Rupture Disc Research Articles

Shale 2.0: From Efficient to Effective Shale Development

Guest editorial Hydrocarbons from shale were first produced commercially as long ago as 1821, and from the 1860s through the 1920s gas was produced from shallow, low-pressure, naturally fractured shales in the eastern US. However, today’s shale “revolution” did not really begin until 1985. That was when George Mitchell started developing a model for economically viable exploitation of the Barnett Shale. It took almost 20 years and literally hundreds of wells to find the right formula, based on two transformative technologies: horizontal drilling and multistage hydraulic fracturing. Shale 1.0: The Quest for Operational Efficiency Since roughly 2005—the beginning of what I call Shale 1.0—we have successfully revived old shale plays and developed new ones. Every year, North American companies complete thousands of wells in shale reservoirs. However, even in mature plays like the Barnett, where productivity per well has doubled or tripled over the past decade, as many as 30% of all perforation clusters contribute absolutely nothing to production. That is the same as drilling 30 totally nonproductive wells out of every 100. To improve shale economics, operators and oilfield service companies have focused considerable brainpower and technical resources on reducing the unit cost of production through greater operational efficiency. In many cases, we have brought drilling and completion costs down 50%, largely through application of new technologies, efficient project management, and supply chain negotiations. In some cases, advanced drilling technologies, automation, and real-time data have slashed average time to total depth from 48 days to just 8. Not all new technologies are exotic. For example, installation of rupture disk valves—which replace coiled tubing or drillpipe-conveyed perforations for the first stage in horizontal wells—reduced completion costs in 15 Eagle Ford wells by more than USD 100,000 per well. The shale revolution has yielded many economic and social benefits, including growth in jobs and local businesses across the US, lower domestic energy costs, reduced CO2 emissions, and—perhaps most important—access to a new national resource that holds enormous potential for long-term energy security. According to the Institute for Energy Research, the US has more than 200 years’ capacity of technically recoverable oil reserves and 110 years’ worth of natural gas at current rates of consumption, much of those from unconventional plays. In fact, shale oil is leading the current growth in US crude production. The US Energy Information Administration conservatively predicts global shale oil production will reach more than 4 million BOPD by 2030. Other analysts double that estimate.

자연발화 점화기 및 파열판 기술 동향

Survey on the hypergolic igniter and its rupture discs for liquid rocket engines was performed. The patents of the igniters for US MC-1 and Russia RD-170 engines and the discs for NASA`s space vehicle were analyzed. The types of discs and holders, characteristics related to rupture pressures and working fluids, and ASME standards of the discs were examined. Also, survey on structural analyses of the disc were performed. Typical design features and experimental results of the currently developing igniter by the authors were presented.

Transfer of a β-glucuronidase marker gene to triticale (xTriticosecale Wittmack) via particle bombardment (biolistic) method

Abstract This study was carried out to investigte the biotechnology laboratory of Department of Field Crops, Ankara University with the aim of investigating the optimum parameters of gene transfer to mature embryo and leaf segment explants of Triticale (x Triticosecale Wittmack) via particle bombardment (Biolistic) method. Mature embryo and leaf segment explants obtained from Triticale (x Triticosecale Wittmack) were bombardment with accelerated gold or tungsten particles coated with the plasmid pBI221.23 containing the b -glucuronidase (GUS: u idA ) marker gene. Different bombardment distances from the stopping plate (6, 9, 12, cm) and different rupture disk pressures (900, 1100, 1550 psi ) were used as physical parameters. Blue cells expressing the b -glucuronidase gene were detected by using a histochemical assay. The variation in the number of blue spots in bombarded explants was used to determine the gene transfer efficiency. The mature embryos of triticale were found to be more amenable for the direct delivery of foreign DNA by the particle bombardment technique than the leaf segments. Also the gold particles were more suitable than tungsten particles in the gene transfer efficiency. The highest gene transfer results were obtained in mature embryos when 6 cm bombardment distance and 1100 psi rupture disk pressure were used.

Rupture Disk Valve Improves Plug-and-Perf Applications

Technology Update Plug-and-perf completions have proved to be the most flexible multistage well completion schemes. The main reason is that each stage can be perforated and treated optimally because options can be exercised right up to the moment the perforating gun is fired. This allows the engineer to apply knowledge from each previous stage to the stage under treatment. For example, using real-time microseismic fracture mapping techniques provides a view of where previous fractures have propagated, which enables adjustments to be made to perforating depth and pumping schedules for subsequent stages. Some people have argued that the plug-and-perf technique is too time consuming and that it is too slow at the start because of the need to run the first stage perforating guns in with coiled tubing, stick pipe, or a downhole tractor, thus adding an unnecessary expense. A new technique introduced by Schlumberger adds significant operating efficiency and lowers the cost of cemented, multistage fracturing by eliminating the initial perforating run. The technique uses the KickStart pressure-activated rupture disk valve to enable the first stage treatment to be combined with casing operations. In addition to reducing downtime, the technique has been shown to lower fracture initiation pressure, thereby eliminating the risk of closed perforation tunnels caused by shale swelling, and to increase the likelihood of fracturing the stage to completion. The extensive study of geomechanics has shown that rock formations fracture at their weakest point and that the weakest point aligns with the plane of maximum horizontal stress whenever the overburden (vertical) stress exceeds lateral stresses, which occurs most of the time. The pressure-activated rupture disk valve has a unique helical port design that exposes the formation outside the casing to fracture pressure, thereby ensuring that the fracture will align with the maximum horizontal stress plane and propagate at the weakest point in the formation. A major benefit of this alignment is the reduction of tortuosity at the fracture initiation point, which significantly reduces the probability of a premature screenout of the initial fracture treatment at the toe of the completion.

Efficient in vitro plant regeneration and generation of transgenic plants in barley (Hordeum vulgare L.) using particle bombardment

Plant regeneration from immature embryos of 15 Indian barley genotypes (Hordeum vulgare L.) was examined. Highest percent callus induction and number of regenerated plantlets were obtained in cultivars BL 2 (94.4 %; 12.1), RD 2668 (92.6 %; 9.1) and RD 2552 (90.8 %; 7.8). The highly responding cultivar BL 2 was selected for further development of transformation protocol. The plasmid DNA isolated from pCAMBIA1381 harbouring hptII gene as selectable marker and gusA gene as reporter was used. Particle bombardment was used for transformation of immature embryos and regeneration of transgenic plants in Indian barley genotype for the first time. Transformation experiments were carried out using different parameters and optimum conditions for DNA delivery was standardized. The transient expression of gusA gene was investigated as a preliminary test of optimum DNA delivery and for selecting the most appropriate bombardment parameters. The optimum conditions were: gold microparticles (diameter 1.0 μm) shot with 1,100 psi rupture disc pressure. The 3 cm distance between rupture disk and macrocarrier and 9 cm target tissue distance yielded high transient GUS expression. The immature embryos were bombarded twice to increase area for efficient gene delivery. Osmotic medium optimization with 0.4 M sorbitol and preculture of immature embryos for 5 days prior to bombardment resulted into efficient gene transfer in barley. Selection of transformed tissue was performed after 7 days resting step on selection medium containing 50 mg l−1 hygromycin. After two more selection steps, green shoots were rooted on MSB5 medium with 50 mg l−1 hygromycin. PCR analysis using primers specific for hptII and gusA genes and Southern blot analysis with hptII probes confirmed the stable integration of transgene in barley genome. Molecular analysis of T1 generation plantlets revealed the amplification of selectable marker hptII gene in the progeny.

아크릴산 제조공정 사고사례를 통한 소각 시스템의 안전성 향상 방안

최근 대기환경규제의 강화로 화학공장에서 발생하는 폐가스를 소각 처리하는 경우가 증대되고 있다. 이러한 소각설비는 저장탱크 상부와 배관을 통해 연결되어 화염을 통하여 폐가스를 연소 소각시키기 때문에, 배관을 따라 화염이 역화될 경우에는 치명적인 사고로 연결될 수 있다. 본 연구는 아크릴산 제조공정의 소각시스템에서 발생한 중대산업사고에 대해 폭발의 3요소와 화염의 전파 원인을 분석하여 사고 예방대책 및 안전성 향상 방안을 다음과 같이 제시하였다. 첫째, 소각시스템의 송풍기를 재 가동하기 전에는 공기 또는 불활성 가스로 충분히 희석하여 폭발을 예방하여야 한다. 둘째, 폭굉으로 전이된 화염이 저장탱크로 전파되지 않도록 소각설비의 전단 및 저장탱크 상부에 폭굉용 화염방지기를 설치하는 것이 필요하다. 섯째, 폭연용 화염방지기를 그대로 사용할 경우에는 그 전단에 파열판을 설치하거나 저장탱크 상부와 소각설비의 배관을 후드식으로 연결하여 폭굉으로 전이된 화염을 저장탱크 밖으로 분출시켜야 한다. 마지막으로, 소각설비에 연결된 송풍기의 제어반(MCC)에 순간정전 보상장치인 시간지연계전기(TDR: time delay relay)등을 설치하여 순간정전 후에도 자동으로 재가동될 수 있도록 조치해야 한다. Recently, waste gas incineration is increasing due to strong environmental regulatory system in Korea. These incinerating facilities are usually connected with the top of the storage tank through pipeline and incinerate off gas with the flame. Therefore, the flame originated from these facilities is likely to move back into pipeline and might cause an explosion of the storage tank. Accordingly, the purpose of this study is to suggest the preventive measures and the way to improve the safety of these incineration systems through the cause analysis of a major industrial accident occurred in a acrylic acid manufacturing process in Korea. As a result of the study, the preventive measures are suggested as follows. (1) Air or inert gas inflow facilities should be well designed to dilute flammable gases into air or inert gas sufficiently before the blower is restarted in order to prevent the explosion (2) It is needed for the detonation-type flame arresters to be installed on the top of the storage tanks. (3) In case of using the deflagration-type flame arresters, it is necessary to install a rupture disk before the arresters, or blow off the flame outside tanks by connecting the tank top and the incinerator with hood-type pipe. (4) TDR should be installed to be restarted automatically after the momentary power failure.

Plastid transformation of tomato (Solanum lycopersicum L.) with HIV-1 p24 gene by biolistic particle delivery system

Plastid transformation in tomato (Solanum Lycopersicum L.) is carried out using vector carrying HIV-1 p24 gene and a selection of aadA gene, spectinomycin for resistance to antibiotics, and streptomycin. We used the hepta adaptor to replace the rupture disk retaining cap and microcarrier launch assembly. Three days after bombardment, the leaves and cotyledons were cut into small pieces each of 3 × 3 mm and placed on medium MS salts and B5 vitamins containing 2.0 mg/l Zeatin, 0.2 mg/l IAA, 50 mg/l spectinomycin for leaves, and medium MS salts and B5 vitamins containing 2.0 mg/l BAP, 1.0 mg/l IAA, 0.5mg/l Kinetin, 50 mg/l spectinomycin for cotyledons. Selected further time on the medium containing spectinomycin was up to 300 mg/l. PCR analysis of aadA and HIV-1 p24 genes of the tomato plastid transformation lines showed the presence of DNA amplification with the corresponding 250bp and 700bp. Southern blot analysis confirmed that the foreign genes were inserted into the tomato plastid genome. The result indicated the presence of HIV-1 p24 in the tomato plastid genome with the presence of DNA band of 5.8 kb. However, it is heteroplasmic transformant because it has a DNA band of 3.5 kb of wide type plant.

탄소성해석을 이용한 파열판의 파열예측

파열판은 고압장치에서 안전장치로써 사용하고 있으며, 추진기관에서는 파열을 임의로 제어하기 위한 장치로써 사용한다. 본 논문은 파열판의 파열압력 시험결과와 유한요소해석 결과를 비교하기 위한 것이다. 본 논문에서는 AISI 316L을 이용하여 제작한 파열판의 파열시험을 수행하였으며, 탄소성 물성치와 진 응력-변형률 관계의 다양한 가정을 이용하여 파열판의 파열압력을 계산하였다. 파열시험과 탄소성해석 결과를 통하여 파열판의 크기에 대한 파열압력의 변화를 확인하였다. 시험과 유한요소해석을 통해 파열압력은 파열판의 크기에 의존하며, 탄소성해석을 수행한 결과 다중 선형 응력-변형률 선도만이 의미있는 예측치를 계산할 수 있었다. 파열시험을 통하여 파열판의 크기에 따라 파열위치가 다르다는 것을 확인할 수 있었다. 시험과 해석 결과는 파열판의 크기 변화를 통하여 파열판의 파열압력을 제어하기 위해 사용할 수 있다. Rupture disks are a kind of safety device in high pressure equipment and they are used to control rupture pressure in the solid rocket motor. In this paper, a series of rupture experiments was performed using rupture disks made of AISI 316L and rupture pressure of rupture disks was calculated through various assumptions in relation between elasto-plastic material properties and true stress-strain curve. Experiment and FEA indicated rupture pressure is determined by size of rupture disks. As a result of elasto-plastic analysis, only multi-linear stress-strain curve was able to calculate meaningful estimations. Experimental results also showed rupture location are decided by the size of rupture disks. Experimental and FEA results will be applied to control rupture pressure of disks.

Development of sodium leak detectors for PFBR

The 500MWe Prototype Fast Breeder Reactor (PFBR) is under advanced stage of construction at Kalpakkam near Chennai in India. The wide and high operating temperature, highly chemically active nature of sodium and its reaction with air make the sodium instrumentation complex over the conventional instrumentation. Over the years, traditional instruments such as wire type leak detectors, spark plug type leak detectors were developed and used in different sodium systems. The redundant and diverse leak detection method calls for development of special instrumentation for sodium systems which include sodium ionization (leak) detector for detecting minute sodium leak in addition to those systems based on mutual inductance principle. For detection of sodium leak from reactor Main Vessel (MV), diverse methods are used such as miniature, remotely locatable, Mutual Inductance type Leak Detector(MILD) and specially modified spark plug type leak detector. The design of MILD is suitably modified for detecting leak in double wall pipes and Diverse Safety Rod drive Mechanism (DSRDM). Steam/water leak in steam generator produces hydrogen and leads to high pressure and temperature in the system. Rupture disc is used as a safety device which punctures itself due to sudden pressure rise. To detect the discharge of sodium and its reaction products at the downstream of the rupture disc due to bursting of the rupture disc, cross wire type leak detector has been designed, developed and tested. The selection of the leak detection system depends on the location where leak has to be detected. This paper describes the recent developments carried out in leak detector systems to meet the challenges involved in developing robust sensors for PFBR including miniaturization of leak detectors and the ability to locate or withdraw them remotely through a long guide tube with complex profile.

Use of dynamic simulation for reactor safety analysis

Dynamic simulations of chemical processes are widely used to develop effective plantwide control structures that provide stable regulatory control at some desired operating condition. This paper illustrates that they can also serve a very useful role in the analysis of safety problems in the event of emergency situations. The dynamic response of the process when various failures occur is critical to the design of safety systems for the process (alarms, overrides, interlocks, safety valves and rupture disks). For example, a failure of the supply of cooling water will lead to rapid increases in pressures and temperatures in the process. Determining the rates of increase in these important variables and the time period to reach critical limits (safety response time) permits the engineer to quantitatively design effective safety systems.Chemical reactors are typically the most sensitive and potentially the most dangerous units in many processes, particularly when exothermic reactions and low per-pass reactant conversions are involved. This paper illustrates how Aspen Dynamic simulation can be used for predicting the dynamic changes in critical variables. Dynamic emergency safety simulations are presented for five processes with several types of cooled reactors (CSTR and tubular) and residence times varying from 0.16 to 60min. Safety response times vary from several seconds to several minutes, depending on both the reactor, the system in which it is installed and the level of reactant conversion.

A study on the grooving process of a cross-scored rupture disc

High-pressure facilities such as pressure vessels and storage equipment are widely used in all areas of manufacturing. Although many safety regulations have been enacted, mechanical defects and system operator errors sometimes cause industrial disasters. Since industrial disasters at high-pressure facilities cause greater loss of life and property, the installation of pressure-relief devices is mandatory. A rupture disc (also known as a bursting disc) is a type of non-reclosing pressure-relief device, equipped with a leak-tight seal. It is designed to prevent disasters and damage to equipment by immediate, complete rupture when the internal pressure of the plumbing reaches a predetermined level. Various types of rupture discs are cross-scored, and are activated by the reversal of a dome shape and pressure load. They are designed with an X-shaped groove on their surfaces to facilitate bursting without fragmentation. In this research, the processing characteristics of the grooving process, one of the major processes in the production of a cross-scored rupture disc, are investigated via experiments and finite element analysis (FEA) to obtain a design basis for cross-scored rupture discs required by high-pressure facilities with varying kinds of performance. The mechanical properties and chemical composition of the stainless steel used to produce cross-scored rupture discs are determined with a tensile testing machine and an electron microscope. The characteristics of the grooving process are then measured and compared with FEA results.

Optimization of factors influencing microprojectile bombardment-mediated genetic transformation of seed-derived callus and regeneration of transgenic plants in Eleusine coracana (L.) Gaertn

Microprojectile bombardment mediated genetic transformation parameters have been standardized for seed derived callus of Eleusine coracana. Plasmid pCAMBIA 1381 harboring hygromycin phosphotransferase (hptII) as selectable marker gene and β-glucuronidase (gus A) as reporter gene, was used for the optimization of gene transfer conditions. The transient GUS expression and survival of putative transformants were taken into consideration for the assessment of parameters. Optimum conditions for the microprojectile bombardment mediated genetic transformation of finger millet were 1,100 psi rupture disk pressure with 3 cm distance from rupture disk to macrocarrier and 12 cm microprojectile travel distance. Double bombardment with gold particles of 1.0 μm size provided maximum transient GUS expression and transformation efficiency. Osmotic treatment of callus with 0.4 M sorbitol enhanced efficiency of particle bombardment mediated genetic transformation. Regenerative calli were bombarded at optimum conditions of bombardment and placed on regeneration medium with hygromycin to obtain transformed plants. The integration of hptII and gus A genes was confirmed with PCR amplification of 684 and 634 bp sizes of the bands respectively from putative transformants and Southern blot hybridization using PCR amplified DIG labeled hptII gene as probe. PCR analysis with hptII gene specific primers indicated the presence of transgene in T1 generation plants. Thus a successful genetic transformation system was developed using particle bombardment in E. coracana with 45.3% transformation efficiency. The protocol will be helpful for the introgression of desired genes into E. coracana.

Experimental study on the blowdown load during the steam generator feedwater line break accident in the evolutionary pressurized water reactor

Integral effect tests using the ATLAS facility were performed to obtain the thermal-hydraulic parameters such as dynamic and static pressures, local temperatures, and flow rates during a feedwater line break of a steam generator. The break of a feedwater line was simulated using a double rupture disc assembly in order to satisfy the requirements for the break opening time of around a few milliseconds. In the present study, estimated break opening time was less than 1.5ms and broken areas were 48.1% and 93.4% of the feedwater line, respectively. The maximum dynamic pressures of about 1.57bar were obtained inside of feedwater box that was closest to the break location of the feedwater line. After the break of the feedwater line, propagation of the pressure wave along the distance from the break location inside the steam generator was clearly and pertinently observed in all the tests. From a structural integrity point of view, however, the risk induced by this maximum dynamic load could be treated to be insignificant.Based on the present experimental data, an analysis was performed using the best-estimate thermal-hydraulic system code, MARS 3.1 with an aim of qualitatively validating the test results and also evaluating the blowdown load prediction capability of the best-estimate system code in the simulation of steam generator feedwater line break. Calculation results on overall trends of the dynamic pressure behavior are comparable with the test results which indicate the feasibility of dynamic load prediction using the MARS code. As the break opening time became shorter and the broken area became larger, the dynamic pressures were calculated to be significant values in the sensitivity analyzes.

Finite Element Analysis for the Influence of the Clamping Holder Corner on the Bulging of Thin Metal Shells

Peripherally clamped thin shallow hyperbolic metal shells under internal pressure are widely used as rupture discs, quick opening devices and the structures in metal plastic processing. In the bulging process of shells, if the corner radius of the up-holder is too large, negative-curvature zone close to boundary will be enlarged. Contrarily, if the radius is too small, shear rupture will happen in the clamped rim. The contact between the shell and the up-holder corner in deformation is explored by elasto-plastic finite element analysis, and the results are verified with experiments. Influence of the up-holder corner on the mechanical behavior of bulging shells is closely related to the non-dimensional parameter ru/s0 (ratio of the corner radius ru to the original thickness s0). The influence can be partitioned into four regions by three demarcation points, ru/s0 = 0.52, 1.50, and 2.00. The four regions are respectively full effect region, unstable region, near-stable region, and no effect region.

Twenty five years of operating experience with the Fast Breeder Test Reactor

Abstract Sodium cooled fast breeder reactors constitute the second stage of India's three -stage nuclear energy programme, for effective utilization of the country's limited reserves of natural uranium and exploitation of its large reserves of thorium. The Fast Breeder Test Reactor (FBTR) at Indira Gandhi Centre for Atomic Research (IGCAR), Kalpakkam, is a loop type, sodium cooled fast reactor. Its main aim is to provide experience in fast reactor operation, large scale sodium handling and to serve as a test bed for irradiation of fast reactor fuels & materials. FBTR was built on the lines of the French Rapsodie-Fortissimo reactor, with modifications to make it a generating plant. FBTR went critical on 18th Oct 1985 with a small core of 22 fuel subassemblies of a unique, high Pu carbide fuel. The core was rated for 10.5 MWt. The TG was rolled and synchronized to the grid in July 1997. Reactor power was progressively increased by enlarging the core, to reach 18.6 MWt. Several challenges in reactor operation came on the way, which were successfully overcome. A large number of modifications were carried out to improve the plant performance. The reactor coolant used (Sodium) is highly reactive when exposed to atmosphere and also becomes highly active on exposure to neutron radiation. These properties of sodium make it essential to handle it carefully and safely within a leak tight containment. During course of operation of the reactor, a number of sodium laden components viz. pumps, valves, cold traps, Rupture discs, level probes, shielding plugs, control rod drive mechanisms, experimental assemblies, piping etc. are required to be removed for various maintenance, modification and replacement jobs. This paper details the experience with operation and maintenance of India's only one fast reactor power station.

Experimental investigation on the self-ignition of pressurized hydrogen released by the failure of a rupture disk through tubes

Hydrogen is expected to be used as a clean energy carrier. However, when high-pressure hydrogen is suddenly released into the air through tubes, self-ignition can occur by a diffusion ignition mechanism. In this paper, the phenomena of self-ignition and flame propagation during the sudden release of high-pressure hydrogen were investigated experimentally. Experimental results show that self-ignition can occur when bursting pressure is sufficiently high in spite of the shortness of the tube. For example, self-ignition was observed at a bursting pressure as high as 23.5 MPa with 50 mm long tube. When self-ignition successfully occurs, a hydrogen jet flame is produced by the ignition. The flame is then stabilized at the tube outlet. From photodiode signals and flame images, the propagation of a flame inside the tube is confirmed and the flame is detected near the rupture disk as the bursting pressure increases. When the tube length is not long enough to produce self-ignition, a hydrogen flame is observed in the only boundary layer at the end of tube and it quenches after the flame exits the tube. Consequently, the formation of a complete flame across the tube is important to initiate self-ignition, which sustains a diffusion flame after jetting out of the tube into the air. Also, in order to establish a complete flame across the tube, it is necessary to have sufficient length such that the mixing region is generated by multi-dimensional shock–shock interactions.

Physics of spontaneous ignition of high-pressure hydrogen release and transition to jet fire

The aim of this study is to gain an insight into the physical phenomena underlying the spontaneous ignition of hydrogen following a sudden release from high-pressure storage and transition to sustained jet fire. The modelling and large-eddy simulation (LES) of the spontaneous ignition dynamics in a tube with a non-inertial rupture disk separating the high-pressure hydrogen storage and the atmosphere is described. Numerical experiments confirmed that due to the stagnation conditions a chemical reaction first commences in the tube boundary layer, and subsequently propagates throughout the tube cross-section. The dynamics of flame formation outside the tube, simulated by the LES model, has reproduced the combustion patterns, including vortex induced “flame separation”, which have been experimentally observed by high-speed photography. It is concluded that the LES model can be applied for hydrogen safety engineering, e.g. for the development of innovative pressure relief devices.

Microprojectile bombardment mediated genetic transformation of embryo axes and plant regeneration in cumin (Cuminum cyminum L.)

Pre-cultured cumin embryos were bombarded under 27 inches Hg vacuum, 25 mm distance from rupture disc to macrocarrier, 10 mm macrocarrier flight distance using 1100 psi rupture disc and 9 cm microprojectile travel distance. An average of 110 embryos was used per shot and 91% embryos showed transient GUS expression after 24 h. Shoot tips and roots of T0 plantlets exhibited GUS expression done after 3 months of bombardment. Transformation was confirmed with PCR amplification of 0.96 and 1.3 kb band of hptII and gus genes respectively from T0 transgenics and southern blot analysis using PCR amplified DIG labeled hptII gene as probe. It is the first successful attempt of transformation of cumin plant through direct gene transfer using particle gene gun and adequately exhibiting the possibility of stable transformation in cumin.

Experimental and theoretical investigation of gas–liquid flow pressure drop across rupture discs

Experiments of air–water two-phase flow pressure drop through rupture discs have been carried out. The tested rupture discs of DN 25 and DN 40 are made of graphite with and without vacuum support. The experiments were performed under the following conditions of two-phase parameters; mass flux from 2000 up to 4000 kg/m 2 s, quality from 1 to 20% and system pressure from 3 to 7 bar. The results demonstrate that the effect of the above-mentioned parameters is very significant at high ranges of mass flow quality, due to the increasing of two-phase flow resistance, energy dissipations, friction losses and interaction of the two phases. Based on the presented experimental results and the data published in the literature, new correlation has been developed to calculate the two-phase pressure across rupture discs. The model includes the relevant primary influencing parameter, fit the data well, and is sufficiency accurate for engineering purposes. The reproductive accuracy of the proposed model and the statistical comparison, based on about 1000 measured data in the literature, demonstrated that the proposed model is the best overall agreement with the data. The standard deviation of the data is less than 10%. The results reported enable practical designs with standard products and optimization of the geometry of the rupture discs installed in nuclear reactors.

Alternative Techniques for Injecting Massive Quantities of Gas for Plasma-Disruption Mitigation

Injection of massive quantities of noble gases or D2 has proven to be effective at mitigating some of the deleterious effects of disruptions in tokamaks. Two alternative methods that might offer some advantages over the present technique for massive gas injection are ?shattering? massive pellets and employing close-coupled rupture disks. Laboratory testing has been carried out to evaluate their feasibility. For the study of massive pellets, a pipe-gun pellet injector cooled with a cryogenic refrigerator was fitted with a relatively large barrel (16.5-mm bore), and D2 and Ne pellets were made and were accelerated to speeds of ~ 600 and 300 m/s, respectively. Based on the successful proof-of-principle testing with the injector and a special double-impact target to shatter pellets, a similar system has been prepared and installed on DIII-D, with preliminary experiments already carried out. To study the applicability of rupture disks for disruption mitigation, a simple test apparatus was assembled in the laboratory. Commercially available rupture disks of 1-in nominal diameter were tested at conditions relevant for the application on tokamaks, including tests with Ar and He gases and rupture pressures of ~ 54 bar. Some technical and practical issues of implementing this technique on a tokamak are discussed.