Maximum Reactivity Research Articles

Repurposing ABS to Produce Polyamide 6 (PA6)-Based Blends: Reactive Compatibilization with SAN-g-MA of a High Degree of Functionalization

In this study, recycled acrylonitrile-butadiene-styrene terpolymer (ABSr) was reused to produce polyamide 6 (PA6)-based blends. This was achieved through reactive compatibilization using styrene-acrylonitrile-maleic anhydride (SAN-g-MA) copolymer with a high degree of functionalization (6–10% MA). The PA6/ABSr and PA6/ABSr/SAN-g-MA blends were prepared through melt processing and injection molding and then analyzed for their rheological, mechanical, thermomechanical, thermal, and structural properties, as well as morphology. The torque rheometry revealed a maximum reactivity of the PA6/ABSr (70/30 wt%) blend with low SAN-g-MA (5 phr—parts per hundred resin) content, while above this threshold, torque began to decline, indicating compatibilizer saturation in the interface. These findings were further substantiated by the increase in complex viscosity and the lower melt flow index (MFI) of the PA6/ABSr/SAN-g-MA (5 phr) blend. The 5 phr SAN-g-MA reactive compatibilization of the PA6/ABSr blends significantly enhanced its impact strength, elongation at break, tensile strength, and heat deflection temperature (HDT) by 217%, 631%, 12.6%, and 9.5%, respectively, compared to PA6/ABSr. These findings are promising for the plastic recycling field, paving the way for the production of new tailor-made materials at a reduced price.

Cerebrovascular reactivity and response times describe recent ischemic symptomatology in patients with moyamoya

Abstract Moyamoya is a non-atherosclerotic intracranial steno-occlusive condition that places patients at high risk for ischemic stroke. Randomized trials of surgical revascularization demonstrating efficacy in ischemic moyamoya have not been performed, and as such, biomarkers of parenchymal hemodynamic impairment are needed to assist with triage and evaluate post-surgical response. In this prospective study, we test the hypothesis that parenchymal cerebrovascular reactivity (CVR) metrics in response to a fixed-inspired 5% carbon dioxide challenge correlate with recent focal ischemic symptoms. Hypercapnic reactivity blood oxygenation level-dependent (BOLD) MRI (echo time=35ms; spatial resolution=3.5x3.5x3.5mm) and catheter angiography assessments of cortical reserve capacity and vascular patency, respectively, in moyamoya disease and syndromic participants (n=73) were performed in sequence. Cerebrovascular reactivity uncorrected for response time (CVRRAW) was quantified, and time regression analyses were applied to quantify maximum cerebrovascular reactivity (CVRMAX) and cerebrovascular reactivity response time (CVRDELAY). Symptomatology was categorized by a stroke neurologist by hemisphere: symptomatic (lateralizing ischemic symptoms < 6 months) or asymptomatic (no ischemic symptom history). Values are presented as median [interquartile range]; logistic regression assessed the association of cerebrovascular reactivity metrics with symptoms, controlling for age and sex. A total of 109 hemispheres, including 39 symptomatic and 70 asymptomatic hemispheres, met inclusion criteria. Symptomatic hemispheres displayed reduced CVRRAW (p<0.01) (symptomatic=0.45 [0.28-0.70] z-statistic/ΔEtCO2 vs. asymptomatic=0.67 [0.44-0.98] z-statistic/ΔEtCO2), lengthened CVRDELAY (p<0.001) (symptomatic=47.6 [37.7-57.0] seconds vs. asymptomatic=37.7 [30.4-46.4] seconds), and reduced CVRMAX (p=0.037) (symptomatic=1.31 [0.99-1.94] z-statistic/ΔEtCO2 vs. asymptomatic=1.64 [1.29-2.12] z-statistic/ΔEtCO2). CVRDELAY (p<0.001) was found to be significantly related to age in asymptomatic hemispheres (0.33-unit increase/year). Of assessed measures, the receiver operating characteristic curves suggest that CVRDELAY is associated most closely with recent ischemic symptoms (p<0.001). Findings support that cerebrovascular reactivity metrics are uniquely altered in hemispheres with recent ischemic symptoms, further motivating their utilization as biomarkers of ischemic symptomatology and potential treatment efficacy in moyamoya disease and syndrome.

Emission Characteristics and Environmental Impact of VOCs from Wooden Furniture-manufacturing Industry in China

Volatile organic compounds （VOCs） from the wooden furniture-manufacturing industry are an important emission source. To study the emission characteristics of VOCs from the wooden furniture-manufacturing industry and associated environmental impacts, nine typical wooden furniture manufacturers in China were selected to carry out sample collection and VOCs detection. The maximum incremental reactivity （MIR） method and secondary organic aerosol （SOA） formation potential method were used to quantify the corresponding contributions to the generation of O3 and SOA. The results showed that： ① The concentrations of VOCs emitted from different types of coating exhaust gas were different. The emission concentration of VOCs in solvent-based coating exhaust gas was significantly higher than that in water-based coating exhaust gas and ultra-violet （UV） coating exhaust gas, and the VOCs emission concentrations ranged between 2.82 - 155.37, 1.13 - 104.45, and 0.57 - 1.15 mg·m-3, respectively. ② The main organic group in solvent-based coating exhaust gas was esters, accounting for 45.88%, and butyl acetate （31.07%） was the main VOCs species. The main organic group in water-based coating exhaust gas and UV coating exhaust gas was alcohols, and the main VOCs species in water-based coating exhaust gas and UV coating exhaust gas were both ethanol, accounting for 46.63% and 34.32%, respectively. ③ The OFP of VOCs emitted by solvent-based coating, water-based coating, and UV coating were 149.23, 50.90, and 1.87 mg·m-3, respectively, and the primary contributing components of OFP of different types of coating were m/p-xylene （26.61%）, ethanol （36.35%）, and ethanol （23.98%）, respectively. ④ The SOA of VOCs emitted by solvent-based coating, water-based coating, and UV coating were 0.76, 0.25, and 0.01 mg·m-3, respectively. The SOA generation of various types of coating was dominated by aromatics（96.35%-98.96%）, and the main active compounds were toluene, ethylbenzene, and xylene. ⑤ Comparing the environmental impact of exhaust gas from solvent-based coating, water-based coating, and UV coating, it was found that the OFP and SOA generated by the VOCs emitted from solvent-based coating were much higher than those for water-based coating and UV coating. Therefore, the implementation of water-based coating and UV coating substitution strategy from the source could effectively reduce VOCs emissions and abate OFP and SOA productions.

How molecular architecture defines quantum yields

Understanding the intricate relationship between molecular architecture and function underpins most challenges at the forefront of chemical innovation. Bond-forming reactions are particularly influenced by the topology of a chemical structure, both on small molecule scale and in larger macromolecular frameworks. Herein, we elucidate the impact that molecular architecture has on the photo-induced cyclisations of a series of monodisperse macromolecules with defined spacers between photodimerisable moieties, and examine the relationship between propensity for intramolecular cyclisation and intermolecular network formation. We demonstrate a goldilocks zone of maximum reactivity between the sterically hindered and entropically limited regimes with a quantum yield of intramolecular cyclisation that is nearly an order of magnitude higher than the lowest value. As a result of the molecular design of trifunctional macromolecules, their quantum yields can be deconvoluted into the formation of two different cyclic isomers, as rationalised with molecular dynamics simulations. Critically, we visualise our solution-based studies with light-based additive manufacturing. We formulate four photoresists for microprinting, revealing that the precise positioning of functional groups is critical for resist performance, with lower intramolecular quantum yields leading to higher-quality printing in most cases.

Photochemical Action Plots Map Orthogonal Reactivity in Photochemical Release Systems.

The wavelength-by-wavelength resolved photoreactivity of two photo-caged carboxylic acids, i. e. 7-(diethylamino)-coumarin- and 3-perylene-modified substrates, is investigated via photochemical action plots. The observed wavelength-dependent reactivity of the chromophores is contrasted with their absorption profile. The photochemical action plots reveal a remarkable mismatch between the maximum reactivity and the absorbance. Through the action plot data, the study is able to uncover photochemical reactivity maxima at longer and shorter wavelengths, where the molar absorptivity of the chromophores is strongly reduced. Finally, the laser experiments are translated to light emitting diode (LED)irradiation and show efficient visible-light-induced release in a near fully wavelength-orthogonal, sequence-independent fashion (λLED1=405nm, λLED2=505nm) with both chromophores in the same reaction solution. The herein pioneered wavelength orthogonal release systems open an avenue for releasing two different molecular cargos with visible light in a fully orthogonal fashion.

Determining the Reactivity of Selected Biomass Types Considering Their Application in Pyrometallurgical Processes of Metal Production.

In this paper, results of research on the reactivities of selected biomass types considering their application in pyrometallurgical processes of metal production are presented. Walnut shells, sunflower husk pellets and spent coffee grounds were selected as biomass materials. Their use as potential reducers in the process of metallurgical slag decopperisation is an innovative approach to this subject. The thermogravimetric findings show that all three tested biomass types are classified as highly reactive. The time to reach maximum reactivity ranges from 1.5 to 3 min and, the lowest value is recorded for the sample of spent coffee grounds. The sample hold time of two hours enables copper content reduction to approx. 1 wt% for practically all the reducers tested. A longer duration of liquid slag contact with the reducer results in a decreased copper content in the slag to a value below 1 wt%. Copper concentrations of 0.5 wt% and lower are observed with a hold time of 4 h. The preliminary results indicate that there is great potential for the use of this type of material in non-ferrous metallurgy, which may translate into replacing fossil raw materials and thus introducing the principles of a sustainable process in this case of metal production.

Crystallographic dependence of carbon deposition in the Fischer-Tropsch synthesis over cobalt catalysts: HCP versus FCC

A very challenging issue with Co-catalyzed FTS, surface carbon deposition and thus FTS catalyst deactivation, remains unresolved for many years. This research is designed to overcome the challenge by using theoretical calculations together with the FTS experiments. Our theoretical calculations for the first time reveal that HCP Co not only have much higher anti-carbon deposition stability but also exhibits a better anti-carbonization capability than FCC Co; the higher stability of HCP Co is attributed to its much denser active sites with the step B5-type active unit to eliminate surface carbon species. Our FTS experiments confirm the theoretical calculation results. The great dependence of anti-carbon deposition stability on the crystallographic structure and morphology of the catalysts revealed here may open a new avenue for better, stable catalysts with maximum mass-specific reactivity.

Neutronic characteristic analysis of the GAMA microreactor

The GAMA Microreactor is a low-power nuclear power plant dedicated for remote area with a power output of 300 kWe. The primary characteristics of the GAMA Microreactor are its system compactness, design simplicity, and safe operation without moving parts. The fuel is uranium hydride powder, which works simultaneously as a moderator, contained within a stainless-steel vessel and surrounded by a graphite reflector. Liquid sodium-filled heat pipes are embedded in the fuel powder to extract fission-generated heat via passive coolant flow due to capillary action. As a part of the design process, neutronic parameters of the GAMA Microreactor have been determined using SCALE6.2 and OpenMC codes. Among the analyzed parameters are the excess reactivity as a function of burn-up, shutdown margin, control rod worth, temperature coefficient of reactivity (TCR), fuel density coefficient of reactivity (DCR), and reactivity coefficient due to hydrogen dissociation. From the calculation results, the GAMA Microreactor has a maximum excess reactivity of 0.049 at the operational temperature (700 °C) and 0.0788 at ambient temperature. The TCR value is negative (−2.267 pcm/°C) at the beginning of the cycle (BOL) and −4.9618 pcm/°C at the end of the cycle (EOC). Hydrogen dissociation imposes negative reactivity on the reactor both at the BOL (−0.2631 Δk/k-%dissociation) and EOC (−0.3524 Δk/k-%dissociation). Therefore, the GAMA Microreactor maintains its inherent safety characteristics over a considerably long operation time.

Characterizing BVOC emissions of common plant species in northern China using real world measurements: Towards strategic species selection to minimize ozone forming potential of urban greening

Biogenic volatile organic compounds (BVOCs) emitted by plants play a crucial role in ozone (O3) formation. Avoiding urban air quality trade-offs of urban greening involves selecting low-emission and O3 forming potential (OFP) plants. Using a dynamic enclosure system and the TD-GC-MS technique, we measured BVOC emissions from 47 common urban greening plant species in northern China. The potential to form O3 was estimated based on the emission quantification of 63 compounds and their maximum incremental reactivity (MIR) values. The results indicated that isoprene and most of monoterpene dominated BVOC emissions. Most of the broad-leaved trees were isoprene emitter, whereas needle-leaved and some broad-leaved trees emitted monoterpene and sesquiterpene. Alkene emissions, such as 1-hexene, were relatively low, while Phoebe zhennan exhibited higher aromatics such as m-ethyltoluene. Broad-leaved trees had a higher potential for O3 generation compared to needle-leaved trees. BVOC emission rates and OFP varied significantly among plant species, ranging from 0.08 to 112.23 μg/(g h) and 0.33–1130.75 μg/(g h), respectively. To minimize BVOC emissions and O3 pollution, we determined a list of preferred urban greening plants using hierarchical cluster analysis combined BVOC emission rates and OFPs. Based on our findings, we recommend incorporating plants with low BVOC emissions and OFPs, such as Eucommia ulmoides, Firmiana platanifolia, and Cercis chinensis, in future urban greening plans to prevent strengthening O3 pollution in northern China.

Flexible and stretchable high performance enzymatic biofuel cells implantable in tube-type artificial blood vessel kit

Enzymatic biofuel cells (EBFCs) are emerged as promising power sources for implantable devices, offering excellent form factor and performance. For these applications, EBFCs require customer tailored structure and more than 10 μW power. In this study, flexible and stretchable EBFCs are suggested, assessing their performance using tube-type artificial blood vessel (TABV) cell kit with sheep blood fuel. To fabricate the EBFCs, buckypaper (BP) is molded to polydimethylsiloxane (PDMS) to fabricate BP@PDMS electrode that shows excellent strain rate (95 %) and durability (1500 cycles) in tensile and fatigue tests. Additionally, electrochemical evaluations are implemented to measure the performance of anode and cathode fabricated with BP@PDMS. In anode including 1,10-phenanthroline-5,6-dione and glucose dehydrogenase, maximum reactivity of glucose oxidation is 1.05 mA/cm2, while in cathode including bilirubin oxidase, that of oxygen reduction is 0.61 mA/cm2. Regarding flexibility, anode and cathode are little affected by current density irrespective of bending angle, proving that the fabricated anode and cathode have good flexibility. To emulate the behavior of EBFCs in actual blood vessel, EBFCs are implanted in TABV cell kit, fueling sheep blood. Observed open circuit voltage of 0.59 V and maximum power of 26 μW reveals that fabricated EBFCs have superior potential to be considered as power sources for implantable devices.

Sites and Zones of Maximum Reactivity of the most Stable Structure of the Receptor-binding Domain of Wild-type SARS-CoV-2 Spike Protein: A Quantum Density Functional Theory Study

Today, it is well known that Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has four types of proteins within its structure, between them the spike protein (S). The infection mechanism is carried out by the entry of the virus into the human host cell through the S protein, which strongly interacts with the human cell receptor angiotensin-converting enzyme 2 (ACE2). In this work, we propose an atomic model of the Receptor Binding Domain (RBD) of the S spike protein of the wild-type SARS-CoV-2 virus. The molecular structure of the model was composed of 50 amino acids that were chemically bonded, starting with Leucine and ending with one amino acid Tyrosine. The novelty of our work lies in the importance of knowing the sites and zones of maximum reactivity of the RBD from the fundamental levels of quantum mechanics considering the atomic structure of matter. For this, the local and global reactivity indices of the RBD were calculated, such as frontier orbitals, Highest Occupied Molecular Orbital (HOMO) and Lowest Unoccupied Molecular Orbital (LUMO), Fukui indices, chemical potential, chemical hardness, electrophilicity index; with this, it will be possible to know what type of molecules are more likely to interact with the RBD structure, and in this way, new knowledge will be generated at the quantum, atomic and molecular level to inhibit the virulent effects of wild-type SARS-CoV-2. Finally, in order to identify the functional groups within the most stable structure and thereby verify the future reactions that can be carried out between the RBD structure and biomolecules, the Infrared (IR) absorption spectrum was calculated. For this work, we used Material Studio v6.0 which uses the density functional theory (DFT) implemented in its DMol3 computational code. The IR spectrum was obtained using the Spartan ‘94 computer code. One novelty would be that we found nine amino acids more that could make the RBD and ACE2 binding further the already known. Thus, the Mulliken charge distribution indicates that the highest concentrations of positive and negative charge are found in the zones 477S, 478T, 484E, and 501N amino acids letting ionic or Van der Waals possible interactions with other structures.

Emission factors and source profiles of volatile organic compounds from the automobile manufacturing industry

Controlling volatile organic compounds (VOCs) emitted from the automobile manufacturing industry requires establishing VOCs emission factors (EFs) and source profiles refinedly. In this study, 41 samples involved 32 VOCs discharge links were collected from three factories. The EFs and VOCs source profiles were estimated by the material balance method and weighted average method, respectively. The ozone formation potential (OFP) of the 110 VOCs species were calculated by the maximum incremental reactivity (MIR). According to estimations, the ranges of EFs were 0.23–1.66 kg VOCs/SUV car and 2.14–14.86 g VOCs/m2 painted area. EFs of six materials were firstly estimated, which are electrophoretic primer (152.31 ± 97.39 g VOCs/SUV car, 0.97 ± 0.38 g VOCs/m2 painted area), sealant (48.39 ± 26.20 g VOCs/SUV car, 0.46 ± 0.25 g VOCs/m2 painted area), floating coat (87.40 ± 75.63 g VOCs/SUV car, 0.86 ± 0.74 g VOCs/m2 painted area), colored paint (127.24 ± 168.24 g VOCs/SUV car, 1.25 ± 1.66 g VOCs/m2 painted area), varnish (205.46 ± 218.14 g VOCs/SUV car, 2.01 ± 2.15 g VOCs/m2 painted area), and cleaning solvent (328.54 ± 404.94 g VOCs/SUV car, 3.23 ± 3.98 g VOCs/m2 painted area). OVOCs (37.40–51.60 %) and aromatics (36.40–37.00 %) were the dominant components. n-Butyl acetate, 1,2,4-trimethylbenzene, undecane, n-hexanal, acetone, 1,2,3-trimethylbenzene, 1,3,5 -trimethylbenzene, m/p/o-xylene, 3-ethylbenzene, and 4-ethylbenzene were the major VOCs species, accounting for 68 % of total VOCs in the automobile manufacturing industry. Considering the OFP values of species, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, 1,2,3-trimethylbenzene, m/p-xylene, acetaldehyde, methyl ethyl ketone are the key active species that should be prioritized for control.

Investigating acquisition of magnetic properties and biocompatibility of Gadolinium substituted Strontium phosphosilicate for magnetic imaging in orthopaedics

The ability to acquire in situ magnetic resonance properties in biological apatites to facilitate real time MRI was investigated by substituting a series of hierarchically increasing Gadolinium over Strontium in the study. Samples were synthesized using an aqueous sol–gel pathway to ensure maximum reactivity and favour Silica-based species. Structural features were investigated using diffraction and IR spectra followed by VSM to calculate magnetization as a function of the field revealing the paramagnetic behaviour of the samples when doped. Morphological features visualized through FE-SEM showed sustained structural integrity of parent material characteristic of the P63/M space group and the EDAX spectra confirmed the hypothesised substitution when sintered as well. When immersed with SBF a loss of secondary phases and formation of amorphous calcium phosphate flakes were confirmed by diffraction and morphological studies. Biocompatibility was evaluated against first contact cells i.e. RBC via haemolytic study and L929 cells wherein Alamar assay show the samples least toxic at 25 μg/ml beyond which cell viability decreases providing enough evidence of applicability of Strontium phosphosilicate as a bioactive ceramic.

Evaluation of Pozzolanic activity and lime reactivity of fly ash, GGBS, mica powder and pumice as binders

This article presents the effect of the pozzolanic activity and lime reactivity of various siliceous materials, like fly ash, GGBS (Ground granulated blast furnace slag), mica and pumice powders. The pozzolanic activity is evaluated as per ASTM and lime reactivity test as per IS 1727. Based on the ASTM C311 tests, at 28 days GGBS, pumice and fly ash showed 71%,12% and 9% improvement in strength respectively in comparison with the control mix for 20% replacement of binder. Mica powder showed decrease of strength in comparison with the control mix. It has been observed that all binders satisfy the criteria of requirement of strength as per ASTM C311 activity index which is greater than 0.75. Based on the lime reactivity tests carried out as per IS 1727 carried out, maximum lime reactivity has been observed in case of GGBS (26%), followed by fly ash (25%), pumice (9%) and mica powder (8%) in comparison with the control mix with 20% replacement of hydrated lime.

Transient Dynamics of a Food Chain Model with Vigilance in the Biparameter Spaces

This article focuses on the asymptotic and transient behavior of a food chain model with vigilance in the biparameter spaces. Firstly, the local asymptotic stability conditions of the positive equilibrium point are obtained. Then, the transient dynamical behavior of the positive equilibrium point is analyzed based on eight parameters. Using numerical simulation, the stable regions of the model with single and double parameters are plotted, as well as the value changes of resilience, reactivity, and amplification envelope within the stable regions. The results show that the coexistence equilibrium point is always reactive, and the corresponding parameter ranges for system stability are large, but the resilience values are small. The vigilance parameter of the middle- and lower-level organisms has the greatest impact on the system’s resilience and reactivity, and the lowest vigilance corresponds to the maximum resilience and reactivity. Our results provide important references for effective management and protection of wild animal populations by the potential for transient amplification, disturbance growth time, and amplitude.

Recent research progress on modified activated carbon from biomass for the treatment of wastewater: A critical review

AbstractWater is one of the most vital substances on the planet that supports and sustains life. One of the most crucial challenges of our time is water. It is a basic need for all living beings. Worldwide, a large amount of wastewater is produced daily from home and industrial sources, creating problems such a water shortage and environmental degradation. Water that has already been utilized is called wastewater. It has been observed that the wastewater released varies in composition according to the kind of industry and the municipal sources. Microorganisms, heavy metals, organic pollutants, pesticides, phthalates, polycyclic aromatic hydrocarbons, emerging contaminants, and potentially dangerous wastes are all present in it. Among the most effective methods for removing these contaminants in recent times is the adsorption phenomenon. The presence of various contaminants in wastewater can be efficiently reduced by the simple, efficient, and affordable process of adsorption. Selection of suitable adsorbent is the crucial technique in this operation of adsorption. A versatile adsorbent is activated carbon (AC). Their maximum surface reactivity, large surface area, and microporous form are what give them their adsorptive capabilities. To enable recovery and filter, eliminate, or change the toxic components from gases and liquid solutions, they are used to purify, decolorize, deodorize, dechlorinate, separate, and concentrate. As a result, a variety of industries are interested in AC for the process of adsorption. This review paper briefs the characteristics of AC and their preparation techniques. It discusses the numerous approaches for modifying the surface of AC with significant adsorption capability. It also emphasizes the usage of AC with the elimination of different toxins found in waste water.

Criticality safety of fuel assemblies with missing fuel rods

The present work is concerned with the problem of determining the reactivity of an assembly from which an unknown number of fuel pins are removed at random locations. Because it is usually designed to be under-moderated, the reactivity of an incomplete assembly will pass by an optimum when the number and position of the missing rods vary. Estimating this maximal reactivity is paramount for criticality safety but is difficult to achieve in practice, because of a prohibitive combinatorial factor, that forbids any direct approach of the problem.It is shown that the maximum reactivity of an isolated PWR assembly with missing fuel rods can be estimated with very few calls on time expensive computer simulations. Drawing a parallel with the field of neutron transport in random geometries, it is indeed shown that the problem can be reduced to an optimum search in an appropriate bounded, bi-dimensional space.

Picomolar level sensorial dual colorimetric gold nanoparticle sensor for Zn2+ and Hg2+ ions synthesized from bark extract of Lannea Grandis Coromandelica and its wide range applications in real sample analysis

In this work a facile, rapid, reproducible and non-toxic approach has been demonstrated for synthesis of most stable AuNPs from bark extract of Lannea Grandis Coromandelica. UV–Visible spectroscopy, FTIR, TEM, SAED, EDX, XRD, DLS, Zeta Potential, FE-SEM, AFM and XPS techniques were employed for the characterization of synthesized LGC-AuNPs. The UV–Vis spectra of LGC-AuNPs gave SPR peak at 536 nm while the TEM analysis revealed LGC-AuNPs have 20.75 nm size with spherical in shape. DLS study showed the AuNPs have average diameter 50.18 nm. The synthesized AuNPs exhibited very high selectivity, rapid response in recognition towards Zn2+ and Hg2+ ions by changing its color within 20 sec. This proposed sensor can detect very low picomolar level of Zn2+ and Hg2+ ions (LOD value for Zn2+ and Hg2+ were found 1.36 pM and 24.60 pM respectively). Here we also studied effect of several factors such as variation of conc of gold, temperature, incubation time, pH, salt, solvent (polar protic and polar aprotic) to know in which condition AuNPs have high stability and sensitivity. The data revealed that synthesized AuNPs was stable up to two years at pH 6.5 at room temperature in water media and under this condition, it shows maximum sensitivity and reactivity. Moreover, here interference study was carried out to identify high selectivity of synthesized LGC-AuNPs probe in presence of different metal ions. The real sample analyses also revealed the great applicability of this probe. Therefore, this simple, rapid, low-cost, sensing activity appeared to hold great sensibleness for detection of heavy metal ions in real sample.

Investigation of reactivity control strategies for a micro-transportable gas-cooled thermal reactor

Micro nuclear reactors have gained increasing attention in recent years due to their high efficiency and long lifetime, making them an attractive solution for meeting the energy needs of remote and off-grid locations. Previous work has proposed a conceptual design for a micro solid nuclear reactor cooled by a helium-xenon mixture. The main aim of this study is to examine the effects of introducing burnable poisons on the neutronic performance of the designed micro nuclear reactor and to improve the design of the sliding reflector segment for reactivity control. The computational results indicate that the inclusion of burnable poisons can decrease the initial excess reactivity and radial power peaking factor, while not having a significant impact on the lifetime of the core. The use of 0.4%wt Gd2O3 and 0.75%wt ZrB2 as burnable poisons results in a reduction of 6.0 $ and 7.4 $ in the maximum reactivity of the core, respectively, while the core lifetime is reduced by 169 EFPD and 545 EFPD, respectively. By partitioning the sliding reflector, a linear introduction of reactivity can be achieved, and the influence of introducing burnable poisons on the reactivity control ability of the sliding reflector is relatively small.

Study on the emission characteristics of VOCs under the condition of biomass blending combustion

In order to understand the emission characteristics of volatile organic compounds (VOCs) in the flue gas under the mixed combustion of biomass, the study on the emission characteristics of VOCs in the flue gas was carried out on a 58 MW circulating fluidized bed (CFB) unit. The results show that the co-firing of biomass can significantly reduce the emissions of VOCs and NOx and SO2. Changes in blended fuel particle size and combustion temperature reduce VOCs emissions. The most obvious change in the emission reduction of VOCs is reflected in the increase of the biomass mixing ratio from 20 % to 30 %. Biomass contains less S and N elements is the reason for the reduction of NOx and SO2 emissions. The emission of pollutants such as VOCs was the lowest when the biomass blending ratio was 40 %. Based on the actual operation of the power plant, 30 % is the optimal mixing ratio. The analysis showed that the amount of VOCs components had a strong positive correlation with the proportion of biomass in the fuel. The emission of VOCs under the condition of biomass blending has different characteristics from coal-fired boilers and biomass boilers. Under the two different mixing ratios, benzene series accounted for the largest proportion of VOCs emissions, reaching 44.38 % (20 %) and 33.75 % (40 %), respectively. The emission of benzene series is dominated by benzene and toluene, the emission of alkanes is dominated by n-hexane, and the emission of esters is dominated by ethyl acetate. The ozone formation potential (OFP) was analyzed by the maximum incremental reactivity method. The contribution of ozone generation potential at 20 % and 40 % mixing ratios was mainly from benzene series, which contributed 69.88 % and 70.24 %, respectively, and alkanes. contribution can also account for 25.76 % and 17.75 %.