Volume Density Property Research Articles

The Influence of Differences in Volume Density and Blotong Application on the Physical Properties of Ultisol Soil and Sweet Potato Plant Growth

This study investigates the effects of variations in volume density and blotong application on the physical properties of Ultisol soil and the growth of sweet potato plants. The main objectives of the research are to assess how different levels of volume density and blotong application affect soil characteristics and plant growth. The study employs a qualitative approach, incorporating literature review and library research to explore existing knowledge and methodologies related to soil physics and plant physiology. The research involves conducting experiments where Ultisol soil samples with varying volume densities are treated with different levels of blotong application. Parameters such as soil bulk density, porosity, water retention capacity, and sweet potato plant growth parameters are measured and analyzed. The results reveal significant correlations between volume density, blotong application, and soil physical properties. Higher volume density generally leads to decreased soil porosity and water retention capacity, while blotong application demonstrates a positive impact on soil structure and plant growth. The findings highlight the importance of optimizing soil volume density and implementing blotong application techniques to enhance soil fertility and support healthy plant growth, particularly in Ultisol soil conditions. In conclusion, this research contributes valuable insights into sustainable agricultural practices for improving soil quality and crop productivity, emphasizing the significance of tailored management strategies for different soil types and crops.

Effect of BN addition on mechanical and electrical properties of oxidative sintered porous Si3N4-BN composites

In order to explore the effects of BN addition on the mechanical and electrical properties of oxidative sintered Si3N4-BN composites, Si3N4-BN composites with BN powder dosage of 0-40 wt% are prepared by molding technology, and the effects of different BN contents on the phase, morphology, bulk density, porosity, flexural strength at room temperature, dielectric constant and dielectr loss of the composite system are studied. With the increase of BN content, at different temperatures, the oxidation product B2O3 of BN and the oxidation product SiO2 of Si3N4 firstly react on the surface to form B2O3–SiO2 glass phase, which densify the surface and affects the oxidation degree of internal grains. At the same time, a small amount of B2O3 escaping from the surface, so that the open pores of the composites decrease firstly and then increase slightly, and the dielectric constant increases firstly and then decreases. The results show that when the amount of BN micronized powder is 10 wt%, the oxidation sintered Si3N4-BN composite material at 1500 °C have pores that retain the sheet structure of boron nitride, and the amorphous material flows to fill the pores, so it have high volume density (1.85 g/cm3), low porosity (apparent porosity 6.37%), and high mechanical properties (flexural strength 127.86Mpa), higher dielectric constant (3.94) and lower dielectr loss (4.0 × 10−4).

Thermodynamic, mechanical, and electronic properties of ettringite and AFm phases from first-principles calculations

The aluminate containing hydration products of Portland cement, mainly referring to ettringite and AFm phases (AFm, Mc, Hc and Friedel’s salt), are important for chloride chemical binding and microstructure development of cement pastes since they are easily transformed with different additives and solutions. First principles calculations are employed to find their thermodynamic equilibrium crystal structures. Various equivalent hydrostatic pressures are applied onto these structures to study their volume change, thermodynamic and elastic moduli. Among them, Mc shows the smallest interlayer space, highest volume stability, density, elastic modulus, and stiffness property. The volume of hydrated phase can increase by 12.5 % due to the conversion from Mc to Friedel’s salt. Electronic properties suggest that there are non-bonding electrons in the O-p orbitals of CO32– in the Mc and charge transfer from CO32– to the Ca2+ made the bonding states between O-p of CO32– and Ca-d stronger. This could provide a theoretical basis for improving the mechanical and durability properties of concrete by adding supplementary cementitious materials, such as limestone powders appropriately.

Fabrication of carbon fibers from the cupric ion impregnated and thermally stabilized poly(hexamethylene adipamide) precursor

The conversion of poly (hexamethylene adipamide) or polyamide 66 precursor fiber to carbon fibers was accomplished through thermal stabilization and carbonization processes. Thermal stabilization was conducted of cupric chloride (CuCl2)–ethanol-impregnated polyamide 66 (PA66) fibers in the air. To determine the influence of heating rate on the fiber structure and properties of the resultant carbon fibers, carbonization experiments were performed at selected temperatures of 500, 700, 900, and 1100°C using 2.5 and 5 °C/min heating rates with no dwelling. The results conclusively revealed that the volume density and tensile properties of the PA66 fiber were higher at 2.5 °C/min heating rate. After fixing the heating rate as 2.5°C/min, further carbonization experiments were conducted at temperatures from 500 to 1100°C, using increments of 100°C with no dwelling time. Linear density, volume density, fiber diameter, carbon yield, elemental composition, tensile, and electrical properties exhibited a strong dependence on the carbonization temperature. After taking into account the effects of structural defects (i.e., microvoids), tensile strength, and tensile modulus of the carbon fibers increased to 794 MPa and 92.4 GPa, respectively, when carbonized at 1100°C. X-ray diffraction analysis of the carbon fibers further revealed the existence of a greatly disordered (i.e., amorphous) structure, which developed during the carbonization process. FT-IR analysis confirmed the formation of highly aromatic carbon clusters at temperatures of 500°C and higher. The outcomes of electrical conductivity in this study confirm that the PA66 precursor was converted into a semi-conducting state once it was carbonized.

Effect of Heat Treatment Temperature on Properties of Phosphogypsum Based Wall Materials

The waste of land resources and the destruction of ecological environment caused by the massive storage of phosphogypsum are becoming increasingly prominent. In order to solve this problem, industrial solid waste phosphogypsum was used to the main raw material in this paper and aimed at the building materials utilization of phosphogypsum, and prepared a phosphogypsum‐based wall material. Through the pretreatment of phosphogypsum at different temperatures, the influence of heat treatment temperature on the performance of phosphogypsum based wall materials was explored. The experimental results show that with the increase of heat treatment temperature, the setting time, volume density and mechanical properties of phosphogypsum‐based wall materials gradually increase, and the hygroscopicity first increases and then decreases. Based on the performance and energy consumption, the best performance after 160°C heat treatment, when the content of hemihydrate gypsum in phosphogypsum is 53.62%, sample bulk density is 1.304 g/cm^3, moisture absorption is 30.7%, compressive strength is 3.74 MPa.

Research on the Pre-sintering Temperature During the Preparation of (1-x) NBT–xBaTiO3 Serial Ceramics

According to the formula of (1-x)NBT-xBaTiO3, this study selects different composition points and measures the volume density and piezoelectric property of the samples at different pre-sintering temperatures, ultimately determining the optimal pre-sintering temperature. Experiments show that for ceramic based on (1-x)NBT-xBaTiO3, when x<0.06 the optimal pre-sintering temperature should be 900°C; when x≥0.06, it should be 950°C.

New examples of Stein manifolds with volume density property

In the present paper, we shall provide new examples of Stein manifolds enjoying the (algebraic) volume density property and compute their homology groups.

Microstructure and enhanced volume density properties of FeMn78C8.0 alloy prepared via a cleaner microwave sintering approach

Smelting fine ore into a block with the lower phosphorus content before entering the furnace can achieve cleaner production and value-added efficiency for ferromanganese alloy enterprises, and microwave sintering technology shows bright application prospects in the secondary utilization of waste materials and environmental-friendly preparation of high-performance alloy materials. In this work, FeMn78C8.0 grade bulk alloy with enhanced volume density properties was efficiently prepared via an environmental-friendly microwave sintering approach, using high-carbon ferromanganese powder with low processing efficiency in factories as the raw material. Results indicate that adding certain carbon can prevent the oxidation behavior of Mn and Fe elements during the sintering process, and the qualified FeMn78C8.0 alloy can be obtained by controlling sintering temperature and duration time, with the optimum sintering conditions determined at 1168 °C for 11 min and with the alloy powder of <75 μm accounting for 63%. Meanwhile, some fine pores and cracks on the surface of FeMn78C8.0 alloy are conducive to the densification of the alloy sample and the internal alloying process of the carcass, further to enhance the volume density properties; and influence of the powder of <75 μm on the volume density properties is more profound than that by the powder of 75 μm–150 μm. Additionally, a higher value of volume density of 5.86 g cm−3 is obtained at 1200 °C holding for 10 min, far beyond the traditionally produced alloy by electric furnace with an average value of 5.56 g cm−3. The work highlights the efficient application of microwave sintering to the secondary utilization of ferromanganese powder and the environmental-friendly preparation of alloy materials.

Generic aspects of holomorphic dynamics on highly flexible complex manifolds

We prove closing lemmas for automorphisms of a Stein manifold with the density property and for endomorphisms of an Oka–Stein manifold. In the former case, we need to impose a new tameness condition. It follows that hyperbolic periodic points are dense in the tame non-wandering set of a generic automorphism of a Stein manifold with the density property and in the non-wandering set of a generic endomorphism of an Oka–Stein manifold. These are the first results about holomorphic dynamics on Oka manifolds. We strengthen previous results of ours on the existence and genericity of chaotic volume-preserving automorphisms of Stein manifolds with the volume density property. We build on work of Fornaess and Sibony: our main results generalise theorems of theirs, and we use their methods of proof.

Microencapsulation of Microbial Transglutaminase by Ultrasonic Spray-Freeze Drying

Microencapsulation of partially purified microbial transglutaminase (mTG) was investigated using ultrasonic spray-freeze drying (USFD), and the optimum coating materials (gum arabic, maltodextrin, inulin) ratio and the process parameters (flow rate and nozzle frequency) were determined using a D-optimal combined design. Also, the microencapsulated samples by USFD were compared with microencapsulated samples by conventional freeze drying (CFD) and conventional spray drying (CSD) in terms of microencapsulation efficiency, enzyme stability at extreme pH and high temperature conditions, and the presence of metal ions, physical (moisture content, particle morphology, particle and pore size, surface area, pore volume distribution, density and flow properties, caking degree, color), and reconstitution (wettability and solubility) properties. As a result, the optimum coating materials composition was determined as 60% gum arabic and 40% inulin, and process conditions were found to be flow rate of 6.83 ml/min and nozzle frequency of 48 kHz applying desirability function method. Microcapsules with smaller particle size, pore volume, and porosity, with lower moisture content and good reconstitution characteristics, were obtained by USFD with a maximum microencapsulation efficiency of ~ 97%.

Proper holomorphic immersions into Stein manifolds with the density property

In this paper we prove that every Stein manifold S admits a proper holomorphic immersion into any Stein manifold of dimension 2 dim S enjoying the density property or the volume density property.

Chaotic Holomorphic Automorphisms of Stein Manifolds with the Volume Density Property

Let X be a Stein manifold of dimension $$n\ge 2$$ satisfying the volume density property with respect to an exact holomorphic volume form. For example, X could be $$\mathbb {C}^n$$ , any connected linear algebraic group that is not reductive, the Koras–Russell cubic, or a product $$Y\times \mathbb {C}$$ , where Y is any Stein manifold with the volume density property. We prove that chaotic automorphisms are generic among volume-preserving holomorphic automorphisms of X. In particular, X has a chaotic holomorphic automorphism. A proof for $$X=\mathbb {C}^n$$ may be found in work of Fornaess and Sibony. We follow their approach closely. Peters, Vivas, and Wold showed that a generic volume-preserving automorphism of $$\mathbb {C}^n$$ , $$n\ge 2$$ , has a hyperbolic fixed point whose stable manifold is dense in $$\mathbb {C}^n$$ . This property can be interpreted as a kind of chaos. We generalise their theorem to a Stein manifold as above.

The forming region and mechanical properties of SiO2-Al2O3-MgO glasses

The glasses of 93.9% (xSiO2-yAl2O3-zMgO)-5% CaO-1% B2O3-0.1% Fe2O3 were prepared, and the relationship between mechanical properties and structural stability were characterized by means of Raman spectroscopy and optical band gap values. The glass forming region is found to be x=50–70%, y=10–25% and z=15–32%. As x=65%, y=10% and z=25% (SAM-4), the investigated glass possesses the optimum volume density, oxygen packing density, optical band gap, banding strength, compression strength and compression modulus, which are 2.517g/cm3, 77.047mol/l, 3.56eV, 77.04MPa, 202.74MPa and 106.70GPa, respectively. Meanwhile, starting from the representative point of SAM-4 to radiate around, the volume density, oxygen density, Raman intensity and mechanical properties of the glasses are all decreasing constantly, and the optical band gap of the glasses is increasing on the contrary. Moreover, the optical band gap value and Raman spectroscopy of SAM-4 all prove that the number of oxygen bonds in the bridge reach the maximum and the highest structural stability is achieved, which further shows that it is an important reason why its mechanical properties is significantly improved.

Non-algebraic examples of manifolds with the volume density property

Some Stein manifolds (with a volume form) have a large group of (volume-preserving) automorphisms: this is formalized by the (volume) density property, which has remarkable consequences. Until now all known manifolds with the volume density property are algebraic, and the tools used to establish this property are algebraic in nature. In this note we adapt a known criterion to the holomorphic case, and give the first examples of non-algebraic manifolds with the volume density property: they arise as suspensions or pseudo-affine modifications over Stein manifolds satisfying some technical properties. As an application we show that there are such manifolds that are potential counterexamples to the Zariski Cancellation Problem, a variant of the Tóth-Varolin conjecture, and the problem of linearization of C ∗ \mathbb {C}^* -actions on C 3 \mathbb {C}^3 .

New Concept in Reduced‐Calorie Sponge Cake Production by Xylitol and Oligofructose

AbstractIn the present study, the influence of sucrose replacement with xylitol and oligofructose on volume, apparent and solid density, porosity, water activity, crust color, texture and sensory properties of reduced‐calorie sponge cakes was investigated (control: 100% sucrose, X1: 100% xylitol, X2: 77% xylitol‐23% oligofructose, X3: 23% xylitol‐57% sucrose‐20% oligofructose and X4: 25% xylitol‐75% sucrose). Based on the results X3 indicated the highest volume and porosity and the lowest apparent density. X3 also possessed the same firmness with sucrose cakes, while other reduced‐calorie samples showed lower firmness compared to control. In terms of crust color, all reduced‐calorie samples excluding X1 had darker crust than control. Control cakes showed the highest water activity than other samples. The sensory scores of all reduced‐calorie cakes were similar to control at the 1st and 7th days of evaluation, while dietetic samples got higher scores than sucrose cakes at the 14th day after production. Xylitol had no significant effect on solid density (P &gt; 0.05).Practical ApplicationsDue to high level of sucrose in cake formulation, and problems such as obesity and increased blood sugar as the result of over consumption of these products, it is necessary to find a way to eliminate or reduce sucrose in cake formulation. Bulking agents are allowed for low calorie and diabetic diets, since their metabolism is slow and incomplete. The purpose of this research is using different concentrations of xylitol and oligofructose as bulking agents in reduced‐calorie cakes. Based on our findings, partial substitution of sucrose with xylitol and oligofructose (X3: xylitol‐sucrose‐oligofructose) showed the best results. On the other hand, complete substitution of sucrose with xylitol (X1) did not provide suitable physical and sensory properties.

Algebraic (volume) density property for affine homogeneous spaces

Let X be a connected affine homogenous space of a linear algebraic group G over $$\mathbb {C}$$ . (1) If X is different from a line or a torus we show that the space of all algebraic vector fields on X coincides with the Lie algebra generated by complete algebraic vector fields on X. (2) Suppose that X has a G-invariant volume form $$\omega $$ . We prove that the space of all divergence-free (with respect to $$\omega $$ ) algebraic vector fields on X coincides with the Lie algebra generated by divergence-free complete algebraic vector fields on X (including the cases when X is a line or a torus). The proof of these results requires new criteria for algebraic (volume) density property based on so called module generating pairs.

(Volume) density property of a family of complex manifolds including the Koras-Russell cubic threefold

We present modified versions of existing criteria for the density property and the volume density property of complex manifolds. We apply these methods to show the (volume) density property for a family of manifolds given by x 2 y = a ( z ¯ ) + x b ( z ¯ ) x^2y=a(\bar z) + xb(\bar z) with z ¯ = ( z 0 , … , z n ) ∈ C n + 1 \bar z =(z_0,\ldots ,z_n)\in \mathbb {C}^{n+1} and holomorphic volume form d x / x 2 ∧ d z 0 ∧ … ∧ d z n \mathrm {d} x/x^2\wedge \mathrm {d} z_0\wedge \ldots \wedge \mathrm {d} z_n . The key step is to show that in certain cases transitivity of the action of (volume preserving) holomorphic automorphisms implies the (volume) density property, and then to give sufficient conditions for the transitivity of this action. In particular, we show that the Koras-Russell cubic threefold { x 2 y + x + z 0 2 + z 1 3 = 0 } \lbrace x^2y + x + z_0^2 + z_1^3=0\rbrace has the density property and the volume density property.

Lie Algebra generated by locally nilpotent derivations on Danielewski surfaces

We give a full description of the Lie algebra generated by locally nilpotent derivations (short LNDs) on smooth Danielewski surfaces Dp given by xy=p(z) . In case deg(p)≥3 it turns out to be not the whole Lie algebra VF ω alg (Dp) of volume preserving algebraic vector fields, thus answering a question posed by Lind and the first author. Also we show algebraic volume density property (short AVDP) for a certain homology plane, a homogeneous space of the form SL₂ (C)/N , where N is the normalizer of the maximal torus and another related example.

ON ALGEBRAIC VOLUME DENSITY PROPERTY

A smooth affine algebraic variety X equipped with an algebraic volume form ω has the algebraic volume density property (AVDP) if the Lie algebra generated by complete algebraic vector fields of ω-divergence zero coincides with the space of all algebraic vector fields of ω-divergence zero. We develop an effective criterion of verifying whether a given X has AVDP. As an application of this method we establish AVDP for any homogeneous space X = G/R that admits a G-invariant algebraic volume form where G is a linear algebraic group and R is a closed reductive subgroup of G.

Riemann surfaces in Stein manifolds with the Density property

We show that any open Riemann surface can be properly immersed in any Stein manifold with the (Volume) Density property and of dimension at least 2. If the dimension is at least 3, we can actually choose this immersion to be an embedding. As an application, we show that Stein manifolds with the (Volume) Density property and of dimension at least 3, are characterized among all other complex manifolds by their semigroup of holomorphic endomorphisms.