Error rates for narrow-band digital FM with discriminator detectionin mobile radio systems

Error rates for a narrowband digital FM system with discriminator detection in a land mobile radio channel characterized by fading and Doppler frequency shift are obtained using a new analytical method. The fading rate is assumed to be much slower than the bit rate so that signal distortion through a narrow bandpass filter can be analyzed via a quasistatic approach. An experiment was conducted using a Rayleigh fading simulator, and the error rate measurements are shown to agree well with the calculated results, except at high SNR (signal-to-noise ratio) where an irreducible error rate was observed     

Numerical simulation of caisson installation and dissipation in kaolin clay and calcareous silt

Caissons are widely used to support fixed platforms in shallow water or moor floating platforms in deep water. Although the installation and pullout behaviours of caissons have been explored extensively, few studies are on the dissipation of excess pore pressures induced by installation of the caisson. The pull-out capacity or bearing capacity of the caisson under undrained conditions is enhanced by dissipation of excess pore pressure, given the caisson is installed in normally consolidated cohesive soil. This paper reports numerical simulations of caisson installation and the subsequent dissipation. The analyses were carried out using a coupled effective stress-pore pressure large deformation finite element (LDFE) approach incorporating the modified Cam-Clay model. The robustness of the LDFE model was validated by comparing the penetration resistance with centrifuge testing data and the guidelines. Caissons in two fine grained soils, kaolin clay and calcareous silt, were explored. The geometry of the caisson was varied to encompass the typical sizes of caissons. The dissipation responses at four locations near the caisson tip were interpreted. A normalised dissipation time around caissons is proposed, by modifying the conventional expression for a cone.     

Possibilities of the Formation of Enol-Ethers in Lignin by Soda Pulping

In the alkaline decomposition of a β-O-4 type lignin model compound (erythro-guaiacylglycerol-β-guaiacyl ether, compound 1), an isomeric pair of C₆C₂ enol-ether (2-methoxy-4-[2-(2-methoxyphenoxy)-vinyl]-phenol, compound 2) was detected as the main decomposition product with no trace of C₆C₃ enol-ether (4-[3-hydroxy-1-(2-methoxyphenoxy)-propenyl]-2-methoxy-phenol, compound 3) or other dimers. In contrast, compound 2 was not detected in the alkaline decomposition products of compound 3. Under alkaline conditions, the γ-hydroxymethyl group of compound 3 was reduced to form 2-methoxy-4-[1-(2-methoxyphenoxy)-propenyl]-phenol (compound 4). In the HSQC analysis of soda lignin, the formation of substructures of C₆C₂ type enol-ether (related to compound 2) was confirmed. However, no substructures related to compound 4, which could be formed if a substructure of C₆C₃ type enol-ether was formed under alkaline conditions, were detected. Therefore, it could be concluded that C₆C₃ type enol-ethers could not be intermediates of alkaline decomposition products of lignin.     

Fluorine geochemistry in bedrock groundwater of South Korea

High fluoride concentrations (median=4.4 mg/L) in deep bedrock groundwater of South Korea prevent the usage of it as a drinking water source. The hydrogeochemistry of deep thermal groundwaters (N=377) in diverse bedrocks has been studied in order to evaluate the geologic and geochemical controls on fluoride concentrations in groundwater. The groundwater samples were clustered geologically, and the average and median concentrations of fluoride were compared by the Mann-Whitney U test. The order of median fluoride concentration with respect to geology is as follows: metamorphic rocks> or =granitoids > or =complex rock>volcanic rocks> or =sedimentary rocks. This result indicates that the geological source of fluoride in groundwater is related to the mineral composition of metamorphic rocks and granitoids. With respect to groundwater chemistry, the fluoride concentration was highest in Na-HCO3 type groundwater and lowest in Ca-HCO3 type groundwater. Ionic relationships also imply that the geochemical behavior of fluoride in groundwater is related to the geochemical process releasing Na and removing Ca ions. The thermodynamic relationship between the activities of Ca and F indicates that fluoride concentration is controlled by the equilibrium of fluorite (CaF2). In other words, the upper limits of fluoride concentration are determined by the Ca ion; i.e., Ca concentrations play a crucial role in fluoride behavior in deep thermal groundwater. The result of this study suggests that the high fluoride in groundwater originates from geological sources and fluoride can be removed by fluorite precipitation when high Ca concentration is maintained. This provides a basis for a proper management plan to develop the deep thermal groundwater and for treatment of high fluoride groundwater frequently found in South Korea.     

Effect of the New York State cigarette fire safety standard on ignition propensity, smoke constituents, and the consumer market

Objectives: This study examines empirical evidence from the New York experience testing tobacco industry arguments made in opposition to fire safety standards for cigarettes. Design: Percentages of cigarettes exhibiting full length burns (FLBs), cigarette sales before and following the implementation of the New York standards, a sample of retail cigarette prices, brand availability, and selected smoke constituent yields were compared between cigarettes sold in New York and two other states. Cigarette paper analysis was conducted on cigarettes sold in New York. Results: New York cigarette brands averaged 10.0% FLBs as compared to 99.8% for California and Massachusetts brands. Reduced ignition propensity (RIP) appears to have been achieved by cigarette paper banding. Cigarette sales, prices, and brand availability do not appear to have been affected by the New York standards. Yields of the majority of smoke constituents tested did not differ substantially between RIP cigarettes sold in New York as compared to the same brands sold in Massachusetts. Average yields of tar, carbon monoxide, and two compounds were slightly higher, the yields of seven compounds were higher for one brand only, and nicotine was lower, among New York brands tested. Conclusions: RIP cigarette brands have been designed to meet the New York fire safety standards. Their introduction has not affected cigarette sales or prices in New York. There is no evidence that the small increases in smoke constituent yields affect the already highly toxic nature of cigarette smoke. Data on smoking caused fires, deaths, and injuries dating from after the change in law are not yet available. Such data will be able to address the question of whether the demonstrated reduced ignition standards are associated with reduced fires and injuries. Based on the New York experience, prior industry objections to producing RIP cigarettes are unfounded. Other states and nations should adopt similar standards.     

Antioxidative activities of bran extracts from twenty one pigmented rice cultivars

Ethanol–water (70:30, v/v) extracts from the bran of rice seeds from twenty one pigmented and one nonpigmented rice cultivars were evaluated for antioxidative activities using the following tests: inhibition of peroxidation of linoleic acid; inhibition of peroxidation of rabbit lipid erythrocyte membranes; reduction of potassium ferricyanide, and scavenging of superoxide anions and hydroxyl radicals. With some exceptions, extracts from the pigmented rice seeds had higher antioxidative activity than did the nonpigmented variety. The following pigmented cultivars had the highest antioxidative activities in all tests: Jumlalocal-1, Parnkhari 203, DZ78, LK1-3-6-12-1-1, and Elwee. A significant correlation was also noted between reducing power, inhibition of erythrocyte ghost membrane peroxidation, and superoxide anion and hydroxyl radical scavenging. The results suggest that: (a) ferricyanide reducing power might be a useful and simple index for large-scale evaluation of antioxidative potencies of natural products present in rice; (b) pigmented rice varieties with high antioxidative activities provide a source of antioxidants and a genetic resource to develop new health-promoting rice cultivars.     

On stability of an input amplitude constrained predictive control system

This paper presents stability results for discrete-time model-based predictive control system subject to an input amplitude constraint. It is shown that the input amplitude constrained control system may provide a stable control system in the sense of BIBO when the system to be controlled is of a class of the system poles which consist of multiple integrators and a stable polynomial. The solution of Diophantine equations and their properties are addressed. Simulation study is also carried out and it is shown that the output of the system may converge to the reference signal for certain degree of constraints.     

Hydrogen adsorption on and diffusion through MoS2 monolayer: First-principles study

We investigate the hydrogen adsorption on and diffusion through the MoS₂ monolayer based on density-functional theory. We show that the hydrogen atom prefers to bond to the S atom at the monolayer, leading to enhanced conductivity. The hydrogen atom can also adsorb at the middle of the hexagon ring by overcoming an energy barrier of 0.57 eV at a strain of 8%. Also, we show that the MoS₂ monolayer is flexible and any mechanical deformation of the monolayer is reversible because the extension of the Mo–S bond is much smaller than the applied strain. The monolayer can block the diffusion of hydrogen molecule from one side to the other due to a high energy barrier (6.56 eV). However, the barrier can be reduced to 1.38 eV at a strain of 30% and even totally removed by creating S vacancies and applying a strain of 15%. The MoS₂ monolayer may find applications in sensors to detect hydrogen, and as mechanical valve to control the concentration of hydrogen gas.     

An analysis of the successful 1992 Massachusetts tobacco tax initiative

In November 1992, voters in Massachusetts (United States) passed a statewide tax initiative adding an extra 25 cents to the price of a pack of cigarettes. The Massachusetts Coalition for a Healthy Future, led by volunteers from the Massachusetts Division of the American Cancer Society, achieved this victory, despite a public anti-tax mood and $7.3 million spent by the tobacco industry. The tax has since generated millions of dollars for tobacco education and control programmes, leading to acceleration of the decline of tobacco consumption in the state. An analysis of the passage of this initiative should help other states considering this approach to tobacco control.