Facile and scalable preparation of ZIF-67 decorated cotton fibers as recoverable and efficient adsorbents for removal of malachite green

Recently, metal–organic frameworks (MOFs) have received considerable attention as highly efficient adsorbents for dye wastewater remediation. However, the immobilization of MOFs on the substrate surfaces to fabricate easy recyclable adsorbents via a facile route is still a challenge. In this work, ZIF-67/cotton fibers as adsorbents for dye removal were prepared in a large-scale using a simple coordination replication method. The successful fabrication of the ZIF-67/cotton fibers was confirmed by FTIR, XRD, XPS, SEM and BET analysis, respectively. As expected, the as-prepared ZIF-67/cotton fibers exhibited high adsorption capacity of 3787 mg/g towards malachite green (MG). Meanwhile, the adsorption kinetics and isotherm obeyed the pseudo-second-order kinetics and Langmuir model, respectively. Moreover, its removal efficiency towards MG was not significantly influenced by the pH and ionic strength of aqueous solution. Most importantly, the ZIF-67/cotton fibers can remove MG from synthetic effluents, and it can be easily regenerated without filtration or centrifugation processes, with the regeneration efficiency remaining over 90% even after 10 cycles. Additionally, the ZIF-67/cotton fibers presented excellent antimicrobial performance against E. coli and S. aureus. Hence, the distinctive features of the as-prepared ZIF-67/cotton fibers make it promisingly applicable for the colored wastewater treatment.

Synthesis of 3D-porous scaffold from cockle shells waste-based hydroxyapatite with addition silica from tin tailings

This study aims to synthesize a porous scaffold based on hydroxyapatite and silica using the polymer sponge replication method. In bone tissue engineering technology, the development of porous scaffolds is a topic that is intensively studied because it is expected to be a solution to various problems of conventional bone therapy. In addition to proposing a porous scaffold synthesis method, we also utilize natural waste-based materials such as cockle shells and tin tailings as raw materials in this research. Investigation through x-ray diffraction (XRD) pattern with the goodness of fit coefficient, X 2 = 0.09 shows that the coprecipitation method is effective for the synthesis of hydroxyapatite. Analysis of XRD pattern of tin tailings sand with a value of X 2 = 0.008 showed that the diffraction pattern was related to silica with space group P 41 21 2. The polymer sponge replication method with polyurethane template succeeded in obtaining scaffolds with macropores above 300 μm. Based on the diffraction pattern of the three porous scaffolds prepared with different percentages of HA, it is known that all porous scaffolds have peaks related to HA and silica. It indicates that the decomposition temperature of polymer does not provide sufficient energy for the HA and silica to transform or react chemically.

LEED 2009 Recertification of Existing Buildings: Bonus Effect

This study aimed to assess the impact of a four-point bonus system on recertification in Leadership in Energy and Environmental Design for Existing Buildings (LEED-EB) 2009 office space projects in four metropolitan cities: Washington, DC, Chicago, New York, and San Francisco. We analyzed 123 paired LEED-EB 2009 projects where each pair (i.e., certification–recertification) was used on the same building. The percentage of average score was used to evaluate differences in certification–recertification strategies: (1) gold-gold with and without the bonus, (2) silver-gold with and without the bonus, and (3) platinum-platinum with the bonus. The replication method was used to evaluate the overall tendency for four metropolitan cities. We found that while LEED-EB 2009 projects used a four-point recertification bonus, achievements in the materials and resources (MR) and indoor environmental quality (EQ) categories declined in each of the four metropolitan cities. We identified this overall tendency at three levels of certification–recertification: gold-gold, silver-gold, and platinum-platinum. We hypothesized that if the use of a four-point recertification bonus in LEED-EB 2009 projects resulted in lower achievements in the MR/EQ categories, then the use of the 10-point recertification bonus in LEED-EB 4.1 projects could lead to a deterioration in the sustainability of existing office buildings.

A Multisite Preregistered Paradigmatic Test of the Ego-Depletion Effect

We conducted a preregistered multilaboratory project ( k = 36; N = 3,531) to assess the size and robustness of ego-depletion effects using a novel replication method, termed the paradigmatic replication approach. Each laboratory implemented one of two procedures that was intended to manipulate self-control and tested performance on a subsequent measure of self-control. Confirmatory tests found a nonsignificant result ( d = 0.06). Confirmatory Bayesian meta-analyses using an informed-prior hypothesis (δ = 0.30, SD = 0.15) found that the data were 4 times more likely under the null than the alternative hypothesis. Hence, preregistered analyses did not find evidence for a depletion effect. Exploratory analyses on the full sample (i.e., ignoring exclusion criteria) found a statistically significant effect ( d = 0.08); Bayesian analyses showed that the data were about equally likely under the null and informed-prior hypotheses. Exploratory moderator tests suggested that the depletion effect was larger for participants who reported more fatigue but was not moderated by trait self-control, willpower beliefs, or action orientation.

A STUDY ON THREE-DIMENSIONAL PRINTING REPLICATION FOR USABILITY OF ARTIFACTS

In the field of cultural heritage, replication has been performed for preservation, exhibition, and education purposes. In particular, due to advancement in computer technology, replication which combines the three-dimensional (3D) scanning and printing has widely performed. These technologies have been able to ensure morphological similarity as well as to avoid damaging artifacts in a contactless manner. In this study, a design mock-up for producing replacements was made for the purpose of preserving original forms, usability, and mass production for ritual utensils used in ancestral memorial rites annually. 3D precision scanner was used to obtain external information of ritual utensils and shape information of pattern parts. The measurements on height, width, and thickness of the body, and two handles and three feet showed fine shape differences, respectively. Therefore, representative models were selected and reconstructed. In addition, the upper and lower parts of the body, handles, and feet were separately manufactured for mass production by using sand casting. A model manufactured during the reverse design like above was completed by considering average shrinkage (4%) for the casting of copper-tin alloys. A model was completed and 3D-printed with a material extrusion technique, and a design mock-up for replication was created. In this study, a 3D printing technology was applied to ritual utensils and presented a replication methodology applicable to used artifacts. For this purpose, a model suitable for the replication method was produced based on the data obtained by 3D scanning of ritual utensils. A design mock-up, which is 3D-printed with a material extrusion technique, has enhanced design completeness by performing continuous design and dimensional inspection.

A Novel Decoding Method for the Erasure Codes

The erasure codes are widely used in the distributed storage with low redundancy compared to the replication method. However, the current research studies about the erasure codes mainly focus on the encoding methods, while there are few studies on the decoding methods. In this paper, a novel erasure decoding method is proposed; it is a general decoding method and can be used both over the multivariate finite field and the binary finite field. The decoding of the failures can be realized based on the transforming process of the decoding transformation matrix, and it is convenient to avoid the overburdened visiting problem by tiny modification of the method. The correctness of the method is proved by the theoretical analysis; the experiments about the comparison with the traditional methods show that the proposed method has better decoding efficiency and lower reconstruction bandwidth.

An Experimental Study of Porous Hydroxyapatite Scaffold Bioactivity in Biomedical Applications

Hydroxyapatite is one of the most bioactive materials used in tissue engineering due to its excellent biocompatibility and chemical composition which is equivalent to the mineral element of bone. In this study, polymer sponge replication method was used to fabricate porous hydroxyapatite scaffolds. Pure phase of hydroxyapatite scaffolds and the chemical bonding were verified via Fourier Transform Infrared and X-ray diffraction. Emission scanning electron microscopy (F E S E M) examination showed that the proposed scaffold has high interconnected pores that were achieved just after sintering at temperatures 1350 ºC for 2 hours. The percentage porosity values were estimated to be between 75–78 percent. The bioactivity of porous scaffolds was also investigated. They were submerged in a slurry of simulated body fluid (S B F) for seven, fourteen, and twenty-one days, respectively. Both FESEM and XRD analysis have confirmed the bioactivity of the prepared porous hydroxyapatite scaffold through the formation of a dense layer of apatite on its surface. Based on the results, the porous hydroxyapatite scaffolds could be recommended as a critical option for bone defects as well as replacement applications.

Fabrication of Silica (SiO2) Foam from Rice Husk Ash (RHA): Effects of Solid Loadings

Silica (SiO2) foams have been widely applied in numerous fields, mainly filters and catalysts supports, due to their characteristics of high permeability, high porosity and specific surface area. In this study, foams of SiO2 from rice husk ash (RHA) was fabricated via polymeric sponge replication method. Polymeric foam initially was used as template and dipped into SiO2 slurry followed by drying and sintering to yield the replica of the original polymeric foam. Different solid loadings of SiO2 as-derived from RHA (20 to 35 wt. %) slurry and sintering temperature of 1150 °C were applied. Phase identification and chemical composition of the green and sintered foams were conducted using X-Ray Diffraction (XRD) and X-Ray Fluorescence (XRF). Morphological observations were performed using Scanning Electron Microscopy (SEM). Density and porosity of the SiO2 foams were characterized using Archimedes method. Compressive strengths of the foams were determined as per ASTM C773-88 (1999). XRD analyses confirmed that the SiO2 as derived from the RHA were of tridymite and cristobalite phases with as high as 93% purity, as confirmed by XRF analyses. The density of SiO2 foams fabricated was in the range of 0.614 to 0.989 g/cm3, whereas the porosity values was in the range of 70% to 82%%. Compressive strengths were found to increase from 0.05 to 0.30 MPa respectively, proportionate with the increased SiO2 solid loading. Excellent properties of the SiO2 foams definitely signifies that the polymeric replication method is indeed a promising technique for SiO2 as derived from RHA foam fabrication.