Journal of Mathematical and Fundamental Sciences
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Enhanced Hydrogen Storage Capacity Over Electro-synthesized HKUST-1
Get PDFHKUST-1 [Cu3(1,3,5-BTC)2] (BTC = 1,3,5-benzene-tri-carboxylate) was synthesized using an electrochemical method and tested for hydrogen storage. The obtained material showed a remarkably higher hydrogen uptake over reported HKUST-1 and reached until 4.75 wt% at room temperature and low pressure up to 1.2 bar. This yield was compared to HKUST-1 obtained from the solvothermal method, which showed a hydrogen uptake of only 1.19 wt%. Enhancement of hydrogen sorption of the electro-synthesized product was due to the more appropriate surface area and pore size, effected by the preferable physical interaction between the hydrogen gasses and the copper ions as unsaturated metal centers in the frameworks of HKUST-1
Preliminary Estimation of Engineering Bedrock Depths from Microtremor Array Measurements in Solo, Central Java, Indonesia
Get PDFIn the last decade the city of Solo, located in Central Java, Indonesia, has grown significantly and become a major city. Many industries and hotels have been built in the city and its surroundings. This study aimed to determine the engineering bedrock depths in Solo, an important parameter in seismic hazard analysis. The microtremor array method was used to obtain 1D S-wave velocity profiles and construct layer depth maps. The spatial autocorrelation (SPAC) method was used to calculate the dispersion curves, while the S-wave velocity structure was derived using a genetic algorithm (GA). The results of the S-wave velocity structure in Solo show that there are four stratigraphic layers, where the engineering bedrock depths in Solo exist within the range from 145 to 185 m. The shape of the bedrock basin is elongated in an east-west direction
Inhibition of Mammary Gland Cancer Development by Propolis and Mangostin in Female Mice Balb/C
Get PDFThe development of breast cancer involves many processes, including angiogenesis and metastasis. Some factors play a major role in angiogenesis, such as HIF-1α, and in metastasis, such as FAK and Wnt2. The aim of this study was to observe the effect of propolis and mangostin on the development of mammary gland cancer and on the expression of Wnt2 and FAK in Balb/C mice. Mammary gland tumors were induced in Balb/C mice by DMBA. The mice were divided into 5 treatment groups: negative control (K"‘); positive control treated with doxorubicin (14.04 mg/kg bw) (Dx); mice treated with propolis (0.32 mg/kg bw) (P) or mangostin (0.128 mg/kg bw) (M); and mice treated with a combination of propolis (0.32 mg/kg bw) and mangostin (0.128 mg/kg bw) (MP). Both mangostin and propolis did not affect the body weight of the mice. Treatment with propolis or treatment with propolis combined with mangostin was able to reduce tumor development activity in Balb/C mice. Moreover, the combination of mangostin and propolis was able to lower Wnt2, FAK and HIF-1α expression. It can be concluded that the combination of propolis and mangostin has potential to inhibit cancer development through downregulation of Wnt2, FAK, and HIF1α expression
The Reliability of Wireless Sensor Network on Pipeline Monitoring System
Get PDFThe wireless sensor network (WSN) is an attractive technology, which combines embedded systems and communication networks making them more efficient and effective. Currently, WSNs have been developed for various monitoring applications. In this research, a wireless mesh network for a pipeline monitoring system was designed and developed. Sensor nodes were placed at each branch in the pipe system. Some router fails were simulated and the response of each node in the network was evaluated. Three different scenarios were examined to test the data transmission performance. The results proved that the wireless mesh network was reliable and robust. The system is able to perform link reconfiguration, automatic routing and safe data transmission from the beginning node to the end node
Modelling Multiple Dosing with Drug Holiday in Antiretroviral Treatment on HIV-1 Infection
Get PDFA within-host mathematical model to describe the dynamics of target cells and viral load in early HIV-1 infection was developed, which incorporates a combination of RTI and PI treatments by using a pharmacokinetics model. The local stability of uninfected steady state for the model was determined using an alternative threshold. The pharmacokinetics model was employed to estimate drug efficacy in multiple drug dosing. The effect of periodic drug efficacy of pharmacokinetic type on outcome of HIV-1 infection was explored under various treatment interruptions. The effectiveness of treatment interruption was determined according to the time period of the drug holidays. The results showed that long drug holidays lead to therapy failure. Under interruption of treatments combining RTI and PI therapy, effectiveness of the treatment requires a short duration of the drug holiday.
New Estimation Rules for Unknown Parameters on Holt-Winters Multiplicative Method
Get PDFThe Holt-Winters method is a well-known forecasting method used in time-series analysis to forecast future data when a trend and seasonal pattern is detected. There are two variations, i.e. the additive and the multiplicative method. Prior study by Vercher, et al. in [1] has shown that choosing the initial conditions is very important in exponential smoothing models, including the Holt-Winters method. Accurate estimates of initial conditions can result in better forecasting results. In this research, we propose new estimation rules for initial conditions for the Holt-Winters multiplicative method. The estimation rules were derived from the original initial conditions combined with the weighted moving average method. From the experimental results it was found that the new approach of the Holt-Winters multiplicative method can outperform the original Holt-Winters multiplicative method
On Commutative Characterization of Graph Operation with Respect to Metric Dimension
Get PDFLet G be a connected graph with vertex set V(G) and W={w1, w2, ..., wm} ⊆ V(G). A representation of a vertex v ∈ V(G) with respect to W is an ordered m-tuple r(v|W)=(d(v,w1),d(v,w2),...,d(v,wm)) where d(v,w) is the distance between vertices v and w. The set W is called a resolving set for G if every vertex of G has a distinct representation with respect to W. A resolving set containing a minimum number of vertices is called a basis for G. The metric dimension of G, denoted by dim (G), is the number of vertices in a basis of G. In general, the comb product and the corona product are non-commutative operations in a graph. However, these operations can be commutative with respect to the metric dimension for some graphs with certain conditions. In this paper, we determine the metric dimension of the generalized comb and corona products of graphs and the necessary and sufficient conditions of the graphs in order for the comb and corona products to be commutative operations with respect to the metric dimension
Stability in Functional Integro-differential Equations of Second Order with Variable Delay
Get PDFIn this paper, we investigate the stability of the zero solution of an integro-differential equation of the second order with variable delay. By means of the fixed point theory and an exponential weighted metric, we find sufficient conditions under which the zero solution of the equation considered is stable