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Penetration of Alkaline Solutions into Wool Fibers Determined by Changes in the Rigidity Modulus Полный текст
1955
Kärrholm, Marianne | Nordhammar, Gösta | Friberg, Ove
An apparatus is described for determination of the torsional rigidity and rigidity modulus of textile fibers. The apparatus is a modification of the torsion pendulum and is especially suitable for determination of changes in torsional moduli, e.g., after some treatment. Tests have been made on wool fibers subjected to treatments with either potassium hydroxide in ethanol or sodium hydroxide in butanol kerosene. In the first case the rigidity modulus decreased about 10% on account of the treatment, while no change occurred in the second case. The rigidity modulus is a much more sensitive indicator of changes in the outer parts of the fiber than is Young's modulus.
Показать больше [+] Меньше [-]Pectinesterase and Pectin in Commercial Citrus Juices as Determined by Methods Used at the Citrus Experiment Station
1955
Rouse, A. H. | Atkins, C. D.
Lateral Flow Above a Sloping Water Table Полный текст
1955
Luthin, James N. | Day, Paul R.
The lateral movement of water above a water table has been studied under steady-state conditions. The dependence of the capillary conductivity on soil moisture tension has been considered in making a theoretical analysis of the problem. Lateral flow was induced in a sand-filled tank by maintaining a small difference in head between constant reservoirs located on either side of the sand-filled tank. The experimentally determined values of hydraulic head and quantity of flow were then compared to the theory which considered the variations of capillary conductivity with soil moisture tension. The hydraulic head determined at various points of the flow section in the steady state experiment agreed approximately with values calculated from theory. The flow calculated from knowledge of the capillary and hydraulic conductivities agreed with the measured flow. The methods of numerical analysis which were used to develop the theory can be applied to other steady-state flow problems involving variable conductivities.
Показать больше [+] Меньше [-]The fecundity of tilapia species Полный текст
1955
Lowe, Rosemary H.
Fecundity may be defined for the purposes of this paper as the number of young produced during the lifetime of individual; this number is determined by many factors; among which the more important are, the length of the breeding seasons, the frequency of spawning during a breeding season, the number eggs laid at a spawning, and the care taken ofthe eggs before and after hatching. Under, favorable and uniform conditions Tilapia may spawn at frequent intervals throughout their reproductive life, but where there are marked seasonal changes in climate they may have a brief and well defined annual breeding season. The number of spawnings year is determined by two variables duration of the breeding seasons, which appears to depend on climatic conditions,the frequency of spawning during the season, which may be characteristic of the species.
Показать больше [+] Меньше [-]Evaluation of Yarn Properties and Processing Performance of Pima S-1 Cotton Полный текст
1955
Brown, John J. | Howell, Nathaniel A. | Fiori, Louis A. | Sands, Jack E.
Results are reported of a pilot plant evaluation of Pima S-1 cotton using an Egyptian variety, Karnak, and an American-Egyptian variety, Pima 32, as controls. The three cottons were processed alike on conventional equipment into a range of relatively fine single- and 2-ply yarns. Certain organizational details were varied within limits to aid in the evalution of the processing performance of the three cottons, and to determine the contributions each cotton made toward product quality. Each cotton was divided into three lots which were carded at 4, 6, and 8 lb/hr, respectively. Each lot was then combed, with 15 and 18% noils being removed. Twist- strength relationships were determined by spinning the yarns with a range of twist multipliers from 3.00 to 4.00 in increments of 0.25; draft-strength relationships were determined by spinning the yarns with a range of drafts from 14 to 53, using the twist multiplier found previously to produce maximum strength. The effect of the method of creeling was determined by spinning the same yarn number from a series of hank rovings both single and double creeled. Evaluation was made of gain in strength of 2-ply over single yarns using the same twist multiplier in both single and ply yarns. Also, an assessment was made of the response of these three cottons to three conditions of mercerizing and to subsequent dyeing. An analysis was made of opening-, picking-, and carding-waste percentages and of the uniformity of slivers and yarns. Yarn quality was determined by measuring skein and single-strand strengths, elongation, and appearance, and from the coefficient of variation of the strength values and Uster uniformity tester measurements. It was found that, within the limits of this study, the general processing performance of the Pima S-1 was equal to that of the Karnak and Pima 32 cottons. Regardless of the organizational variables used in the evaluation, the Pima S-1 cotton produced yarns of better appearance and uniformity than did the other two cottons. Also, yarns made from Pima S-1 were stronger than those made from Karnak, and were generally equal in strength to yarns made from Pima 32. Double creel produced stronger and more uni form yarns than did single-creel spinning for all the cotton varieties tested. The per formance of Pima S-1 in 2-ply constructions was equal to that of the two control cottons. The general response of Pima S-1 to mercerizing and to subsequent dyeing was slightly better than that of the other cottons.
Показать больше [+] Меньше [-]Temperature, light and the tomato
1955
Verkerk, K.
In good illumination, six tomato varieties all responded to an increase in day or/and night temperature by faster stem and fruit growth, earlier but smaller fruit yield with fewer fruits in shorter and lighter clusters, and a reduction in root, stem and leaf weight. Optimum temperatures for moderate growth and high fruit yield were 20°-23° C during the day and 11°-17° C during the night. The night temperature should be at least 6°C lower than during the day.In poor illumination, plants responded to an increase in light intensity or day length by higher dry weight and leaves that were less thin and darker green; leaf dry weight increased more than leaf area. Cluster size and consequently yield was the first feature to suffer considerably by light reduction. Extra artificial light in winter before planting out gave faster growth and sturdier plants which flowered and fruited earlier than controls. The less the illumination, the more important the correct day and night temperatures. Emphasis was laid on balance between vegetative and generative growth, which was determined by the ratio of light and temperature, which in itself determined the balance between photosynthesis, and growth and respiration.
Показать больше [+] Меньше [-]Temperature, light and the tomato Полный текст
1955
Verkerk, K.
In good illumination, six tomato varieties all responded to an increase in day or/and night temperature by faster stem and fruit growth, earlier but smaller fruit yield with fewer fruits in shorter and lighter clusters, and a reduction in root, stem and leaf weight. Optimum temperatures for moderate growth and high fruit yield were 20°-23° C during the day and 11°-17° C during the night. The night temperature should be at least 6°C lower than during the day.In poor illumination, plants responded to an increase in light intensity or day length by higher dry weight and leaves that were less thin and darker green; leaf dry weight increased more than leaf area. Cluster size and consequently yield was the first feature to suffer considerably by light reduction. Extra artificial light in winter before planting out gave faster growth and sturdier plants which flowered and fruited earlier than controls. The less the illumination, the more important the correct day and night temperatures. Emphasis was laid on balance between vegetative and generative growth, which was determined by the ratio of light and temperature, which in itself determined the balance between photosynthesis, and growth and respiration.
Показать больше [+] Меньше [-]Air Permeability of Parachute Gloths Полный текст
1955
Goglia, M.J. | LaVier, H.W.S. | Brown, C.D.
The air permeability of 8 standard nylon parachute cloths was determined, using samples 6.05 in. in effective diameter. Fifty-nine experimental nylon cloths manu factured by the Bally Ribbon Mills were subjected to the same test procedure, as were 2 experimental fabrics of Orlon and Dacron, and 4 different samples of wire screen. Upon assuming that the pressure gradient in the flow through a parachute fabric is proportional to the arithmetic sum of an inertial (βρυ²) and the viscous contribution (αμυ), the existence of a parameter, β/α (whose measure is length), can be inferred. This length can be employed to characterize the geometry of the cloth. Experimental work to date in the case of the 8 standard nylon cloths, the Orlon and Dacron fabrics, 14 of the Bally Ribbon cloths, and the 4 wire screen samples indicates a justification of the assumption. Employing the characteristic length so determined permits writing a single relation common to all cloths between a "flow-through-drag coefficient," Cr, and a Reynolds num ber based on the characteristic length, viz., Cf = 2 + (2/N Rₑ). A procedure is suggested for estimating the parameters α and β from physical meas urements for plain-weave cloth; thus an indication of the permeability is predicted from construction details of the fabric.
Показать больше [+] Меньше [-]Soil Properties Related to Forest Cover Type and Productivity on the Lee Forest, Snohomish County, Washington Полный текст
1955
Forristall, Floyd F. | Gessel, S. P.
Five one-tenth acre plots were established on Lee Forest to investigate forest site and type and soil relationships. One plot was in each of the following types and sites: western hemlock-Douglas fir, site class III; Douglas fir, site class II; Douglas fir, site class III; western red cedar, site class III; red alder, site class I. Soils were sampled on these plots and the following data taken: effective depth, bulk density, texture, moisture equivalent, reaction, total nitrogen, and cation exchange capacity. In addition, weight and nitrogen content of the forest floor were determined and soil moisture followed throughout the 1953 growing season. Depth to a hardpan layer was an important criterion for productivity rating. High bulk densities impeded root growth and determined effective soil depth. The critical density differed for the different tree species. Total soil nitrogen and total cation exchange capacity were much greater in the more productive forest soils. The western red cedar and the red alder plots had shallow soils with excess soil moisture during a considerable portion of the year. Low soil moisture did not appear to be a factor in tree growth on any of the plots in the 1953 growing season although the soil on the red alder plot did become quite dry in late August and early September. The dominating influence in determining forest type seemed to be poor soil drainage.
Показать больше [+] Меньше [-]The Reaction between Cellulose and Formaldehyde Полный текст
1955
Kärrholm, E Marianne
The moduli at bending, torsion, and stretching were determined for viscose rayon fiber with different amounts of formaldehyde. A maximum value of all three moduli was obtained at about 5% fixed formaldehyde. The properties at cyclic loading were also investigated. The results indicate that the number of crosslinks are increased at increasing amounts of fixed formaldehyde up to 5%. At higher values, the length of the crosslinks is increased. Formaldehyde polymers, soluble in sodium sulfite, may cause considerable changes in the mechanical properties.
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