Removal of lead ions from aqueous solutions using powdered corn cobs

This paper is a report on an investigation conducted on adsorption of lead ions (Pb²⁺) onto powdered corn cobs (PCC). Corn cobs were collected from a selected location in Nigeria. The corn cobs were crushed and pulverised into different particle sizes. Its compositions and adsorption properties of Pb²⁺ onto PCC were studied. The effects of pH, particle size of PCC, and initial concentration of Pb²⁺ on the adsorption properties were monitored. The adsorption capacities were analysed by using standard adsorption models. The models were evaluated statistically (total error, coefficient of determination (CD), model of selection criterion (MSC), and root mean square error). The study revealed that PCC contained 2.33%, 86.89%, 10.78%, 0.52%, and 4.56% ash, volatile, moisture, solubility in water, and solubility in 0.25 M of HCl by mass, respectively. Acid digestion of a gram of PCC indicated that PCC contained no chromium and lead, but contained 131 mg Fe, 54.79% carbon, 8.03% hydrogen, 0.41% nitrogen, 0.010 mg of Al, and 1.70 mg calcium. The isotherm models parameters were 28.509 L/mg and 0.141 mg/g; 0.138 mg/g and 11.494 L/mg; 0.142 L/mg and 0.013 mg/g; 0.129 mg/g and 25.641 L/mg, 28.509 L/mg, 3.795 mg/g and 2.336 for Langmuir, Freundlich, Temkin, activated sludge, and Redlich–Peterson. The PCC particle size, initial pH, and initial Pb²⁺ concentration had effects on the adsorption parameters. The statistical evaluations showed that the best model for adsorption of lead ions from raw water onto PCC based on lower errors, high CD (0.88), reliability (97.5%), and MSC (1.86) was Freundlich and followed by activated sludge model. It was concluded that PCC is a good adsorbent like powdered eggshell and other carbon‐based materials.     

Mitigating Pilot Contamination for Channel Estimation in Multi-cell Massive MIMO Systems

Massive multiple-input multiple-output (MIMO) is a crucial technology platform for the fifth-generation of cellular systems (5G). However, massive MIMO systems are affected by pilot contamination, which influences the data rate of the system. This contamination is caused by the non-orthogonality of the pilot sequences transmitted by users in a cell similar to the neighboring cells. The current study proposes a channel-estimation scheme that employs comprehensive knowledge of large-scale gained by applying an orthogonal pilot reuse sequence to eliminate pilot contamination in edge users with reduced channel quality based on the approximation of large-scale fading, and the performance of this scheme is evaluated using the maximum ratio transmission and zero-forcing precoding techniques. Largely interfering users in neighboring cells are established based on an estimation of large-scale fading, and these users are included in the joint channel processing. The channel quality of users is enhanced by allocating orthogonal pilot reuse sequences to the center user and the edge users based on their levels of pilot contamination estimated from the large-scale fading to mitigate this problem when the number of antenna elements M is infinite. The findings of the simulation indicate that improved channel approximation and reduced performance loss could lead to a high data rate.

     

Novel Universal Windowing Multicarrier Waveform for 5G Systems

Fifth Generation (5G) systems aim to improve flexibility, coexistence and diverse service in several aspects to achieve the emerging applications requirements. Windowing and filtering of the traditional multicarrier waveforms are now considered common sense when designing more flexible waveforms. This paper proposed a Universal Windowing Multi-Carrier (UWMC) waveform design platform that is flexible, providing more easily coexists with different pulse shapes, and reduces the Out of Band Emissions (OOBE), which is generated by the traditional multicarrier methods that used in the previous generations of the mobile technology. The novel proposed approach is different from other approaches that have been proposed, and it is based on applying a novel modulation approach for the Quadrature-Amplitude Modulation (64-QAM) which is considered very popular in mobile technology. This new approach is done by employing flexible pulse shaping windowing, by assigning windows to various bands. This leads to decreased side-lobes, which are going to reduce OOBE and boost the spectral efficiency by assigning them to edge subscribers only. The new subband windowing (UWMC) will also maintain comprehensively the non-orthogonality by a variety of windowing and make sure to keep window time the same for all subbands. In addition, this paper shows that the new approach made the Bit Error Rate (BER) equal to the conventional Windowed-Orthogonal Frequency Division Multiplexing (W-OFDM). This platform achieved great improvement for some other Key Performance Indicators (KPI), such as the Peak to Average Power Ratio (PAPR) compared with the conventional (W-OFDM) and the conventional Universal Filtered Multicarrier (UFMC) approaches. In particular, the proposed windowing scheme outperforms previous designs in terms of the Power Spectral Density (PSD) by 58% and the (BER) by 1.5 dB and reduces the Complementary Cumulative Distribution Function Cubic Metric (CCDF-CM) by 24%.     

Mechanism of Soret‐Dufour,magnetohydrodynamics, heat and mass transfer flow with buoyancy force,and viscous dissipation effects

This paper examined the mechanism of both positive and negative effects of Soret‐Dufour with heat and mass transfer processes over an accelerating permeable surface. The partial differential flow equations were simplified using similarity variables, and the resulting equations were solved numerically using the spectral homotopy analysis method (SHAM). The SHAM is used in separating nonlinear equations into linear and nonlinear. The physics of each pertinent flow parameters was used to examine their influence on velocity, temperature, and concentration fields. The effect of Soret‐Dufour was examined separately, and its negative effect was used to determine its influence on velocity, temperature, and concentration fields. The result revealed that positive Soret‐Dufour enhances the boundary layer, whereas negative Soret‐Dufour parameter decreases the boundary layer. The result presented in this paper is in good agreement with existing works in literature.     

Measurement and correlation of physical properties of aqueous solutions of tetrabutylammonium hydroxide,piperazine and their aqueous blends

The density, viscosity and refractive index of aqueous solutions of tetrabutylammonium hydroxide (TBAOH), pi-perazine (PZ) and their aqueous blends are determined at several temperatures (303.15 to 333.15 K). All these measured physicochemical properties decreases with an increase in temperature. The density data is used to cal-culate the coefficient of thermal expansion and excess molar volume of al aqueous binary and ternary solutions. The coefficient of thermal expansion increases with increase in temperatures and concentrations. The negativity of excess molar volume for al the aqueous solution decreased with increase in temperature. Each physical prop-erty is correlated with temperature by least square method and the corresponding coefficients for each property are presented. The prediction values from correlations for the physical properties are in good agreement with the experimental values.     

Steady magnetohydrodynamic Poiseuille flow of two immiscible non-Newtonian and Newtonian fluids in a horizontal channel with Ohmic heating

In this paper, an analytical study has been carried out on a steady magnetohydrodynamics (MHD) Poiseuille flow of two immiscible fluids in a horizontal channel with ohmic heating in the presence of an applied magnetic field. The channel is divided into two sections, Region I and Region II, respectively. Region I contains an electrically conducting, third grade, non-Newtonian fluid while Region II is a Newtonian fluid. The regular Perturbation series method is used to transform the coupled nonlinear differential equations governing the flow into a system of linear ordinary differential equations in both fluid regions. Suitable interface matching conditions were chosen to obtain separate solutions for each fluid in both regions and the results were displayed graphically for various values of physical parameters, such as pressure gradient, suction parameter, Hartmann number, Prandtl number, viscosity, and conductivity ratios to show their effects on the flow. The effect of skin friction and Nusselt number was shown with the aid of tables. The results obtained among other findings clearly shows that as the value of the magnetic parameter increases, the velocity and temperature of the fluid decrease.     

Failure Analysis of a Dissolved Air Flotation Treatment Plant in a Dairy Industry

Environmental pollution in Nigeria presents an urgent need to assess wastewater treatment facilities in various industries. This article presents an assessment of dissolved air flotation (DAF) operation in a dairy industry. The industry was visited, wastewater treatment facilities were assessed (based only on efficacy to remove selected environmental health-related pollutants) and measurements of essential design and characterization parameters were taken. The study revealed that the averages of flow rate, biochemical oxygen demand at 5 days (BOD₅), chemical oxygen demand (COD), suspended solids (SS) and total solids (TS) of the influent wastewater into the plant (DAF) were 3.45 L/s, 1652.37, 3304.67, 2333.82, and 4396.10 mg/L compared to effluent quality of 560.37, 1127.33, 172.33, and 1866.67 mg/L for BOD₅, COD, SS, and TS, respectively. The pH of the wastewater is being adjusted by addition of lime before the effluent equalization tank and individual efficacies of the system were 66.09, 65.89, 65.89, 57.54, 8.68, and 94.49% for BOD₅, COD, SS, TS, DS, and total nitrogen, respectively, with overall efficacy of 38.10%. It was concluded that failure (lower overall efficacy) of the system can be attributed to setting of lime in the oversized equalization tank (50 m³ instead of 16.82 m³ per 8 h shift), the lack of application of standardized engineering code and practices (provision of underground tank in the process, lack of complete coagulation processes, coagulation and flocculation units), lack of adequate aeration unit and lack of reliable systems for automatically adjusting dosage of coagulant and flocculant. Although, DAF unit is the centerpiece of a DAF-based system design, there are several other supporting systems important to optimal DAF operation. These observations, coupled with the analysis in this report, demonstrate that the facilities necessary to minimize continuous environmental pollution are lacking. Pollution will become an increasing problem unless pollution preventing codes and standards are developed; incorporated into government regulations and the regulations are enforced.     

Computational methods for Traditional Chinese Medicine: a survey

Traditional Chinese Medicine (TCM) has been actively researched through various approaches, including computational techniques. A review on basic elements of TCM is provided to illuminate various challenges and progresses in its study using computational methods. Information on various TCM formulations, in particular resources on databases of TCM formulations and their integration to Western medicine, are analyzed in several facets, such as TCM classifications, types of databases, and mining tools. Aspects of computational TCM diagnosis, namely inspection, auscultation, pulse analysis as well as TCM expert systems are reviewed in term of their benefits and drawbacks. Various approaches on exploring relationships among TCM components and finding genes/proteins relating to TCM symptom complex are also studied. This survey provides a summary on the advance of computational approaches for TCM and will be useful for future knowledge discovery in this area.     

RS Codes with Filtered-OFDM: A Waveform Contender for 5G Mobile Communication Systems

In recent years, the proportion of elderly population in various countries has gradually increased. Increasing with age, it can entail illness. When these diseases are sudden, the elderly often die because there is no immediate treatment. Elderly care has become an important issue. According to this issue, we want to monitor the physiological data of the elderly, such as heartbeat, blood pressure, etc., through wearable devices. Once an abnormal condition is detected, the wearable device can be used to immediately request treatment from a nearby clinic or hospital. In order to improve the network quality of this service, we use the architecture of the mobile edge computing. The mobile edge computing provides features such as immediacy, low latency, proximity etc. However, the process of data transmission on the mobile edge computing has the risk of being stolen and identity authentication is also an important issue. Therefore, we propose a secure protocol based on cryptography to protect personal information with lightweight authentication. The proposed scheme aims to achieve mutual authentication, non-repudiation, integrity, user privacy, and defend against known attacks.

     

Mesoporous Silica Preparation Using Sodium Bicarbonate as Template and Application of the Silica for Hydrocracking of Used Cooking Oil into Biofuel

Silicon - The hydrocracking of used cooking oil into biofuel over mesoporous silica was systematically studied. This research aims to induce the silica pores using NaHCO3 and employ the heteropore...