Access to homebuyer credit and housing satisfaction among households buying affordable apartments in urban Vietnam

This study examines the relationship between the access to homebuyer credits and housing satisfaction among those buying affordable apartments, using a sample of 1,000 respondents from our own survey in 2016 in Hanoi, Da Nang and Ho Chi Minh Cities. Our regression analysis reveals the education level, the size and value of apartments are closely linked with the access to preferential homebuyer credits. Notably, we find that the access to preferencial home loans has a strongly positive impact on housing satisfaction, after controlling for all other factos in the model. Thus, the finding confirms that preferencial home loan programs play an important role in helping low income households own affordable apartments and increase their housing satisfation. We also find that some other features of their apartments, such as the number of bath rooms and balconies, the distance from the apartment building to schoosl, bus stations and markets, are strongly linked with housing satisfaction

SAXS Investigation on Morphological Change in Lamellar Structures During Propagation Steps of Graft‐Type Polymer Electrolyte Membranes for Fuel Cell Applications

The changes of the lamellar periods (L1D), thickness of lamellar crystals (Lc), and amorphous layers (La) within the stacked lamellae of poly(styrenesulfonic acid)‐grafted poly(ethylene‐co‐tetrafluoroethylene) polymer electrolyte membranes (ETFE‐PEMs), induced by the preparation and water‐absorbing steps are investigated using the small‐angle X‐ray scattering method. The L1D values of all the samples quickly increase at a grafting degree (GD) range of less than 19% and then level off. The solvent‐induced recrystallization is observed at the early stage of grafting (GD 34%), leading to the conclusion that most water molecules in the PEMs with higher GDs exist at the outside of the lamellar stacks. Accordingly, for the PEMs with low GD (<19%), all the hydrophilic graft‐polymers (ion‐channels) locate in the lamellar stacks and are strongly restricted by lamellar crystalline layers, which suppress the swelling of the PEMs. The unique lamellar structures of ETFE‐PEMs characterized by La and Lc are well connected with the high conductance and mechanical properties of the membranes, and are suitable for fuel cell applications

Determination of Cobalt in Seawater Using Neutron Activation Analysis after Preconcentration by Adsorption onto γ-MnO2 Nanomaterial

The γ-MnO2 nanomaterial has been used to adsorb cobalt in the seawater at Phan Thiet City, Binh Thuan Province, Vietnam. Its concentration is determined by using the neutron activation analysis (NAA) method at the Dalat nuclear research reactor. Factors affecting the uptake of cobalt on the γ-MnO2 material such as the pH, adsorption time, and initial cobalt(II) concentration are investigated. The irradiated experiment data are calculated using the K0-Dalat program. The results obtained show that the trace dissolved cobalt in Phan Thiet seawater is found equal to 0.25 ± 0.04 μg/L (n=5, P=95%) with the adsorption efficiency being higher than 95% (n=4, P=95%)

Insights into Molten Salts Induced Structural Defects in Graphitic Carbon Nitrides for Piezo-Photocatalysis with Multiple H2O2 Production Channels

Recently, the production of hydrogen peroxide (H2O2) from water (H2O) and oxygen (O2) in the presence of graphitic carbon nitrides (g-C3N4) via a piezo-photocatalytic process has considerably ignited global interest in achieving sustainability. To fabricate porous g-C3N4, soft templates are frequently employed, leading to structural modifications originating from heteroatoms. However, many recent reports have ignored the roles of trace quantity of heteroatoms. Hence, to understand the impacts of the mentioned factors, we fabricated g-C3N4 containing oxygen and halogen atoms in the structures for piezo-photosynthesis of H2O2. Based on our analyzed results, oxygen atoms might be inserted into g-C3N4 in-plane structures, while halogen atoms tend to become intercalated between g-C3N4 layers. Furthermore, the presence of ammonium molten salts during the synthesis alters the concentration of mono and cluster vacancies of carbon and nitrogen in the materials. These defective contributions would meaningfully accelerate catalytic performance by providing trapping states. From the mechanistic view, different reduction and oxidation channels would play a pivotal role in generating H2O2. Thus, this study highlights the importance of modulating in-plane and out-of-plane structures of g-C3N4, benefiting catalytic properties under simultaneous irradiation

Solid-state crystallization, oxygen-vacancy rich mesopores and stable triad-silanol nests in ZSM-5 catalyst induced by electron-beam irradiation and calcination

Mesopores and silanol nests are known two technological keys that essentially control the catalytic performance of ZSM-5 zeolite. However, designing and controlling them without using chemicals so that the produced ZSM-5 can have strongly enhanced catalytic properties and more importantly can be applied at industrial scale have still been a big challenge up to now. The present study employed the 10 MeV electron beam (EB) generated from an industrial linear accelerator to introduce both the O-vacancy rich mesopores and stable triad-silanol nests in ZSM-5. The structural modification of irradiated ZSM-5 samples was explored by using SEM and FTIR combined with positron annihilation spectroscopy (PAS) including positron annihilation lifetime (PAL), Doppler broadening (DB) of electron–positron annihilation energy and electron momentum distribution (EMD). Obtained results indicated that EB irradiation could recover the defective-crystal structure as well as intensively modify the structures of ZSM-5. In particular, the mechanism for the solid-state crystallization and the formation of the O-vacancy rich mesopores (maximum size of ∼4.5 nm) in ZSM-5 under the combined EB irradiation (10−110 kGy) and calcination (600 °C) was, for the first time, proposed. The mechanism for the formation of stable triad-silanol nests in the channels of irradiated and calcined ZSM-5 zeolites was also explored. The present study, therefore, opens a new research path of applying both EB irradiation and calcination to produce ZSM-5 with novel features for industrial catalytic application at large-production scale

Morphological characterization of grafted polymer electrolyte membranes at a surface layer for fuel cell application

The morphology and elemental compositions at the surface of poly(styrene sulfonic acid) (PSSA) grafted poly(ethylene-co-tetrafluoroethylene) polymer electrolyte membranes (ETFE-PEMs) in a grafting degree (GD) range of 0%–127% are investigated by using FE-SEM and XPS analyses. The concentrations of elemental components at the surface are not a linear function of GDs, resulting from different grafting speeds at the surface and bulk. In addition, low accumulation of PSSA grafts on the surface of ETFE-PEMs in the low GDs of 0%–19%, as well as their homogeneous distribution through the membranes at least at a GD of 19% are observed. At higher GDs of 19%–127%, the PSSA accumulation on the surface is relatively limited, indicating the presence of more PSSA grafts inside the bulk than on the surface. The surface signatures of ETFE-PEMs over the entire GD range can be determined based on the grafting process. These interesting observations suggest the significant advantages of interfacial properties of ETFE-PEMs for fuel cell applications