The generalization of orthogonal frequency division multiplexing with subcarrier power modulation to quadrature signal constellations

A novel modulation technique termed as orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM) has been proposed for achieving spectral-efficient data transmission in wireless communication systems. OFDM-SPM utilizes the power of each subcarrier in an OFDM block as an extra degree of freedom to convey extra information bits besides the bits transmitted by conventional signal modulation. OFDM-SPM has originally been introduced with binary phase shift keying (BPSK) symbol modulation, and was shown to provide great gains and various merits such as doubling the spectral efficiency, reducing transmission power and transmission times by half. Displaying its capabilities as a scheme to be adopted for future wireless communication systems, a question detrimental to the adoption of OFDM-SPM has yet to be answered. This is whether the gains that OFDM-SPM brings persist when paired with higher order modulation schemes, especially two dimensional signal constellation schemes such as M-ary PSK. In this paper, OFDM-SPM is paired with quadrature phase shift keying (QPSK) symbol modulation as an example of a higher order two dimensional modulation scheme. The performance analysis of this scheme along with its numerical simulations are carried out where the bit error rate (BER) and throughput performances of the scheme are given in both an additive white Gaussian noise (AWGN), and multipath Rayleigh fading channels. These simulations are done for different power allocation policies. Unlike other 3D modulation methods, the results show that OFDM-SPM can be used with higher order modulation schemes while maintaining all the gains exhibited in OFDM-SPM with BPSK. This gives OFDM-SPM a unique advantage when compared to other 3D modulation schemes such as OFDM-IM and OFDM-SNM, which lose the gain in spectral efficiency as the modulation order becomes higher. Furthermore, the results of OFDM-SPM with QPSK were compared to that of conventional OFDM with 16-QAM symbol modulation. OFDM-SPM displayed superiority both in terms of BER and throughput achieving a gain of approximately 2.5-3 dB. These findings clearly point out that OFDM-SPM is a promising modulation scheme, which should be investigated more vigorously and considered as a strong candidate for adoption in future 6G and beyond wireless communication systems.This research was partly funded by TUBITAK under Grant/Award Number: 119E408

Physio-Chemical and Mechanical Behaviour of(Pinussylvestris) as Binders on Foundry Core Strength

The mechanical potential of sand core binders made withPinussylvestris has been examined. Ota silica base sand bonded with 6% of cassava starch in admixed proportion of Pinussylvestris was tested for tensile, compressive strength and permeability to establish the binding efficiency. Tensile strength of the green baked core were oven baked at 50°C, 100°C, 150°C and 200°C.The cylindrically shaped permeability specimens were tested with permeability meter. Study revealed thatPinussylvestris showed an improve properties at 6% cassava starch at 200°C

Prediction of Flow Duration Curve for Seasonal Rivers in Iraq

This paper presents a new method to estimate the flow duration curves [FDCs] for ungauged river basins whose natural and meterological characteristics are known. This study highlights the modeling of the lower three-quarters of the section of the flow duration curves [FDCs]. Eight sub-catchments were used to develop and evaluate the proposed flow duration model in the north of Iraq. The logarithmic type function has been found appropriate for the lower three-quarters of the section of [FDCs] for all river sub-catchments located in the study area. Parameter values of the logarithmic function model were calculated using topographic, hydrological and climatic characteristics of the basins under study by two regional regression models: first CA-MAP (catchment area-mean annual precipitation) model and second MAF-PE (mean annual flowpotential evapotranspiration) model. Generally, it is found that both models used were predicting a good estimate at the end of the flow duration curve (low-flows). In most cases, the statistics and graphical results showed that the agreement between observed and estimated FDCs is very good by using MAF-PE model as compared to CA-MAP model

Effect of reagent type on the froth floatation of Sokoto phosphate ore

Effect of reagent type on the froth floatation of Sokoto phosphate ore for its beneficiation has been established. The samples of the Sokoto phosphate mineral ore used for the research work were sourced from mining locations in Dange-Shuni, Bodinga, Yabo, Wurno, and Rabbah Local Government Areas of Sokoto State. Size-Assay analysis conducted on scrubbed Sokoto Phosphates nodules revealed that nodules had a size distribution with 80% passing 29.3 mm. Flotation Tests using AERO704 (fatty Acid), Alkyl Hydroxamates, Melamine as collectors (alone or mixed with diesel), MIBC as frother, Calcium Hydroxide and Sulphuric Acid as pH regulators and Dextrin, Sodium Silicate and Aluminium Chloride as depressants produced poor P2O5 separation in the flotation products due to very poor liberation associated with very fine mineral grains. Based on the results obtained, AERO704 Collector gave the best result with aP2O5 recovery pH of 10

Effect of particle size on the froth floatation of Sokoto phosphate ore

Effect of particle size on the froth floatation of Sokoto phosphate ore for its beneficiation has been investigated and established. The research has been conducted using various reagents, pH(s) at different sieve size fractions. Bench scale flotation tests were carried out on -250+180μm, -180+106μm, -106+75μm, -75+45μm and -45+38μm particle size fractions after screening in order to determine the optimum flotation feed size distribution using 1 liter Denver flotation cell. The results of the scoping flotation studies using a conditioning Pulp Density of 60%Solids, pH9, 800g/t reagent dosage for AERO704 Promoter (Fatty Acid) and flotation pulp density of 28.5% Solids show that +106μm particle size gave the highest assay content of 20.4% P2O5 with a recovery of 76.2% compared to +38μm (19.9%P2O5 and recovery of 43.2%) and +180μm (19.4%P2O5 and 24.1% recovery) in their floats (concentrates) but with no perfect separation as the tailings fraction also contained similar grades with slight differences

Cardiogenic Shock

Cardiogenic shock is the second most common cause of circulatory shock, occurs secondary to myocardial infarction, which accounts for 80% of the cases, and remains one of the leading causes of death in patients with acute myocardial infarction. Cardiogenic shock carries a high morbidity and mortality despite recent advances in medical and mechanical therapies. Cardiogenic shock also occurs in non-acute coronary syndrome conditions, such as Takotsubo cardiomyopathy, fulminant myocarditis, end stage heart failure, and others. In this chapter, we provide a brief review on the pathophysiology, diagnosis, and acute management of cardiogenic shock patients. We will focus more on the management of acute coronary syndrome related cardiogenic shock, given that it is the most common etiology

Orthogonal frequency division multiplexing with subcarrier power modulation for doubling the spectral efficiency of 6G and beyond networks

With the emergence of new applications (eg, extended reality [XR] and haptics), which require to be simultaneously served not just with low latency and sufficient reliability, but also with high spectral efficiency, future networks (ie, 6G and beyond) should be capable of meeting this demand by introducing new effective transmission designs. Motivated by this, a novel modulation technique termed as orthogonal frequency division multiplexing with subcarrier power modulation (OFDM-SPM) is proposed for providing highly spectral-efficient data transmission with low-latency and less-complexity for future 6G wireless communication systems. OFDM-SPM utilizes the power of subcarriers in OFDM blocks as a third dimension to convey extra information bits while reducing both complexity and latency compared to conventional schemes. In this article, the concept of OFDM-SPM is introduced and its validity as a future adopted modulation technique is investigated over a wireless multipath Rayleigh fading channel. The proposed system structure is explained, an analytical expression of the bit error rate (BER) is derived, and numerical simulations of BER and throughput performances of OFDM-SPM are carried out. OFDM-SPM is found to greatly enhance the spectral efficiency where it is capable of doubling it. In addition, OFDM-SPM introduces negligible complexity to the system, does not exhibit error propagation, reduces the transmission delay, and decreases the transmission power by half.Türkiye Bilimsel ve Teknolojik Araştirma Kurumu, 119E40

Extract of Combretum micranthum as corrosion inhibitor for Al – Si – Mg alloy in simulated sea water environment

The leaf extract  of  Combretum micranthum (CM) was  tested  as  green  corrosion  inhibitor for Al-Si-Mg alloy in 3.5wt% NaCl solution using gravimetric and linear polarization methods at 300C, 500C and 700C, from 1, 2, 3, 4, 5 hours of exposure time with concentration of the extract 0, 0.2, 0.4, 0.6, 0.8 and 1.0 v/v  respectively. The result obtained indicate that the leaf extract of CM is a good corrosion inhibitor in the simulated sea  water medium. The inhibition efficiency of the extract increased with an increase in concentration of the CM extract and decreased with increase in temperature. On the other hand, inhibition efficiency (IE%) synergistically decreased on addition of surfactant (Monoethylamine). The adsorption of the inhibitor on Al-Si-Mg surface is exothermic, Spontaneous and is best described by Langmuir, Freundlick and El-Awady adsorption models. The calculated values of activation energy, enthalpy of activation entropy of activation, free energy of process is by physical adsorption. Equally, methanol extract CM is a good adsorption inhibitor for the corrosion of Al-Si-Mg in 3.5wt% NaCl solution. Tafel polarization analysis indicates that the studied plant extract is a mixed type inhibitor. http://dx.doi.org/10.4314/njt.v35i4.2

Anti-Corrosion and Passivation Potential of AA6063-Type Al-Mg-Si Alloy with Avogadro Natural Oil in HCl Solution

The electrochemical study of the passivation potential of AA6063-type Al-Mg-Si alloy in Avogadro Natural Oil/HCl Interface was studied using weight loss and potentiodynamic techniques. The result shows that the corrosion rate increases with an increase in exposure time but decrease as the concentration of inhibitor increases. The result of both weight loss and potentiodynamic show good agreement as can been seen that the inhibition efficiencies was found to increase as concentration of inhibitor increases. Equally the additive helps to retard the rate of corrosion and increase the polarization resistance thereby lowering the corrosion density of the system. The presence of the additive was also seen to affect both the cathodic and anodic half which shows that the inhibitor acts as a mixed-type inhibitor. The surface morphology of as-corroded samples assessed with scanning electron microscopy show that the attack was severely reduce in the presence of the Avogadro natural oil