Value Of DH Research Articles

Effects of different nutrient supply options on system productivity, nitrogen use efficiency and soil enzyme activities in maize - wheat cropping system cropping system

The field experiments were conducted during during kharif and the following rabi seasons of 2011-12 and 2012-13 with five different treatments in maize (Zea mays L.) and wheat (Triticum aestivum (L.) emend Fiori & Paol.) cropping systems. Application of 50% RDF + 50% RDN recorded maximum WEY of maize (3.23 and 4.58 t/ha) and system productivity (8.20 and 9.03) over rest of the treatments, but remained statistically similar with other treatments except control during 2011-12 and 2012-13, respectively. The highest ANUE (5.07 and 15.36 kg grain yield increase/kg N applied) of maize crop was recorded at 50% RDF + 25% RDN + BF, followed by 50% RDF + 25% RDN during both the years. The highest ANUE (17.64 and 17.18 kg grain yield increase/kg N applied) of wheat crop were recorded from 37.5% RDF + 37.5% RDN + BF during both the years, respectively. Application of 50% RDF + 50% RDN to maize resulted in increased the value of MBC (18.0 and 18.4%), DH (22.9 and 18.6%), alkaline phosphatase (33.3 and 29.6%) and urease (37.1 and 37.8%) over control during 2011 and 2012, respectively. An increased value of MBC (38 and 34.6%), DH (29.2 and 29.8%), alkaline phosphatase (37.2 and 34.9%) and urease (30.1 and 25.6%) was recorded with the application of 37.5% RDF + 37.5% RDN + BF to wheat over control during both the years, respectively. Bangladesh J. Bot. 53(3): 429-438, 2024 (September)

Graph-codes

The symmetric difference of two graphs G1,G2 on the same set of vertices [n]={1,2,…,n} is the graph on [n] whose set of edges are all edges that belong to exactly one of the two graphs G1,G2. Let H be a fixed graph with an even (positive) number of edges, and let DH(n) denote the maximum possible cardinality of a family of graphs on [n] containing no two members whose symmetric difference is a copy of H. Is it true that DH(n)=o(2n2) for any such H? We discuss this problem, compute the value of DH(n) up to a constant factor for stars and matchings, and discuss several variants of the problem including ones that have been considered in earlier work.

Computational Insight of Phase Transformation and Drug Release Behaviour of Doxycycline-Loaded Ibuprofen-Based In-Situ Forming Gel.

This research investigates the gel formation behaviour and drug-controlling performance of doxycycline-loaded ibuprofen-based in-situ forming gels (DH-loaded IBU-based ISGs) for potential applications in periodontal treatment. The investigation begins by exploring the physical properties and gel formation behaviour of the ISGs, with a particular focus on determining their sustained release capabilities. To gain a deeper understanding of the molecular interactions and dynamics within the ISGs, molecular dynamic (MD) simulations are employed. The effects of adding IBU and DH on reducing surface tension and water tolerance properties, thus affecting molecular properties. The phase transformation phenomenon is observed around the interface, where droplets of ISGs move out to the water phase, leading to the precipitation of IBU around the interface. The optimization of drug release profiles ensures sustained local drug release over seven days, with a burst release observed on the first day. Interestingly, different organic solvents show varying abilities to control DH release, with dimethyl sulfoxide (DMSO) demonstrating superior control compared to N-Methyl-2-pyrrolidone (NMP). MD simulations using AMBER20 software provide valuable insights into the movement of individual molecules, as evidenced by root-mean-square deviation (RMSD) values. The addition of IBU to the system results in the retardation of IBU molecule movement, particularly evident in the DMSO series, with the diffusion constant value of DH reducing from 1.2452 to 0.3372 and in the NMP series from 0.3703 to 0.2245 after adding IBU. The RMSD values indicate a reduction in molecule fluctuation of DH, especially in the DMSO system, where it decreases from over 140 to 40 Å. Moreover, their radius of gyration is influenced by IBU, with the DMSO system showing lower values, suggesting an increase in molecular compactness. Notably, the DH-IBU configuration exhibits stable pairing through H-bonding, with a higher amount of H-bonding observed in the DMSO system, which is correlated with the drug retardation efficacy. These significant findings pave the way for the development of phase transformation mechanistic studies and offer new avenues for future design and optimization formulation in the ISG drug delivery systems field.

Determining the deformation properties of crushed rock under compressive compression conditions

The object of this study is the process that forms fill materials from crushed rock under load for managing the condition of side rocks in a coal-bearing massif with preparatory workings. Deformation properties of crushed rock under laboratory conditions were evaluated on the basis of a study of compressive compression of the fill material. It was registered that there is a quadratic functional dependence between the change in the bulk density of crushed rock of different granulometric composition and the specific potential energy of deformation. It was experimentally established that the specific potential energy of deformation reaches the limit values at the maximum compression of crushed rock when the fill material consists of parts of different sizes. For experimental samples with different thickness of the rock layer h0 (m), there was a linear relationship between their longitudinal deformation Dh (m) and the external load F (kN), which determined the behavior of the deforming body at critical levels. Under such conditions, with a relative change in the volume of the fill material dV=0.36, that is, with the same relative deformation at any values of the parameter h0 (m) and the compaction coefficient of the crushed rock kcon=1.57, the maximum stiffness of the rock supports was ensured. With a limited amount of external static load on the experimental samples, in the process of their deformation when the parameter h0 was reduced by 2 times before their compression, the compaction coefficient of the crushed rock increased from kcon=1.33 to kcon=1.57. At the same time, the specific potential energy of deformation increased by 40 %, which made it possible to ensure the maximum rigidity of the fill material at the minimum value of the longitudinal deformation Dh (m) of the experimental samples

Proteolysis of β-Lactoglobulin Assisted by High Hydrostatic Pressure Treatment for Development of Polysaccharides-Peptides Based Coatings and Films

Peptides usually have many bioactive functions. The variety of peptide binding and the modularity of the components allow for their application to additional tissues and materials; hence broadening the range of possible coatings and films. β-lactoglobulin (b-LG) forms spherical microgels or can be used in the formation of coated particles, with the core formed by aggregated b-LG and the coat by polysaccharides. The enzymatic proteolysis of b-LG assisted by high hydrostatic pressure (HHP) treatment was studied. Pretreatment of HHP enhanced the hydrolysis degree (DH) of b-LG. The highest value of DH without pretreatment was 24.81% at 400 MPa, which increased to 27.53% at 200 MPa with pretreatment, suggesting a difference in the DH of b-LG caused by the processing strategy of HHP. Molecular simulation suggested that the flexible regions of b-LG, e.g., Leu140-Ala142 and Asp33-Arg40, might contribute to enzymatic proteolysis. The b-LG hydrolysate exhibited the highest capacity of scavenging free DPPH and OH radicals at 200 MPa. In addition, the 1–2 kDa and 500–1000 Da peptides fractions significantly increased from 10.53% and 9.78% (under 0.1 MPa) to 12.37% and 14.95% under 200 MPa, respectively. The higher yield of short peptides under HHP contributed to the antioxidant capacity of b-LG hydrolysates. Enzymatic hydrolysis also largely reduced the immunoreactivity of b-LG, which is of high importance in the practical application of b-LG in the field of coatings and films in regard to biocompatibility. Hydrolysis of b-LG assisted by high-pressure treatment showed promising potential in the preparation of bioactive peptides for further development of polysaccharide-peptide-based coatings and films.

Performance Analysis of Iteratively Decoded Convergent Source Mapping with Sphere Packing-Assisted Differential Space-Time Spreading Technique for Efficient Video Transmission

With the substantial growth in number of wireless devices, future communication demands overarching research to design high-throughput and efficient systems. We propose an intelligent Convergent Source Mapping (CSM) approach incorporating Differential Space-Time Spreading (DSTS) technique with Sphere Packing (SP) modulation. The crux of CSM process is assured convergence by attaining an infinitesimal Bit-Error Rate (BER). Data Partitioning (DP) H.264 video codec is deployed to gauge the performance of our intelligent and efficient system. For the purpose of efficient and higher data rates, we have incorporated compression efficient source encoding along with error resiliency and transmission robustness features. The proposed system follows the concept of iterations between the Soft-Bit Source-Decoder (SBSD) and Recursive Systematic Convolutional (RSC) decoder. Simulations of the DSTS-SP-assisted CSM system are presented for the correlated narrowband Rayleigh channel, using different CSM rates but constant overall bit-rate budget. The SP-assisted DSTS systems are mainly useful in decoding algorithms that operate without requiring Channel State Information (CSI). The effects of incorporating redundancy via different CSM schemes on the attainable performance and convergence of the proposed system are investigated using EXtrinsic Information Transfer (EXIT) charts. The effectiveness of the proposed system is demonstrated through IT++ based proof-of-concept simulations. The Peak Signal-to-Noise Ratio (PSNR) analysis shows that using Rate-2/6 CSM with minimum Hamming distance ( d H , min ) of 4 offers about 5 dB gain, compared to an identical overall system code rate but with Rate-2/3 CSM and d H , min of 2. Furthermore, for a consistent value of d H , min and overall rate, the Rate-2/3 CSM scheme beats the Rate-5/6 CSM by about 2 dB at the PSNR degradation point of 2 dB. Moreover, the proposed system with Rate-2/3 CSM scheme furnishes an E b / N 0 gain of 20 dB when compared with the uniform-rate benchmarker. Clearly, we can say that higher d H , min and lower CSM values are favourable for our proposed setup.

Removal Efficiency of Lipid-regulating Drug Clofibric Acid from the Aquatic Environment by Calcined Anionic Clay ZnAl-CO3

Clofibric acid (CA) is widely used as regulator of lipid levels in blood; it is considered one of the residual drugs that have a high persistence in the aquatic environment. After wastewater treatment, only a small amount of CA can be removed. The aim of this work was to investigate the reduction of CA in contaminated wastewater using calcined anionic clay ZnAl-CO3, which was chosen for its higher adsorption capacity, recyclability, and non-regeneration of sludge. The maximum retention amount, Qm, exceeded 2220 mg g–1, and the value of DH° suggested a physical process. The removal rate achieved 90 %, and the remaining quantity was widely below the tolerance thresholds. Retention was achieved by hydrogen bonds and electrostatic interactions between the adsorbate molecules. Recycling tests clearly suggested that this material is recyclable, promising, and very effective compared to other adsorbents. This retention contributes to the attenuation of persistent lipid regulator.

Theory for admittance voltammetry of reversible two step electron transfer process with DC bias at rough and fractal electrodes

We developed a phenomenological theory for DC-bias dependent electrochemical impedance response and admittance voltammetry of reversible two-step electron transfer (EE) process at randomly rough and fractal electrodes. The power spectrum of roughness is used to incorporate the statistical information of surface randomness. For the finite fractal model, statistical morphological parameters of roughness, viz., fractal dimension (DH), topothesy length (ℓτ) and lower cut-off length (ℓ), significantly influence the admittance response. The magnitude of admittance increases with an increase in the roughness of fractal electrode (e.g. increase in the value of DH or ℓτ or decrease in ℓ) for both the electron transfer steps. The magnitude of admittance with the variation of DC potential at fixed temporal frequency unravels the multi-electron transfer process. The two step electron transfer process has two characteristic peaks in their plot. The enhanced roughness of electrode increases the height of the admittance peaks and the regions around it (obtained at different fixed frequencies). Our theory is validated with experimental data for the ethyl viologen system at a moderately rough Pt electrode. Finally, our current methodology for admittance voltammetry has the dual advantage of impedance as well as of voltammetry.

Study of hydrogen storage and electrochemical properties of AB2-type Ti0.15Zr0.85La0.03Ni1.2Mn0.7V0.12Fe0.12 alloy

A C15 AB2 Laves-type Ti0.15Zr0.85La0.03Ni1.2Mn0.7V0.12Fe0.12 alloy was prepared by arc melting and annealing. Phase-structural composition, microstructure, hydrogen absorption-desorption properties, thermodynamic and electrochemical performances were characterized by X-ray diffraction, scanning electron microscopy, hydrogen absorption-desorption measurements and electrochemical characterization and were related to the use of the alloys as metal hydride battery anodes.The alloy contains a C15 FCC intermetallic compound as the main phase and a LaNi secondary phase as the minor constituent (∼1 wt%).During the electrochemical tests, the anode electrodes quickly, after just a few activation cycles, reached a maximum discharge capacity. This was related to the catalytic effect of the La-rich secondary phase which acted as a catalyst of hydrogen absorption-desorption.Annealing resulted in increase of the maximum discharge capacity from 345 mAh/g for the as cast alloy to 370 mAh/g. Furthermore, the annealed alloy showed a better high rate dischargeability and a higher cyclic stability. After 100 cycles with 100% DOD at discharge current density of 1C, the discharge capacity of the annealed alloy was very high, at a level of 90% of the initial capacity.The rates of hydrogen diffusion have been characterized by Potentiostatic Intermittent Titration Technique and Electrochemical Impedance Spectroscopy. With increasing an extent of transformation into the hydride, the H diffusion rate in the bulk of the alloy particles decreased. The maximum value of DH measured by PITT for the annealed alloy was observed for the nearly fully discharged electrode, (SOC 2%).

Comparative Study on Morphological and Electrochemical Properties of Nickel–Cobalt Double Hydroxide, Cobalt Hydroxide, and Nickel Hydroxide

The morphological and electrochemical properties of nickel–cobalt double hydroxide (Ni-Co DH), cobalt hydroxide [Co(OH)2], and nickel hydroxide [Ni(OH)2] prepared directly on a transparent conductive oxide substrate via a simple one-pot wet-chemical method have been investigated and compared. All samples were composed of nanosheets vertically aligned on the substrate. Comparison of the results showed that Ni-Co DH with submicrometer-scale pores had more compact structure than Ni(OH)2 or Co(OH)2. Moreover, the highly symmetric cyclic voltammetry (CV) curves of Ni-Co DH indicated its good electrochemical reversibility. The specific capacitance value of Ni-Co DH was ∼ 286 F/g and ∼ 210 F/g at scan rate of 2 mV/s and 100 mV/s, respectively, indicating its better rate capability, particularly at high scan rate, than Ni(OH)2 or Co(OH)2. In addition, after CV cycling test, the Ni-Co DH nanosheets showed no noticeable morphological change. Furthermore, the electrochromic performance of Ni-Co DH was sustained over 10000 s. Thus, Ni-Co DH prepared via a facile one-step process exhibited promising characteristics as a cost-effective functional material for use in electrochemical devices.

Real world data on young patients with high-risk diffuse large B-cell lymphoma treated with R-CHOP or R-CHOEP - MYC, BCL2 and BCL6 as prognostic biomarkers.

BackgroundDouble expression of MYC and BCL2 proteins (DE) and double-hit MYC+BCL2/BCL6 translocations (DH) were established as important biomarkers in patients with diffuse large B-cell lymphoma (DLBCL) by the 2016 revision of the World Health Organization classification of lymphoid neoplasms. Whether this applies to the subgroup of young patients with high risk DLBCL is not known. We previously found that in a uniform retrospective population-based cohort of patients aged 18–60 years with high-risk DLBCL, the addition of etoposide to R-CHOP chemotherapy (R-CHOEP) resulted in improved survival mainly in patients with germinal center B-cell like (GCB) immunophenotype. The aim of this study was to investigate the prognostic and predictive value of DE and DH in this patient cohort.MethodsData on all young Danish patients diagnosed with de novo high-risk DLBCL 2004–2008 and treated with R-CHOP or R-CHOEP were obtained from the Danish Lymphoma database (n = 159). Tumor samples were available from 103 patients. MYC and BCL2 proteins were analyzed with quantitative immunohistochemistry (IHC) using different cut off values. MYC-, BCL2- and BCL6-translocations were examined with fluorescent in situ hybridization (FISH).ResultsDE with MYC>75% and BCL2>85% was an independent negative prognostic marker of progression free survival (PFS) in patients treated with R-CHOP but not R-CHOEP (p<0.001), also after exclusion of patients with DH. A predictive effect of DE for response (PFS) to R-CHOEP vs. R-CHOP was almost significant (p = 0.07). DH was not prognostic in this patient cohort.ConclusionIn young patients with high-risk DLBCL, treatment with R-CHOEP may overcome the negative prognostic impact of DE observed in patients treated with R-CHOP.

Role of ammonium ion on the aggregation and adsorption properties of sodium dodecylsulfate

ABSTRACTThe role of mixed counterion toward the aggregation behavior of sodium dodecylsulfate (SDS) is quantified by determining the critical micelle concentration (cmc) of SDS micelle in the presence of added NH4Cl salt. The dependence of cmc of SDS on added salt is explained in the light of the modified Corrin–Harkins equation and the nonlinearity of this plot is shown due to the exchange of Na+ ion by added ion. The aggregation number (N) of SDS micelle is also calculated using the steady-state fluorescence method, where sudden change in N value was observed in two different concentration regions of the modified CH plot. Furthermore, the hydrodynamic diameter (dH) of dodecyl sulfate micelles was determined using the dynamic light scattering method. In scattering studies, a sharp change in the value of dH occurred at around 50 mM of added salt, which might hint toward the shape change of dodecyl sulfate micelle. The surface excess values of SDS in the presence of mixed inorganic counterion are also calculated in the light of the Gibbs adsorption isotherm.

Magnetic flux gradient observation during fatigue crack propagation: A case study of SAE 1045 carbon steel used for automotive transmission parts

The objective of this study is to evaluate the application of the metal magnetic memory (MMM) technique for investigations on fatigue crack propagation in a ferromagnetic material. Fatigue failure caused by stress concentration is serious in practical engineering. However, early fatigue damages cannot be detected by using traditional nondestructive testing (NDT) methods. Therefore this paper study about NDT method called metal magnetic memory (MMM) that has potentials for evaluating the fatigue damage at the early damage and critical fracture stages. While its capacity to evaluate the distribution of self-magnetic leakage field signals on the component’s surface is well-established, there remains a need to scrutinize the physical mechanism and quantitative analysis aspects of this method. To begin with, a fatigue test involving a loading of 7kN was conducted on a SAE 1045 carbon steel specimen. This material is frequently used in the manufacturing of automotive transmission components that include the axle and spline shaft. MMM signals were measured along a scanning distance of 100 mm and analysed during the propagation stage. Other than revealing that the value of the magnetic flux gradient signals dH(y)/dx increased in tandem with the crack length, the results also led to the detection of the crack growth location. It was anticipated that the dH(y)/dx value will also exhibit an upward trend with a rise in the fatigue growth rate of da/dN . A modified Paris equation was utilized to correlate dH(y)/dx with da/dn through the replacement of the stress intensity factor range Δ K . This resulted in the log-log plot of da/dN versus dH(y)/dx portraying an inclination similar to the log-log plot of da/dN versus Δ K . A linear relationship was established between dH(y)/dx and Δ K with the R2 value as 0.96. Players in the automotive industry can benefit from the disclosure that dH(y)/dx can effectively replace Δ K for the monitoring of fatigue crack growth behaviour.

Effects of magnetic heat treatment on microstructure and hydrogen permeation properties of Nb-Ti-Ni alloy membranes

In this paper, effects of magnetic heat treatment (MHT) on structure and hydrogen permeation properties of Nb49Ni25Ti26 alloy membrane have been investigated. XRD and SEM were employed to characterize its phases and microstructure. Also, hydrogen diffusion coefficients (DH) of the alloy membrane were measured in Devanathan-Stachurski (D-S) dual-cell system. The results indicate that MHT-treated alloys still maintain their two-phase structure, consisting of the primary bcc-Nb (Ni, Ti) solid solution phase and (bcc-Nb(Ni, Ti) + β2-NiTi) eutectic phase, with their DH increment after MHT at 0° and 90° respectively. The maximum value of DH is 6.3822 × 10−9 H2 m2/s for the alloy membrane treated by MHT at 0° angle (magnetic field direction is parallel to membrane surface), the increase of DH is possibly due to the grain orientation, and the formation of smaller solid solution phase region with higher specific area. Such results suggest that reasonable MHT benefits to the improvement of hydrogen permeation properties of Nb49Ni25Ti26 alloy membrane.

Antimicrobial and radical scavenging properties of bovine collagen hydrolysates produced by Penicillium aurantiogriseum URM 4622 collagenase.

A 2(3) full factorial design was used to identify the main effects and interactions of pH, collagen concentration and temperature on the degree of collagen hydrolysis (DH) by collagenase from Penicillium aurantiogriseum URM 4622. Increases in both pH and collagen concentration improved DH, and a positive interaction effect was observed for these variables. On the other hand, temperature had a negative main effect on DH. The maximum value of DH (4.65μg/mL) was achieved at 7.5mg/mL collagen concentration, pH8.0 and 25°C. The peptide profile showed several peptides with molecular weights lower than 2kDa and exhibited antibacterial activity against Escherichia coli, Bacillus subtilis and Staphylococcus aureus. An antioxidant activity of 84.7 ± 0.24% towards the radical ABTS• + was obtained with 50mg/mL hydrolysates. This study demonstrated that collagen hydrolysed by P. aurantiogriseum URM 4622 collagenase possesses interesting antibacterial and antioxidant activities.

Drafting, kissing and tumbling process of two particles with different sizes

We numerically study the drafting, kissing and tumbling (DKT) phenomenon of two non-identical circular particles sedimenting in a two-dimensional infinite channel by using the lattice Boltzmann equation with a multiple-relaxation-time collision model. The main emphasis of this work is to investigate the effect of the longitudinal distance and diameter ratio between two particles on the flow pattern during sedimentation. The method is first validated by simulating the sedimentation of one single particle and two identical particles. For two particles with different sizes, two cases are considered: in Case-1, the larger particle is initially located above the smaller one; in Case-2, the smaller particle is initially above the larger one. The simulation results are compared with the case of two equal-sized particles. The results show that two particles with different sizes are easier to separate than two identical ones. In particular, the effects of initial longitudinal distance (Dh) and diameter ratio on the occurrence of the DKT process are studied in detail. With changing these two parameters, the results reveal the transitions between the DKT phenomena. It is shown that the DKT process can take place (only once) regardless of any value of Dh in Case-1, while in Case-2, the two particles will never undergo the DKT process when increasing Dh beyond a certain threshold. The results also show that, as the particle diameter ratio γ is increased starting from 1, in Case-1 the two particles will interact by undergoing two transitions of the DKT phenomena: from the repeated to the one-off DKT process, while in Case-2 there exists an additional mode: the gap increases continuously from the start.

Self-organized one-atom thick fractal nanoclusters via field-induced atomic transport

We report on the growth of a monolayer thick fractal nanostructures of Ag on flat-top Ag islands, grown on Si(111). Upon application of a voltage pulse at an edge of the flat-top Ag island from a scanning tunneling microscope tip, Ag atoms climb from the edge onto the top of the island. These atoms aggregate to form precisely one-atom thick nanostructures of fractal nature. The fractal (Hausdorff) dimension, DH = 1.75 ± 0.05, of this nanostructure has been determined by analyzing the morphology of the growing nanocluster, imaged by scanning tunneling microscopy, following the application of the voltage pulse. This value of the fractal dimension is consistent with the diffusion limited aggregation (DLA) model. We also determined two other fractal dimensions based on perimeter-radius-of-gyration (DP) and perimeter-area (D′P) relationship. Simulations of the DLA process, with varying sticking probability, lead to different cluster morphologies [P. Meakin, Phys. Rev. A 27, 1495 (1983)]; however, the value of DH is insensitive to this difference in morphology. We suggest that the morphology can be characterized by additional fractal dimension(s) DP and/or D′P, besides DH. We also show that within the DLA process DP = DH [C. Amitrano et al., Phys. Rev. A 40, 1713 (1989)] is only a special case; in general, DP and DH can be unequal. Characterization of fractal morphology is important for fractals in nanoelectronics, as fractal morphology would determine the electron transport behavior.

Effects of sintering behavior on piezoelectric properties of porous PZT ceramics

Porous lead zirconate titanate (PZT) ceramics were fabricated by the gel-casting process of particle-stabilized wet foams and sintered at different temperatures. The bulk density and grain size of porous PZT ceramics increased with the increase of sintering temperature from 1150 to 1250 °C, which exerted remarkable influence on the value of relative permittivity (εr) and piezoelectric strain coefficient (d31 and d33). The relationship between microstructure and electric properties was explained by the space-charge theory reasonably. Under the joint effects of bulk density and grain size, the value of dh and gh decreased with the increase of sintering temperature, resulting in the decrease of hydrostatic figure of merit (HFOM) values from 12633 to 3427×10–15 Pa−1.

Critical energy of direct detonation initiation in gaseous fuel–oxygen mixtures

The critical energy of some gaseous fuels and oxygen mixtures at different initial pressure and equivalence ratios are measured based on an experiment system we developed. The determination of direct initiation of detonation is based on the overpressure signal from a pressure transducer. The effective energy responsible for the direct initiation is considered as the first quarter cycle of the current discharge. The effect of initial pressure and equivalence ratio on the critical energy of direct initiation is firstly investigated in some typical gaseous fuel (i.e., C2H2, C2H4, C3H8, H2) and oxygen mixtures. It shows that the relationship between critical energy and initial pressure is inversely exponential and it is ‘U’ shaped between critical energy and equivalence ratio. The study of the effect of different oxygen concentration and argon dilution on the critical energy of stoichiometric acetylene and oxygen is carried out, the results indicate that oxygen concentration significantly affects the critical energy, and the critical energy increases with increasing amount of argon dilution. This study finally quantitatively research on the detonation hazard parameter (DH) of each stoichiometric mixture. The value of DH in increasing order for the mixtures are as following: C2H2–O2, C2H2–O2–50%Ar, C2H4–O2, C2H2–O2–65%Ar, C2H2–O2–70%Ar, C3H8–O2 and H2–O2, the results also indicate the critical energy is different by orders of magnitude if fuels do not belong to the same group.

Temperature Dependence of Proton Diffusion in Ih Ice

The temperature dependence of the proton diffusion constant, DH+, in methanol-doped ice was studied over the wide temperature range of 80−260 K. For that purpose, we measured the time-resolved fluorescence of a flavin mononucleotide (FMN) and riboflavin in ice doped with HCl or HF. The analysis of the fluorescence quenching provided the value of DH+. We found that the temperature dependence of DH+ at T > 235 K is rather small, whereas at T < 235 K, it is rather large. These temperature-dependence results are similar to previous conductivity measurements. We used a stepwise, two-coordinate qualitative proton transfer model to explain the temperature dependence of DH+ in ice.