Automatic analysis of human posture equilibrium using empirical mode decomposition

The present study proposes a new approach for the assessment of the human balance control. This approach is based on the decomposition of the center of pressure displacement using empirical mode decomposition (EMD) that provides an effective time-frequency analysis of non-stationary signals. Twenty-eight healthy subjects performed quiet standing in four conditions—feet apart/together with respect to eyes open/closed—while recording the stabilometric signals in the anteroposterior (AP) and mediolateral (ML) directions. The EMD method decomposes each stabilometric signal into several subsignals called intrinsic mode functions (IMFs). Stabilogram-diffusion analysis technique is applied to generate the diffusion curve of each IMF signal. Each diffusion curve is modeled as a second-order system and provides representative features, such as the gain parameter. Analysis of the gain parameter shows the major effect of visual input and feet conditions on the strategy to control/stabilize the balance. Significant differences were found between young and elderly, and between women and men. In addition, the impact of feet position seems to be higher in ML direction than in AP direction.     

Spice use in food: Properties and benefits

Spices are parts of plants that due to their properties are used as colorants, preservatives, or medicine. The uses of spices have been known since long time, and the interest in the potential of spices is remarkable due to the chemical compounds contained in spices, such as phenylpropanoids, terpenes, flavonoids, and anthocyanins. Spices, such as cumin (cuminaldehyde), clove (eugenol), and cinnamon (cinnamaldehyde) among others, are known and studied for their antimicrobial and antioxidant properties due to their main chemical compounds. These spices have the potential to be used as preservatives in many foods namely in processed meat to replace chemical preservatives. Main chemical compounds in spices also confer other properties providing a variety of applications to spices, such as insecticidal, medicines, colorants, and natural flavoring. Spices provide beneficial effects, such as antioxidant activity levels that are comparable to regular chemical antioxidants used so they can be used as a natural alternative to synthetic preservatives. In this review, the main characteristics of spices will be described as well as their chemical properties, different applications of these spices, and the advantages and disadvantages of their use.     

Soil and water quality assessment along the Red Sea coast,Egypt

The paper reports an assessment of the soil and water in the coastal strip between Marsa Alam and Shalateen at the southern part of the Red Sea coast of Egypt. There is limited potential for agricultural development. There is a need for water re-use and some potential for tourism.     

Automated trade‐off between time and cost in planning repetitive construction projects

An automated model is developed to support the optimization of the planning and scheduling of repetitive construction projects. The model provides the capability of optimizing two important objectives commonly sought in scheduling repetitive construction projects: minimizing project duration; and minimizing project cost. The model performs this multi‐objective optimization using a genetic algorithm approach. The output of the model is a set of optimal solutions that represent the trade‐off between time and cost in planning repetitive construction projects. Furthermore, the model can be utilized to find a single scheduling solution that provides the minimum overall project cost by simply adding project indirect cost to the obtained project direct cost for each of the obtained scheduling solutions on the Pareto optimal curve. Other important time‐related costs are also considered in the model including: early completion incentives, late completion penalties and lane rental costs. Providing the planners of repetitive construction projects with an automated set of optimal time–cost trade‐off solutions should contribute to cost‐effective and speedy delivery of this type of construction project. An application example is analysed to illustrate the use of the model and demonstrate its capabilities in generating optimal trade‐off solutions between minimizing the project time and cost for repetitive construction projects.     

Electrogenerated base-promoted synthesis and antimicrobial activity of 2-imino-1,3-thiazolidin-4-one derivatives

Electrogenerated cyanomethylanions obtained by reduction of dry acetonitrile at a steel grid cathode were used to promote the addition of ethyl bromoacetate to thiourea derivatives. The reaction yields the corresponding 2-imino-1,3-thiazolidin-4-one. The reaction pathway was discussed based on the kinetic and thermodynamic data obtained by computational methods. In addition, the biological activity of these new compounds was also investigated.     

A Taguchi design approach for the enhancement of a detergent-biocompatible alkaline thermostable protease production by Streptomyces mutabilis strain TN-X30

The ability of microorganisms to grow at high temperature, alkaline pH, and high salinity makes them an attractive target for enzyme-production with several industrial applications. One strain TN-X30 has been selected as protease producer and identified as Streptomyces mutabilis after a phenotypic and molecular study. Its production of protease was improved using Taguchi L27 design. The strategy was carried out to identify the optimum levels and the interaction of the screened factors. Following this step, maximum protease activity (10,895 U/ml) was achieved after 6-days of incubation. The TN-X30 protease activity had an optimum of pH and temperature of 10 and 65°C, respectively. Thermodynamic parameters at 60°C were enthalpy 14.26 kJ/mol, entropy −220 J/mol/K, and Gibbs free energy 90.53 kJ/mol. TN-X30 protease production displayed a 16-fold increase reaching 175,000 U/ml in a 100-L fermentor. Furthermore, the lyophilization in presence of sorbitol enhanced the stability of the TN-X30 protease which remained active at 75% after 24-months of storage. The lyophilized TN-X30 protease exhibited exceptional stability indexes in presence of some known commercialized detergent components as NEODOL® 25-7, Dehydol® LT 7, Na₂ CMC, Galaxy LAS, Galaxy LES 70, Galaxy 110, Galaxy CAPB Plus, and Sulfacid K. The lyophilized enzyme also displayed high stability with respect to both solid and liquid detergents. Finally, TN-X30 protease exhibited remarkable destaining of blood, egg, and chocolate stained cloth pieces. These findings may promote TN-X30 protease for use as bioadditive in detergent formulation, thereby reducing environmental chemical threat.     

Synthesis of a novolac‐based 3‐aminopropylsiloxane resin and its application for the removal of Cu2+, Cr3+, and Ni2+ from electroplating wastewater

Novolac resin was modified with 3‐aminopropyltrimthoxysilane to obtain phenol‐formaldehyde‐aminopropylsiloxane resin (PF‐APS). Fourier transformation infra‐red spectra, thermogravimetric analysis, elemental analysis, and pH‐metric titration were used to characterize PF‐APS. Its chemical formula was suggested to be C₁₄H_12.49N_0.1O₂Si_0.1. The resin shows high experimental metal ions uptake capacity within short time of equilibration. The metal capacity was determined by atomic absorption spectrometry to be 0.787 mEq Cu/g. Maximum separation efficiencies of Cu²⁺, Cr³⁺, and Ni²⁺ from aqueous solutions on PF‐APS were at pH 8.0 and time of stirring 60 min; 94.0%, 90.8%, 83.2%, respectively. No significant interference from the background ions Na⁺, Cl^?, and was observed on the separation process. The heavy metal ions were eluted using 0.01 mol L^?1 EDTA at 65°C releasing >94% of the separated metal ions. The method of separation was applied successfully to remove the heavy metal ions Cu²⁺, Cr³⁺, and Ni²⁺ from electroplating wastewater from Dekirnis, Dakahlia Governorate, Egypt. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40993.     

Impact of the Cd2+ treatment on the electrical properties of Cu2ZnSnSe4 and Cu(In,Ga)Se2 solar cells

The present contribution aims at determining the impact of modifying the properties of the absorber/buffer layer interface on the electrical performance of Cu₂ZnSnSe₄ (CZTSe) thin‐film solar cells, by using a Cd²⁺ partial electrolyte (Cd PE) treatment of the absorber before the buffer layer deposition. In this work, CZTSe/CdS solar cells with and without Cd PE treatment were compared with their respective Cu(In,Ga)Se₂ (CIGSe)/CdS references. The Cd PE treatment was performed in a chemical bath for 7 min at 70 °C using a basic solution of cadmium acetate. X‐ray photoemission spectroscopy measurements have revealed the presence of Cd at the absorber surface after the treatment. The solar cells were characterized using current density–voltage (J–V), external quantum efficiency, and drive‐level capacitance profiling measurements. For the CZTSe‐based devices, the fill factor increased from 57.7% to 64.0% when using the Cd PE treatment, leading to the improvement of the efficiency (η) from 8.3% to 9.0% for the best solar cells. Similar observations were made on the CIGSe solar cell reference. This effect comes from a considerable reduction of the series resistance (R_S) of the dark and light J–V, as determined using the one‐diode model. The crossover effect between dark and light J–V curves is also significantly reduced by Cd PE treatment. Copyright © 2015 John Wiley & Sons, Ltd.     

Points of View of Experts at CERAWeek 2021

正From March 1 to 5, the 2021 "Cambridge Energy Week"(CERAWEEK) meeting was held online.With the theme of "The New Map: Energy, Climate and Charting the Future", this "Cambridge Energy Week"discusses energy transformation, geopolitics,economy and market, investment and fnancing, innovation and technology, and talents needed in the future.