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Let δ be a (d-1)-dimensional simplicial complex and let h(δ)=(h0,h1,...,hd) be its h-vector. A recent result of Murai and Terai guarantees that if δ satisfies Serre's condition (Sr), then (h0,h1,...,hr) is an M-vector and hr+hr+1+...+hd is nonnegative. In this article, we extend the result of Murai and Terai by giving r extra necessary conditions. More precisely, we prove that if δ satisfies Serre's condition (Sr), then iihr+i+1ihr+1+...+i+d-rihd, 0≤i≤r≤d, are all nonnegative  

Graphene nanoplatelets with different oxidation degrees, from low polar few-layer graphene (FLG) to high polar graphene oxide (GO) in the same current and concentration of the oxidizing agent in low concentrated electrolytes ((NH4)2SO4, Sodium Do-decyl Sulfate (SDS), and HNO3) are prepared through a one-step and cost-effective electrochemical synthesis route to find the effect of electrolyte on the surface polarity of powders. In order to use a wide variety of electrolytes, basic, neutral, and acidic electrolytes in a concentration as low as 0.2 M are used. Exfoliated graphene nanoplatelets without any further process are obtained to simplify and accelerate the synthesis process. Several... 

The existence of nonrandom patterns in codon assignments is supported by many statistical and biochemical studies. The canonical genetic code is known to be highly efficient in minimizing the effects of mistranslation errors and point mutations. For example, it is known that when an error induces the conversion of an amino acid to another, the biochemical properties of the resulting amino acid are usually very similar to that of the original. Prior studies include many attempts at quantitative estimation of the fraction of randomly generated codes which, based upon load minimization, score higher than the canonical genetic code. In this study, we took into consideration both the relative... 

A comprehensive dynamic model of a four motorized wheels electric vehicle has been developed and different types of motor control laws were addressed. The first part of this study deals with the full description of the model scope in which the structure of the model, including the sub-models, has been expressed. Subsequently, the sub-models including the fire sub-model, the body motion, and the motor dynamics are fully investigated, and with the use of simulink software, the computer model of the vehicle is simulated. Finally, the motor control laws are presented and the vehicle dynamic behavior studied under different driving conditions. Detailed analyses and comparison of the simulation... 

The effects of weld nugget size and expulsion on the performance of low carbon steel resistance spot weld have been investigated in the present paper. Failure mode, peak load and failure energy obtained in tensile-shear test have been used to describe the performance of spot weld. The influence of voids and porosity as well as electrode indentation associated with expulsion on peak load and failure energy is discussed. The results showed that although expulsion does not reduce the load carrying capacity of spot welds, it decreases their energy absorption capability which was attributed to the change of failure location due to excessive electrode indentation associated with expulsion. © 2008... 

The heat-affected zone (HAZ)softening is considered one of the most significant challenges during welding of ferrite–martensite dual-phase (DP) steels. In fact, the strain localization in the softened area results in a premature fracture that degrades the mechanical properties of the joint. Herein, the objective is to investigate the effectiveness of improved cooling using a high thermal diffusivity backing plate (BP) to reduce HAZ softening and enhance the mechanical properties of friction stir-welded DP700 steel. Accordingly, friction stir butt welding of DP700 steel was conducted using copper and mild steel BPs. The findings show that the replacement of steel BP with copper significantly... 

In this study, butt welds of an advanced high strength dual phase steel were fabricated using friction stir welding at a constant rotational speed of 800 rpm and different transverse speeds of 100, 150 and 200 mm/min. It was observed that sound welds can be obtained at transverse speeds of 100 and 150 mm/min. At transverse speed of 100 mm/min, the entire stir zone processed at temperatures higher than Ac3. By increasing transverse speed to 150 mm/min, temperature in the bottom region of the stir zone lied between Ac1 and Ac3, while the middle and the top regions experienced temperatures higher than Ac3. The lower peak temperature in the bottom region of the stir zone resulted in finer and... 

The heat-affected zone (HAZ) softening is considered one of the most significant challenges during welding of ferrite–martensite dual-phase (DP) steels. In fact, the strain localization in the softened area results in a premature fracture that degrades the mechanical properties of the joint. Herein, the objective is to investigate the effectiveness of improved cooling using a high thermal diffusivity backing plate (BP) to reduce HAZ softening and enhance the mechanical properties of friction stir-welded DP700 steel. Accordingly, friction stir butt welding of DP700 steel was conducted using copper and mild steel BPs. The findings show that the replacement of steel BP with copper significantly... 

The current research focuses on suggesting a new potential application of polymeric materials for capacitor applications by focusing on polystyrene (PS)/ethylene-α-octene copolymer (EOC) blends. Polymeric materials have high dielectric strength (≈ 200 for PS), good processability, and flexibility. However, their low dielectric constants make them not suitable for capacitor applications. Therefore, suggesting a method for enhancing their dielectric constant accompanied by low tan δ proposes an excellent substitute for commonly used ceramic dielectrics. The current article investigates the control of the dielectric properties of PS/EOC blends by manipulating the graphene nanoplatelets (GNPs)... 

A laboratory-scale multistage anaerobic biofilm reactor of three compartments with a working volume of 54-L was used for treating a synthetic medium-strength wastewater containing molasses as a carbon source at different influent conditions. The start-up period, stability and performance of this reactor were assessed at mesophilic temperature (35 °C). During the start-up period, pH fluctuations were observed because there was no microbial selection or zoning, but as the experiment progressed, results showed that phase separation had occurred inside the reactor. COD removal percentages of 91.6, 91.6, 90.0 and 88.3 were achieved at organic loading rates of 3.0, 4.5, 6.75 and 9.0 kg COD/m3 day,... 

Resistance spot welding was used to join austenitic stainless steel and galvanized low carbon steel. The relationship between failure mode and weld fusion zone characteristics (size and microstructure) was studied. It was found that spot weld strength in the pullout failure mode is controlled by the strength and fusion zone size of the galvanized steel side. The hardness of the fusion zone which is governed by the dilution between two base metals, and fusion zone size of galvanized carbon steel side are dominant factors in determining the failure mode. © 2007 Elsevier B.V. All rights reserved  

In this note, we show that under certain assumptions the matrix Riccati differential equation X′ = A(t)X + XB(t)X + C(t) with periodic coeffi cients admits at least one periodic solution. Also, we give an illustrative example in order to indicate the validity of the assumptions and the novelty of our result. © 2021, Tsing Hua University. All rights reserved  

Solar Chimney Power Plant (SCPP) is a renewable energy system that indirectly converts solar energy to electricity. However, the efficiency of SCPP is not sufficient for practical applications. Integrating SCPPs with Photovoltaic-Thermal systems (PVT) could enhance their performance to levels acceptable for industrial adoption. This study investigates the combined SCPP-PVT performance for the weather conditions of Austin (Texas), San Diego (California), and Phoenix (Arizona), all on a similar latitude. Various configurations of this combined system are numerically simulated, and their efficiencies are compared with a conventional SCPP, SCPP-Photovoltaic (PV), and stand-alone PV modules.... 

A 2-D numerical model was developed to predict the shape of weld pool in stationary GTA welding of commercial pure aluminium, without considering fluid flow in the weld pool. A Gaussian current density and heat input distribution on the surface of the workpiece were considered. The parameters of Gaussian distribution were modified by comparing calculated results with experimental ones. It was found that these distribution parameters are functions of applied current and arc length. Effects of arc length, applied current and welding time on the geometry of the weld pool were investigated. To check the validity of the model, a series of experiments were also conducted. In general, the agreement... 

TiO2 a nanotube array was prepared using an anodization process. The process proceeded in a two-electrode cell containing of platinum sheet as the cathode electrode. Two phosphate-base electrolyte solutions containing different amounts of HF and NH4F were prepared. Different concentration of fluorine ions were examined in respected electrolytes. Current transient techniques were used to produce the TiO2 nanotubes at constant voltage of 18-25V. It was revealed that anodization at 18-22V, in so-called electrolytes would end up to nano-tubular structure. However the tubular structure prepared at 20V and from phosphate electrolyte containing of 0.5 wt% NH4F as well as 0.5 wt% HF, was recognized... 

Poly(ethylene terephthalate) (PET) nanocomposites were prepared through a solution casting method using Multi wall carbon nanotubes (MWCNT) and organically modified montmorillonite (OMMT) as nanoparticles and their morphological and thermal properties investigated. The X-ray diffraction and transmission electron microscopy measurements showed that decreasing the ratio of MWCNT to OMMT for the same amount of OMMT creates better conditions for intercalation of PET macromolecules and promotes the transformation of OMMT nanostructures from the intercalated to exfoliated state. It was concluded that the Ozawa's model was not suitable to interpret the crystallization behavior of the... 

A comprehensive new dynamic model of a four-wheel independent drive electric vehicle has been developed and different types of the motor control laws were addressed. The first part of this study deals with the full description of the model scope in which the structure of the model including the sub-models has been fully developed. Subsequently, the sub-models including the tire sub-model, the body motion, and the motor dynamics were investigated, and the computer model of the vehicle has been simulated. Finally, the proposed motor control laws and the vehicle dynamic behavior of the vehicle were presented. Detailed analyses of the vehicle performance and comparison of the simulation results... 

Processor allocation in todays many core MPSoCs is a challenging task, especially since the order and requirements of incoming applications are unknown during design stage. To improve network performance, balance the workload across processing cores, or mitigate the effect of hot processing elements in thermal management methodologies, task migration is a method which has attracted much attention in recent years. Runtime task migration was first proposed in multicomputer with load balancing as the major objective. However, specific NoC properties such as limited amount of communication buffers, more sensitivity to implementation complexity, and tight latency and power consumption constraints... 

Processor allocation in todays many core MPSoCs is a challenging task, especially since the order and requirements of incoming applications are unknown during design stage. To improve network performance, balance the workload across processing cores, or mitigate the effect of hot processing elements in thermal management methodologies, task migration is a method which has attracted much attention in recent years. Runtime task migration was first proposed in multicomputer with load balancing as the major objective. However, specific NoC properties such as limited amount of communication buffers, more sensitivity to implementation complexity, and tight latency and power consumption constraints...