Oil and gas pipeline leakage incidents occur from time to time, causing environmental pollution, property damages and other serious consequences. Flattening the oil and gas pipelines to stop the flow ...can effectively reduce losses. The extrusion device can quickly arrive at the incident scene and flatten the pipeline within a short time using hydraulic power or mechanical force so as to stop the flow. However, due to the springback problem, a small amount of oil or gas will still leak. Therefore, studying the bending springback of flattened oil and gas pipelines is very essential to solving the oil or gas leakage problem. This paper analyzes the theories related to flattening and closure of oil and gas pipelines. Springback is an inevitable result of the elastic redistribution of the internal stress in a flattened pipeline. Regarding the bending springback problem of flattened steel pipelines, based on the assumptions of plane strain, this paper applies the plate bending theory and establishes a theoretical model for the bending springback process of flattened steel pipelines and obtains the factors affecting the bending springback of flattened pipelines. At the same time, it uses the model in conjunction with the experiment to analyze the relationship between the springback of a flattened pipeline and the closure efficiency.
The objective of this study was to investigate the effects of experimental conditions for measuring the water vapor transmission rate (WVTR) of high-density polyethylene (HDPE) bottles using a ...steady-state sorption method. Bottles were filled with desiccant, closed with caps and heat induction sealed, and then stored in stability chambers at controlled temperature and relative humidity. Weight gain of the bottles was determined every 1 or 2 weeks until a linear weight gain profile was obtained. WVTR of the bottles was determined from the slope of the linear portion of the weight gain versus time profile. The effects of desiccants and temperature/humidity were studied. Results show that, with a sufficient amount of anhydrous calcium chloride in bottles, a negligibly low and sufficiently constant headspace humidity is maintained, and a steady-state permeation rate is achieved. For all 8 sizes of bottles used in this study, steady-state was achieved in 1 or 2 weeks after the experiment was started. This method provided reproducible WVTR data for HDPE bottles. Apparent moisture permeability of all 8 sizes of bottles was (2.3
±
0.3)
×
10
−7, (2.6
±
0.2)
×
10
−7, and (3.4
±
0.2)
×
10
−7
cm
2/s at 25
°C, 30
°C, 40
°C, respectively. Moisture permeability determined from the current study was similar to data reported in the literature, indicating that the steady-state weight gain method can be used to obtain reliable WVTR of containers for pharmaceutical products.
Developing Solid Oral Dosage Forms: Pharmaceutical Theory and Practice, Second Edition illustrates how to develop high-quality, safe, and effective pharmaceutical products by discussing the latest ...techniques, tools, and scientific advances in preformulation investigation, formulation, process design, characterization, scale-up, and production operations. This book covers the essential principles of physical pharmacy, biopharmaceutics, and industrial pharmacy, and their application to the research and development process of oral dosage forms. Chapters have been added, combined, deleted, and completely revised as necessary to produce a comprehensive, well-organized, valuable reference for industry professionals and academics engaged in all aspects of the development process. New and important topics include spray drying, amorphous solid dispersion using hot-melt extrusion, modeling and simulation, bioequivalence of complex modified-released dosage forms, biowaivers, and much more.
The current study was conducted to examine the microstructure of the 2 pct Mg-55 pct Al-1.6 pct Si-Zn (wt pct) coating on steel in detail and analyse the formation mechanisms of various reaction ...products in the coating. The coating microstructure was comprised of an
α
-Al dendrite framework, and an interdendritic network, occupied by a number of solidification products, which were fine Al-Zn mixtures, Mg
2
Si, Si, MgZn
2
, and lamellar MgZn
2
/Zn mixtures. It was found that the Al-Zn mixtures observed in the interdendritic region were the decomposition products of the high Zn
α
-Al components of various eutectic reactions taking place during solidification. A method was developed to differentiate the Si and Mg
2
Si phases optically with colour contrasts. It was found that, when Si and Mg
2
Si formed, they occupied the entire interdendritic spaces at the locations where they formed. Judging from the Al-Mg-Si liquidus projection, the Mg
2
Si phase should form first during solidification, followed by the simultaneous formation of Mg
2
Si and Si. On the other hand, the MgZn
2
phase formed into two different morphologies, with a large blocky shape and fine precipitates embedded in the lamellar Zn/MgZn
2
mixtures, both surrounded by Al-Zn mixtures. It was observed that all eutectic reactions involved the formation of an
α
-Al component, which formed in a divorced manner
via
either growing on existing dendrite arms, or sometimes as isolated islands embedded in blocky MgZn
2
.
As a widely used food preservative, methyl paraben was experimentally evidenced with serious hormone-like adverse effects. Herein, a high performance thin-layer chromatography platformed ...bioluminescent bioautography and image analysis for the selective quantification and confirmation of methyl paraben was proposed and validated in vinegar and coconut juice. First, the detectability of the bioautography to the analyte on different layer materials was estimated, revealing that normal silica gel was the best choice. After that, the liquid of sample extract and working solution were separated to overcome the background noises due to co-extracted matrices. The separation result was then coupled to the optimized bioautography, enabling instant and straightforward screening of the targeted compound. For accurate quantification, bioluminescent inhibition pattern caused by the analyte was processed by image analysis, giving useful sensitivity (LOD > 16 mg/kg), precision (RSD < 10.1 %) and accuracy (spike-recovery rate 76.9 %–112.2 %). Finally, the suspected result was confirmed by determining its MS fingerprint, further strengthening the reliability of screening.
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•A facile HPTLC detection of methyl paraben in juice and vinegar was proposed.•The image-giving bioautography enabled high throughput screening of the analyte.•Quantification was easily realized by image analysis.•An EIS-MS analysis was linked to confirm the molecular fingerprint of the suspect.
Recently, a group of researchers conducted experimental studies on the high-temperature oxidation behaviour of Si-containing steels and published a series of papers in several international journals. ...Many of the research “findings” in these papers were inconsistent and contradictory with previous results. Based on the different findings, it was claimed that they arrived at “new insights” to the oxidation behaviour of Si-containing steels and discovered a “new method” to reduce the oxide scale amount generated during reheating of Si-containing steels. After examining the experimental methods used, it was revealed that most of the “new findings” were likely the direct consequence of the use of a very low gas flow rate (30 mL/min) in their experiments. This resulted in an extremely low oxygen supply rate when the oxygen concentration in the experimental gas was low, which in turn limited the reaction rate that could be possibly achieved by gas–steel reaction if abundant gas had been made available. The kinetics results and scale thickness/structures thus produced were therefore misleading, which also led to the erroneous interpretation of the results. This paper comments on the main results presented in these papers and briefly discuss several fundamental issues related to the design of steel oxidation experiments.
In recent years, growing food safety and quality concerns have emerged and created an urgent need for the development of rapid and reliable food control technologies. This study proposes a novel ...surface-enhanced Raman spectroscopy (SERS) substrate printing technology that utilizes commercial filter paper functionalized by silver nanoparticles. We modified the Automatic TLC Sampler using a two-dimensional (2D) printer. The modification allows for various sampling modes which can be applied to 2D printing. The shape and size of nano silver on the substrate were determined, and the substrate sensitivity, uniformity, and stability were evaluated. As demonstrated by the experimental outcomes, the proposed technology is highly sensitive and reproducible, that is, the limit of quantitation was 10–5 mg/kg, and the spot-to-spot and block-to-block Raman intensity variations were below 4.2%. We also successfully applied the technology to pears and apples for thiram recognition, yielding outstanding detectability down to 2.5 × 10–6 and 3.9 × 10–7 mg/mL (equal to 2.5 × 10–3 and 3.9 × 10–4 mg/kg), respectively. These were well below the maximum residue limit (7 mg/kg). More importantly, the linear relationships between thiram levels and the SERS intensity allow for sensitive monitoring of minute variations in agricultural insecticide residues. This proposed detection method can realize in situ detection with a strong signal fingerprint.
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•A separable SERS sensor platformed by HPTLC was developed.•A flexible AgNP@GFP substrate with high SERS activity was fabricated.•A novel and facile interfacing method for HPTLC-SERS ...was developed.•Performances of the developed method was validated with MG in the fish sample.•The promising usability of HPTLC as a versatile platform was demonstrated.
Facile and effective coupling of SERS sensor to chromatographic tools has been an attractive goal in the field of food analytical chemistry for years. Platformed by HPTLC, a separable SERS sensor was developed in this study and its analytical power was exemplarily evaluated by screening trace malachite green in fish. To enable enough detectability and reproducibility of SERS measurements, a flexible substrate based on the hybrid of AgNP and glass fiber paper was easily fabricated. Meanwhile, the crude extract of fish muscle was separated on the aluminum foil backed HPTLC plate, resulting in spiral isolation of the analyte from co-extracted matrix. Guided by the visible standard in parallel, bands of interest were thereafter transferred to the eluent by a handy puncher. Jointly with the as-prepared flexible substrate, the band eluent was measured by Raman spectroscopy, responding sensitive and characteristic fingerprint signals. Meanwhile, performances of the established SERS sensor were also examined, showing adequate detectability (LOD < 10 μg/kg), precision (RSD%<11.8%) and linearity (R2 = 0.9975 from 0.05 to 10 ng/band) for screening purpose. Apart from that, the analysis robustness for practical application was further validated with fish sample, giving spike-recovery rates from 78.8 to 87.3%. This work demonstrated that HPTLC platformed SERS sensor can reach an ideal balance between efficiency, throughput and reliability, and therefore might be a promising tool especially suitable for screening trace contaminants in sophisticated mixtures.
•A process for preparing hydrogen-rich gas by Fe/Ca in-situ catalytic biochar fixed-bed counter-flow steam gasification is proposed.•The gasification intensity of the biochar loaded with CaO is ...66.44% higher than that of the biochar without loading.•The hydrogen production yield of Fe2O3 loaded biochar at 850℃ was 13.25 % higher than that of unloaded biochar, which was 2.54L/g·C.•The intensity of counter-flow gasification at 900 ℃ is 60.89% higher than that of downdraft gasification.
It is important to explore a relatively cheap and efficient biomass steam gasification process for the high-value utilization of biomass. Biochar was used as raw material for steam gasification, and the steam gasification of counter-flow biochar fixed bed was enhanced by the in-situ catalysis of Fe2O3 and CaO. By changing the steam flow rate and heating temperature, the operating characteristics of counter-flow gasification were explored and compared with updraft and downdraft gasification.
The experimental results show that the addition of CaO in counter-flow gasification can improve the gasification intensity of biochar at lower temperature and steam flow rate. At 750 ℃, the biochar loaded with CaO at steam flow rate of 3.75 ml/min has a maximum heating temperature LHV of 11.49 MJ/Nm3. As the heating temperature increases, the hydrogen production yield gradually decreases. At temperature of 850 ℃ and steam flow rate of 3.75 ml/min, the gasification intensity of CaO loaded biochar was 66.44 % higher than that of unloaded biochar, and the gasification intensity was increased by 15.04 % by loading Fe2O3. However, the addition of Fe2O3 can improve the hydrogen production yield of biochar. At 850 ℃ gasification temperature, the hydrogen production yield is 23.25 % higher than that of biochar without catalysis.
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