Md. Rezaul Karim

On the Utilization of Pozzolanic Wastes as an Alternative Resource of Cement

Recently, as a supplement of cement, the utilization of pozzolanic materials in cement and concrete manufacturing has increased significantly. This study investigates the scope to use pozzolanic wastes (slag, palm oil fuel ash and rice husk ash) as an alkali activated binder (AAB) that can be used as an alternative to cement. To activate these materials, sodium hydroxide solution was used at 1.0, 2.5 and 5.0 molar concentration added into the mortar, separately. The required solution was used to maintain the flow of mortar at 110% ± 5%. The consistency and setting time of the AAB-paste were determined. Mortar was tested for its flow, compressive strength, porosity, water absorption and thermal resistance (heating at 700 °C) and investigated by scanning electron microscopy. The experimental results reveal that AAB-mortar exhibits less flow than that of ordinary Portland cement (OPC). Surprisingly, AAB-mortars (with 2.5 molar solution) achieved a compressive strength of 34.3 MPa at 28 days, while OPC shows that of 43.9 MPa under the same conditions. Although water absorption and porosity of the AAB-mortar are slightly high, it shows excellent thermal resistance compared to OPC. Therefore, based on the test results, it can be concluded that in the presence of a chemical activator, the aforementioned pozzolans can be used as an alternative material for cement.

Development of a Zero-Cement Binder Using Slag, Fly Ash, and Rice Husk Ash with Chemical Activator

The increasing demand and consumption of cement have necessitated the use of slag, fly ash, rice husk ash (RHA), and so forth as a supplement of cement in concrete construction. The aim of the study is to develop a zero-cement binder (Z-Cem) using slag, fly ash, and RHA combined with chemical activator. NaOH, Ca(OH)2, and KOH were used in varying weights and molar concentrations. Z-Cem was tested for its consistency, setting time, flow, compressive strength, XRD, SEM, and FTIR. The consistency and setting time of the Z-Cem paste increase with increasing RHA content. The Z-Cem mortar requires more superplasticizer to maintain a constant flow of % compared with OPC. The compressive strength of the Z-Cem mortar is significantly influenced by the amounts, types, and molar concentration of the activators. The Z-Cem mortar achieves a compressive strength of 42–44 MPa at 28 days with 5% NaOH or at 2.5 molar concentrations. The FTIR results reveal that molecules in the Z-Cem mortar have a silica-hydrate (Si-H) bond with sodium or other inorganic metals (i.e., sodium/calcium-silica-hydrate-alumina gel). Therefore, Z-Cem could be developed using the aforementioned materials with the chemical activator.

Modeling and verification of Extensible Authentication Protocol for Transport layer Security in Wireless LAN environment

Today complex edge services are positioned on the Wireless LAN, different cryptographic protocols with complex as well as reactive communication models and event dependencies are increasingly being specified and adopted. To ensure that such protocols (and compositions thereof with existing protocols) do not result in unacceptable behaviors (e.g., deadlocks or live locks); a methodology is desirable for the automated checking of the “correctness” of these protocols. In this paper, we present ingredients of such a methodology. Specifically, we show how SPIN, a tool used for the formal systems verification purposes, can be used to verify as well as quickly identify problematic behaviors (if any) in core component of emergent Wireless LAN with non trivial communication authentication constructs — such as Extensible Authentication Protocol (EAP) for Transport layer Security (TLS). In our analysis, we identify essential elements, model and verify the EAP — TLS protocol using SPIN. It will evidently provide an insight into the scope and utility of formal methods based on state space exploration in testing larger and complex systems, for example, the complete Wireless LAN authentication suit.

An efficient dynamic superset bit-vector approach for mining frequent closed itemsets and their lattice structure

Efficient approach to mine frequent closed itemsets and their lattice structure.We propose a new memory efficient dynamic superset bit-vector (DSBV) structure.New candidate pruning techniques are developed.DSBV establishes hierarchical subset-superset relationship of itemset lattice.Extensive experiments to show scalability and supremacy of our proposed approach. Fast discovery of association rules from millions of transactions in a variety of large databases has now become a major challenge in data mining domain. Frequent itemsets and frequent closed itemsets are key sources of mining association rules. Association rules can be mined efficiently from lattice of itemsets. Non-redundancy, accuracy, time efficiency and memory usage are the factors those need to be considered while developing algorithms in order to extract meaningful association rules. In this paper, we propose an efficient bit-vector approach that exploits dual properties, tidset and superset information of an itemset in order to mine frequent closed itemsets with their lattice structure. We introduce a new memory efficient data structure called dynamic superset bit-vector to establish the relationship among frequent closed itemsets in a lattice. The novelty of our approach is that it effectively uses dual data structures called a dynamic bit-vector and a dynamic superset bit-vector jointly in order to reduce the search space and eliminate the generators of non-closed itemsets. Our proposed approach efficiently builds up the subset-superset relationship among the closed itemsets of the lattice structure in a bottom-up manner. Extensive experiments using real-life datasets and pervasive performance comparison with the existing works prove the efficiency and scalability of our proposed approach.

Evaluation of cytotoxic, analgesic, antidiarrheal, and phytochemical properties of Hygrophila spinosa (T. Anders) whole plant.

Abstract Background: Synthetic drugs are going to be replaced by plant-derived traditional drugs due to their cost effectiveness, relatively less harmfulness, and efficacy against multidrug resistance organisms. Hygrophila spinosa (Acanthaceae) has been used in a wide range of ailments including flatulence, diarrhea, dysentery, gonorrhea, and menorrhagia. Therefore, we investigated the cytotoxic, antinociceptive, and antidiarrheal effects of H. spinosa ethanol extract (EExHs). Methods: Preliminary phytochemical screening was accomplished by established methods modified in experimental protocol. EExHs was undertaken for cytotoxic assay by Brine shrimp lethality bioassay, antinociceptive action by acetic acid induced writhing test, and antidiarrheal activity by castor oil induced antidiarrheal test. Data were analyzed by GraphPad Prism 6.0 software using Dunnett’s test for multiple comparisons. Results: Reducing sugar, steroid, glycoside, tannin, alkaloid, saponins, and flavonoids were found to be present in EExHs. Lethal concentration (LC50) of EExHs for brine shrimps was 50.59 µg/mL which was relatively lower than that of the standard drug vincristine sulfate. In acetic acid induced writhing test, oral administration of EExHs at three different doses (125, 250, and 500 mg/kg) decreased writhing in dose-dependent manner while the highest dose (500 mg/kg) achieved the maximum percentages of pain inhibition (58.8%). Diclofenac sodium (25 mg/kg) was used as a reference antinociceptive drug. The antidiarrheal action of EExHs was not found to be very promising for further use; however, the pure compounds from EExHs could be analyzed to justify the effects. Conclusions: This research demonstrates that the secondary metabolites guided cytotoxic and analgesic effects could be extensively studied in multiple models to confirm the effects.

Mining non-redundant closed flexible periodic patterns

Abstract Mining periodic patterns from time series databases is needed to predict any future situation. Flexible pattern mining is a special kind of periodic pattern mining where intermediate events can be overlooked purposely. Mining such patterns from time series data is advantageous due to its capability of modeling various real life scenarios. The goal of mining closed flexible patterns is to avoid unnecessary flexible patterns but preserving the same information of a complete set of patterns. Though it has wide range of application domains, existing algorithms failed to mine closed flexible patterns without generating any false positive, i.e. non-closed and ∕ or redundant patterns. In this paper, a new algorithm N R C F P (Non-Redundant Closed Flexible Pattern) has been proposed that generates complete set of non-redundant closed flexible patterns in time series databases. Three pruning techniques- B a c k S c a n (existing), R a n g e S c a n (proposed) and C o l u m n - p r u n i n g (proposed) have been applied to avoid generation of non-closed patterns, redundant flexible patterns and fictitious patterns. Proposed N R C F P efficiently mines non-redundant closed flexible periodic patterns. The performance of our algorithm has been extensively analyzed using several real-life databases based on runtime and memory consumption and compared with existing state-of-the-arts approach to prove effectiveness of the algorithm with respect to required processing time and memory consumption. Some applications of our proposed algorithm in various real life domains are discussed.

In silico ADME/T and 3D QSAR analysis of KDR inhibitors -

Tyrosine kinases (KDR) have been considered as a potential targets for the design of new anticancer agents. Recently, a series of N-4-chlorophenylnaphthamides has been reported with KDR inhibitory activity. In order to demonstrate the pharmacokinetics and the relationship between the structures and their inhibition of KDR, 3D-QSAR and in silico ADME/T analysis were performed on a dataset of 13 compounds. Quantum chemical parameters such as LUMO energy, HOMO energy, ionization energy (I), electron affinity (A), chemical potential (μ), hardness (η) and electrophilicity (χ) of the compounds are calculated by using semi-empirical SCF-MO method at PM3 level of theory and various SlogP descriptors from MOE software. In silico ADME/T analysis was performed by using different software’s Discovery Studio 2.5, TOPKAT and QikProp 4.3. From in silico ADME and Toxicity studies, it was revealed that selected derivatives have good oral absorptions and metabolisms with no BBB penetration. QSTR (Quantitative Structure Toxicity Relationship) studies by using TOPAK in various computational animal models, showed high LD50 values and the compounds are found to be noncarcenogenic. Moreover, three different QSAR models were generated by Partial Least Squares (PLS) Regression method having correlation coefficient (Q2) of 0.86382, 0.84372, and 0.82629, respectively. These models conclude a significant relationship of KDR inhibition with dipole moment (D), LUMO energy (ELUMO), hardness (η) and electrophilicity (χ), and hydrophobicity of compounds, regarding N-4-chlorophenylnaphthamides.

Influence of Slag and Slag Cement on the Strength of Sustainable Concrete

Cement is an essential constituent for the production of concrete. Nowadays, the supplementary use of cement such as industrial by-product and agricultural waste material has become an integral part of concrete construction due to their cost effective and sustainable environmental benefits. The industrial (metallurgical) by product-Granulated Blast Furnace Slag (GBFS) contains a non-crystalline silicon dioxide with high specific surface area and high pozzolanic reactivity. The use of GBFS either in cement or concrete has been increased due to its better performance in concrete in terms of strength and durability. In this paper, a critical review on the influence of slag and slag cement on the strength of sustainable concrete has been presented. The researches carried out in the past on the use of GBFS as partial replacement of cement in mortar and concrete, basically, the strength development of GBFS blended concrete and cement are reviewed in this study. These test results confirmed that the strength of cement mortar and concrete is varied with percent of slag replacement, fineness of slag and cement used, curing temperature as well as curing method. Based on the information available in literature, slag and slag cement could be a valuable material for the production of sustainable concrete.

A Proposed Low-cost Security System Based on Embedded Internet Control

In an era when computing systems are approaching towards mobility, smaller size, and the area of computer applications are becoming wider and broader, embedded Internet control facilitates the control of useful devices with the tremendous opportunity of the Internet, ad hoc networks, mobile telecommunications, etc. Embedded Internet control also facilitates the development of low cost systems, which are normally feasible for the requirements of Third World countries. In this paper the objective of the described project was to develop a security system for office or home doors, which could be controlled in embedded Internet technology. The approach is to design the required sensor and actuator, client and server, and thereby enable the control through the mobile phone. The paper extends the use of F-Bus protocol in Nokia 3310 mobile phones to send and receive SMS form servers