impairment. There are no effective therapeutic drugs and technologies available in domestic or foreign countries currently. Neural stem cells (NSCs), with the potential for multidirectional differentiation, are a potential treatment for SCI. However, it has been demonstrated that NSCs primarily differentiated into astrocytes rather than neurons due to the inflammatory microenvironment, and the current challenge remains to direct the differentiation of NSCs into neurons in the lesion site. It was reported that the microtubule-stabilizing agent paclitaxel (PTX) was able to promote the differentiation of NSCs into neurons rather than astrocytes after SCI. SDF-1α can recruit NSCs and thus guide the migration of stem cells. In this study, we developed a functional collagen scaffold by loading SDF-1α and nanoparticle-encapsulated PLGA-PTX into a 3D collagen porous scaffold, allowing for slow release of PTX. When the functional scaffolds were implanted into the injury site, it provided a neural regeneration conduit channel for the migration of NSCs and neuronal differentiation. Neural regeneration promoted the recovery of motor function and reduced glial scar formation after SCI. In conclusion, a 3D collagen porous scaffold combined with PLGA-PTX and SDF-1α is a promising therapeutic strategy for SCI repair.

PERENCANAAN ULANG BANGUNAN PENGAMBILAN BERTIPE MORNING GLORY MENGGUNAKAN PONDASI BORED PILE PADA BENDUNGAN LOGUNG

The existing square tower of intake has 1,397.57m3 volume and using shallow foundation Logung Dam with its weight stability will cause inefficient structures and potential to earthquake force effect. It is necessary to have an alternative planning of the intake tower. The authors intends to redesign the intake with morning glory type and used bored pile; to find out the position of intake tower, dimension, reinforcement, duration, cost estimate, and to compare the redesign.The required data were of topographic map, irrigation, and raw water discharge, bearing capacity, and work unit price analysis of project 2016. Manning Method was applied to find out the dimension; Shell Slab Method with Column Approach to calculate the structure of the intake tower, and Skempton Method to calculate bearing capacity. The redesign results in the position of ∅ 1.75-m intake tower on conduit channel with 728,08 m3 volume; the dominant load of operational-earthquake combination with different values; D22-200 steel bar for y-direction, D19-150 for x-direction on conduit channel, D19-150 for x,y-direction on intake tower segment 1, D16-150 for x,y-direction on intake tower segment 2, and D13-150 for x,y-direction on intake tower segment 3; on 105 workdays; at a total cost of IDR 2,327,806,700 with 40.64 % efficiency cost.

Study of the relation between hydraulic jump and the flood water level in the river on the downstream of a spillway

Kuningan Dam which is located in Kuningan District, West Java has 21,8 km2 watershed area. This dam also acts as a flood control facility which functions supported by the reservoir’s topography and its spillway building. The spillway building releases excess water from the dam into the downstream area. In the downstream part of the spillway, usually, hydraulic jump phenomenon occurs which depends on the flood water level of the river. The hydraulic jump used in the designing process of stilling basin length. The stilling basin in the spillway building generally designed using Q100. The spillway in Kuningan Dam is designed as a closed conduit channel. In this study, the Kuningan Dam spillway is re-designed as an open channel using ogee type spillway. Based on the modeling result, the length of hydraulic jump that occurs when modeled with the return period discharge of Q25 is 21.54 m, Q50 is 16.65 m, and Q100 is 0.98 m. It is seen that in Q25 the jump was the furthest, so an elaborate study regarding hydraulic jump phenomenon and design standards of the spillway is required.

Long-term efficacy of polydimethylsiloxane (Macroplastique) injection for Mitrofanoff leakage after continent urinary diversion surgery.

To assess the long-term efficacy of polydimethylsiloxane (Macroplastique) injection (MPI) in the treatment of Mitrofanoff leakage secondary to valve incompetence. Between 1995 and 2012, the records of 24 consecutive patients who underwent MPI for Mitrofanoff urinary leakage after continent cutaneous urinary diversion (CCUD) surgery were examined. All patients had a valve deemed of sufficient length (>2 cm) to attempt Macroplastique coaptation. Treatment outcomes were divided into three categories based on physician assessment: success (dry), partial success (>50% reduction in incontinence pads) and failure. Success rates were assessed according to the type of reservoir and conduit channel. The mean (range) follow-up was 30 (6-96) months. One patient had initial difficulty catheterising, and subsequently required major revision surgery. In all, 12 patients (50%) failed the treatment and subsequently underwent operative revision to the channel. Three patients (12.5%) achieved complete success; one patient had an appendix channel through native bladder and the remaining two had Monti channels through colon. Nine patients (37.5%) had partial success; success rates were higher with appendix channels (four of six) and colonic reservoirs (six of seven) when compared with Monti channels (eight of 18, 44%) and ileal reservoirs (zero of two). Five of the nine patients with partial success eventually required further surgical revision for deteriorating continence at a mean (range) of 41 (14-96) months, whilst the other four have maintained sufficient continence with MPI alone. Macroplastique bulking cured only 12.5% patients, but leakage was substantially improved in a further 37.5% allowing major surgery to be avoided or postponed in one half of the cohort. Appendix Mitrofanoffs do better than the Monti Mitrofanoff, with channels through colonic segments generally doing better than those through ileal bladders. MPI should be considered as a less invasive alternative to avoid or delay major reconstructive surgery.

The feedback effect caused by bed load on a turbulent liquid flow

Experiments on the effects due solely to a mobile granular layer on a liquid flow are presented (feedback effect). Nonintrusive measurements were performed in a closed conduit channel of rectangular cross section where grains were transported as bed load by a turbulent water flow. The water velocity profiles were measured over fixed and mobile granular beds of same granulometry by Particle Image Velocimetry. The spatial resolution of the measurements allowed the experimental quantification of the feedback effect. The present findings are of importance for predicting the bed-load transport rate and the pressure drop in activities related to the conveyance of grains.

Study of the Hydrodynamic Parameters of Nonstationary Isoentropic Flow of a Viscous Polymer in the Melt Conduits of Melting and Molding Machines

A method was developed for calculating the characteristics of the flow rate and pressures of a viscous polymer based on the numerical control volume method, which allows considering the volume change in the form of flow and the force effect in it. The method was tested for standard MSM (MF-600-KSh24, MF-1000-KK18). The results obtained are sufficiently close to the process parameters of the machines. The method can be recommended for design calculations for melt conduits in both ordinary and in high-speed MSM. The pressure change in nonstandard situations of blocking of the melt conduit channel is similar to the phenomenon of hydrohammering and is subject to consideration in determining the wall thickness and selecting the construction materials for melt conduits, especially for high-output MSM. The dynamic flow characteristics indicate that the traditional structure of the automatic regulation system should be replaced by a compensation system, which will allow increasing the quality of the fibre in a wide range of MSM outputs.