Fire resistance of fired clay bricks-fly ash composite cement pastes

This work aims to study the effect of substitution of fly ash for homra on the hydration properties of composite cement pastes. The composite cements are composed of constant proportion of OPC (80%) with variable amounts of fly ash and homra. The addition of fly ash accelerates the initial and final sitting time, whereas the free lime and combined water contents decrease with fly ash content. The fly ash acts as nucleation sites which may accelerate the rate of formation of hydration products which fill some of the pores of the cement pastes. The fire resistance of composite cement pastes was evaluated after firing at 250, 450, 600, 800 °C with rate of firing 5 °C/min with soaking time for 2 h. The physico-mechanical properties such as bulk density and compressive strength were determined at each firing temperature. Moreover, the phase composition, free lime and microstructure for some selected samples were investigated. It can be concluded that the pozzolanic cement with 20 wt% fly ash can be used as fire resisting cement.     

Uses of electron‐beam irradiation to prepare pH‐ and temperature‐sensitive hydrogels from reactive poly(vinyl alcohol) grafts

Thermosensitive poly(vinyl alcohol)‐graft‐(maleic anhydride), PVA‐MA, and poly(vinyl alcohol)‐graft‐(N‐isopropylacrylamide maleic anhydride) (PVA‐MA‐NIPAAm) copolymers containing carboxyl groups were prepared using electron beam irradiation at dose 80 kGy. The swelling ratios of the cross‐linked gels were measured at various temperatures. The LCST values were measured using DSC technique. The temperature dependence of the swelling ratios of the cross‐linked copolymers and terpolymers were measured at different temperatures. The swelling ratios of copolymers increased with increasing temperature up to 25–38°C, then decreased. The swelling behavior of both copolymers and terpolymers was referred to formation of hydrogen bonds between amide group of NIPAAm moieties and carboxyl group in MA moieties and to hydrophobic interaction due to methyl groups of NIPAAm. The swelling behaviors of these gels were analyzed in buffer solution at various pH. Swelling ratios of all gels were relatively high and they showed reasonable sensitive to pH. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

New bisphenol novolac epoxy resins for marine primer steel coating applications

Bisphenol derived from reaction of phenol with benzaldehyde was prepared in the presence of sulfuric acid as catalyst. Bisphenol novolacs were synthesized in both melting and solution processes using p-formaldehyde and formalin solution in the presence of oxalic acid catalyst. ¹H NMR analysis shows a high methylene bridge contents using the novolacs synthesized in a melting process. The bisphenol novolac epoxy resin was prepared by reaction with epichlorohydrine in the presence of sodium hydroxide as a catalyst. The prepared novolac epoxy resins were cured with 1,2-amino ethyl piperazine (AEP) as a curing agent. The cured resins were evaluated as organic coating for steel. The mechanical properties of the cured epoxy resins were evaluated by measuring both impact resistance and hardness. The chemical resistances of the cured resins were evaluated through salt spray resistance, hot water immersion, solvent resistance, acid and alkali resistance measurements. The data indicate that the cured epoxy resins have excellent chemical resistances as organic coatings among other cured resins.     

Effect of radiation and soaking on trypsin inhibitor and protein content of chickpea (Cicer arientinum L.)

Composition of Ascochyta-blight resistant chickpea for proximate components, vitamins, energy and trypsin inhibitor, was determined. The influence of irradiation and soaking at ambient temperatures (25–35°C) on trypsin inhibitor activity (TIA) and protein content of chickpea, was investigated. A significant linear relation (r = ?0.960 to ?0.987) was found between the loss of TIA and soaking time of irradiated and unirradiated seeds (p < 0.05) and the rate of loss increased with increasing radiation dose (0.25–1.00 kGy). However, effect of radiation alone was negligible. Maximum decrease (30.7%) in TIA (from 330.0 to 228.6 TIU/g) occurred during soaking for 12 h of 1.00 kGy sample. The protein contents increased from an initial value of 21.7% to 23.4% and 22.7% as a result of soaking for 12 h in tap and distilled waters respectively. Radiation treatment exhibited little or no effect.     

Thermal Shift Assay for Small GTPase Stability Screening: Evaluation and Suitability

Thermal unfolding methods are commonly used as a predictive technique by tracking the protein’s physical properties. Inherent protein thermal stability and unfolding profiles of biotherapeutics can help to screen or study potential drugs and to find stabilizing or destabilizing conditions. Differential scanning calorimetry (DSC) is a ‘Gold Standard’ for thermal stability assays (TSA), but there are also a multitude of other methodologies, such as differential scanning fluorimetry (DSF). The use of an external probe increases the assay throughput, making it more suitable for screening studies, but the current methodologies suffer from relatively low sensitivity. While DSF is an effective tool for screening, interpretation and comparison of the results is often complicated. To overcome these challenges, we compared three thermal stability probes in small GTPase stability studies: SYPRO Orange, 8-anilino-1-naphthalenesulfonic acid (ANS), and the Protein-Probe. We studied mainly KRAS, as a proof of principle to obtain biochemical knowledge through TSA profiles. We showed that the Protein-Probe can work at lower concentration than the other dyes, and its sensitivity enables effective studies with non-covalent and covalent drugs at the nanomolar level. Using examples, we describe the parameters, which must be taken into account when characterizing the effect of drug candidates, of both small molecules and Designed Ankyrin Repeat Proteins.     

One-dimensional coordination polymers based on first-row transition metals: A solid-state study of weak backbone interactions

We present further data on the solid-state structures of one-dimensional coordination polymers based upon dipositive transition metal hexafluoro-acetylacetonate (hfacac) complexes. A variety of linking subunits are employed in order to investigate and probe the relatively weak interactions that make up the backbones of these polymers. Reported in this study are metal complexes containing manganese, zinc, copper, and cobalt and a range of donor building blocks encompassing an array of bonding motifs, including pyridyl—metal, pyridyl(N-oxide)—metal, and hydrogen bonding. The specific linkers utilized are 4,4′-dipyridyl N,N′-dioxide hydrate, 2,5-bis(4-ethynylpyridyl)furan, 4,4′-trimethylenedipyridine, and trans-1-(2-pyridyl)-2-(4-pyridyl)-ethylene. A detailed discussion of the products is presented, as is a comparison to known compounds of a similar nature. All compounds are characterized via single-crystal X-ray diffraction and elemental analysis for the bulk of the sample.     

Optimal Deep Convolutional Neural Network for Vehicle Detection in Remote Sensing Images

Object detection (OD) in remote sensing images (RSI) acts as a vital part in numerous civilian and military application areas, like urban planning, geographic information system (GIS), and search and rescue functions. Vehicle recognition from RSIs remained a challenging process because of the difficulty of background data and the redundancy of recognition regions. The latest advancements in deep learning (DL) approaches permit the design of effectual OD approaches. This study develops an Artificial Ecosystem Optimizer with Deep Convolutional Neural Network for Vehicle Detection (AEODCNN-VD) model on Remote Sensing Images. The proposed AEODCNN-VD model focuses on the identification of vehicles accurately and rapidly. To detect vehicles, the presented AEODCNN-VD model employs single shot detector (SSD) with Inception network as a baseline model. In addition, Multiway Feature Pyramid Network (MFPN) is used for handling objects of varying sizes in RSIs. The features from the Inception model are passed into the MFPN for multiway and multiscale feature fusion. Finally, the fused features are passed into bounding box and class prediction networks. For enhancing the detection efficiency of the AEODCNN-VD approach, AEO based hyperparameter optimizer is used, which is stimulated by the energy transfer strategies such as production, consumption, and decomposition in an ecosystem. The performance validation of the presented method on benchmark datasets showed promising performance over recent DL models.     

Chitosan-Based Smart Polymeric Hydrogels and Their Prospective Applications in Biomedicine

With increasing scientific research, knowledge, and socioeconomic awareness, research, and industrial communities are now much more interested in biopolymers-based composite materials with multifaceted functionalities. Biopolymers are easily obtainable, economical, non-hazardous, and abundant. Several natural and synthetic polymers have been used to prepare hydrogels, microbeads, and microfibers for controlled drug release. Due to marvelous properties, chitosan has been widely explored for medical and pharmaceutical applications. In recent years, considerable attention has been paid to the chitosan-based hydrogels for biomedical applications, especially for transplantation, and for improving interfacial interactions for the living tissues. Hydrogels can be synthesized by co-polymerization, condensation, and cross-linking. This review spotlights recent advances in physicochemical characteristics, modification strategies, and smart blended hydrogels for an array of biomedical and pharmaceutical applications. The whole discussion reveals that among all the biopolymers, chitosan is the finest carrier for biomedical applications.