Drillability prediction in some metamorphic rocks using composite penetration rate index(CPRI)–An approach

Assessment of drillability of rocks is vital in the selection,operation,and performance evaluation of cutting tools used in various excavation machinery deployed in mining and tunneling.The commonly used rock drillability prediction methods,namely,drilling rate index(DRI)and Cerchar hardness index(CHI)have limitations in predicting the penetration rate due to differential wear of the cutting tool in rocks with varied hardness and abrasivity.Since cutting tools get blunt differently in different rocks,the stress beneath the tip of the bit decreases until it reaches a threshold value beyond which the penetration rate becomes constant.In this research,a new composite penetration rate index(CPRI)is suggested based on the investigations on four metamorphic rocks viz.quartzite,gneiss,schist and phyllite with varied hardness-abrasivity values.The penetration-time behavior was classified into active,moderate,passive,and dormant phases based on the reduction in penetration rate at different stages of drilling.A comparison of predicted penetration rate values using DRI and CPRI with actual penetration rate values clearly establishes the supremacy of CPRI.Micro-structure and hardness-based index was also developed and correlated with CPRI.The new indices can help predict cutting tool penetration and its consumption more accurately.

Switching variability index based multiple strategy CFAR detector

A switching variability index （SVl） constant false alarm rate （CFAR） detector is proposed for improving the detection performance of VI-CFAR detectors in multiple targets backgrounds. When the presence of non-homogeneity in CFAR reference windows is indicated by a VI-CFAR detector, a switching- CFAR detector is introduced to optimize the performance of the VI-CFAR detector in homogeneous, multiple targets and clutter edge backgrounds. The structure and parameters selection method of the SVI-CFAR detector is presented. Comparisons with classic CFAR detectors and recently proposed detectors are also given. Theoretical analysis and simulation results show that SVICFAR detector maintains the good performance of the VI-CFAR detector in homogeneous and clutter edge backgrounds, while greatly improving the capacity of anti-multi targets.

Experimental study on the degree and damage-control mechanisms of fuzzy-ball-induced damage in single and multi-layer commingled tight reservoirs

Fuzzy-ball working fluids(FBWFs)have been successfully applied in different development phases of tight reservoirs.Field reports revealed that FBWFs satisfactorily met all the operational and reservoir damage control requirements during their application.However,the damage-control mechanisms and degree of formation damage caused by fuzzy-ball fluids have not been investigated in lab-scale studies so far.In this study,the degree of fuzzy-ball-induced damage in single-and double-layer reservoirs was evaluated through core flooding experiments that were based on permeability and flow rate indexes.Additionally,its damage mechanisms were observed via scanning electron microscope and energy-dispersive spectroscopy tests.The results show that:(1)For single-layer reservoirs,the FBWF induced weak damage on coals and medium-to-weak damage on sandstones,and the difference of the damage in permeability or flow rate index on coals and sandstones is below 1%.Moreover,the minimum permeability recovery rate was above 66%.(2)For double-layer commingled reservoirs,the flow rate index revealed weak damage and the overall damage in double-layer was lower than the single-layer reservoirs.(3)There is no significant alteration in the microscopic structure of fuzzy-ball saturated cores with no evidence of fines migration.The dissolution of lead and sulfur occurred in coal samples,while tellurium in sandstone,aluminum,and magnesium in carbonate.However,the precipitation of aluminum,magnesium,and sodium occurred in sandstone but no precipitates found in coal and carbonate.The temporal plugging and dispersion characteristics of the FBWFs enable the generation of reservoir protection layers that will minimize formation damage due to solid and fluid invasion.

Wavelet and pain rating index for inhalation anesthesia: A randomized controlled trial

BACKGROUND Wavelet index(WLi)and pain rating index(PRi)are new parameters for regulating general anesthesia depth based on wavelet analysis.AIM To investigate the safety and efficacy of using WLi or PRi in sevoflurane anesthesia.METHODS This randomized controlled trial enrolled 66 patients scheduled for elective posterior lumbar interbody fusion surgery under sevoflurane anesthesia between September 2017 and February 2018.A random number generator was used to assign the eligible patients to three groups:Systolic blood pressure(SBP)monitoring group,WLi monitoring group,and PRi monitoring group.The main anesthesiologist was aware of the patient grouping and intervention used.The primary endpoint was anesthesia recovery time.Secondary endpoints included extubation time,sevoflurane consumption,number of unwanted events/interventions,number of adverse events and postoperative visual analogue scale for pain.RESULTS A total of 62 patients were included in the final analysis(SBP group,n=21;WLi group,n=21;and PRi group,n=20).There were no significant differences among the three groups in patient age,gender distribution,body mass index,American Society of Anesthesiologists class,duration of surgery,or duration of anesthesia.Anesthesia recovery time was shorter in the WLi and PRi groups than in the SBP group with no significant difference between the WLi and PRi groups.Extubation time was shorter in the WLi and PRi groups than in the SBP group.Sevoflurane consumption was lower in the WLi and PRi groups than in the SBP group.Nicardipine was more commonly needed to treat hypertension in the WLi and PRi groups than in the SBP group.CONCLUSION Regulation of sevoflurane anesthesia depth with WLi or PRi reduced anesthesia recovery time,extubation time and sevoflurane consumption without intraoperative unwanted events.

Quick System-Level DDR3 Signal Integrity Simulation Research

Double data rate synchronous dynamic random access memory （DDR3） has become one of the most mainstream applications in current server and computer systems. In order to quickly set up a system-level signal integrity （SI） simulation flow for the DDR3 interface, two system-level SI simulation methodologies, which are board-level S-parameter extraction in the frequency-domain and system-level simulation assumptions in the time domain, are introduced in this paper. By comparing the flow of Speed2000 and PowerSI/Hspice, PowerSI is chosen for the printed circuit board （PCB） board-level S-parameter extraction, while Tektronix oscilloscope （TDS7404） is used for the DDR3 waveform measurement. The lab measurement shows good agreement between simulation and measurement. The study shows that the combination of PowerSI and Hspice is recommended for quick system-level DDR3 SI simulation.

Effect of seed treatment for laboratory germination of Albizia chinensis

Seeds of Albizia chinensis（Osb.） Merr. in addition to water were also treated with different treatments by incubating in ethyl alcohol, acetone, and petroleum ether at room temperature for different durations. Seed heat treatment was done at temperatures of 30, 40 and 60℃ for different durations up to 24 h. To overcome dormancy caused by the impermeable seed coat, seeds were nicked and also treated with concen- trated sulphuric acid for different durations. Seeds responded to treat- ments with sulphuric acid and nicking only. Treatment with sulphuric acid for 20 and 30 min showed maximum germination at all incubation temperatures as compared to untreated controls and seeds treated with sulphuric acid for 10 min and nicking. Seedling length was greatest from seeds treated with sulphuric acid for 20 and 30 min and incubated at 30 ℃. Seedling dry weight was highest from nicked seeds incubated at 20℃ The most favourable incubation temperature was 30 ℃ as evidenced from GR （germination rate index） and Gv （germination value）. After ascertaining the seed response and performance we recommend that seeds ofAlbizia chinensis be treated with sulphuric acid for 20 or 30 min and incubation temperature of 25 to 30℃.

Observations of TEC Depletion,Periodic Structure of TEC,ROTI and Scintillation Associated with ESF Irregularities over South China

The observations of Global Positioning System(GPS) scintillation,Total Electron Content(TEC)depletion,the periodic structure of TEC and Rate of TEC Index(ROTI) over south China were presented.Data were collected from GPS observations at stations of Shenzhen and Guangzhou from 2011 to 2012.This study reported that the ratio of simultaneous occurrences of TEC depletions with strong scintillations was higher than that of TEC depletions with weak scintillations in vernal and autumnal equinoxes of 2011 over South China.The number of the periodic structures of TEC with depletion contained was greater than that with no depletion contained corresponding to strong scintillations.The structure of the slab of plasma irregularities could be responsible for the simultaneous occurrences of TEC depletion with strong scintillations and ROTI.Before and during the occurrences of strong scintillation,there was Large-Scale Wave Structure(LSWS) which provided the seed ionization perturbation to trigger ESF irregularities and contributed to the periodic structure of TEC.

Kinetics of Soil Potassium Release Under Long-Term Imbalanced Fertilization in Calcareous Soils

Knowledge on potassium ion(K^+) release from soils makes K fertilizer recommendation more efficient and profitable.Kinetics of K^+release under continuous fertilization of no fertilizer(CK), urea(N), triple superphosphate(P), and urea + triple superphosphate(NP) without K fertilizer was investigated in calcareous(chloritic and kaolinitic) soils on the Miandarband Plain in Kermanshah Province of Iran.The results showed that the kinetics of K^+release included an initial reaction and a slow reaction.The phosphateand NH_4^+-induced K^+release followed the same rate process during the rapid(2–192 h) and slow release periods(192–1 090 h).There were no significant differences in the cumulative K^+released from the chloritic and kaolinitic soils among all the treatments.The cumulative K^+released was positively correlated with P adsorption capacity for the chloritic(r = 0.461, P < 0.05) and kaolinitic soils(r = 0.625, P < 0.01), and negatively correlated with K fixation potential for the chloritic(r = 0.720, P < 0.01) and kaolinitic soils(r =-0.513, P < 0.01).There was a significant(P < 0.001) interactive effect of K fixation potential × P adsorption capacity on the cumulative K^+released for both soil groups.The initial release rate(IRR) index(a·b, where a and b are the rate coefficients of the power function equation) for the chloritic soils was significantly(P < 0.05) higher under applications of P and NP than N and CK.The IRR index values among different fertilization treatments were in the order of NP = P > N = CK for the chloritic soils, and N =P > NP > CK for the kaolinitic soils.This study showed that K fixation potential and P adsorption capacities controlled K^+release from soils.This information will be helpful for precise fertilizer recommendations for the studied soils.