阅读说明：本技术 一种高强度固土岩粉状材料、制备方法及应用 (High-strength soil-fixing rock powdery material, preparation method and application ) 是由 王寿龙 朱分清 甘善杰 缪胜林 杨立华 陈龙海 杜江宇 毛非非 于 2021-01-06 设计创作，主要内容包括：本发明公开了一种高强度固土岩粉状材料、制备方法及应用,本发明通过特定的材料制备方法调配原料的成分组成,根据不同的土质类型,依据其不同特性配制不同原料配比的固土岩材料,在常温常压的状态下,固土岩材料自生硬凝,并与土颗粒矿物在界面上发生同构反应,固体化体内部形成空间网络交错结构,从而具有高强度、高水稳性和抗渗、抗冻的性能。通过高强度固土岩粉状材料的应用,针对路段的强度进行跟踪观测,观测到路段路表外观平整,无沉陷和车辙,无纵横向和反射裂缝出现。(The invention discloses a high-strength soil-fixing rock powdery material, a preparation method and application thereof. By applying the high-strength soil-fixing rock powder material, the tracking observation is carried out aiming at the strength of the road section, and the road section is observed to have flat surface appearance, no settlement and rutting, no longitudinal and transverse cracks and no reflection cracks.)

1. The high-strength soil-fixing rock powdery material is characterized in that: the soil-fixing rock powdery material comprises the following components in parts by weight:

60-80 parts of an active silica-alumina mixture; 10-30 parts by weight of a stabilizing material; 5-15 parts by weight of a chemical activator;

the active silicon-aluminum mixture comprises the following components in parts by weight:

6-18 parts of palygorskite; 6-17 parts of brucite diatomite; 0-10 parts by weight of zeolite; 10-40 parts of nickel-iron slag and 5-45 parts of fly ash; 0-17 parts of coal gangue; 5-15 parts of steel slag;

the stabilizing material comprises the following components in parts by weight:

5-15 parts of iron tailings; 5-15 parts of limestone; 0-10 parts of graphite tailings; 5-10 parts of lead-zinc tailings;

the chemical excitant comprises the following components in parts by weight:

1-10 parts of water glass; 1-4 parts by weight of potassium hydroxide; 1-4 parts by weight of monopotassium phosphate; 2-8 parts of gypsum.

2. The high strength earthy rock powdery material of claim 1, characterized in that: the zeolite is clinoptilolite; the nickel-iron slag is obtained by a blast furnace smelting process, and the steel slag is obtained by a hot splashing method process.

3. The high strength earthy rock powdery material of claim 1, characterized in that: CaCO of said limestone₃+MgCO₃The content is more than or equal to 90 percent.

4. The high strength earthy rock powdery material of claim 1, characterized in that: the water glass modulus is 1.8-2.4, and the gypsum is anhydrite.

5. The method for preparing a high-strength soil stabilization rock powdery material according to any one of claims 1 to 4, characterized in that: the method comprises the following steps:

s1, mixing and grinding the active silicon-aluminum mixture, heating to 580-620 ℃, preserving heat for 4-6 h, and then rapidly cooling to room temperature within 2 h;

s2, mixing and grinding the mixture obtained in the step S1, a stabilizing material and a chemical excitant according to a proportion until the grinding fineness reaches 80um and the screen residue is less than 15 percent, thus obtaining the solid-soil rock powdery material.

6. The method for preparing a high-strength firming rock powdery material according to claim 5, characterized in that: the water content of the active silicon-aluminum mixture is less than 5%, and the specific surface area of the mixed powder is 350-450 m²/kg。

7. The use of the high strength firming rock powdered material of claim 1, wherein: adding the soil-fixing rock powdery material according to 3-25% of the mass of the soil, uniformly mixing with the soil, compacting the mixture by a compacting process, covering, moisturizing and preserving health, and obtaining the solidified soil with excellent performance after the soil is aged.

Technical Field

The invention relates to the field of building materials, in particular to a high-strength soil-fixation rock powdery material, a preparation method and application.

Background

In ancient times in China, in order to meet the basic production and living needs of people, local materials are used, and grass tendon, ginger stone and glutinous rice mortar are used for improving the engineering properties of soil. With the progress of society, the invention and the development of cement and lime, the cement and lime are used for improving and solidifying soil at first, along with the rapid development of Chinese economy, the infrastructure enters the high-tide investment period, the cement and lime industry develops rapidly, and meanwhile, the serious problem which cannot be ignored is brought; the large consumption of energy and resources, the water and soil loss and the instability of natural ecology caused by cutting mountains and splitting stones and excessively exploiting river sand, and the deterioration of the living environment of human beings is aggravated; meanwhile, environmental pollution of different degrees can be generated in the process of producing cement and lime.

Although cement and lime are indispensable main materials in engineering construction, the two materials have limitations in soil solidification, and the concrete main points are as follows: for cement stabilized soil, the strength generated is limited due to the limitation of soil conditions, and the dry shrinkage coefficient and the temperature shrinkage coefficient are large, so that dry shrinkage and temperature shrinkage cracks are easily generated, the water stability, the compression resistance, the impermeability and the scouring resistance of the cement stabilized soil are reduced, the reflective cracks of a road surface are easily caused, and the service life of the road surface is shortened. Therefore, in highway construction codes, cement stabilized soil is prohibited as a base course of high-grade highways. The cement has strict requirements on construction conditions, the initial setting time and the final setting time of the cement are short, the engineering has high requirements on construction speed, and in the actual construction process on site, all the procedures of construction are difficult to complete in a short time due to the influence of factors such as construction conditions and the like. The lime stabilized soil has low strength and slow growth, has certain limitation on construction progress, has strict requirements on lime mixing amount, can reduce the strength when exceeding the standard range of the mixing amount, has poor water stability, is easy to soften when meeting water, has larger shrinkage rate than cement, cannot meet the general requirements of engineering, and is not suitable for serving as a pavement base layer of a high-grade road. Engineering practice proves that the single cement and lime building material cannot meet the development requirement of high-quality engineering construction.

The solidification technology specially used for solidifying the soil is generated at present, the soil technology is started to rise from the last 40 th century, and the soil technology is developed into a comprehensive interdisciplinary subject so far. The soil solidification technology relates to the fields of foundations of the construction industry, underground engineering of highways and municipal roads, dam reinforcement engineering, deep foundation pit engineering, garbage solidification, sand fixation, dust prevention and the like. Compared with traditional solidifying materials such as cement, lime and the like, the material has better engineering mechanical property, low cost, environmental protection and economic advantages of saving natural resources, and is widely researched and applied to the infrastructure of agricultural engineering, hydraulic engineering and road engineering. However, the current soil solidification technology which really has engineering implementation value only remains the step of adding a certain proportion of chemical agents into soil, and loose soil is cemented into a stable structure with certain engineering mechanical strength through the gelation effect of the chemical agents.

The soil solidifying agent is prepared from traditional solidifying materials such as lime and cement, a high-clustering-ion soil solidifying agent, an organic enzyme protein soil solidifying agent, an organic-inorganic combined solidifying agent and the like, and the soil solidifying effect is realized by binding original loose soil particles together so as to achieve certain mechanical strength. Such soil consolidation techniques have the following disadvantages in practical implementations: 1) the mechanical strength is limited, and the mechanical strength required by road construction is difficult to achieve due to the need of mixing with different local soils; 2) the stability is poor, the optimal mechanical strength can be achieved after cementing is finished, the later strength cannot be stably increased, the gelled structure cannot be recovered after being damaged by external force, and the mechanical strength of the whole structure is not continued; 3) the frost resistance is poor, and the gel structure after construction in a low-temperature environment (lower than 0 ℃) can not reach the engineering mechanical index required by road construction.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a high-strength soil-fixation rock powdery material, a preparation method and application, and solves the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: the high-strength soil-fixing rock powdery material comprises the following components in parts by weight:

60-80 parts of an active silica-alumina mixture; 10-30 parts by weight of a stabilizing material; 5-15 parts of chemical excitant;

the active silicon-aluminum mixture comprises the following components in parts by weight:

6-18 parts of palygorskite; 6-17 parts of brucite diatomite; 0-10 parts by weight of zeolite; 10-40 parts of nickel-iron slag and 5-45 parts of fly ash; 0-17 parts of coal gangue; 5-15 parts of steel slag;

the stabilizing material comprises the following components in parts by weight:

5-15 parts of iron tailings; 5-15 parts of limestone; 0-10 parts of graphite tailings; 5-10 parts of lead-zinc tailings;

the chemical excitant comprises the following components in parts by weight:

1-10 parts of water glass; 1-4 parts by weight of potassium hydroxide; 1-4 parts by weight of monopotassium phosphate; 2-8 parts of gypsum.

Preferably, the zeolite is clinoptilolite; the nickel-iron slag is obtained by a blast furnace smelting process, and the steel slag is obtained by a hot splashing method process.

Preferably, CaCO of said limestone₃+MgCO₃The content is more than or equal to 90 percent.

Preferably, the modulus of the water glass is 1.8-2.4, and the gypsum is anhydrite.

A preparation method of a high-strength soil-fixation rock powdery material comprises the following steps:

s1, mixing and grinding the active silicon-aluminum mixture, heating to 580-620 ℃, preserving heat for 4-6 h, and then rapidly cooling to room temperature within 2 h;

s2, mixing and grinding the mixture obtained in the step S1, a stabilizing material and a chemical excitant according to a proportion until the grinding fineness reaches 80um and the screen residue is less than 15 percent, thus obtaining the solid-soil rock powdery material.

Preferably, the water content of the active silica-alumina mixture is less than 5%, and the specific surface area of the mixed powder grinding is 350-450 m²/kg。

The application of the high-strength soil-fixing rock powdery material is characterized in that the soil-fixing rock powdery material is added according to 3% -25% of the mass of soil, the soil and the soil are uniformly mixed, a mixture is compacted through a compaction process, and the mixture is covered with the soil for moisture preservation and health preservation, so that the solidified soil with excellent performance can be obtained after the soil reaches the age.

The invention has the beneficial effects that:

1. the invention uses a specific material preparation method to prepare the component composition of the raw materials, prepares the soil-fixing rock materials with different raw material proportions according to different soil types and different characteristics, and under the state of normal temperature and normal pressure, the soil-fixing rock materials are self-hardened and condensed and have isomorphic reaction with soil particle minerals on the interface, and a space network staggered structure is formed inside a solidified body, thereby having high strength, high water stability, and anti-permeability and anti-freezing performances. By applying the high-strength soil-fixing rock powder material, the tracking observation is carried out aiming at the strength of the road section, and the road section is observed to have flat surface appearance, no settlement and rutting, no longitudinal and transverse cracks and no reflection cracks.

2. The raw materials are combined together by preparation according to corresponding proportions through a set preparation method, a synergistic effect is achieved, the soil stabilization rock powder convenient to transport and use is prepared, meanwhile, a clean preparation process is adopted, industrial wastes are efficiently utilized, and the development strategy of energy conservation, emission reduction and circular economy is fully embodied. The soil-fixing rock powder is directly added into different types of soil, can be obtained from local materials in specific construction, can replace cement, lime and broken stones on the premise of not changing original construction equipment and construction procedures, greatly reduces construction cost, and has high mechanical strength, good stability, strong anti-scouring performance and long service life of highway engineering paved by the soil-fixing rock powder.

3. By applying the soil-fixing rock powder material, the invention can greatly reduce the large consumption of mineral resources and energy resources in the cement and lime industry and reduce the increasingly aggravated pollution to the environment in the infrastructure engineering, and has excellent social and economic benefits and ecological environmental benefits. The consumption of the soil-fixing rock powder is reduced by 5500 tons of CO for each 1 ten thousand tons of cement₂The emission of gas is reduced, and about 2600 tons of coal are saved; 8700 tons of CO can be reduced when the lime is used for replacing 1 ten thousand tons of lime₂The emission of gas saves about 3200 tons of coal; every time the amount of the crushed stone of 1 ten thousand cubic meters is reduced, the vegetation of about 720 cubic meters can be protected, the engineering quality is improved while the environment is protected, the engineering service life is prolonged, and the engineering cost is greatly reduced.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The soil-fixing rock powdery material described by the invention is a soil curing agent and can change the structural performance of soil.

Example 1

The soil-fixing rock powdery material comprises the following components in parts by weight: 60 parts of active silica-alumina mixture; 10 parts of a stabilizing material; 5 parts of chemical activator.

The active silicon-aluminum mixture comprises the following components in parts by weight: 6 parts of palygorskite; 6 parts of brucite diatomite; 1 part by weight of zeolite; 10 parts of nickel-iron slag and 5 parts of fly ash; 1 part by weight of coal gangue; 5 parts of steel slag; the stabilizing material consists of the following components in parts by weight: 5 parts of iron tailings; 5 parts of limestone; 1 part by weight of graphite tailings; 5 parts of lead-zinc tailings; the chemical excitant comprises the following components in parts by weight: 1 part of water glass; 1 part by weight of potassium hydroxide; 1 part of monopotassium phosphate; 2 parts of gypsum.

Example 2

The soil-fixing rock powdery material comprises the following components in parts by weight: 80 parts of active silica-alumina mixture; 30 parts of a stabilizing material; 15 parts of chemical activator.

The active silicon-aluminum mixture comprises the following components in parts by weight: 18 parts of palygorskite; 17 parts of brucite diatomite; 10 parts by weight of zeolite; 40 parts of nickel-iron slag and 45 parts of fly ash; 17 parts of coal gangue; 15 parts of steel slag; the stabilizing material consists of the following components in parts by weight: 15 parts of iron tailings; 15 parts of limestone; 10 parts of graphite tailings; 10 parts of lead-zinc tailings; the chemical excitant comprises the following components in parts by weight: 10 parts of water glass; 4 parts by weight of potassium hydroxide; 4 parts by weight of monopotassium phosphate; 8 parts of gypsum.

Example 3

The soil-fixing rock powdery material comprises the following components in parts by weight: 70 parts of active silicon-aluminum mixture; 20 parts of a stabilizing material; 10 parts of chemical activator.

The active silicon-aluminum mixture comprises the following components in parts by weight: 12 parts of palygorskite; 11 parts of brucite diatomite; 5 parts by weight of zeolite; 25 parts of nickel-iron slag and 25 parts of fly ash; 8 parts of coal gangue; 10 parts of steel slag; the stabilizing material consists of the following components in parts by weight: 10 parts of iron tailings; 10 parts of limestone; 5 parts of graphite tailings; 8 parts of lead-zinc tailings; the chemical excitant comprises the following components in parts by weight: 5 parts of water glass; 2 parts by weight of potassium hydroxide; 3 parts by weight of monopotassium phosphate; 5 parts of gypsum.

Example 4

The soil-fixing rock powdery material comprises the following components in parts by weight: 65 parts by weight of an active silica-alumina mixture; 15 parts of a stabilizing material; 9 parts of chemical excitant.

The active silicon-aluminum mixture comprises the following components in parts by weight: 13 parts of palygorskite; 15 parts of brucite diatomite; 35 parts of nickel-iron slag and 40 parts of fly ash; 5 parts of coal gangue; 11 parts of steel slag; the stabilizing material consists of the following components in parts by weight: 8 parts of iron tailings; 12 parts of limestone; 7 parts of graphite tailings; 6 parts of lead-zinc tailings; the chemical excitant comprises the following components in parts by weight: 7 parts of water glass; 3 parts by weight of potassium hydroxide; 4 parts by weight of monopotassium phosphate; 3 parts of gypsum.

Example 5

The soil-fixing rock powdery material comprises the following components in parts by weight: 75 parts of active silica-alumina mixture; 18 parts by weight of a stabilizing material; 6 parts of chemical excitant.

The active silicon-aluminum mixture comprises the following components in parts by weight: 10 parts of palygorskite; 15 parts of brucite diatomite; 8 parts by weight of zeolite; 16 parts of nickel-iron slag and 41 parts of fly ash; 11 parts of steel slag; the stabilizing material consists of the following components in parts by weight: 12 parts of iron tailings; 14 parts of limestone; 8 parts of graphite tailings; 6 parts of lead-zinc tailings; the chemical excitant comprises the following components in parts by weight: 4 parts of water glass; 3 parts by weight of potassium hydroxide; 2 parts by weight of monopotassium phosphate; 8 parts of gypsum.

Example 6

On the basis of the first to fifth embodiments, the preparation method of the soil-fixing rock powdery material comprises the following steps: mixing and grinding the active silica-alumina mixture, heating to 580-620 ℃, preserving heat for 4-6 h, and then rapidly cooling to room temperature within 2 h; the mixture obtained in the above process is mixed and ground with a stabilizing material and a chemical activator according to a proportion, the grinding fineness reaches 80um, and the screen residue is less than 15 percent, thus obtaining the solid rock powdery material.

The application of the soil-fixing lithification material comprises the following steps: the soil-fixing rock powdery material is added according to 3% -25% of the mass of soil, according to different engineering technical requirements, the concrete construction is implemented according to JTJ034-2000 technical Specification for construction of highway pavement base course, the soil is uniformly mixed, the mixture is compacted through a compaction process, and after the soil is covered with the mixture, the mixture is moisturized and maintained, and after the soil reaches the age, the solidified soil with excellent performance can be obtained.

In the specific construction process, the specific proportion of the ingredients of the rock coagulant is mainly designed according to the principle of guaranteeing diagenetic factors in soil, namely, the formula of the soil-fixing diagenetic material is designed based on chemical composition analysis and mineral composition analysis of a constructed soil object, and the concrete construction method ensures that clay mineral, inorganic polymer, active metal element and heavy metal element in the construction raw material are more than 25%, 2% and 6%.

Different from the conventional soil solidifying agent, the slag dry powder soil solidifying agent is designed based on the geological and lithification principle and physical and chemical engineering methods, the soil solidifying capability is realized not by simple 'cementation' action, but by the 'gelation' and 'lithification' action of the soil, the soil undergoes several different evolution stages, and the structural engineering mechanical strength of the constructed solidified body is increased.

Along with the requirement of highway construction in China, a large amount of building materials are mainly used by adopting cement, lime and broken stones, and the traditional materials have the following problems in engineering: the engineering mechanical strength is not high, the water stability is poor, the anti-scouring capability is not strong, and dry shrinkage and temperature shrinkage cracks are easy to generate, so that the service life of the engineering structure is too short. Meanwhile, the materials consume a large amount of mineral resources and energy, generate large greenhouse gases and cause environmental pollution. The application of the invention improves the engineering quality and reduces the investment cost on the premise of not changing the original production equipment and production procedures, can realize the utilization of a large amount of existing industrial wastes, can adopt a clean preparation process during the production of the product, really realizes energy conservation and emission reduction, is environment-friendly and economical, and provides a new green industrial chain for the reutilization of industrial solid wastes.

Soil is formed by the combined effects of physical, chemical, biological and man-made processes on rocks, and the matrix produced by rock weathering is the source of soil formation. Because of the loss of a large amount of water-soluble elements such as potassium, sodium, calcium, magnesium, iron, aluminum and the like in the rock and the decomposition, loss and structural transformation of the original minerals, the soil becomes a loose state with inertia. The invention relates to a technical method for promoting the coagulation and the lithification of soil by adding a soil-fixing lithification material into the soil and fully mixing the materials based on the geological principle to form a polymer and have a rock-forming element composition with reasonable compatibility, thereby forming a basic structural material with proper engineering mechanical strength.

The soil-fixing lithification material is a slag dry powder soil curing agent which is based on a material source foundation formed by soil, is mixed with soil to enable the soil to be gelled again and achieve expected engineering mechanical strength, is based on factors formed by solidified structural elements and consolidation conditions of geological lithification according to a material theory and a petrophysical theory, and is experimentally researched and developed by applying a chemical engineering gelling and curing technology based on the requirement of building engineering mechanical specification.

Because the soil types are different all over the country and the physical and chemical properties of the soil are obviously different, the soil-fixing lithification material adopts different formulas aiming at the soil consisting of different primary minerals, secondary mineral components and various physical properties, and forms a complete product series which can adapt to the properties of various types of soil. However, all the products of the soil-consolidating lithification materials are consistent in action principle, and their gelation and solidification action on soil includes three layers and can be roughly divided into three stages:

the first stage, the initial skeleton stage. This is one of the most initial stages. After the soil-fixing lithification material is uniformly mixed with soil, under the action of chemical excitation of water and external force physical pressure, the soil solidifying agent is mixed with the soil containing a certain amount of water to form three-dimensional net-shaped crystals in the soil, and the three-dimensional net-shaped crystals are inserted into gaps of soil particles to form a strength framework, so that the soil is gelled and hardened, and effective early engineering mechanical strength is formed.

The second stage, the gelling stage. At this stage, the ingredients of the soil-fixing lithification material and soil particles take part in chemical reaction to excite the self-substance of the soil to generate a hard substance insoluble in water, and the hard substance is filled in the high-strength framework, so that the solidified soil forms an irreversible solid plate body and has good stability and durability. The gaps of the soil stabilization framework are filled, the chemical stability of the soil consolidation body in the stage is enhanced again, a solid foundation is laid for hardening and solidification in the next stage, and the engineering mechanical property of the consolidation body is enhanced again.

And the third stage, curing and molding stage. This is the final stage of the highest hierarchy. Along with the constantly firm of soil aggregate chemical structure, under the physical action of outside sustained pressure, reduce the water film thickness of soil granule, improve the adsorption affinity between the soil granule, the closely knit degree of increase, the soil aggregate is constantly condensed and is lithified, and unnecessary water of discharge and mobility chemical composition stabilize mineral and constantly take place the consolidation reaction, and soil further lithification. The rock-making effect of the soil after the plate is formed is carried out at the stage, and the rock formation of the soil generates strong later-stage engineering mechanical strength, stability and water resistance, and finally the soil becomes an excellent engineering structural material. The duration of this process is relatively long and is related to the physical conditions of the external force and the environmental factors of temperature, humidity, hydrological conditions, etc.

According to the invention, the soil is consolidated into the soil concretion by adding the rock coagulant into the soil, the physical structure and the mechanical property of the soil are rapidly and remarkably changed, the mechanical strength of the soil concretion prepared by the method within seven days can reach 5-6 MPa, and a qualified building material capable of meeting engineering technical requirements is formed, so that abundant soil resources are converted into an excellent engineering structural material. It includes the following advantages: the construction method has the advantages that the adaptability is strong, the construction method is suitable for various types of soil, the construction is convenient, the original construction machinery and construction process are not changed, local materials can be obtained, and the transportation cost of the building materials is greatly reduced; and secondly, a set of manufacturing method for matching soil and the rock coagulant based on different chemical and mineral compositions of soil is created, the preparation quality of the soil coagulant can be strictly guaranteed, the popularization and the promotion are convenient, the technical indexes tend to be standardized and easy to realize, and the construction efficiency can be improved.

Experiment: taking a 1000-meter experimental road section for construction, tracking and observing, wherein the concrete conditions are as follows:

1. the technical indexes of the physical properties of the soil at the construction site are as follows:

according to the test index, the soil for engineering belongs to silt soil and has a small amount of viscous components.

2. By adopting the component proportion in the third embodiment, the proportion of the fine soil on the constructed subbase layer is as follows: the construction is carried out according to the proportion of 100:4 of the rock coagulant, and the construction is carried out on the base layer according to the proportion of fine soil: the construction is carried out with the ratio of the rock coagulant to the rock coagulant of 100: 10. The unconfined compressive strength test is carried out on the soil of the test road section, and the obtained parameters are as follows:

through the core sample test of the test section, the mechanical strength completely meets the design strength requirement of engineering pavement base course construction technical specification (JTJ 034-2000). And further tracking and observing the strength of the test road section for three years, and observing that the road surface of the road section in the experimental range is flat in appearance, and has no settlement, no track, no longitudinal and transverse cracks and no reflection cracks.

The raw materials are combined together by preparation according to corresponding proportions through a set preparation method, a synergistic effect is achieved, the soil stabilization rock powder convenient to transport and use is prepared, meanwhile, a clean preparation process is adopted, industrial wastes are efficiently utilized, and the development strategy of energy conservation, emission reduction and circular economy is fully embodied. The soil-fixing rock powder is directly added into different types of soil, can be obtained from local materials in specific construction, can replace cement, lime and broken stones on the premise of not changing original construction equipment and construction procedures, greatly reduces construction cost, and has high mechanical strength, good stability, strong anti-scouring performance and long service life of highway engineering paved by the soil-fixing rock powder.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and/or modifications of the invention can be made, and equivalents and modifications of some features of the invention can be made without departing from the spirit and scope of the invention.