Cube Unit Research Articles

Prediction of hardness and durability of alfalfa cubes processed from fractionated sun-cured and dehydrated alfalfa chops

Analysis of hardness and durability values of cubes manufactured from fractionated sun-cured and dehydrated alfalfa chops was performed to determine predictive equations. The initial moisture contents of dehydrated and sun-cured chops were 6% and 7% (wet basis), respectively. A forage particle separator was used to fractionate (separate) leaf and stem fractions. The leaf and stem fractions were combined to obtain five different samples each for sun-cured and dehydrated alfalfa with leaf content ranging from 0% to 100% in increments of 25% by mass. A single cubing unit having die dimensions of 30 mm by 30 mm in cross section and an effective depth of compression of 0.38 m was designed and constructed. A hydraulic cubing machine was used to apply compressive pressures of 9.0, 12.0 and 14.0 MPa on the sample chops. After compression, the plunger was held in place for 10 and 30 s, before the compacted forage was extracted. The lowest hardness and durability values for dehydrated and sun-cured cubes were obtained at leaf contents of 50% and 100%, respectively. Statistical analysis was conducted considering hardness and durability as dependent variables and pressures, holding time and leaf content as independent variables to determine best-fit regression equations.

A new method of creating expandable structure for spatial objects

This paper presents a new method of creating expandable structure for spatial objects which are constructed by connecting a serial of parallelogram mechanisms whose edges are all equal in length with revolute joints. Any spatial object can be constructed with a certain number of basic cube units, and each basic cube unit is designed into an expandable one by being constructed with parallelogram mechanisms. By designing the basic cube unit in certain ways, not only can it be expanded and contracted synchronously, but also it can be expanded in some parts and contracted in others. During expansion, the basic cube unit is mobile with one degree of freedom. As a result, any spatial object assembled with these basic cube units is created into expandable structure, and that the entire structure can be expanded and contracted without being affected, even if there are some broken parts in it. To verify the feasibility of the method, two examples are provided.

Compression of fractionated sun-cured and dehydrated alfalfa chops into cubes—Specific energy models

The objective of this study was to determine the specific energy requirements for the compression of fractionated sun-cured and dehydrated alfalfa chops, when subjected to different pressures and holding times. The compression behavior of fractionated sun-cured and dehydrated alfalfa chops was studied using a single cubing unit capable of making one cube in a single stroke of the plunger. The cube die dimensions were 30 mm × 30 mm in cross-section and an effective depth of compression of 0.38 m. The initial moisture content of dehydrated and sun-cured chops were 6% and 7% (wb), respectively. A stack of two sieves (instead of five) was used along with a pan to achieve leaf and stem separation. The nominal opening sizes of two sieves with square holes were 3.96 and 1.17 mm, respectively. Leaf and stem fractions were combined later to obtain five different samples each for sun-cured and dehydrated alfalfa with leaf content ranging from 0% to 100% by mass in increments of 25%. The chop moisture content and preheat temperature before compaction was 10% (wb) and 75 °C, respectively. The cube die temperature was maintained at 90 ± 5 °C. The mass of chops used for making each cube was 23 ± 02 g. A hydraulic press was used to apply 9.0, 12.0 and 14.0 MPa of pressures through a plunger. After compression, the plunger was held in place for 10 and 30 s, before the compacted forage was extracted. Empirical equations were fitted to the data relating specific energy for cube making to pressure, residence time, and leaf content.

CUBING CHARACTERISTICS OF FRACTIONATED SUN-CURED AND DEHYDRATED ALFALFA CHOPS

A single cubing unit was designed and constructed to study the cubing characteristics of fractionated sun-curedand dehydrated alfalfa chops. The moisture content of dehydrated and sun-cured chops were 6% and 7% (wet basis),respectively. A forage particle separator was used to separate leaf and stem fractions. The leaf and stem fractions werecombined to get five different samples each for sun-cured and dehydrated alfalfa with leaf content ranging from 0 to 100%in increments of 25%. A hydraulic cubing machine with a maximum capacity of 14.0 MPa was used to apply compressivepressures on the chops. The effect of chop moisture content (6%, 10%, and 14%), leaf content (0, 25%, 50%, 75%, and 100%),chop preheat temperature (50.C, 75.C, and 100.C), cube die temperature (75.C, 90.C, 150.C, and 200.C), applied pressure(2.5, 5.0, 7.5, 9.0, 10.0, 12.0, and 14.0 MPa) and chop residence time in the cubing unit (10, 12, 15, and 30 s) on cube qualitywas studied. Cube quality was assessed based on its density, color, long fiber content, durability and hardness. Results weresubjected to statistical analysis to determine the effect of the processing and material variables on cube quality. The densityof dehydrated and sun-cured cubes increased with an increase in pressure, residence time, leaf content and cube dietemperature. Cube hardness increased with an increase in pressure and residence time. Cube durability increased with anincrease in pressure, residence time, and die temperature. Change in leaf content had an insignificant effect on cubedurability, except for dehydrated alfalfa at 50% leaf content and sun-cured alfalfa at 100% leaf content. Cube greennessdecreased with a decrease in leaf content and residence time, however, greenness increased with an increase in dietemperature.

Microminiature transformers

Requirements for microminiature transformers and inductors in aerospace applications are being met with a line of 1/8-in and 1/4-in cube units. These transformers are used for audio, carrier, broad-band and power supply service in telemetering amplifiers, inertial guidance systems, and other applications. The transformers are manufactured with laminations and bobbin-wound coils, usually under microscopes, to exacting electrical and environmental requirements. Special manufacturing and test equipment has been developed because of the microminiature size. Typical ratings are 25 mW for the 1/8-in cube, 200 mW for the 1/4-in cube. Three typical applications are described.