Disclosure of Invention
In view of the problems that the dispersibility and uniformity of the external fibers in the preparation process of the tobacco sheet by the rolling method are poor, white spots are easy to appear in the product, and the product strength is further influenced in the prior art, the invention aims to provide a method for preparing the high-strength and high-uniformity tobacco sheet by the rolling method, the external fibers are uniformly dispersed in the liquid part by the technologies of proportioning sequence, liquid part preparation and the like, the problem of uniform dispersion of the external fibers in the sheet preparation process is solved, the number of white spots on the surface of the sheet product is effectively reduced, the tensile strength of the novel tobacco sheet by the rolling method is enhanced, the stability of the product quality is ensured, and the method is simple to operate and low in cost.
In order to achieve the purpose, the invention adopts the following technical scheme:
A method for preparing high-strength high-uniformity tobacco sheets by a rolling method comprises the following steps:
1) Mixing the tobacco powder with an adhesive to obtain a dry material;
2) Adding water into the external fiber, and pulping to obtain external fiber slurry;
3) Mixing an atomizing agent with an adhesive and an external fiber slurry to obtain a wet material;
4) Mixing the dry material and the wet material to obtain a mixed material, wherein the mixed material is a semi-dry solid bulk material or a semi-dry solid bulk material;
5) And rolling, forming and drying the mixed material to obtain the tobacco sheet.
In some embodiments of the present invention, the weight of the adhesive in step 1) is 0-10% of the weight of the tobacco powder, and is greater than 0, preferably 4-6%.
In some embodiments of the present invention, the adhesive is selected from one or a combination of several of sodium alginate, sodium carboxymethyl cellulose, chitosan, guar gum, and the like.
In some embodiments of the invention, the adhesive in step 1) is selected from sodium carboxymethylcellulose with a viscosity in the range of 2800 to 4000 mpa-s and a degree of substitution of 0.8 to 1.1, and/or the adhesive in step 3) is selected from sodium carboxymethylcellulose with a viscosity in the range of 1000 to 1300 mpa-s and a degree of substitution of 0.9 to 1.0.
In some embodiments of the invention, the additional fibers are selected from softwood pulp, preferably kraft softwood pulp or sulfite softwood pulp, and the like.
In some embodiments of the present invention, the weight ratio of the additional fibers in the additional fiber slurry is 2% -6%, preferably 3% -5%.
In some embodiments of the invention, the pulping process is specifically pulping using a refiner.
In some embodiments of the present invention, the freeness of the additional fiber slurry is in the range of 20 ° to 40 ° SR, preferably 25 ° to 35 ° SR.
In some embodiments of the invention, the wet weight of the additional fiber slurry ranges from 5 to 20g, preferably from 9 to 15g.
In some embodiments of the invention, the wet material comprises 35% -50% by weight of an atomizing agent, 0.1% -3% by weight of an adhesive, 50% -62% by weight of an additional fiber slurry, preferably 38% -48% by weight of an atomizing agent, 0.2% -2% by weight of an adhesive and 50% -60% by weight of an additional fiber slurry.
In some embodiments of the invention, the wet stock is maintained at a temperature of 40-80 ℃, preferably 50-70 ℃.
In some embodiments of the invention, step 3) further comprises other auxiliary materials, wherein the addition sequence of the other auxiliary materials is after the addition of the fiber slurry.
In some embodiments of the invention, the mixing sequence in step 3) is an atomizer, an adhesive, an additional fiber slurry, and stirring is performed after each mixing.
In some embodiments of the present invention, the stirring speed is 150 to 300rpm, and/or the stirring time is 5 to 20 minutes.
In some embodiments of the present invention, the weight ratio of the dry material to the wet material in the step 4) is 5:2-4.
Compared with the prior art, the invention has the following beneficial effects:
1. According to the method for preparing the high-strength and high-uniformity tobacco sheet by the rolling method, the adhesive is respectively added in the preparation process of the dry material and the wet material, and the additional fibers are subjected to pulping treatment, so that the additional fibers are uniformly dispersed in the tobacco sheet, the number of white spots on the sheet surface is effectively reduced, the strength and uniformity of the tobacco sheet by the rolling method are improved, and the quality stability of the tobacco sheet by the rolling method is improved.
2. The method for preparing the high-strength high-uniformity tobacco sheet by the rolling method provided by the invention is simple to operate, can be realized by adopting the existing equipment, and the additional fibers are uniformly dispersed in the preparation process of the tobacco sheet, so that the obtained product has high tensile strength and no obvious white spots on the surface, and has important significance for promoting the application of domestic novel rolling tobacco sheets in heating non-burning tobacco products.
Detailed Description
The method for preparing the high-strength and high-uniformity tobacco sheet by the rolling method of the present invention is described in detail below.
In order to improve the strength and uniformity of the tobacco sheet prepared by the rolling method, the inventor adds the adhesive in two steps, mixes the adhesive with tobacco powder to prepare dry materials, mixes the adhesive with an atomizing agent and an external fiber slurry to prepare wet materials, and synergistically improves the dispersion uniformity of the external fibers through the external fiber pulping treatment and the specific batching sequence, so that the tobacco sheet prepared by the rolling method has high strength and high uniformity.
The invention provides a method for preparing high-strength high-uniformity tobacco sheets by a rolling method, which comprises the following specific technical scheme:
A method for preparing high-strength high-uniformity tobacco sheets by a rolling method comprises the following steps:
1) Mixing the tobacco powder with an adhesive to obtain a dry material;
2) Adding water into the external fiber, and pulping to obtain external fiber slurry;
3) Mixing an atomizing agent with an adhesive and an external fiber slurry to obtain a wet material;
4) Mixing the dry material and the wet material to obtain a mixed material, wherein the mixed material is a semi-dry solid bulk material or a semi-dry solid bulk material;
5) And rolling, forming and drying the mixed material to obtain the tobacco sheet.
In the invention, the step 1) and the step 2) are not sequential, and the sequence is adjustable. The preparation method of the tobacco powder comprises the steps of uniformly mixing tobacco raw materials according to a formula, and crushing the tobacco raw materials into tobacco powder with the granularity meeting the requirement, wherein the granularity of the tobacco powder is preferably 200-400 meshes. In the invention, the raw material of the external fiber is not particularly limited, and the external fiber can be the external fiber commonly used in the papermaking field and the tobacco sheet preparation field by a papermaking method, and the atomizing agent is not particularly limited, and can be a common atomizing agent in the field, such as 1, 3-butanediol, or a combination of propylene glycol and/or glycerol and 1, 3-butanediol. The adhesive added in the wet material in the step 3) mainly plays roles of dispersing and thickening, promotes the uniform dispersion of the external fibers and prevents the flocculation or precipitation of the external fibers. The mixed material obtained in the step 4) is a semi-dry solid bulk material or a semi-dry solid bulk material, so that the subsequent roll forming is convenient.
In some embodiments of the present invention, the weight of the adhesive in step 1) is 0-10% of the weight of the tobacco powder, and greater than 0, and may be 0-2%, 2-4%, 4-6%, 6-8% or 8-10%, preferably 4-6%.
In some embodiments of the present invention, the adhesive is selected from one or a combination of several of sodium alginate, sodium carboxymethyl cellulose, chitosan, guar gum, and the like.
In some preferred embodiments of the present invention, the adhesive in step 1) is selected from sodium carboxymethyl cellulose, the viscosity is in the range of 2800 to 4000 mpa.s, the degree of substitution is 0.8 to 1.1, and/or the adhesive in step 3) is selected from sodium carboxymethyl cellulose, the viscosity is in the range of 1000 to 1300 mpa.s, and the degree of substitution is 0.9 to 1.0.
In some embodiments of the invention, the additional fibers are selected from the group consisting of softwood pulp, preferably kraft softwood pulp or sulfite softwood pulp, and the like.
In some embodiments of the present invention, the weight ratio of the additional fibers in the additional fiber slurry is 2% -6%, and may be 2% -3%, 3% -4%, 4% -5%, 5% -6%, or may be 2% -4%, 3% -5%, 4% -6%, and preferably 3% -5%.
In some embodiments of the invention, the pulping process is specifically pulping using a refiner.
In some embodiments of the present invention, the beating degree of the additional fiber slurry ranges from 20 ° to 40 ° SR, and may be from 20 ° to 25 ° SR, from 25 ° to 30 ° SR, from 30 ° to 35 ° SR, and from 35 ° to 40 ° SR, or may be from 20 ° to 30 ° SR, from 25 ° to 35 ° SR, and from 30 ° to 40 ° SR, and preferably from 25 ° to 35 ° SR.
In some embodiments of the present invention, the wet weight of the additional fiber slurry may be 5-20 g, 5-10 g, 10-15 g, 15-20 g, 5-11 g, 6-12 g, 7-13 g, 8-14 g, 9-15 g, 10-16 g, 11-17 g, 12-18 g, 13-19 g, 14-20 g, and preferably 9-15 g.
In some embodiments of the invention, the wet material comprises 35% -50% by weight of an atomizing agent, 0.1% -3% by weight of an adhesive, 50% -62% by weight of an additional fiber slurry, preferably 38% -48% by weight of an atomizing agent, 0.2% -2% by weight of an adhesive and 50% -60% by weight of an additional fiber slurry.
In some embodiments of the present invention, the wet material is maintained at a temperature of 40 to 80 ℃, which may be 40 to 50 ℃, 50 to 60 ℃, 60 to 70 ℃,70 to 80 ℃, or 40 to 60 ℃, 50 to 70 ℃, 60 to 80 ℃, preferably 50 to 70 ℃.
In some embodiments of the invention, step 3) further comprises other auxiliary materials, wherein the addition sequence of the other auxiliary materials is after the addition of the fiber slurry. In the invention, the other auxiliary materials comprise one or more of essence, spice, combustion improver, calcium carbonate, preservative and the like.
In some embodiments of the invention, the mixing sequence in step 3) is an atomizer, an adhesive, an additional fiber slurry, and stirring is performed after each mixing. According to the invention, the atomizing agent is mixed with the adhesive to promote uniform distribution of adhesive particles, then the adhesive particles are mixed with the external fiber slurry, the atomizing agent and water molecules in the slurry form strong hydration short chains through hydrogen bonds, the strong hydration short chains are attached to the uniformly distributed adhesive molecular chains through the hydrogen bonds or Van der Waals force, so that a similar branch structure is formed on the adhesive molecular chains, the space density of the molecular chains is increased, the dispersion state of the external fibers is kept, flocculation or precipitation of the external fibers is prevented, uniform dispersion of the external fibers is facilitated, and uniform dispersion of the external fibers in the wet materials is also facilitated, and the additional fibers in the subsequent mixed materials are kept in a dispersion state, so that the strength and uniformity of the tobacco sheets prepared by a rolling method are improved.
In some embodiments of the present invention, the stirring speed may be 150 to 300rpm, and may be 150 to 200rpm,200 to 250rpm,250 to 300rpm, and preferably 200 to 250rpm. In some embodiments of the present invention, the stirring time is 5 to 20 minutes, which may be 5 to 10 minutes, 10 to 15 minutes, or 15 to 20 minutes.
In some embodiments of the present invention, the weight ratio of the dry material to the wet material in step 4) is 5:2-4, which may be 5:2-2.5, 5:2.5-3 or 5:3.5-4, so as to facilitate the formation of a semi-dry solid bulk material or a semi-dry solid bulk material after mixing.
In some embodiments of the present invention, the roll forming includes multi-stage rolling, preferably 4-6 stages.
The following describes the invention in further detail with reference to preferred examples. Where numerical ranges are provided in the examples, it is understood that unless otherwise stated herein, both endpoints of each numerical range and any number between the two endpoints are significant both in the numerical range. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. In addition to the specific methods, devices, materials used in the embodiments, any methods, devices, and materials of the prior art similar or equivalent to those described in the embodiments of the present invention may be used to practice the present invention as would be apparent to one of skill in the art having possession of the prior art and having possession of the present invention.
All the steps of the present invention may be performed sequentially or randomly, preferably sequentially, unless otherwise specified. For example, the method comprises steps 1) and 2), meaning that the method may comprise steps 1) and 2) performed sequentially, or may comprise steps 2) and 1) performed sequentially.
In the following examples and comparative examples, the methods for detecting the respective properties were as follows:
the viscosity of the adhesive is detected according to GB1886.232-2016 sodium carboxymethylcellulose as a food additive for national food safety standard, and the higher the value is, the higher the viscosity is.
The tensile strength of the product is detected according to GB/T12914 method for measuring tensile strength of paper and paper boards at constant speed, and the higher the numerical value is, the better the rigidity (tensile strength) is.
The product uniformity is characterized by taking 10 pieces of 100X 100mm flake samples randomly according to YC/T16-2014 reconstituted tobacco, measuring and counting the number of white spots with the diameter larger than 2.0mm on the samples by using a ruler, and representing the number of white spots of the reconstituted tobacco by using the arithmetic average value of the number of white spots on the 10 pieces of samples and trimming to be an integer, wherein the smaller the number is, the higher the uniformity is.
Example 1
A method for preparing high-strength high-uniformity tobacco sheets by a rolling method comprises the following steps:
s1, crushing a tobacco raw material, adding an adhesive, and uniformly mixing and stirring to obtain a dry material, wherein the weight of the adhesive is 4% of that of the tobacco raw material, the adhesive is sodium carboxymethylcellulose, the viscosity is 2800 mPa.s, and the substitution degree is 0.8.
S2, mixing the external fibers with water to prepare slurry, and pulping to obtain external fiber slurry, wherein the weight ratio of the external fibers in the external fiber slurry is 3%, the external fibers are softwood pulp, a pulping process adopts a pulping machine to pulp, and the pulping degree of the external fiber slurry is 25 DEG SR and the wet weight is 9g.
S3, mixing the atomizing agent, the adhesive and the external fiber slurry in proportion and sequence, and uniformly stirring to obtain a wet material (shown as a in figure 1 a), wherein the weight ratio of the atomizing agent in the wet material is 38%, the weight ratio of the adhesive is 2%, the weight ratio of the external fiber slurry is 60%, and the temperature of the wet material is kept at 50 ℃. The adding sequence of the materials is that an atomizing agent, an adhesive and external fiber slurry are added, and after each material is added, the next material is added after stirring for 5 min. The adhesive used is sodium carboxymethylcellulose, the viscosity is 1000 mPa.s, and the substitution degree is 0.9.
S4, mixing the dry materials and the wet materials according to the weight ratio of 5:2 to obtain a mixed material, wherein the mixed material is a semi-dry solid bulk material.
And S5, rolling, forming and drying the mixed material to obtain the tobacco sheet.
Example 2
A method for preparing high-strength high-uniformity tobacco sheets by a rolling method comprises the following steps:
S1, crushing a tobacco raw material, adding an adhesive, and uniformly mixing and stirring to obtain a dry material, wherein the weight of the adhesive is 5% of that of the tobacco raw material, the adhesive is sodium carboxymethyl cellulose, the viscosity is 3400 mPa.s, and the substitution degree is 0.95.
S2, mixing the external fibers with water to prepare slurry, and pulping to obtain external fiber slurry, wherein the weight ratio of the external fibers in the external fiber slurry is 4%, the external fibers are softwood pulp, a pulping process adopts a pulping machine to pulp, and the pulping degree of the external fiber slurry is 30 DEG SR and the wet weight is 12g.
S3, mixing the atomizing agent, the adhesive and the external fiber slurry in proportion and sequence, and uniformly stirring to obtain a wet material (shown as b in fig. 1), wherein the weight ratio of the atomizing agent in the wet material is 43%, the weight ratio of the adhesive is 1%, the weight ratio of the external fiber slurry is 56%, and the temperature of the wet material is kept at 60 ℃. The adding sequence of the materials is that an atomizing agent, an adhesive and additional fiber slurry are added, and after each material is added, the next material is added after stirring for 15 min. The adhesive used is sodium carboxymethylcellulose, the viscosity is 1150 mPa.s, and the substitution degree is 0.95.
S4, mixing the dry materials and the wet materials according to the weight ratio of 5:3 to obtain a mixed material, wherein the mixed material is a semi-dry solid bulk material.
And S5, rolling, forming and drying the mixed material to obtain the tobacco sheet.
Example 3
A method for preparing high-strength high-uniformity tobacco sheets by a rolling method comprises the following steps:
s1, crushing a tobacco raw material, adding an adhesive, and uniformly mixing and stirring to obtain a dry material, wherein the weight of the adhesive is 6% of that of the tobacco raw material, the adhesive is sodium carboxymethyl cellulose, the viscosity is 4000 mPa.s, and the substitution degree is 1.1.
S2, mixing the external fibers with water to prepare slurry, and pulping to obtain external fiber slurry, wherein the weight ratio of the external fibers in the external fiber slurry is 5%, the external fibers are softwood pulp, a pulping process adopts a pulping machine to pulp, and the pulping degree of the external fiber slurry is 35 DEG SR and the wet weight is 15g.
S3, mixing the atomizing agent, the adhesive and the external fiber slurry in proportion and sequence, and uniformly stirring to obtain a wet material (shown as a figure 1C), wherein the weight ratio of the atomizing agent in the wet material is 48%, the weight ratio of the adhesive is 0.2%, the weight ratio of the external fiber slurry is 51.8%, and the temperature of the wet material is kept at 70 ℃. The adding sequence of the materials is that an atomizing agent, an adhesive and additional fiber slurry are added, and after each material is added, the next material is added after stirring for 20 min. The adhesive used was sodium carboxymethylcellulose, the viscosity was 1300 mPa.s and the degree of substitution was 1.0.
S4, mixing the dry materials and the wet materials according to the weight ratio of 5:4 to obtain a mixed material, wherein the mixed material is a semi-dry solid bulk material.
And S5, rolling, forming and drying the mixed material to obtain the tobacco sheet.
Example 4
A method for preparing high-strength high-uniformity tobacco sheets by a rolling method comprises the following steps:
S1, crushing a tobacco raw material, adding an adhesive, and uniformly mixing and stirring to obtain a dry material, wherein the weight of the adhesive is 5% of that of the tobacco raw material, the adhesive is sodium carboxymethyl cellulose, the viscosity is 3400 mPa.s, and the substitution degree is 0.95.
S2, mixing the external fibers with water to prepare slurry, and pulping to obtain external fiber slurry, wherein the weight ratio of the external fibers in the external fiber slurry is 4%, the external fibers are softwood pulp, a pulping process adopts a pulping machine to pulp, and the pulping degree of the external fiber slurry is 30 DEG SR and the wet weight is 12g.
S3, mixing the atomizing agent, the external fiber slurry and the adhesive in proportion and sequence, and uniformly stirring to obtain a wet material (shown as d in figure 1), wherein the weight ratio of the atomizing agent in the wet material is 43%, the weight ratio of the adhesive is 1%, the weight ratio of the external fiber slurry is 56%, and the temperature of the wet material is kept at 60 ℃. The adding sequence of the materials is atomizing agent, external fiber slurry and adhesive, and after each material is added, the next material is added after 50min of stirring. The adhesive used is sodium carboxymethylcellulose, the viscosity is 1150 mPa.s, and the substitution degree is 0.95.
S4, mixing the dry materials and the wet materials according to the weight ratio of 5:3 to obtain a mixed material, wherein the mixed material is a semi-dry solid bulk material.
And S5, rolling, forming and drying the mixed material to obtain the tobacco sheet.
Comparative example 1
A method for preparing a high-strength high-uniformity tobacco sheet by a rolling method is the same as in example 2 except that no adhesive is added in step S3, and comprises the following steps:
S1, crushing a tobacco raw material, adding an adhesive, and uniformly mixing and stirring to obtain a dry material, wherein the weight of the adhesive is 5% of that of the tobacco raw material, the adhesive is sodium carboxymethyl cellulose, the viscosity is 3400 mPa.s, and the substitution degree is 0.95.
S2, mixing the external fibers with water to prepare slurry, and pulping to obtain external fiber slurry, wherein the weight ratio of the external fibers in the external fiber slurry is 4%, the external fibers are softwood pulp, a pulping process adopts a pulping machine to pulp, and the pulping degree of the external fiber slurry is 30 DEG SR and the wet weight is 12g.
S3, mixing the atomizing agent and the external fiber slurry in proportion and sequence, and uniformly stirring to obtain a wet material (shown as e in figure 1), wherein the weight ratio of the atomizing agent in the wet material is 43.43%, the weight ratio of the external fiber slurry is 56.57%, and the temperature of the wet material is kept at 60 ℃. The adding sequence of the materials is atomizing agent and external fiber slurry, and after each material is added and stirred for 15min, the next material is added.
S4, mixing the dry materials and the wet materials according to the weight ratio of 5:3 to obtain a mixed material, wherein the mixed material is a semi-dry solid bulk material.
And S5, rolling, forming and drying the mixed material to obtain the tobacco sheet.
Comparative example 2
A method for preparing a high-strength high-uniformity tobacco sheet by a rolling method is the same as in example 2 except that no additional fiber slurry is added in step S3, and comprises the following steps:
S1, crushing a tobacco raw material, adding an adhesive, and uniformly mixing and stirring to obtain a dry material, wherein the weight of the adhesive is 5% of that of the tobacco raw material, the adhesive is sodium carboxymethyl cellulose, the viscosity is 3400 mPa.s, and the substitution degree is 0.95.
S3, mixing the atomizing agent and the adhesive in proportion and sequence, and uniformly stirring to obtain wet materials, wherein the weight ratio of the atomizing agent in the wet materials is 97.73%, the weight ratio of the adhesive in the wet materials is 2.27%, and the temperature of the wet materials is kept at 60 ℃. The adding sequence of the materials is an atomizing agent and an adhesive, and after each material is added and stirred for 15min, the next material is added. The adhesive used is sodium carboxymethylcellulose, the viscosity is 1150 mPa.s, and the substitution degree is 0.95.
S4, mixing the dry materials and the wet materials according to the weight ratio of 5:3 to obtain a mixed material, wherein the mixed material is a semi-dry solid bulk material.
And S5, rolling, forming and drying the mixed material to obtain the tobacco sheet.
Evaluation results
Tensile strength detection and uniformity characterization were performed on the tobacco sheets obtained in examples 1 to 4 and comparative examples 1 to 2, respectively. The tensile strength test structure is shown in table 1 below:
table 1 results of evaluating tensile Strength of products obtained in examples 1 to 4 and comparative examples 1 to 2
| Evaluation item | Example 1 | Example 2 | Example 3 | Example 4 | Comparative example 1 | Comparative example 2 |
| Tensile strength KN/m | 0.21 | 0.22 | 0.20 | 0.19 | 0.19 | 0.14 |
As can be seen from Table 1, the tobacco sheet products obtained in examples 1 to 4 have good tensile strength, and the tensile strength of the tobacco sheet prepared by the roll method after adding the additional fiber slurry is significantly improved by about 50% compared with that of the tobacco sheet without adding the additional fiber. The tensile strength of example 4 and comparative example 1 was slightly lower than that of examples 1 to 3, presumably because the tensile strength was slightly lowered after the addition sequence of example 4 was changed (the addition of the additional fiber slurry was first added and then the adhesive was added), probably because the addition sequence had an effect on the dispersibility of the additional fibers and thus on the strength of the tobacco sheet, and comparative example 1 was due to the absence of the adhesive in the wet stock. Comparative example 2 has significantly lower tensile strength due to the absence of added fiber slurry.
As can be seen from the uniformity of dispersion of the additional fibers in the wet materials prepared in examples 1 to 4 and comparative example 1 in FIG. 1, the additional fibers in the wet materials of examples 1 to 3 were uniformly dispersed (a to c in FIG. 1) without significant flocculation, while as can be seen from FIG. 1d after changing the addition sequence (adding the additional fiber slurry first and then adding the adhesive) in example 4, there was significant additional fiber flocculation in the wet materials and the stirring time was prolonged by more than 3 times that of example 2, and as can be seen from FIG. 1 e without adhesive in the wet materials of comparative example 1. As can be seen from the "white spots" on the surfaces of the tobacco sheet products prepared in examples 1-4 and comparative example 1 in FIG. 2, the surfaces of the products prepared in examples 1-3 have no obvious flocculation "white spots" (a-c in FIG. 2), while the addition sequence of example 4 is changed (adding the additional fiber slurry first and then adding the adhesive) and the addition sequence of example 2 d shows that the wet sheet has obvious "white spots" of about 7/100 cm2, the surface of the sheet of comparative example 1 has the fiber flocculation phenomenon, the density of the "white spots" is about 5/100 cm2, which indicates that the addition of the adhesive with the viscosity of 1000-1300 mPa.s in a certain sequence in the preparation process of the wet sheet can improve the dispersion uniformity of the external fibers in the wet sheet, thereby improving the dispersion uniformity of the additional fibers in the rolled tobacco sheet and improving the strength and quality stability of the sheet product.
The above embodiments are merely illustrative of the principles of the present invention and its effectiveness, and are not intended to limit the invention. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the invention. Accordingly, it is intended that all equivalent modifications and variations of the invention be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.