Resource-Efficient Technologies最新文献

Organic phase change materials (PCMs) have been utilized as latent heat energy storage medium for effective thermal management. In this work, a PCM nanocomposite, consisting of a mixture of two organic PCMs (referred to as eutectic gel PCM) and minimal amount (0.5 wt%) of nanographite (NG) as a supporting material, was prepared. Differential scanning calorimeter was used to determine the melting temperature and latent heat of pristine PCM, paraffin (61.5 °C and 161.5 J/g), eutectic gel PCM (54 °C and 158 J/g) and eutectic gel PCM nanocomposite (53.5 °C and 155 J/g). The prepared PCM nanocomposites exhibited enhanced thermal conductivity and ultrafast thermal charging characteristics. The nanocomposites were employed for two different applications: (i) providing hot water using an indigenously fabricated solar water heating (SWH) system and (ii) solar rechargeable glove that can be rapidly warmed and used. Experimental results on SWH system show that the use of PCM nanocomposites helps to increase the charging rate of PCM while reducing the discharging rate of heat by PCM to water, thus enhancing the maximum utilization of solar energy and hence improving the efficiency of the SWH system. The experimental results on solar rechargeable glove revealed that the glove has the ability to retain the temperature up to 3 hours.

This study aimed to develop new techniques for the remediation of contaminated soils based on the application of zero-valent iron nanoparticles (nZVI) and bioremediation with compost from organic wastes and a mixed technique of both. An assessment of the effectiveness of remediation in two soils contaminated with hydrocarbons and heavy metals was carried out, with the aim of looking for positive synergies by combining the two techniques, and demonstrating their viability on an industrial scale. The application of nZVI for in situ immobilization of As and Cr in two different soils (Soil I from a contaminated industrial site and Soil II, contaminated artificially) showed a decrease in the concentration of As in Soil I and Soil II, as well as a decrease in Cr concentration for Soil I and Soil II in the leachate of both soils. The addition of compost and nanoparticles under uncontrolled environmental conditions in biopiles was able to produce a decrease in the concentration of aliphatic hydrocarbons of up to 60% in the two soils. Especially, degradation and transformation of longer chains occurred. A significant reduction of ecotoxicity was observed throughout the process in the biopile of soil II, not reaching the LC50 even with 100% of the sample after the treatment, in both earthworm and seeds growth tests.

Optical emission spectroscopy (OES) combined with the models of plasma light emission becomes non-intrusive and versatile method of plasma parameters determination. In this paper we have studied the densities of charge carriers and electron temperature in Ar plasma of pulsed DC magnetron in different experimental conditions. Electron density and temperature were determined by fitting of relative emission line intensities calculated from collisional-radiative model (CRM) to experimental ones. The model describes the kinetics of the first 40 excited states of neutral argon Ar and takes into account the following processes: electron impact excitation/deexcitation, spontaneous light emission, radiation trapping, electron impact ionization, and metastable quenching due to diffusion to walls. Then, ions density was determined from relative intensity of 488 nm Ar⁺ emission line and simple CRM accounting excitation from ground states of neutral Ar and ion Ar⁺. The values of electron and ion density agree very well. To test the stability of results, we performed Monte-Carlo calculations with random variation of experimental spectrum as well as of excitation cross-sections and estimated confidence intervals and errors for plasma parameters. Also, we validated OES study by comparison with Langmuir probe measurements. The agreement between optical and probe techniques is satisfactory.

The utilization of different types nanomaterials (NMs) in environmental remediation and wastewater treatment requires information on the potential harmful effects on human and environmental health. In this light, the utilization of human cell models together with cells from lower organisms, representative of different environmental compartments, could represent a valuable tool for the in vitro screening of the potential toxicity of different NMs used in nanoremediation. Among NMs, n-TiO₂, because of its peculiar optical and chemical properties, is widely applied for photosensitized UV oxidation of organic pollutants. Moreover, development in design of metal- and non metal- doped TiO₂ with extended photocatalytic activity in the visible region represents the subject of ongoing research.

In this work, the cytotoxic effects of three different types of recently synthetized Fe-doped n-TiO₂ were compared in two cell models widely utilized for screening cellular toxicity of NMs in humans and aquatic organisms, human vascular endothelial cells (HECV) and immune cells (hemocytes) of the marine invertebrate, the mussel Mytilus spp, respectively. Parallel studies were carried out using N-doped n-TiO₂. The results indicate both distinct and common behavior (agglomeration state) in different media (human cell culture medium and mussel hemolymph serum) and biological effects (cytotoxicity, nitric oxide production) of different types of doped- n-TiO₂ in different cell models. Although in vitro studies represent a first step in the toxicological assessment of NMs, studies comparing their effects on human and aquatic invertebrate cells that take into account the effects of different exposure media represent an useful tool for evaluating potential cytotoxicity of those NMs, like TiO₂-based photocatalytic NMs, widely applied in environmental remediation, and whose potential risks are poorly understood.

This work describes the biodiesel production from used frying oil using a hydrodynamic cavitation reactor as well as separation and purification of fatty acid methyl esters (FAME). Under the optimized process conditions, i.e., methanol to oil molar ratio of 4.5:1 and catalyst (KOH) concentration of 0.55 wt%, the conversion achieved was 93.86 mol%. Higher conversion (93.6%) was obtained in only 20 min as compared to 88.5% in 1 h in stirred tank reactor. Due to the completion of transesterification reaction, the amount of intermediate diglycerides and monoglycerides present in the reaction mixture was less. It helps for the complete separation of methyl ester and glycerol layers without hindrance in 1 h. Small amount KOH catalyst used for completion of reaction reduces amount of KOH and soap in ester layer which further helps to form a less stable emulsion during water washing step. The complete separation was observed at 70 °C temperature in just 3 h. Thus, this study indicates that the increased production capacity can be achieved by shortening the time for the separation and purification.

In recent times, the rate of energy consumption goes on increasing and the world is desperately searching for new sources of fuel. Biodiesel (fatty acid methyl esters) is an alternative renewable energy resource for the next generation. Biodiesel has several advantages which include its non-toxic nature, it is biodegradable and it reduces greenhouse gas emissions. β-Tricalcium phosphate (β-Ca₃(PO₄)₂) catalyst was synthesized from fish waste. Fish waste contains calcium phosphate which is converted into β-tricalcium phosphate since it has low crystallinity and hydroxyl (OH) groups which decrease the potential to be a good catalyst for the synthesis of biodiesel through transesterification. This paper explores the synthesis of biodiesel using β-tricalcium phosphate (β-Ca₃(PO₄)₂) as a heterogeneous catalyst. Pongamia pinnata (Karanja) oil was extracted from seeds through the solvent extraction process. Intended for the development of easier transesterification process, stable and active heterogeneous β-tricalcium phosphate (β-Ca₃(PO₄)₂) catalyst was synthesized and used for the P. pinnata (Karanja) oil transesterification process. The synthesized heterogeneous catalyst was characterized by XRD, FT-IR, SEM and EDX to determine its structural and morphological characteristics. The catalyst exhibited good catalytic activity on reuse. Biodiesel yield was greatly dependent on operating parameters such as catalyst concentration, methanol to oil molar ratio, reaction temperature and reaction time. Effect of co-solvent on biodiesel was studied by using different co-solvents in transestrification reactions. High quality and maximum biodiesel yield (97 %) was obtained under the optimized reaction conditions (methanol to oil molar ratio, 10:1 (tetrahydrofuran (THF):methanol 1:1); reaction time 90 min; catalyst concentration 2.5 wt % and stirrer speed 650 rpm at 65 °C). Reusability of catalyst was examined up to five runs and found the catalyst was reusable up to five times without much loss of catalytic activity.

In this study a systematic and model-based approach for a process development focusing on pressurized hot water extraction (PHWE) is investigated, considering potential thermal degradation of high-value compounds. For extraction of 10-deacetylbaccatin III (10-DAB) from yew as a representative test system, water at 120 °C provided the best compromise between extraction yield and thermal degradation. A yield of almost 100% with regard to the overall amount of 10-DAB was reached in only 20 min. Each experiment for model parameter determination was carried out with 1.9 g of plant material at a flowrate of 1 mL/min and an applied pressure of 11 bar. All experimental values are assessed by a physico-chemical (rigorous) extraction model with experimental values and simulation results showing high conformity. In order to demonstrate the usability of the extraction model and model parameter determination a scale-up prediction was calculated. The scale-up experiments were predicted precisely and thus the model validated. The experiments and the simulation results for a column with a volume of 104 mL and a mass of 22 g yew needles were consistent with the milli-scale used for model parameter determination.

The focus of pharmaceutical product development lies on assuring excellent product quality at the end of a cost-efficient process. The Quality-by-Design (QbD) concept shifts the focus from quality assurance through testing to quality control by process understanding, resulting in very robust processes with high quality product. QbD was originally intended by authorities for biologics, where product quality proven completely by analytics is not desired. Product quality has to be controlled by means of appropriate processes and operations as well.

These demands were developed in order to improve patients' safety by optimal drug quality at more efficient manufacturing processes reducing costs for healthcare systems. Furthermore, production of biologics includes feedstock variability and complex multi-step manufacturing processes in batch operation with variable lots – condition, which apply to botanicals as well.

The use of rigorous (physico-chemical) process modeling in combination with QbD results in a high degree of process understanding. This offers, contrary to popular prejudices, great benefit for manufacturers with little extra effort during development.

The methodical QbD-based approach is pursued to develop a process for extraction and purification of 10-deacetylbaccatin III from yew needles. A short history and key elements of the QbD-based application are introduced.

The line of argument for basic process conception is described and initial risk assessment is shown. Typical raw material variation and vaporization are identified as causes of process variability, therefore, the implications to subsequent process steps are pointed out. Finally, influences of load and flow rate on the chromatographic separation of 10-deacetylbaccatin III are shown to exemplify sensitivity of purification design.

Using the electrospinning method, we produced biodegradable scaffolds from poly-l-lactide acid polymer (PLLA – poly-l-lactide acid). Using DC magnetron sputtering of the copper target we modified the surface of the scaffolds. For investigate scaffolds morphology, structure and elemental composition were used scanning electron microscopy, X-ray diffraction and X-ray fluorescence analysis. The results of scanning electron microscopy reveal that scaffolds consist of chaotically located fibres. The diameters of fibres range from 0.8 to 2 µm. Initially amorphous scaffold after modification has crystalline structure. The count of oxygen and copper with modification is increased, but count of carbon decreased. For the investigation of the scaffolds wetting ability were used glycerol and water. The wetting angles for the both liquids were similarly comparable. The values for the wetting angles range from 114 ± 5° to 125 ± 5°, what indicated that scaffolds had hydrophobic properties. Testing for antibacterial features indicated that the modified scaffolds are capable to have a bacteriostatic effect. Compared to the number of bacteria cultured without scaffold (11.8 ± 1.26 CFU × 10⁴/ml), two modified samples have bacteriostatic properties (reducing the number of bacteria on 30 and 50%). Economically effective method PLLA scaffolds modification could be used for creating low-cost wound dressings with antibacterial properties.

In this paper the solid wax formation in two live oils of the Samara region fields on five operating pressures with different contents of high molecular substances were examined. For both oil samples a linear relation between wax appearance temperature and pressure was obtained. The study showed the inevitable transition of wax from the liquid phase to solid in the examined live oils under downhole conditions. This fact indicates a high probability of complications during well operations of these oilfields. If measures are not put in place to prevent the deposit formation in wells, there is a chance of complete blockage of tubing and flowlines by wax. These problems will lead to decrease in well flowrates to their shutdown, thereby increasing the operation costs to remove deposits and capital expenditures of oil production. Evaluation of the conditions for the wax precipitation in oil wells will allow to develop technology of prevention and remediation of previously formed organic deposits. The potential solid wax formation depth of both wells for minimum well flowrate of 20 m³ per day are calculated. The technology of continuous injection wax inhibitor in designed depth where formation of solid wax has not been observed yet is proposed.