The emancipatory potential of digital entrepreneurship: A study of financial technology-driven inclusive growth

Digital entrepreneurship possesses immense societal implications beyond its commercial significance. Yet our knowledge of the emancipatory potential of digital entrepreneurship remains limited because few studies have gone beyond the conventional emphasis on profits and wealth creation. Drawing on the emancipatory perspective that views entrepreneurship as change creation through the removal of constraints, this article examines how emancipation can occur through the actions of digital entrepreneurs. Using an empirical investigation of entrepreneurial endeavours set against disadvantaged communities in Indonesia, we uncover constraints facing a developing economy and the role of digital technologies in ameliorating them. Through extensive fieldwork and in-depth case study analyses, we identify constraining societal norms and restrictive practices, as well as the three forms of digital enablement - to emulate services, aggregate capital and equalise opportunities – necessary for the enactment of digitally enabled emancipation. We present a framework to illustrate the enactment of emancipatory digital entrepreneurship for the inclusive development of businesses and communities.     

Solvothermal synthesis of zirconia nanomaterials: Latest developments and future

Due to excellent mechanical properties, thermal stability and catalytic characteristics, zirconia is considered as the most important ceramic materials. Different crystal forms make zirconia play a huge role in solid electrolyte fuel cells, catalysts, thermal barrier coatings, denture materials, mobile phone backplanes, etc. The purpose of this paper is to provide a comprehensive review about solvothermal synthesis of nano-zirconia. Firstly, the reactors and systems of solvothermal synthesis in recent years are introduced. Especially, the advancement of continuously flowing microreactors and field-coupled systems are analyzed. Secondly, influencing factors of zirconia solvothermal synthesis are discussed. In addition, solvent effects on the synthesis of nano-zirconia products are clarified, and suggestions for solvent selection are given. Furthermore, the design and mechanism of solvothermal synthesis of zero-, one-, two-and three-dimensional zirconia nanostructures are revealed. Simultaneously, experimental methods and kinetic studies are summarized. Finally, potential applications and challenges are presented for future research directions.     

Comparative analysis on temperature characteristics of hydrogen-powered and traditional fossil-fueled vehicle fires in the tunnel under longitudinal ventilations

Vehicle fires in the tunnel are a great threat to the safe operation of the tunnel. Due to the rapid development of the hydrogen economy, the fire due to the hydrogen leakage could not be avoided and may bring great damage to the passengers and infrastructure. Due to the large difference between pool fires of traditional fossil-fueled and jet fires of hydrogen-powered vehicles, it is in doubt whether the existing longitudinal ventilation design could still be effective for the safety issue of hydrogen powered vehicles. To solve this problem, it is necessary to compare temperature characteristics of hydrogen-powered and traditional vehicle fires with and without longitudinal ventilations. In present work, we conducted a numerical investigation to discuss the different temperature distributions of traditional and hydrogen-fueled vehicle fires. Results indicate that the high temperature zone of the pool fire only exists above the ceiling of the vehicle. For hydrogen-powered vehicle fire, the high-speed hydrogen jet with the strong inertial force could push the hot smoke flows back to the ground. The ceiling temperature of hydrogen-powered vehicle fire is larger since hydrogen-powered vehicle has a larger heat release rate and the fire hazard of jet fires bring more danger compared with the pool fire. Although the temperature stratification is also obvious for the hydrogen-powered vehicle fire, the air temperature in the lower region could be heated and still high enough to bring a great damage to the passengers’ lives. This is quite different with the traditional pool fire. In addition, the critical ventilation velocity is also discussed. The theoretical equation could well predicted the critical ventilation velocity of traditional vehicle fires. For hydrogen-powered vehicle fires, the critical ventilation velocity could reach up to 6 m/s. The theoretical equation could not well predict the critical ventilation velocity of hydrogen-powered vehicle fires due to exist of hydrogen jet fires.     

Application of seismic attributes in structural study and fracture analysis of DQ oil field,Iran

The determination of the most unstable areas in oil fields is critical for addressing engineering problems of wellbore and sand production as well as geologic problems such as understanding dynamic constraints on hydrocarbon migration and fracture permeability. In this research work, coherency seismic attribute has been used for the determination of the most critical areas in terms of drilling stabilities in the DQ oil field, Iran. The results obtained have shown that the (1) predominant features are the SSE–NNW and N–S trends (2) the central part of the DQ structure shows the highest concentration of segment bundles, (3) the segment bundles seem to be aligned along some lineaments oriented SE–NW and SSE–NNW, and (4) on the eastern and western margins of the map there is an anomalous concentration of segments oriented E–W. It can be concluded that coherency attribute is a valuable tool for structural analysis highlighting those areas containing unstable features.     

Bulk preparation of (−)-epigallocatechin gallate-rich extract from green tea

(−)-Epigallocatechin gallate (EGCg)-rich extract (EGCg > 700 mg g⁻¹) was prepared from green tea leaves through a three-stage process consisting of liquid–liquid extraction and silica column purification. Crude tea extract was dissolved in ethyl acetate. After filtration, the solution was extracted by 10 g L⁻¹ citric acid solution twice, and then passed through silica column. The catechins compounds in the ethyl acetate eluate were back extracted to the aqueous phase, then extracted with a mixed solution of n-hexane/ethyl acetate (2/5, v/v) 3 times, concentrated, and freeze dried. 12.8 g EGCg-rich extract containing 709 mg g⁻¹ EGCg and 965 mg g⁻¹ total catechins was obtained from 300 g green tea leaves, with an EGCg recovery of 26.1% and a yield of 4.3%. This method was suitable for bulk preparation of EGCg-rich catechins from green tea leaves.     

低膦共聚物水质稳定剂的合成工艺研究

以水为溶剂,采用过硫酸铵-次磷酸盐引发体系,用马来酸酐(MA)、2-丙烯酰胺-2-甲基丙磺酸(AMPS)、丙烯酸(AA)为单体合成低膦共聚物水质稳定剂,讨论了合成温度、合成时间、单体配比以及引发剂用量等条件对产物阻垢性能的影响,确定了水质稳定剂的合成工艺。在水相中,膦酸共聚物的最佳合成温度为83~85℃,最佳合成时间为6h,最佳单体配比(MA∶AMPS∶AA)为0.50∶0.05∶0.45,过硫酸铵用量为6%、次磷酸盐相对物质的量含量为0.15时效果最佳。     

Feasibility study and performance assessment for the integration of a steam-injected gas turbine and thermal desalination system

This study proposes a systematic approach for retrofitting a steam-injection gas turbine (SIGT) with a multi-effect thermal vapor compression (METVC) desalination system. The retrofitted unit's product cost of the fresh water (RUPC) was used as a performance criterion, which comprises the thermodynamic, economic, and environmental attributes when calculating the total annual cost of the SIGT–METVC system. For the feasibility study of retrofitting the SIGT plant with the METVC desalination system, the effects of two key parameters were analyzed using response surface methodology (RSM) based on a central composite design (CCD): the steam air ratio (SR) and the temperature difference between the effects of the METVC system (?T_METVC) on the fresh water production (Q_freshwater) and the net power generation (W_net) of the SIGT–METVC system. Multi-objective optimization (MOO) which minimizes the modified total annual cost (MTAC) and maximizes the fresh water flow rate was performed to optimize the RUPC of the SIGT–METVC system. The best Pareto optimal solution showed that the SIGT–METVC system with five effects is the best one among the systems with 4–6 effects. This system under optimal operating conditions can save 21.07% and 9.54% of the RUPC, compared to the systems with four and six effects, respectively.     

Use of a selective extractant-impregnated resin for removal of Pb(II) ion from waters and wastewaters: Kinetics,equilibrium and thermodynamic study

Adsorption of Pb(II) ion by a novel extractant-impregnated resin, EIR, was studied as a function of various experimental parameters using batch adsorption experiments. The new EIR was prepared by impregnating gallocyanine (GCN) onto Amberlite XAD-16 resin beads. The EIR was characterized by nitrogen analysis and SEM micrographs. The new EIR showed excellent selectivity factor values (α) for Pb(II) adsorption respect to other metal ions. The effects of some chemical and physical variables were evaluated and the optimum conditions were found for Pb(II) removal from aqueous solutions. The equilibrium adsorption isotherm was fitted with the Langmuir adsorption model. The maximum adsorption capacity (q_max) of EIR for Pb(II) ions was found to be 367.92 mg g⁻¹. The kinetic studies showed that the intra-particle diffusion is the rate-controlling step. Also, the intra-particle diffusion coefficients, D_ip values, were of the order of 10⁻¹² m² s⁻¹. The values of enthalpy (ΔH°) were positive, which confirms the endothermic nature of adsorption process. Also, the positive entropy changes (ΔS°) were showed that the randomness increased along with the adsorption process. In addition, the obtained negative values of Gibbs free energy (ΔG°) indicated feasible and spontaneous nature of the adsorption process at different temperatures. The new adsorbent was very stable so that it can be successfully used for many consecutive cycles without significant loss in its adsorption capacity.     

水泥及其原材料中碱含量的检测技巧

碱含量的检测是水泥生产和质量控制的重要环节,火焰光度法的检测过程较为复杂繁琐,极易产生误差。简要叙述了火焰光度法检测碱含量的方法原理、检测步骤、结果处理、影响因素及检测技巧等,并重点分析了提高检测准确性的方法和技巧。     

大型煤化工项目建设控制管理研究(上)

介绍了大型煤化工项目建设控制管理研究的目的和意义。以贵州开阳煤化工项目建设为研究对象,对理论条件和实际条件进行了分析。围绕项目建设"四大控制"(成本控制、进度控制、质量控制、安全控制)进行控制管理,坚持以人为本的理念,用科学的管理方法指导现场施工,加快了项目建设进程,使各单项工程一次交验合格率达到了100%。并对项目建设控制管理过程中存在的问题及经验总结进行深入分析,以期为其他大型煤化工项目建设提供借鉴和参考,避免在煤化工项目建设过程中出现类似的问题,推动和加快我国煤化工项目的建设进程。