Tentative search of torsional, axial and colcoldeviative profoundness cavity constellation bills
The glaze and steam perseverance is single of the vastst and the most globalized perseverance in the globe. Petroleum products enplug plastics, fuels, ointments and divers past. With extensions in globe population, waste and claim of petroleum products accept extensiond. Primarily petroleum products are used as disstanding sources. With an extension in claim, unanalogous, unconventional sources are life explored. Government in itself is a intricate rule attribuconsultation to the obscure coercionmations in the world. A cavity is pierced in the world with a part, and tubulars are fast to it to agree axial investigateness and revolution. The tubulars are easeness through which the government issueing is referable attributable attributableifyd to cite the steamh roll. Once the cavity is pierced, the part and tubulars are fascinated quenched, and a vastr tubular is pushed down the cavity and cemented abquenched the annulus to plug the cavity from caving in. The rule is the congruous as government a soak well-behaved-behaved bepolicy with greater profoundness, constrainings, temperatures and intricateities. Some of the glaze and steam sources are so heartfelt or so intricate to be explored, bepolicy with sdeep technological fruit in government, exuberant gain, multicoldeviative and spiritshort well-behaveds, it is now likely to cite unconventional glaze and steam.
When an nature instigates abquenched its equilibrium subject-matter, the nature is said to be in bill. In most of the subjects bills are ineligible, as they strikeion injury to the classification and disperse disposition. When investigateness or disstanding is imparted to a classification, bills appear. In scantiness of apparent inducement, the bills are determined generous bills. Classifications in particularize of generous bills instigate with eventual frequencies, which are resting on the properties of classification. With the plugness of apparent inducement, bills skilled by the classification are determined investigatenessd bills. Bills befit increasingly vast and are most detrimental when the inducement gauge is plug to single of the eventual frequencies. This curiosity-behalf is determined clang. When there is an disstanding lucidance from the classification in stipulations of ebullition, investigate, grating or any other regularity, the resulting bills are determined damped bills.
The ordinatestring constellation is a very covet, flimsy classification prsingle to inordinate bill attribuconsultation to the multitudinous investigatenesss strikeing on it. Primary investigatenesss on the BHA are torque attribuconsultation to revolution and part roll interaction, axial investigatenesss attribuconsultation to lugubriousness and colcoldeviative investigatenesss attribuconsultation to servile of the covet pipe and hitting the regards of the piercehole.
Drillstring bills are categorized fixed on the investigatenesss strikeing on it, which are Torsional, Axial and Coldeviative investigatenesss. These investigatenesss answer to the three likenesss of bill: 1) Torsional bills, 2) Axial bills and 3) Coldeviative bills.
Torsional Bills: Ordinatestring is moved from the deportment to agree torque or saccept investigateness to steamh the roll.
A lab-flake government rig was deceptive coercion the scope of competing in Ordinatebotics International Student Race. OU Ordinatebotics team participated and won the race in 2015. The budattain restrictions scant the faculty and gauge of sensors soared on the rig. The rig was upgraded in 2016 with the joined budget. The subjoined sections narrate the rig firmup and sensors established, dividing them fixed on the classifications: (i) Rig Constituency, (ii) Elevateing Classification, (iii) Rotary Classification, (iv) Prevalence Classification, (v) Gaugement, Instrumentation and Administer Classification and (vi) Ordinatestring Constellation.
Rig Constituency consists of three elder faculty: substructure, mast and journeying arrest.
In-branch built constituencys accept been root to be momentously cheaper than readymade constituencys in the trade. Pastover, the coercionmer agrees flexibility in the option of heap, impute ratings and contemplation styles. This subconstituency was contemplationed to ignoring through doors, so the rig could be used coercion coming educational scopes. The rig subconstituency was deceptive using 1Â½” balance-hearty tubing with balancetotal heap of 84″ x 27″ x 36″. To avow rig restlessness, five retail gait caster wheels were established, each with impute faculty of 1000 lbs. A 47″ x 27″ oblution made of Â¼” compstrike hearty quibble was borrowed coercion installation of prevalence classification and electrical buffet. This left the rig with a interinterspace of 37″ x 27″ x 36″ to adjudicate the roll specimen.
A mast of cantilever contemplation was deceptive quenched of Aluminium, as shown in Fig. 3.1.
Constructing the mast with aluminium deeply the importance by 2.5 durations to that made by steel. A 10-inch-wide C-Channel was befriended by brace 90 determination ceases. The disesteemed was fast to the consultation with hinges coercion reposing and unconcerned bliss of the rig.
The journeying arrest slides on a two of plain superintobject rails fast to the mast. Plain roller demeanours or pildeep arrests fast to the object of the journeying arrest agree nigh ease agitation. Brace spiritshort dishs were flyed on the upright dish. The eminent dish strikeed as a soar coercion the AC motor and inferior dish befriended the swivel. A torque sensor was located in among motor stem and swivel. The aggregate importance of the journeying arrest was gauged to be 77.72 lbs.
Hoisting classification components enplug a envelop strikeing essential-quality cylinder, pneumatic courses, a townsman of pneumatic convertors (Fig. A.1 and Fig. A.2) and a comfortable essential-quality afford course. Regulated comfortable essential-quality-course up to 130 psi was hooked up to the pneumatic convertors. Brace pneumatic courses from the convertors of consummation faculty 120 psi administerled the essential-quality issue and conjoined to the entrance ports of the dual strikeing piston. Dual strikeing essential-quality piston has a 1.125 inch pierce and a 36-inch pat tediousness. The classification has a faculty to elevate a impute of 119.28 lbs.
A culmination solicit classification was established with a 1 HP motor and a consummation RPM of 1170 on the motor soar of the journeying arrest. The motor stem is conjoined to the omega torque sensor via a issue coupling. The torque sensor has a rotating stem to stem conshape with an unobstructed hasten of 5000 RPM. The torque sensor is conjoined to the swivel via another issue coupling. The swivel was contemplationed and affected in-branch with constraining rating of 300 psi and impudence quencheder subject coercion decay hindrance. The chrome dishd rod is wear-resistant to the exfoliation of the seals. Swivel rod is fast to an adapter at the disesteemed of the profoundness dish. A immodest fly flange soared sphere demeanour obviates any impute from life epidemic to the rotary constellation.
It is main to transport steamhtings from the cavity to ordinate advance afront. To conclude this, soak, glaze and sparkle fixed government issueings were fascinated into importance. Soak from the city course withquenched any additives was selected as government issueing behind preamble consume of a plugd loop classification coercion reprevalence and consume of additives and disesteemed issueings into representation. It was to-boot antecedent that the commodities of government issueing on ordinatestring bills was negligible.
A roller interrogate with a constraining rating of 300 psi was established to referable attributable attributableify the soak down the ordinatestring constellation. A 1.5 HP 3-phase motor powers the interrogate. The Omega digital vault issue meter, which was established behind the interrogate, can adviser issuerate up to 15 GPM. Constraining advisering is dsingle by a constraining transducer of rating 500 psi. Constraining contents of up to 50 psi was beholdd attribuconsultation to occasional issue supposing by the roller interrogate. A constraining dampener was built with niggardly couplings and established upstream to the issue meter. This agreed ease and sconsultation issue. An analog constraining fathom was soared aculmination the dampener to adviser contents. Rubber hose with a constraining rating of 300 psi connects the issue meter with the swivel. Government issueing from the swivel then issues into the ordinatestring and comes quenched of the part nozzles and quenched of the cavity through the annulus. As the government issueing is impartial soak, it is ignoringed down the sewer course acovet with the steamhtings and referable attributable attributable attributable recirculated.
The Gaugement, Instrumentation and Administer classification is the most main classification in the automated rig. The sensors are soared on the rig at multitudinous locates coercion unanalogous functions. They agree analog grounds to the grounds merit module Omega DAQ-3001. An electrical buffet is soared at the profoundness oblution coercion shielding the card and other eminent plighters from electrical interference. The grounds from the DAQ module transfers into the deskculmination computer, which is established on the rig constituency coercion administer of the automated rig and storage and vault of grounds. Exceed-fixed VBA program is used coercion the production of the rig.
Subjoined are the sensors established on the rig to adviser accomplishment of the rig and government rule.
184.108.40.206 Dismemberment Laser Sensor
An aluminum fleece is fast to the culmination of the journeying arrest with a inapprehensive tape collect on it. A Banner laser sensor is soared abquenched 0.5 inches balance the journeying arrest on the mast. It can gauge consummation dismemberment up to 3.93 inches with an coerceesight among 0.019 inch to 0.039 inch.
220.127.116.11 Coldeviative Bill Laser Sensor
To gauge colcoldeviative bills of the ordinatestring, an xyz laser sensor is used. It can gauge interval from 1.57 inch to 6.29 inch with an coerceesight of short than 20 micrometer. The sensor was antecedent soared on an aluminium dish fast to the journeying constellation. Bepolicy the fleece was covet and inordinate bills attribuconsultation to part roll interrenewal strikeiond the fleece to swing at violent largeness, providing fallacious and fallacious grounds. Hence the soaring constituency was made of a balance hearty tubing to concede a sturdier constituency. The bill largeness was then deeply and could be beholdd singly at inordinate bills attribuconsultation to violenter RPM and WOB.
18.104.22.168 Optical RPM Sensor
An LED-based, inapprehensive likeness optical RPM sensor, which can gauge up to 15000 RPM, is soared on the incarcerate of swivel. Inapprehensive tape is collect on the issue coupling among the swivel and torque sensor. The sensor is soared at an determination so that the inapprehensive area extensions coercion rectify gaugement.
22.214.171.124 Torque Sensor
It is antecedent that torque gauged by the torque sensor is the torque attribuconsultation to part-roll interaction. An Omega rotating stem to stem torque sensor has been soared balance the swivel with a torque rating of 64 inch-pounds.
126.96.36.199 Axial Bill Sensor
An axial bill senor is established at the profoundness dish of the journeying arrest nigh to the flange soared sphere demeanour. The VBT-1 bill sensor has a micro-electro-mechanical classification which despatchs a voltage proportional to the bill accelerate to the grounds merit module. It gauges bill accelerate from 0-25 mm/sec.
The ordinatestring constellation comprises of 3 faculty, Aluminum pipe, part sub and part.
The pipe is made of Aluminum 6061 with an OD of 0.375 inch and a compactness of 0.035 inch. Twain objects of the pipe accept 3/8″ NPT male compression fittings fast on it. It is conjoined on single object to 3/8″ NPT womanish impudence adapter which is conjoined to the swivel rod and other object is conjoined to 3/8″ NPT womanish facultyub.
The part sub is made quenched of stainshort steel coercion decay hindrance. It has 3/8″ womanish NPT threads on twain objects. A roller sleeve with OD of 1.1 inch and ID of 0.9 inch is slide upon the part sub to strike as a stabilizer and agree ease revolution. It has a unanalogous pierce to locate constriction of multitudinous sizes to veer constraining distil in the classification.
The part is affected in branch using stainshort steel spherical cease and machined to invert the baker huges part agreed coercion the race. The steamhters were bought from vendors and the OD of the steamhters profitable was 0.5 inch. They are made quenched of carbide as unanalogous to the diamond steamhters agreed and to-boot wears down faster. The steamhters are screwed on the steamhter faces and are replaceable.
This chapter narrates the act of the tests pied and the grounds firm. It to-boot talks abquenched some assumptions, sensor calibration and grounds segregation.
The rig and total its components are powered on and the Exceed program indoctrinated. The program has a disunited quibble which takes the capriciouss of the tentative ooze as an input. The singly capriciouss veerd coercion the firm of tests are RPM and WOB. Another capricious, which is the elevation at which the string starts to move was to-boot been divers bepolicy it did referable attributable attributable attributable accept any commodities on the grounds.
A lead cavity of 1.25-inch transversion and 1-inch profoundness was pierced into the roll specimen using a coring part and hammer-chisel to incorporate a superintobject shoe in the cavity. The 6-inch covet superintobject shoe strikeed as a piercecavity wtotal and obviateed part walking. Using a equalize indicator, the roll specimen was adjusted to be spiritless.
The ordinatestring was the fast to the swivel adapter and rig was then slid balance the roll to align the ordinatestring and the superintobject shoe. Using the equalizeing screws the rig was jacked up to be spiritless.
The entrance essential-quality constraining course and soak course were opened up. Once total tentative capriciouss were firm, the program was indoctrinated using the Start besideton. The primitive trudge of the program was to elevate the journeying arrest to the culminationmost standing. At this subject-subject a insurance cease used to tobject the journeying arrest elevateed was fascinated detached. The journeying arrest reluctantly inferiored down and once the part was internally the superintobject shoe, culmination-solicit motor and interrogate motor got strikeivated and string launched to move acovet with soak pressurized internally the pipe. The part fragmentarily crazy the roll and government rule began.
A essay ooze was carried quenched to hinder if the classifications were started properly and grounds was life firm. A townsman of millimeters were pierced during the essay ooze so that the cavity got indoctrinated.
Behind a essay ooze, tentative oozes were carried quenched. Each test was ooze coercion 6 min and plugped using the Plug besideton in the program. The interrogate plugped interrogateing issueing and ordinatestring plugped revolution. Journeying arrest was fragmentarily lifted up to the culminationmost standing. Behind that stcollocate tentative capriciouss were firm and the plain ooze was carried quenched.
Experiments were pied on 2 unanalogous roll specimens. Primitive firm on a very inexplicable and compacted sandstsingle and the other on a very luxurious unconsolidated sandstone. UCS of the inexplicable sandstsingle collocated from 6000 to 9500 psi conjuncture UCS coercion the luxurious sandstsingle collocated from 2000 to 5000 psi.
Grounds was uninterruptedly firm by Omega grounds merit classification module and stored in an exceed quibble. The grounds of curiosity-behalf were WOB, RPM, Torque, Axial Bills, Coldeviative Bills and ROP. Unanalogous frames were generated counter capriciouss of curiosity-behalf to behold stopency and renewal of the capricious inferior search.
WOB is an inresting capricious with regard to our search. WOB was gauged using a impute cell fast to the object journeying arrest connecting the piston. The calibration of WOB was carried quenched in the subjoined act. The rig was slid on a theory flake. A firm estimate of appraises were entered coercion voltage sent to the profoundness pneumatic convertors. A fixed voltage of 2 volts was sent to the culmination pneumatic convertor to agree a fixed constraining of 20 psi hindrance counter aberrant wellrounded and to agree a fixed grating among piston and cylinder regards in either coerce. Balbutiation on the theory flake was recoded as WOB. Judiciously the WOB calibration was pied in a static plight. It was beholdd that WOB balbutiation during the test was unanalogous than the expected appraises fixed on calibration. It was antecedent that the veer of plights from static to dynamic was the strikeion of estrangement. Hence to counterfeit dynamic plights conjuncture calibration, rig was fixedly hammered down with a mallet to strikeion the rig to swing and negate static grating. The stabilized balbutiation on the flake was used coercion calibration. Bepolicy hammering stationary did referable attributable attributable attributable invert the bills happening during the government rule and hence the WOB gaugement by the impute cell was unanalogous from expected fixed on the calibration. Hence mean appraise of the WOB was adapted coercion total tentative ooze and considered as the WOB which is life exerted on the roll coercion steamhting rule.
The mean WOB beholdd had a veer of 19.9 % to -20.6 % from the expected input appraises. In strikeual government rule, the WOB is never fixed. As the government pay the WOB inferiors and ordinateer inferiors the ordinate string to extension and tobject the firm WOB. Hence a Â± 20 % veer from the firm subject-subject is delicious.
RPM grounds was achieveed from the optical RPM sensor which was calibrated using a handheld RPM sensor. At inferior RPM the blunder was abquenched 8 % and at violenter RPM it inferiored down to 0.5 %. So at inferior equalizes the firm subject-subject was inferiord by 4 to satisfy coercion the blunder.
A rotating stem to stem torque sensor was located in among the motor and swivel with a issue coupling on each object. Torque was calibrated using a torque twist. When ooze at void plights withquenched any government strikeion, torque balbutiation achieveed was antecedent to be grating. That extra torque of 1.114 inch pounds was antecedent to be a policy investigateness or the grating internally the swivel and other rotating faculty such as the flange soared sphere demeanour.
A laser dismemberment senor was fast to the mast to expose the heap of colcoldeviative bills. It was aimed at the kernel of the ordinatestring such the pipe was frequently in collocate of the laser. The laser sensor was kept 4 inches detached from the kernel of pipe. NPT connections are inherently nonsensesense concentric and strikeions nonsense-alignment of pipe. The pipe wobbled attribuconsultation to nonsense-alignment and it instigated remote and nigh to the sensor. Hence there was a disclaiming and a fixed appraise coercion dismemberment. The most disclaiming appraise of the dismemberment was used as a allusion cipher and total grounds was shifted towards fixed with -0.24165 inch as a allusion cipher. Greater the heap, pipe travelled remotether detached from the sensor indicating violenter colcoldeviative bills.
An axial bill sensor was fast to the profoundness dish of the journeying arrest. It had micro-electro-mechanical classification internally to expose the bill hasten and sobject a proportional voltage eminent coercion gaugement. The sensor came calibrated from the manufacturer and it had a plain bill-accelerate to voltage relation agreed by the manufacturer.
ROP was plainly adapted by the program by dividing the profoundness pierced by the duration it sok to ordinate and stored in the Exceed quibble. As the Inexplicable sandstsingle was unmanageable to ordinate the sensor could referable attributable attributable attributable gauge any momentous veer in pierced profoundness acovet with the bills of the constellation and the blunder in gaugement. Hence ROP grounds coercion Inexplicable sandstsingle is referable attributable attributable attributable fascinated into importance. Luxurious sandstsingle grounds was firm and analyzed coercion commodities of bills and other parameters.
Grounds was firm from the subject-subject where the part touches the roll to the subject-subject when the program was plugped. Total tests were ooze coercion 6 minutes in which an mean of 100 grounds subject-matters were firm in an exceed quibble. An mean of those grounds was adapted and stored. Mean appraises of torque, axial bills and colcoldeviative bills were frameted counter RPM and WOB disunitedly. A trobject of grounds was analyzed fixed on the frames. With extension of RPM, veer of torque, axial and colcoldeviative bill was beholdd. Congruous custom was carried quenched coercion WOB. The frames are shown in Appendix B.
Inexplicable Sandstone: Looking at the frames (Fig. 5.1), with an extension in RPM at fixed WOB, torque fragmentarily extensions. At abquenched 300 RPM, there is a hasty extension in some subjects which then inferiors. This renewal is abrupt and no misentry has been root coercion the debate coercion the abnormality. It can be antecedent that there would be some abnormally inexplicable flake during government attribuconsultation to which such an extension is beholdd as no such trobject was beholdd in the even luxurious sandstone. Bepolicy unconcealed trobject is a progressive extension in torque with an extension of RPM at fixed WOB. No oscillation of torque was beholdd indicating scantiness of stick-slip.
At fixed RPM, with extension in WOB there is a progressive extension in torque (Fig. 5.2). No inequitable trobject coercion RPM is beholdd as some of the deep RPM subjects to-boot accept violenter torque than violent RPM subjects.
Luxurious sandstone: Observing the frame coercion luxurious sandstsingle (Fig. 5.3), a progressive extension in torque was beholdd with extension in ROM at fixed WOB. No oscillation of torque was beholdd indicating scantiness of stick-slip.
Figure 5.3: Torque vs. RPM frame at fixed WOB coercion tests on luxurious sandstone
There is a lucid and perspicuous trobject coercion extension in torque with extension in WOB at fixed RPM (Fig. 5.4).
Figure 5.4: Torque vs. WOB frame at fixed RPM coercion tests on luxurious sandstone
Inexplicable Sandstone: Frame (Fig. 5.5) shows that there is a progressive extension of torque with extension in RPM at fixed WOB.
Figure 5.5: Coldeviative Bills vs. RPM frame at fixed WOB coercion tests on inexplicable sandstone
No unconcealed trobject is beholdd coercion judicious deep WOB tests (Fig. 5.6). With extension in WOB the colcoldeviative bills inferiord in deep RPM subject and extensiond in violent RPM subjects.
Figure 5.6: Coldeviative Bills vs. WOB frame at fixed RPM coercion tests on inexplicable sandstone
Luxurious sandstone: There is a unconcealed trobject of extension of colcoldeviative bills with extension in RPM (Fig. 5.7) bepolicy it is referable attributable attributable attributable as momentous as in inexplicable sandstone.
Figure 5.7: Coldeviative Bills vs. RPM frame at fixed WOB coercion tests on luxurious sandstone
The grounds is so licentious to perceive a unconcealed trobject coercion commodities of WOB on colcoldeviative bills at fixed RPM (Fig. 5.8). However, the trobject at violenter WOB shows a inferior in colcoldeviative bills. This can be attributed to the stiffening of the pipe attribuconsultation to violenter axial impute OR the pipe is direction and misaligned is making it bobject past on the sensor policy decreasing the deviation.
Figure 5.8: Coldeviative Bills vs. WOB frame at fixed RPM coercion tests on luxurious sandstone
Inexplicable Sandstone: Axial bills foldeep a congruous trobject to torque (Fig. 5.9). With an extension in RPM, axial bills extensiond. Congruous to the trobject coercion torque, some subjects accept abnormally violent bill heap at 300 RPM which can be attributed to abnormally inexplicable flake of coercionmation.
Figure 5.9: Axial Bills vs. RPM frame at fixed WOB coercion tests on inexplicable sandstone
Subjoined the unconcealed trobject axial bills extensiond with an extension in WOB at fixed RPM (Fig. 5.10).
Figure 5.10: Axial Bills vs. WOB frame at fixed RPM coercion tests on inexplicable sandstone
Luxurious sandstone: With extension in RPM, axial bills extensiond (Fig. 5.11). However coercion luxurious sandstsingle the trobject do referable attributable attributable attributable reproduce-exhimorsel the trobject in torque. In truth, it reproduce-exhibits past to the trobject in ROP (Fig. B.10). There is a hasty extension in axial bills at 700 rpm and then it inferiors fragmentarily.
Figure 5.11: Axial Bills vs. RPM frame at fixed WOB coercion tests on luxurious sandstone
The grounds is so licentious to perceive a unconcealed trobject coercion relation among WOB and axial bills (Fig. 5.12).
Figure 5.12: Axial Bills vs. WOB frame at fixed RPM coercion tests on luxurious sandstone
Inexplicable Sandstone: No momentous grounds profitable coercion any segregation.
Luxurious sandstone: ROP extensions with an extension in RPM at fixed WOB (Fig. 5.13). It peaks at abquenched 700 RPM and then it inferiors.
Figure 5.13: ROP vs. RPM frame at fixed WOB coercion tests on luxurious sandstone
At violenter RPM, violenter WOB has an extensiond commodities on ROP (Fig. 5.14). Bepolicy no trust of WOB can be seen at inferior appraises of RPM.
Figure 5.14: ROP vs. WOB frame at fixed RPM coercion tests on luxurious sandstone
- At fixed WOB, with extension in RPM, extension in colcoldeviative bills in inexplicable sandstsingle is violenter than in luxurious sandstsingle which indicates that colcoldeviative bills to-boot depobject on likeness of coercionmation.
- Axial bills are violently resting on torque. No subject what RPM, WOB or the coercionmation likeness is fascinated into representation if there a veer in torque, answering veer attain be beholdd in axial bills.
- WOB has short commodities on inducement of axial bills in luxurious rolls and past commodities in inexplicable rolls. Hence the firmsubject-subject WOB should be inferiord coercion government into inexplicable rolls.
- RPM of 700 is the violentest RPM which can be used to achieve violentest ROP withquenched preamble the extensiond bills into representation. Extension of RPM advance inferiors the ROP which can be attributed to such extensiond bills and velocities that the part does referable attributable attributable attributable attain ample duration to contstrike and draw the roll deportment.
Although the contemplation of the rig was optimized, there is frequently margin coercion progress. With an extension in budattain and scant contemplation constraints, the rig can be deceptive rectify. Subjoined are the recommendations coercion upgrading the rig.
- The luxuriousware program used coercion the administer algorithm can be upgraded to Labview or Dasylab which are past user favorable coercion programming the automation and administer architechture.
- Using Labview or Dasy lab attain avow to produce on a faster computer with a novel unobstructed classification which attain acceleration in faster grounds store and storage.
- A vibrating part can be fast to the journeying arrest when WOB calibration is pied so that blunder attribuconsultation to veer in grating appraises can be negated.
- The issue couplings fast to the torque can be upgraded with a violenter torque rating to obviate scarcity at violenter bills.
- A sconsultation maintenance constituency coercion the torque sensor and laser deviation sensor can be agreed.
If the part can be achieveed or simulated with diamond coated steamhters, then a firm of tests can be contemplationed where relation could be examined among RPM, WOB and the profoundness of steamh.
Forward and objectward gyrate characterization tests could be pied with improved sensors coercion exposeion of gyrate rates.
Hammering strikeion can be enclosed in the government strikeion and its commodities on ROP, colcoldeviative bills, torque and axial bills could be analyzed.
Braun, Simon G. Ewins, David J. Rao, Singiresu S.. (2002). Encyclopedia of Bill, Volumes 1-