External Physical Factors Research Articles

A Study on the Loss in a Superconducting Magnet by the Control Current in a Hybrid Electro-Magnetic Suspension System

A proto-type hybrid electro-magnetic suspension system (hybrid EMS system) was developed by Yonsei university . It is the first step of study on fundamental technology for advanced railroad system development. The proto-type hybrid EMS system consists of a ferromagnetic-core, a superconducting magnet (Bi-2223) for generating magneto-motive force (MMF) and a control coil for levitation control. This system has the characteristic of a control coil generating a magnetic flux to keep the levitation gap in constant value when the gap is attempted to be varied by external physical factors. In doing so, the induced current by the magnetic flux generate loss to the superconducting magnet inducing the possibility of an unstable system. Therefore, we have experimented and documented the results of evaluating the loss in the superconducting magnet generated by the control coil. This paper can be expected to suggest useful data for the design and operation of a hybrid EMS system.

The influence of external factors on bacteriophages—review

The ability of bacteriophages to survive under unfavorable conditions is highly diversified. We summarize the influence of different external physical and chemical factors, such as temperature, acidity, and ions, on phage persistence. The relationships between a phage’s morphology and its survival abilities suggested by some authors are also discussed. A better understanding of the complex problem of phage sensitivity to external factors may be useful not only for those interested in pharmaceutical and agricultural applications of bacteriophages, but also for others working with phages.

The Mechanism of Defects Formation in Silicon Substrates

Components of navigating devices can be affected by acoustic emission and vibration. Therefore prototype samples and electronic components must be tested in such conditions. Heterostructures, which destructed under the action of external physical factors and kinetics of formations of porous defects in silicon substrates, were analyzed.

Application of Hilbert-Huang Transform Method for Analyzing Toxic Concentrations in the Niagara River

A novel application of the Hilbert-Huang transform (HHT) method for the analysis of nonstationary and nonlinear time series is proposed in this paper. The HHT is introduced to the field of water quality analysis both to evaluate trends and to assess the cause-effects relationship between the system under study and external physical factors. The HHT combines two distinct analytical methods: the empirical mode decomposition (EMD) to decompose observed series into independent intrinsic mode functions and the Hilbert transform to transform these time-dependent functions into time-frequency functions. A practical application of the HHT method for data analysis is presented herein for four time series in the Niagara River: flow, water temperature, and incoming concentrations of two polycyclic aromatic hydrocarbons. It is shown that the EMD improves the spectral representation of the original time series, enabling a better detection of periodic trends and dominant time scales. It is concluded that the ability of...

Diversity and distribution of cephalopod species off the coast of Chile

Cephalopods are increasingly acknowledged as an ecologically important group in Chilean ecosystems, but are also one of their less-known biogeographic components. Notably, this group is represented virtually exclusively by non-endemic species, although we hypothesized that their distribution over the coast should be constrained by similar physical determinants to those affecting endemic taxa. We thus present a first evaluation of the latitudinal patterns of diversity and distribution of cephalopod species in Chile, based on geographical data obtained from a review of the available literature. We constructed presence–absence binary matrices of coastal and oceanic species in 20 latitudinal units (2°), for then calculating the respective similarity matrices to obtain a distribution dendrogram using hierarchical cluster analysis (UPGM). The original binary matrices were resampled performing 1000 stochastic reassignments to calculating the 95th percentile as the criterion to identify significant clusters. Statistical comparisons between distributional groupings were performed using ANOSIM. We recorded 86 cephalopods in Chile, including oceanic (71) and coastal (15) species. Species richness showed two major breaks at 30° S and 42° S, and decreased toward higher latitudes. Cephalopod species showed well-defined endpoints of distribution within the Chilean coast, differentiating three main biogeographical units: northern (18–30° S), central (30–42° S) and southern (42–56° S) areas. Biogeographical patterns of cephalopod species in Chile showed no particular difference with those already described for most Chilean taxa. The marked distribution breaks of cephalopods at 30° and 42° S suggest that external forcing and physical factors other than temperature gradients may strongly constrain their dispersal.

Comparative study of immobilized and soluble NADH:FMN-oxidoreductase-luciferase coupled enzyme system

The properties of a coupled enzyme system (NAD(P)H:FMN-oxidoreductase and luciferase) from luminous bacteria were studied. The enzymes and their substrates were immobilized in polymer gels of different types: starch (polysaccharide) and gelatin (polypeptide). Maximum activity yield (100%) was achieved with the enzymes immobilized in starch gel. An increase in K(m) (app) was observed in both immobilized systems as compared with the soluble coupled enzyme system. Immobilization in starch and gelatin gels increased the resistance of the NAD(P)H:FMN-oxidoreductase and luciferase coupled enzyme system to the effects of external physical and chemical factors. The optimum pH range expanded both to the acidic and alkaline regions. The resistance to concentrated salt solutions and high temperature also increased. The coupled enzyme system immobilized in starch gel (with activation energy 30 kJ/mol) was characterized by the best thermostability. The immobilized coupled enzyme system can be used to produce a stable and highly active reagent for bioluminescent analysis.

Study on the influence of moisture content on thermal stability of propellant

This paper studies the influence of moisture content on the thermal stabilities of double-base propellant and multi-nitro ester propellant. The thermal behaviors and chemical kinetic parameters of the above two propellants and their mixtures with water were analyzed by using a CALVET heat flux calorimeter, C80. The thermal decomposition mechanisms of these two propellants with water were conjectured based on the tests. And then, the self-accelerating decomposition temperatures (SADT) of these two propellants and their mixtures with water were calculated and compared according to the kinetic parameters and Semenov model. The results show that the thermal decomposition mechanism of double-base propellant with water may be changing with the varying moisture content by transferring hydrogen proton (H +). However, the thermal decomposition mechanism of multi-nitro ester propellant with water may be unchanging due to the excess of formaldehyde (HCHO). Water plays the external physical factor on the thermal decomposition of multi-nitro ester propellant, and it plays both the physical and the chemical factors on the thermal decomposition of double-base propellant. The SADTs of their mixtures with water are much lower than that of pure propellants, and keep decreasing with the increasing of moisture content.

Influence of electromagnetic radiation on venom of Vipera lebetina obtuse

Primary stage of influence of the external physical factor are some conformative transformations of fibers-receptors which start the intensifying cascade of biochemical reactions. Thus energy of external influence can be on usages of less response of a cage. After an initial stage of absorption of the electromagnetic radiation, one of mechanisms of realisation of action of electromagnetic radiation of a microwave range on live organisms considers updating freely radicalthe reactions proceeding in cages and fabrics under the influence of electromagnetic energy. Problem of studying of influence of nonionising electromagnetic radiation is revealing and an effect explanation at level of the whole organism, at level of the central nervous system. Researches of influence of electromagnetic radiations on biosystems are spent basically in 2 frequency ranges: ultralow electromagnetic frequencies (1-20Hz) and ultrahigh electromagnetic frequencies (0.3GHz-300GHz). The greatest potential danger to biological objects radiations with frequencies which possessing getting action, influence both an organism as a whole, and on its touch and effectorive systems represent, fabrics and various reseptorive structures. In vivo and in vitro experiments with an irradiation were spent on the snakes containing in standartive conditions. Snakes (Vipera lebetina obtusа) were subdivided on two groups, each of 5 snakes. The skilled group of snakes was exposed to an irradiation in a current of 4 minutes. The skilled group of snakes was exposed to an irradiation. Radiation source was the UHF generator. Frequency of radiation has been chosen on the maximum factor of absorption of poison. The irradiation of animals was spent in the special chamber and depending on the purpose of experiments for realisation of modes high (U-14000B) and low (U-7000B) intensity of an irradiation target capacities of a radiator - P - 70Bт were applied. In a day, 2, 3, 4 and 5 days after an irradiation of snakes we took venom, dried up poison in cups Petri placed in eksikator over steams of chloride calcium. After venom drying defined fiber total on method Ƃредф°рда. Simultaneously definition of toxicity of venom was spent on white three-monthly rats. It is necessary to notice, that at an irradiation of snakes electromagnetic radiation of low intensity did not mark change of quantity of the general fiber in poison of snakes. Toxicity of venom also was not exposed to changes. At high intensity of radiation insignificant fluctuations in the maintenance of the general fiber and toxicity of venom of snakes were observed.

Monthly number of preterm births and environmental physical activity

Recent studies have reported links between external physical factors and human homeostasis. to determine whether the monthly values of specific physical environmental factors are associated with the monthly number of preterm births in a major medical center in Israel. The sample included 1006 infants weighing less than 1500g born live to 774 mothers during 96 consecutive months (1995-2002) at a tertiary medical center in Israel. Monthly values of indices of solar, cosmic ray, and geomagnetic activity for the same period were obtained from national data monitoring facilities in the United States of America, Russia, and Finland. The findings were statistically correlated with the monthly number of preterm births. The number of preterm births correlated with the month of the year (1-12), with a progressive rise in the number of infants born as the year progressed (p = .02). The monthly number of preterm births showed a significant and direct correlation with solar activity indices (r = .32, p = .0016), and a significant and inverse correlation with cosmic ray activity indices (r = -0.3, p = .008). The relation was significant only for singelton births and for the whole group of preterm newborns, but not for multiple pregnancies. Our findings suggest that solar and cosmic ray activity may play a role in the timing of premature labor, however in multiple pregnancies additional factors are dominant.

Oceanography of Glacier Bay, Alaska: Implications for biological patterns in a glacial fjord estuary

Alaska, U.S.A, is one of the few remaining locations in the world that has fjords that contain temperate idewater glaciers. Studying such estuarine systems provides vital information on how deglaciation affects oceanographic onditions of fjords and surrounding coastal waters. The oceanographic system of Glacier Bay, Alaska, is of particular interest ue to the rapid deglaciation of the Bay and the resulting changes in the estuarine environment, the relatively high oncentrations of marine mammals, seabirds, fishes, and invertebrates, and the Bay’s status as a national park, where ommercial fisheries are being phased out. We describe the first comprehensive broad-scale analysis of physical and iological oceanographic conditions within Glacier Bay based on CTD measurements at 24 stations from 1993 to 2002. easonal patterns of near-surface salinity, temperature, stratification, turbidity, and euphotic depth suggest that freshwater nput was highest in summer, emphasizing the critical role of glacier and snowmelt to this system. Strong and persistent tratification of surface waters driven by freshwater input occurred from spring through fall. After accounting for seasonal nd spatial variation, several of the external physical factors (i.e., air temperature, precipitation, day length) explained a large mount of variation in the physical properties of the surface waters. Spatial patterns of phytoplankton biomass varied hroughout the year and were related to stratification levels, euphotic depth, and day length. We observed hydrographic atterns indicative of strong competing forces influencing water column stability within Glacier Bay: high levels of freshwater ischarge promoted stratification in the upper fjord, while strong tidal currents over the Bay’s shallow entrance sill enhanced ertical mixing. Where these two processes met in the central deep basins there were optimal conditions of intermediate tratification, higher light levels, and potential nutrient renewal. These conditions were associated with high and sustained hlorophylla levels observed from spring through fall in these zones of the Bay and provide a framework for understanding he abundance patterns of higher trophic levels within this estuarine system.

Simulation of the growth of nanoparticle aggregates reproducing their natural structure in disperse systems

A three-dimensional continuum model of the generation of aggregates of spherical particles is developed that allows us to reproduce natural conditions of structure formation in real disperse systems with an arbitrary viscosity of a dispersion medium. The exchange between translational and rotational degrees of freedom for aggregates, subaggregates, and single particles at an arbitrary interparticle interaction potential, as well as at the preset functions of the distribution over particle sizes and thicknesses of the adsorption layer, is taken into account in the model. The interaction potential of the particles includes electrostatic (among them, screened), elastic, and van der Waals interactions and allows for the effect of external electric, magnetic, and gravitational fields. Structural and statistical characteristics of aggregates formed at different stages of particle coagulation are studied, and the quasi-ordering of single subaggregates in the elastic adsorption layer of particles is revealed. The model can be applied to the study of optical absorption by large aggregates of nanoparticles with natural structure and the kinetics of sol aggregation as functions of the properties of the adsorption layer of particles and the action of external physical factors.

Histological Study of the First Seven Days of Skin Wound Healing in Rats

The aim of this study was to elaborate a histological model of incisional skin wound healing in Sprague-Dawley rats. Under aseptic conditions two paravertebral full thickness skin incisions were performed on the back of 42 anesthetized male rats. Histological sections from tissue specimens were stained by hematoxylin and eosin, van Gieson, PAS + PSD, Mallory's phosphotungstic hematoxylin and azur and eosin and evaluated during the first seven days after surgery. Histological evaluation revealed that the regeneration of injured epidermis was completed five days after surgery. The inflammatory phase was recorded during the first three days of healing with the culmination of this phase between day one and day two. The beginning of the proliferative phase was dated to the first day and the peak during day five and day six. The initiation of the maturation and remodeling phase of the healing process was observed six days after wounding. At the layer of striated muscle, the centronucleated cells were described for the first time six days after surgery. The wound healing process of rat skin was histologically described during the first seven days. Results of this work can serve as an experimental model for further research using external pharmacological and physical factors (laser light, magnetic field) by which the wound healing can be favourably influenced.

A theoretical approach to local attenuation measurements of shear waves by MRE. Preliminary experimental results

Abstract An essential highlight of the presented method is the employment of Magnetic Resonance Elastography (MRE) for local measurements of the attenuation of elastic shear waves introduced into a biological sample. Such a measurement can be accomplished by combining the MRE method with those methods, in which collective displacement of spins is induced by external physical factors, such as variable electric field, strong magnetic field gradient or longitudinal elastic wave. A theoretical basis of the method involving external factors and results of preliminary experiments have been presented in this paper.

Airborne particle deposition onto the ocular surface

Eye irritation is one of the most frequently reported symptoms in relation to working in office-like environments. So far, no consistent association has been found between concentration of airborne particles and prevalence of eye irritation. External physical factors not hitherto considered could have a large influence on particle deposition velocity onto the ocular surface. This may have obscured the role airborne particles play. Based on previously published semi-empirical models, the paper describes the influence of turbulence, gravitational settling, electrical fields, and thermophoresis on deposition velocity. A probabilistic approach was used to determine percentile ranges in deposition velocity when the magnitude of these parameters varied within typical ranges. The calculations suggest that differences in external factors other than particle size may cause differences in the deposition velocity of one order of magnitude or more. Studies trying to find associations between airborne particle concentration levels and eye irritation should take into consideration the influence of external physical factors on deposition velocity. External physical factors other than concentration are likely to have a large influence on the deposition rate of airborne particles onto the ocular surface. Thus, future studies on associations between airborne particle levels and eye symptoms should only be conducted if particle concentration measurements are suitably size resolved. Other relevant external physical factors should also be assessed and included in a multivariate analysis of exposure-response associations.

Dynamics of Phase Transitions in Drying Drops as an Information Parameter of Liquid Structure

The basis of the proposed method is the information-capacity phenomenon of a drying drop – the kinetics of a self-organization process, which, in the same environment, is determined solely by the composition and inner structure of the liquid. A drop of tested liquid of volume 5 μl dries up on the surface of a quartz resonator oscillating with ultrasound velocity. We examine the shear characteristics of a drop, which are extremely sensitive to the occurrence and rise of new-phase structures. The measured quantity is the acoustic-mechanical impedance (AMI) of a drying drop, and the drying dynamics is displayed in the form of two curves, corresponding to the real and imaginary parts of AMI. Their shape is an ID characteristic of the liquid under the same conditions of temperature and humidity. The drying process, represented in the phase plot or in the phase space, changed under the action of external physical factors, such as ultraviolet irradiation, magnetic field, different smells, and dissolvent adding. The relaxation time and solution memory were demonstrated, using salt, protein-salt solutions, and multi-component liquids of different nature.

Brief exposure to high magnetic fields determines microtubule self-organisation by reaction–diffusion processes

A frequent feature of microtubule organisation in living systems is that it can be triggered by a variety of biochemical or physical factors. Under appropriate conditions, in vitro microtubule preparations self-organise by a reaction–diffusion process in which self-organisation depends upon, and can be triggered by, weak external physical factors such as gravity. Here, we show that self-organisation is also strongly dependent upon the presence of a high magnetic field, for a brief critical period early in the process, and before any self-organised pattern is visible. These results provide evidence that external physical factors trigger self-organisation by way of an orientational bias that breaks the symmetry of the reaction–diffusion process. As microtubule organisation is central to many cell functions, this behaviour provides a mechanism by which strong magnetic fields can intervene in biological processes.

Estimation of Atlantic salmon smolt carrying capacity of rivers using expert knowledge

Abstract A mixed salmon fishery with both natural wild salmon stocks and reared salmon exists in the Baltic Sea. The agreed-upon goal of management is to safeguard the wild stocks, and the practical management objectives have been agreed to attain at least a 50% maximum salmon production capacity in each river. This natural production capacity is, however, largely unknown. Here, a new approach has been used to estimate the salmon maximum production capacity of northern Baltic Sea rivers. A probabilistic salmon production capacity model was built entirely upon expert knowledge. The model describes the external physical and biological factors of the rivers and the juvenile salmon stocks' response to these factors. We found that the experts estimated the carrying capacity to be considerably higher than former estimates. A very high uncertainty was, however, connected with these estimates. We also found considerable disagreement over the general carrying capacity level among the experts; the major uncertainty emerged from the conflicting views of the experts. The result implies that perhaps operational management objectives other than those based on maximal smolt production levels should be considered to decrease the uncertainty connected with evaluation of management success.

Biosensor Measurements on Diffusion Coefficients of Physiologically Active Substances in Brain Tissue

Three methods are proposed for determining the diffusion coefficient D for several substances in vivo. The results are discussed along with the prospects for using chemical biosensors for examining the variations in D produced by external physical factors (vortex magnetic fields).

Trace metal (Cd, Cu, Ni and Pb) cycling in the upper water column near the shelf edge of the European continental margin (Celtic Sea)

Abstract This study investigates the relative importance of processes that affect trace metal (TM) cycling in the upper water column at the shelf edge of the Celtic Sea on the western European continental margin. The examined processes include external inputs (by atmosphere and river), physical factors (upwelling, winter mixing and water mass advection) and biological processes (in situ uptake, regeneration and export to deep waters). The concentrations of dissolved Cd, Cu, Ni and Pb were measured with this aim in January 1994 and June 1995 at vertical stations across slope, including stations with upwelling, and in the surface waters along the Celtic Sea shelf. Additionally, deep sea (from sediment trap data) and atmospheric fluxes were estimated. The metal profiles over the slope off the Celtic Sea are quite similar to open ocean profiles already described in the northeast Atlantic, and the concentrations in surface waters are only slightly enriched compared to the nearby open ocean (1.2–1.3× for Cd and Ni). The external sources to the system appear to be of weak influence: the fluvial input is locally strong at the coast and then “diluted” along the large continental shelf; the atmospheric deposition is not significant at the annual scale in comparison to the metal content in the upper waters of the shelf edge (at least for Cd, Ni and Cu). In the upwelling zone, a significant increase in concentrations was observed in the summer surface mixed layer (×2 for nitrate and Cd and ×1.5 for Ni) in comparison to the non-upwelling zone. In winter, concentrations of bioreactive metals increased significantly in the surface waters in comparison to the low summer levels (×5 for nitrate and Cd). Our results suggest that upwelling and winter mixing act as regenerated sources that lead to the resupply of the bioreactive elements above the permanent thermocline with a low export to deeper waters. The tracing of the Mediterranean intermediate waters (MIW) from Gibraltar to the studied area shows indeed that its elemental content at the Celtic shelf edge is mainly due to the conservative mixing of the three “end-member” component waters which are thought to make up the MIW. The remineralization of organic matter within this water mass during its transport to the north would contribute only 20% of the nutrients and Cd concentrations recorded at the Celtic Sea shelf edge. According to the correlation found with nutrients in the 10–200-m layer, dissolved Pb would also be subjected to biological uptake and regeneration within the seasonal thermocline. Particulate scavenging removal of Pb would take place below the permanent thermocline throughout the water column.

Flow-induced energetic bounds to growth in an intertidal sea anemone

General models exploring patterns of maximal size in indeterminately growing, benthic marine organisms have often focused on potential scaling limits associated with either internal ener- getics or external physical factors such as hydrodynamic force. Rarely, however, have these broad- strokes models considered explicitly the possibility that interactions between physiological energy balances and environmental fluid motion might alter the underlying scaling relationships. Here we examine, using simple principles of allometry, the fundamental energetics of a common intertidal sea anemone Anthopleura elegantissima in the context of the rapid flows that characterize its native habitat. We find that fluid mechanical distortion of the feeding apparatus of this species modifies the scaling of predicted energy intake across size, creating a possible mismatch with its expected meta- bolic requirements, and potentially placing a limit on growth. Such a limit would not be expected from standard metabolic or fluid dynamic arguments applied in isolation, reiterating the often-over- looked importance of an organism's structural design and its associated mechanical response to flow.