Maximum Draft Research Articles

A Force Dynamometer for Three-Point Hitches

ABSTRACT A three-point hitch accessory was designed and constructed to measure draft, vertical force, and torque simultaneously and independently in a vertical longitudinal plane caused by an implement. Special features of the force dynamometer are dual-loading range and fast-hitching capability. The force dynamometer is designed for tractors in the 75- to 100 kW power range with maximum draft capacity of 66,700 N in the dynamometer's high-range and 36,000 N in the low-range.

FIBER FORMATION IN THE WET SPINNING OF NYLON 3

The fiber forming process of nylon 3 in the wet spinning process was investigated, using formic acid as the solvent and alcohols, esters and ethers as the coagulants. Following results were obtained:As for the mass transportation in the wet spinning of nylon 3, the solvent (formic acid) diffuses into the coagulant while the coagulant does not permeate into proto-fibers. Thus homogeneously deswelled proto-fibers were obtained.The maximum draft ratio is mainly affected by three factors, that is to say, coagulation power of a coagulant, molecular weight of the polymer and polymer concentration of the spinning dope. The highest value of the maximum draft ratio is attained in a definite range of the coagulation power of coagulants. By decreasing polymer concentration and molecular weight of the polymer the maximum draft ratio is increased.Cross sectional shapes of the proto-fibers are mainly affected by coagulation power of the coagulants. When coagulation power is strong, the cross sectional shape of the fibers is changed and when coagulatian power is weak, the cross sections of the fiber were dog-bone-shaped.As proto-fibers are already crystallized, it is not possible to orientate the prato-fibers by drawing in a coagulation bath.

DRY SPINNING OF NYLON 3 FIBERS

Dry spinning of nylon 3 was investigated for two samples of molecular weight of 90, 000 and 240, 000, using formic acid as solvents. With the polymer having molecular weight of 90, 000 filaments could not be wound continuously, while for the polymer of molecular weight of 240, 000 dry spinning was possible, and filaments could wound continuously. Thus the spinnability of spinning dope is thought important for dry spinning of nylon 3. Even for the maximum draft ratio (ratio of the winding speed to extrusion velosity), about 20 no chain orientation. was observed. Formic acid content in fibers was mainly controlled by spiuning temperature and by output of the dope, and was not affected by winding speed. Cross section of the fibers was dogbone-shaped for the polymer having molecular weight of 90, 000 and was extra-ordinal-shaped for the polymer of molecular weight of 240, 000. Dry-spun fibers could be drawn in such media as silicone oil and hot air, which were thought to have no interaction with polyamides, but in such media as hot water, steam and hot glycerine, which were thouget to have some interaction with polyamides, drawing was impossible, Relations between spinning conditions and properties of fibers are discussed.

EFFECTS OF MOLECULAR WEIGHT AND MOLECULAR WEIGHT DISTRIBUTION ON FIBER SPINNABILITY OF POLYPROPYLENE

This paper is concerned with the effects of melecular weight distribution (MWD) on fiber spinnability of polypropylene. Five kinds of polypropylene were melt-spun using the straight die of 1.00mm diameter with 5mm length in temperature range of 190_??_350°C at the rate of output 0.765cc/min. Details of the sample are following: Three blends (I) having nearly same viscosityaverage molecular weight _??_=1.8×105, ranging in breadth of MWD represented by the ratio of weight-to number-average molecular weight _??_ from 1.2 to 2.0 which were prepared from fractions by mixing in solution, a whole polymer (II) having _??_=3.2×105 and _??_=3_??_4, whole polymer (_??_=1.97×105) (III) from which about 10% of the lower and higher molecular weight portions were removed, respectively, a fraction (IV) having _??_=2.5×105, a fraction (V) added as much as 10% of lower molecular weight fraction (_??_=2.4×104) to (IV). According to the method described in the preceeding paper (Kamide, Inamoto; This journal, 23, 79 (1967)), maximum draft ratio (MDR), i.e. the ratio of the linear velocity at the die-wall to that at the winding wall, at which the continuous melt spinning becomes abruptly impossible, was determined as the parameter of spinnability. Spinning temperature, at which MDR>103 holds, increases with _??_ On the other hand breadth in the range of the spinning temperature corresponding to MDR>103 is independent of _??_. The optimum temperature of melt spinning (OST) is defined as the temperature at which MDR reaches maximum. OST is found to be a kind of material parameter depending on molecular weight and MWD and independent of the spinning conditions. (MDR)max of (I) is qualitatively identical with that of (IV), however, (MDR)max of (II) is by far smaller in comparison with (I) and (IV). Removal of both lower and higher molecular weight portions from the whole polymer makes (MDR)max larger and addition of lower molecular weight portion to fraction makes (MDR)max smaller. (MDR)max of the former ((IV)) is almost the same as that of (I) and (MDR)max of the latter ((V)) is almost the same as that of (II). It became evident from the experimental results described above that the contamination of the lower molecular weight portion which has no spinnability if it were melt-spun by itself is remarkably responsible for the spinnability of polypropylene.

EFFECTS OF MOLECULAR WEIGHT AND MOLECULAR WEIGHT DISTRIBUTION ON FIBER SPINNABILITY OF POLYPROPYLENE

Three kinds of polypropylene were melt spun using the straight die of 0.45mm diameter with 5mm length in the temperature range of 190 to 350°C at the rate of output 0.765cc/min. Details of the sample are following; Four fractions, ranging in molecular weight from 1.07×104 to 74×104 (I), five thermally degradated polypropylenes having molecular weight of 3.2×104 to 30.6×104 (II), of which the details of the preparation were described in the other paper (Kamide, Inamoto and Ohno; J. Chem. High Polymer, 22, 597 (1965)) and unfractioanted polypropylene (_??_=31.7×104) (III). Maximum draft ratio (MDR) is defined as the ratio of the linear velocity at the die-wall to that at the winding-wall, at which the continuous melt spinning becomes abruptly impossible. Relationship between MDR and spinning temperature (at die) (ST) closely depends on molecular weight (MW). Minimum MW having fiber formability is about 3×104 and in this case, the range of temperature suitable for melt spinning (RST) is extremely narrow (190±0.5°C). Although RST becomes wider with increased MW, RST becomes narrower again in the range _??_=40×104. Lower limit of ST, at which the continous melt spinning is possible becomes higher with increased MW. Most of the elongational deformation during the spinning ceases within 20cm. under the die, where the elongatioal viscosity is low. In the more deformed parts, the negligible orientation is observed by the birefringence measurement. The orientation may be attained after solidification and crystallization is completed. Since Poisson ratio of molten polypropylene estimated by using values of the compressibility and the Young's modulus is 0.5, the elongational viscosity at the outlet of the die is calculated as three times the shear rate viscosity (at the die-wall, shear rate is 103 sec-1 in this study), utilizing the results reported (Kamide, Inamoto, Ohno; J. Chem. High Polymer, 22, 529 (1965)) and assuming the apparent activation energy of melt flow of polypropylene as 8kcal/mole. Iso-elongational-viscous state was approximately attained at the optimum spinning temperature. when the temperature of atomosphere near the die is cooled, reduction of spinnability is observed at each spinning temperature, although the optimum spinning temperature does not change as far as the same sample was spun.

Practical Tonnage Capacity of Canalized Waterways

This paper develops the relationship between the practical tonnage capacity of a waterway and its maximum tonnage capacity. The relationship is found to be an approximate ratio of 1 to 4, that is, the PTC of a waterway is approximately 25% of its MTC. The maximum tonnage capacity is computable for all waterways. This tonnage is described as the optimum amount that can pass a lock in 365 days if each time the lock is operated, regardless of direction. Its useable chamber dimensions are completely occupied by a tow with its barges loaded to the maximum draft permitted by the waterway, each lockage is performed in the minimum possible time, and the operation continues for 24 hr each day. Waterways with restrictions such as narrow channels requiring passing places were found to have relatively lower practical tonnage capacity than the waterways developed on the Illinois and Ohio Rivers. The findings are suitable for application to studies of new waterways or the improvement of existing ones.

Miscellaneous Notes on Launching

This paper is a selection of results from actual launching in certain areas which the authors feel are not adequately covered in published information. These notes include comments on the analysis of forces acting on the members of launching poppets, on maximum grease pressures, on a simple method of timing the travel of the ship and on the maximum draft at the stern during pivoting. A side-launching facility for barges is also described.

STUDIES ON THE POLYVYNYL ALCOHOL FIBER

Generally, the conventional concentration of dry spinning solution is about 30% polymer, so the effects of the higher concentration of polymer solution than 30% was investigated.By preparation of the high concentration of polymer solution, the spinning speed which governed the productivity was increased but the maximum spinning draft which represented the spinnability was decreased. These results are explained by the formation of the solidified surface which occurs by the rapid solvent evaporation in the immediate vicinity of the spinneret. Indeed, the structural difference between the skin and the core in the cross section could be observed optically.The rate of shrinkage of fiber in spinning cell is affected by both the concentration of spinning solution and the drying condition. In consideration of the rate of shrinkage of fiber in spinning cell, the rate of extension which was the ratio of the spinning speed to the minimum spinning speed (the fiber travels down the spinning cell by gravity alone) was calculated. It was recognized that the stretchability depends upon this calculated rate of extention, although the stretchability is almost indepent of the spinning draft. Also, according to the observation of the cross section of the non extended fiber, the above mentioned structural difference is the cross section could not be observed.The tenacity or the elongation of fiber is not affected by the concentration of spinning solution.

STUDIES ON ACRYLIC FIBER(XI)

It has been generally recognized that although in the dry spinning process the length and diamenter of the spinning cell are one of the most relevant factors, in this study only a spinning cell, D1 plant shown in Fig. 1. whose length and diameter are fixed is used.The maximum draft, one of the measures of spinnability of dopes increased with the output of dopes up to intermediate quantities of output, beyond which the maximum draft decreased. This tendency varies with the kinds of dopes. The increase of output resulted in the increase of solvent content of undrawn filments because of the increase of diameter of extruded filaments. The maximum draw ratio of undrawn filaments also increaed with the output of dope because of the decrease of orientation of the molecules in the direction of the fiber axis introduced during the spinning. The spinning speeds as high as 500m/min could be accomplished. The increase of spinning speeds brought about the decrease of the diameter of filaments and the staying time of filaments in the spinning cell and the increse of draft. The elongation and the maximum draw ratio of undrawn filaments decreassed and the dry strength increased due to above mentioned factors. The diameter and the number of the jet holes used in the studies ranged 0. 12_??_0.20mm and 30_??_80 respectively. As the diameter and the number of extruded filaments became larger, the DMF content increased. It was recognized that the dimension of spinnerets was also one of the most important factors in dry spinning process.The hot air intake varies up to 3 m3/min. It was found that the DMF content in undrawn filaments not largely varies with the volume of hot air, but is remarkably influenced by the effective length of spinning cell, because the volume range of hot air used in the experiments (i. e. 0.5_??_3m3/min) is larger as compared with the volume of evaporated DMF. When hot air is led into the spinning cell counter-current to the filament, evaporation of the solvent from the filaments became slower.The spinning temperature used in the range is 140_??_220°C. The excessively high temperature in the spinning cell leads to cavit or bubble defects in the filaments due to rapid solvent evaporation. On the other hand, the lowest admissible spinning temperature could be remarkably low and in practice, it is possible to be around 140°C by choosing other spinning conditions properly. The lower spinning temperature leads to improvements in the tensile strength and elongation.The cross-section of undrawn filaments are dumbbell or bone-shaped in most cases. The ratio of longer distance to shorter distance of dumbell-shaped cross-section and the degree of skin formation varies with the solvent evaporating velocity.

ビスコース工業とレオロジー

The rheological behavior in viscose industry (especially, in rayon industry) is discussed to obtain the fundamental knowledges related to the manufactural processes.(1) Viscose (Spinning Solution)The properties of viscose rayon are influenced essentially by the network structures which are constructed in the initial spinning step and relate to the internal structure in viscose solution. It is appropriate by measuring structural viscosity, dynamic viscoelasticity, spinnability and tensile viscosity of viscose in order to detect the internal structure of viscose, which widely changes with conditions and components of viscose. It was found that there exists the considerable relation between these measuring data and maximum draft of spinning and properties of rayon, then we can explain the internal structure of viscose by a distinct conceptions.(2) Coagulation and Regeneration of Viscose (Gelation and Orientation with Spinning)At the spinning of viscose, it takes place the coagulation, orientation and regeneration of cellulose xanthate by physical and chemical reaction in contacted with spinning bath, then these transition processes are first step to fix the fiber structure and important step effecting to fiber properties. In these view point, it is possible to obtain the some suggestions for stretch spinning technics by measuring of stretching form, stress and stress relaxation, birefringence change in connection with these spinning processes.(3) Internal Structure Changes of Regenerated Cellulose FibersFiber structure is completely fixed through washing, refining and drying of regenerated fresh cellulose gels. Then, it is considered that crystallization (corning) and shrinkage of cellulose molecules take place on the several types correspond to the deswelling conditions, and reflect sharply upon the dyeability, feeling etc. From the experiments of stress relaxation, it could be estimated these slight effects of deswelling process upon the many properties of rayon fibers. And, by the measurements of both stress relaxation and stress recovery, it was found that regenerated cellulose fiber has a interesting properties, particularly in stress recovery, which shows the stress increase after returning the strain.

STUDIES ON THE MANUFACTURE OF POLYETHYLENE FIBER

The effects of melt spinning conditions on the spinning aspects by a so-called candle spinning apparatus were investigated.At the excessively high spinning temperature, molten polyethylene are decomposed by heat or air resulting in the decrease of the maximum draft on the spinning process. The polyethylene samples having smaller _??_n show larger maximum draft on melt spinning. The maximum draft of a sample having the _??_n of 41×103 amounts to about one hundred at 180°C.The maximum draft becomes smaller as the linear velocity of the molten polymer extruded through the capillaries of the spinneret becomes larger.It is also discussed how the velocity of the molten polymer in the capillaries effect the expansion of the extruded molten polymer due to the relaxation of molecular chain orientation

RELATION BETWEEN THE MAXIMUM DRAFT AND THE HOLE-DIAMETER OF VISCOSE FILAMENT AT COAGULATED AND NON-REGENERATED STATE

The effects of hole-diameter and the extrusion velocity on the maximum draft, at which all filaments break, were studied with spinometer and ammonium sulfate coagulation bath, to avoid the influence of regeneration of cellulose. The results are as follows:1) The maximum draft is determined mainly by the linear extrusion velocity, regardless of hole-diameter or delivery volume.2) Muller's bath gives slightly higher maximum draft than ammonium sulfate bath, but shows similar behavior. Therefore, the regeneration affects slightly on the maximum draft ratio.3) The maximum draft shows nearly parallel correlation with the spinnability and may be applicable as the qualitative measure.

New Royal Canadian Navy Ice-breaker

The R.C.N. ice-breaker which is being built at Marine Industries, Sorel, Quebec, will in many respects be similar to the United States Coast Guard Eastwind Class. The R.C.N. ship will include, however, some modifications which have been suggested by experience with the U.S. ships and by observations of the behaviour of these and other ice-breaking vessels. The ice-breaker will be 269 feet long with a breadth of 63 feet, 6 inches. Displacement will be 5,400 tons, and the maximum draught 29 feet. It will be propelled by a 10,000 hp. diesel-electric system. The machinery layout will be similar to that of Eastwind, but the bow propeller will be omitted. Accommodation will be provided for a crew of 13 officers and 160 other ranks and for a number of observers of officer rank; for this reason the Ward Room will be enlarged and improved. The vessel is not expected to operate single-handed against enemy concentrations, so the gun armament which was a feature of the original American ship, is to be considerably reduced. This will allow more room for quarters and stores, together with increased provision for radio and radar. A flight deck aft will take helicopters of the type now in use in the R.C.A.F. If necessary, a seaplane can be carried in place of the helicopters. As a result of experience in recent years, the shell plating on icebreakers has been increased. The new R.C.N. ship will have plates 1 5/8 inches thick and of special high-tensile steel. It seems inconceivable that any ice could penetrate such a massive steel wall, but in case it did there will be an inner skin protecting the vital parts of the ship. As with the U.S. ice-breakers the Canadian vessel will be fitted with heeling tanks as a safeguard against being frozen in. Temperatures at sea in the Arctic are not, of course, so extreme as those inland, but even so, special steps are necessary to maintain suitable temperatures inside. In the R.C.N. ship this will be effected throughout by four inches of fiberglass insulation in place of the cork formerly used. The boats carried will be of two types, motor lifeboats for use in open water, and Landing Craft specially strengthened for use in ice, where stores and personnel have to be landed. Experience has shown that this type of vessel is very useful under arctic conditions where the ice-covered beaches are very hard on conventional boats.

A comparison of experiment and calculated wave-profiles and wave-resistances for a form having parabolic waterlines

It has been found possible to calculate the wave-resistance of simple three dimensional forms, and a number of such results have boon obtained which on the whole have shown good agreement with actual measurements when the forms are such as not to violate the assumptions on which the calculations are founded. But the calculation of wave-profiles is at present limited to two dimensional forms having infinite draft. Hence for the purpose of this research two models were made, at the William Froude Laboratory one of the maximum draft possible under mechanical limitations, with vertical sides and a flat bottom, the other having the greatest draft and displacement which would allow of the measurement of its resistance over the desired range of speeds, but with vertical sides for only half its draft and being then rounded oil in vertical section to an edge at the keel. The first model (No. 1254) was used to measure wave-profiles which were compared with those calculated for a model of infinite draft; the second model (No. 1302) was used for the comparison of measured and calculated resistances. It was impossible to use the first model for tins purpose as the added resistance due to eddying round the sharp corners at the bilges would render quite meaningless any calculation of the frictional resistance which must be subtracted from the measured force to bud the wave-resistance. Its wave-resistance was, however, calculated in order to show the similarity in shape between the calculated resistance curves of the two models. Fig. 1 shows perspective sketches of these models and the equations of their surfaces appear below (equations (1) and (7) respectively).

The Wood's Hole Oceanographic Institution: Sonic Soundings, and an Account of a Winter Cruise to the Somers Islands

THE Wood's Hole Oceanographic Institution is an independent organization with its laboratory at Wood's Hole, Massachusetts, where there are also the Marine Biological Laboratory and a branch of the United States Bureau of Fisheries. The first of these has an excellent biological and oceanographical library, and by friendly co-operation this is made freely available to workers in both of the other laboratories. The Oceanographic Institution is the youngest member of the group, for it was founded in 1930 and started work in 193 I under the direction of Professor H. B. Bigelow, the finances coming from the Rockefeller Foundation. The headquarters of the Institution are not the laboratory buildings, but the research vessel Atlantis, built by Messrs. Burmeister and Wain at Copenhagen and taken over in June I931. The Atlantis is a steel, auxiliary, Bermudian-rigged ketch, I42 feet overall, with a maximum draught of 17 feet and a displacement of 460 tons. Her masts are wooden and hollow, the mainmast rising I30 feet from the deck and the mizzenmast about o00 feet. She is double ended, with no bowsprit, and she carries a jib, fore-staysail, mainsail, and mizzen, giving a total of 7200 square feet of canvas. She will sail well within five points of the wind, which is not bad for a vessel of her size and sail area, and built primarily for work; she is stiff enough, steers easily, and her 28o-h.p. Diesel engine will push her along at 8 knots in smooth water. Just abaft the engine-room is the main winch, on whose drum are wound 30,000 feet of '2-inch diameter wire, which has a breaking strain of I2 tons and is still as good as new. This is led from a short boom by the starboard main rigging, and has been used so far for heavy plankton and trawling work, dredging not having yet been attempted. On the starboard side of the mizzenmast is the hydrographic winch, which is used for all light gear, such as watersampling bottles, bottom samplers, small plankton nets, and so on, and also for hoisting the mainsail and the mizzen. On the deck on the port side, amidships, there is a nest of three Nova Scotia dories, so that all work has to be done on the starboard side, where the deck is uninterrupted between the main and mizzen rigging. After the vessel was taken over in Copenhagen, she started on a six weeks' crossing of the Atlantic from Plymouth to Wood's Hole, Massachusetts. After proceeding to a point to the westward of Ireland, the Atlantis sailed due south till she made the Azores, and then worked west and north to her destination. During the whole of this voyage stations were worked for chemical and physical observations on the sea water, samples being taken at many depths down to 2000, and in some cases 3000, metres. These observations can be added to those made by the Michael Sars, the Dana, and other research ships