This study investigated the current practices and challenges for the sustainable fashion of luxury boutique fashion brands (LBFBs) in Vietnam. A series of in-depth interviews with 20 founders and ...managers of LBFBs in Vietnam was conducted. Findings show that sustainable practices improve ethnic cultures, strengthen the usage of local resources, promote sustainable lifestyle, and thereby contributing to sustainable development of the boutique fashion brands. However, the brands face some challenges while dealing with their stakeholders such as shortage of available internal resources, bias in consumer perception and purchase behaviors, and legal barriers to achieve accredited environment certification that, in turn, weaken the sustainable practices in the local context. Results also provide some insightful information for small & medium sized enterprises (SMEs) to adjust their sustainability practices in order to improve their competitive advantages in the marketplace.
Fabrication of a high-performance room-temperature (RT) gas sensor is important for the future integration of sensors into smart, portable and Internet-of-Things (IoT)-based devices. Herein, we ...developed a NO2 gas sensor based on ultrathin MoS2 nanoflowers with high sensitivity at RT. The MoS2 flower-like nanostructures were synthesised via a simple hydrothermal method with different growth times of 24, 36, 48, and 60 h. The synthesised MoS2 nanoflowers were subsequently characterised by scanning electron microscopy, X-ray diffraction, Raman spectroscopy, energy-dispersive X-ray spectroscopy and transmission electron microscopy. The petal-like nanosheets in pure MoS2 agglomerated to form a flower-like structure with Raman vibrational modes at 378 and 403 cm−1 and crystallisation in the hexagonal phase. The specific surface areas of the MoS2 grown at different times were measured by using the Brunauer–Emmett–Teller method. The largest specific surface area of 56.57 m2 g−1 was obtained for the MoS2 nanoflowers grown for 48 h. This sample also possessed the smallest activation energy of 0.08 eV. The gas-sensing characteristics of sensors based on the synthesised MoS2 nanostructures were investigated using oxidising and reducing gases, such as NO2, SO2, H2, CH4, CO and NH3, at different concentrations and at working temperatures ranging from RT to 150 °C. The sensor based on the MoS2 nanoflowers grown for 48 h showed a high gas response of 67.4% and high selectivity to 10 ppm NO2 at RT. This finding can be ascribed to the synergistic effects of largest specific surface area, smallest crystallite size and lowest activation energy of the MoS2-48 h sample among the samples. The sensors also exhibited a relative humidity-independent sensing characteristic at RT and a low detection limit of 84 ppb, thereby allowing their practical application to portable IoT-based devices.
In this paper, the synthesis of nickel ferrite and its use for voltammetric determination of uric acid (UA) are presented. Nickel ferrite was synthesized via a hydrothermal process using spherical ...carbons as hard template followed by calcination at 500 °C. It was found that iron and nickel compositions in nickel ferrite can be controlled by the initial Fe/Ni molar ratio. The stoichiometric nickel ferrite (NiFe
2
O
4
) with hollow spherical morphology was obtained from a reaction mixture with Fe/Ni molar ratio of around 1.2–1.5. Glassy carbon electrode modified with nickel ferrite was employed to quantitatively determine UA by different pulse voltammetric method. Under the optimum conditions, the anodic peak current was linearly proportional to UA concentration in the range of 0.398 to 6.761 μM. The detection limit (3
σ
) was found to be 0.15 μM. The proposed method has been employed to determine UA in human urine samples with acceptable recoveries of 95.15–104.8%. On the other hand, the results obtained from this method were also compared with that from standard HPLC method, showing no statistical difference.
High water-cut oil production is one of the major issues in the petroleum industry. The present study investigates different profile control solutions, with an emphasis on selective methods and ...materials that mostly decrease the permeability of water-saturated reservoir areas. To achieve the selective water flow blockage in fractured porous media, the sodium silicate-based gel-forming composition was developed. The test procedure was created to assess selective and strength characteristics of the presented composition. According to the results of this procedure, adding polyatomic alcohols to the mentioned composition enhances its hydrophilic behavior in water-saturated rocks (work of adhesion increases from 117 to 129 mJ/m2) and reduces the hydrophobic behavior in oil-saturated rocks (work of adhesion drops from 110.3 to 77.4 mJ/m2). The selectivity of the composition performance is validated by its higher wettability of water-saturated reservoir rocks compared with oil-saturated; thus, the composition creates a more stable water shutoff barrier when entering the water zone in a formation. As a result of core flooding experiments in natural, fractured, porous core samples, the efficiency of the water blocking capacity of the composition was proved. In addition, these tests showed the selectivity of the composition because the permeability decrease in water-saturated core samples was higher than in oil-saturated ones. The experimental value of the selectivity coefficient was 152.14.
In the present article, the synthesis of TiO2/diazonium/graphene oxide and its photocatalytic activity for methylene blue (MB) degradation have been demonstrated. The functionalization of graphene ...oxide (GO) with diazonium salt (diazonium-GO) was conducted for enhancing the dispersibility of GO in distilled water. TiO2 was highly dispersed in diazonium-GO to form TiO2/diazonium/graphene. The obtained specimens were characterized by X-ray diffraction, FT-IR spectroscopy, Raman spectroscopy, UV-Vis spectroscopy, scanning electron microscope, transmission electron microscopy, and X-ray photoelectron spectroscopy. It was found that the TiO2 phase in TiO2/diazonium/GO composites can be controlled by adjusting the amount of ethanol or titanium oxide in the reactant mixture. The obtained composites exhibited photocatalytic activities for methylene blue degradation (MB). The composite with ac. 70% anatase can provide the highest MB degradation efficiency. The studying of some intermediates for MB photocatalytic degradation using LC-MS showed that structure of MB by the cleavage and oxidation of one or more of the methyl group substituent on the amine groups lead to form compounds with low molecular masses. Total organic carbon studies confirmed a complete mineralization of MB. The present catalyst was stable and recyclable after three times with a negligible loss of catalytic activity. In addition, the TiO2/diazonium/GO can also photocatalyze for the degradation of some other dyes (phenol, methyl red, and Congo red).
Abstract By using a quantum kinetic equation for electrons, the expression of the acoustoelectric field under the influence of confined acoustic phonons in doped semiconductor superlattices (DSSL) is ...obtained. From these expressions, the acousto-electric field depends on temperature, acoustic wave frequency, Fermi energy level, doped concentration, and quantum number m characterizing the phonons confinement. The results are numerically calculated for the GaAs:Be/GaAs:Si DSSL and show that the appearance of phonons confinement makes the acousto-electric field value become different than the cases of unconfined phonons.
This paper presents an effective biogeography-based optimization (BBO) for optimal location and sizing of solar photovoltaic distributed generation (PVDG) units to reduce power losses while ...maintaining voltage profile and voltage harmonic distortion at the limits. This applied algorithm was motivated by biogeography, that the study of the distribution of biological species through time and space. This technique is able to expand the searching space and retain good solution group at each generation. Therefore, the applied method can significantly improve performance. The effectiveness of the applied algorithm is validated by testing it on IEEE 33-bus and IEEE 69-bus radial distribution systems. The obtained results are compared with the genetic algorithm (GA), the particle swarm optimization algorithm (PSO) and the artificial bee colony algorithm (ABC). As a result, the applied algorithm offers better solution quality and accuracy with faster convergence.
Although employee engagement is essential to hotel performance, few studies have identified context-specific manifestations of employee engagement in the boutique hotel business. Drawing on the ...service-dominant logic and dual processing theory, this study investigated the experiential and rational factors driving employee engagement in hotel brand value co-creation. Data collected from 570 employees working in boutique hotels in Vietnam showed that under the influence of organizational tenure, internal brand communication and external social media brand communication facilitate the employee perceived service climate, which, in turn, triggers employee engagement in brand value co-creation. The study provides beneficial implications for employee management in boutique hotels.
The COVID-19 pandemic has had a profound worldwide impact. Vietnam, a lower middle-income country with limited resources, has successfully slowed this pandemic. The objectives of this report are to ...explore the impact of the COVID-19 pandemic on the research activities of an ongoing hypertension trial using a storytelling intervention in Vietnam. Data were collected in a mixed-methods study among 86 patients and 10 health care workers participating in a clinical trial designed to improve hypertension control. Several questions related to the impact of COVID-19 on patient's daily activities and adherence to the study interventions were included in the follow-up visits. A focus group discussion was conducted among health care workers to discuss the impact of COVID-19 on research related activities. Fewer patients in the intervention group reported that they faced difficulties in adhering to prescribed study interventions, wanted to receive a call from a dedicated hotline, or have a visit from a community health worker as compared with those in the comparison group. Most study patients are willing to participate in future health research studies. When asked about the potential use of mobile phones in health research studies, fewer patients in the intervention group felt comfortable using a mobile phone for the delivery of intervention and interviews compared with those in the comparison condition. Community health workers shared that they visited patient's homes more often than previously due to the pandemic and health care workers had to perform more virus containment activities without a corresponding increase in ancillary staff. Both patients and health care workers in Vietnam faced difficulties in adhering to recommended trial interventions and procedures. Multiple approaches for intervention delivery and data collection are needed to overcome these difficulties during future health crises and enhance the implementation of future research studies.
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