Surface integrity or in other words surface quality is a general term that is widely used in academia and industry to describe the characteristics and attributes of the workpiece surface after being ...modified or altered by manufacturing processes. Quality and integrity of the workpiece surface is a key design factor particularly when the part is likely to sustain severe service conditions such as very high or very low temperatures, corrosive environments, and dynamic loading and unloading. Broaching, as the focal point of this paper, is a machining operation in which roughing, semi-finishing, and finishing of the desired profile is achieved simultaneously by only one stroke of the tool with no further finishing operation required. Hence, the quality and integrity of final part during service life is directly governed by the broaching regime. The present paper aims to study the effects of broaching on the integrity of machined surface. Several samples from two types of steels (AISI 12L14, AISI 1045) and one type of aluminum (Al 7075) were prepared. The samples were examined to study both surface and subsurface characteristics of the broached surface including surface roughness, subsurface microhardness, and subsurface plastic deformation. The results showed gradual effect of successive teeth on the integrity of workpiece surface. It was shown that the surface and, to some extent, subsurface of the machined part were affected by the combined effect of successive teeth; however, it was determined that the effect of last teeth (finishing teeth) was dominant. This can be clearly seen through microhardness and surface roughness readings.
Neural mechanisms that support flexible sensorimotor computations are not well understood. In a dynamical system whose state is determined by interactions among neurons, computations can be rapidly ...reconfigured by controlling the system’s inputs and initial conditions. To investigate whether the brain employs such control mechanisms, we recorded from the dorsomedial frontal cortex of monkeys trained to measure and produce time intervals in two sensorimotor contexts. The geometry of neural trajectories during the production epoch was consistent with a mechanism wherein the measured interval and sensorimotor context exerted control over cortical dynamics by adjusting the system’s initial condition and input, respectively. These adjustments, in turn, set the speed at which activity evolved in the production epoch, allowing the animal to flexibly produce different time intervals. These results provide evidence that the language of dynamical systems can be used to parsimoniously link brain activity to sensorimotor computations.
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•Monkeys performed a timing task demanding flexible cognitive control•The organization of neural trajectories in frontal cortex reflected task demands•Flexible control was best explained in terms of inputs and initial conditions•Recurrent neural network models validated the inferred control principles
Remington et al. employ a dynamical systems perspective to understand how the brain flexibly controls timed movements. Results suggest that neurons in the frontal cortex form a recurrent network whose behavior is flexibly controlled by inputs and initial conditions.
The main purpose of this paper is to investigate the automatic continuity of
)-derivations on Banach algebras and to present several results in this regard. For instance, we prove the following ...theorem:
Let
and
be two Banach algebras such that
has the Cohen’s factorization property and
, and let
be two linear mappings. Let
be a generalized
-derivation associated with a
-derivation
. If for any
there exists an element
such that
, then
is continuous if and only if
is continuous.
The neuroscience of perception has recently been revolutionized with an integrative modeling approach in which computation, brain function, and behavior are linked across many datasets and many ...computational models. By revealing trends across models, this approach yields novel insights into cognitive and neural mechanisms in the target domain. We here present a systematic study taking this approach to higher-level cognition: human language processing, our species' signature cognitive skill. We find that the most powerful "transformer" models predict nearly 100% of explainable variance in neural responses to sentences and generalize across different datasets and imaging modalities (functional MRI and electrocorticography). Models' neural fits ("brain score") and fits to behavioral responses are both strongly correlated with model accuracy on the next-word prediction task (but not other language tasks). Model architecture appears to substantially contribute to neural fit. These results provide computationally explicit evidence that predictive processing fundamentally shapes the language comprehension mechanisms in the human brain.
The main purpose of this paper is to obtain some results on the image of
-derivations on Banach algebras. One of the main results of this paper is to prove that if
is a commutative Banach algebra and
...is a continuous
-derivation such that
is a continuous homomorphism,
and
, then
, where
denotes the Jacobson radical of
. Moreover, we obtain Sinclair’s theorem for
-derivations without assuming continuity. Indeed, under certain conditions, we prove that if
is a
-derivation on a Banach algebra
, then
for every primitive ideal
of
. Some other related results are also discussed.
This study provides a pore-scale investigation of two-phase flow dynamics during primary drainage in a realistic heterogeneous rock sample. Using the lattice Boltzmann (LB) method, a series of ...three-dimensional (3D) immiscible displacement simulations are conducted and three typical flow patterns are identified and mapped on the capillary number (Ca)-viscosity ratio(M) phase diagram. We then investigate the effect of the viscosity ratio and capillary number on fluid saturation patterns and displacement stability in Tuscaloosa sandstone, which is taken from the Cranfield site. The dependence of the evolution of saturation, location of the displacement front, 3D displacement patterns and length of the center of mass of the invading fluid on the viscosity ratio and capillary number have been delineated. To gain a quantitative insight into the characteristics of the invasion morphology in 3D porous media, the fractal dimension D
of the non-wetting phase displacement patterns during drainage has been computed for various viscosity ratios and capillary numbers. The logarithmic dependence of D
on invading phase saturation appears to be the same for various capillary numbers and viscosity ratios and follows a universal relation.
The metabolic syndrome is a common problem world-wide and includes abdominal obesity, hypertension, dyslipidemia, and hyperglycemia disorders. It leads to insulin resistance and the development of ...diabetes mellitus or cardiovascular disease.
Allium sativum
(garlic) has been documented to exhibit anti-diabetic, hypotensive, and hypolipidemic properties. This suggests a potential role of
A. sativum
in the management of metabolic syndrome; however, more studies should be conducted to evaluate its effectiveness. In this review, we discussed the most relevant articles to find out the role of
A. sativum
in different components of metabolic syndrome and cardiovascular disease risk factors. Because human reports are rare, further studies are required to establish the clinical value of
A. sativum
in metabolic syndrome.
Sigma phase is commonly considered to be the most deleterious secondary phase precipitating in duplex stainless steels, as it results in an extreme reduction of corrosion resistance and toughness. ...Previous studies have mainly focused on the kinetics of sigma phase precipitation and influences on properties and only a few works have studied the morphology of sigma phase and its influences on material properties. Therefore, the influence of sigma phase morphology on the degradation of corrosion resistance and mechanical properties of 2507 super duplex stainless steel (SDSS) was studied after 10 h of arc heat treatment using optical and scanning electron microscopy, electron backscattered diffraction analysis, corrosion testing, and thermodynamic calculations. A stationary arc was applied on the 2507 SDSS disc mounted on a water-cooled chamber, producing a steady-state temperature gradient covering the entire temperature range from room temperature to the melting point. Sigma phase was the major intermetallic precipitating between 630 °C and 1010 °C and its morphology changed from blocky to fine coral-shaped with decreasing aging temperature. At the same time, the average thickness of the precipitates decreased from 2.9 µm to 0.5 µm. The chemical composition of sigma was similar to that predicted by thermodynamic calculations when formed at 800⁻900 °C, but deviated at higher and lower temperatures. The formation of blocky sigma phase introduced local strain in the bulk of the primary austenite grains. However, the local strain was most pronounced in the secondary austenite grains next to the coral-shaped sigma phase precipitating at lower temperatures. Microstructures with blocky and coral-shaped sigma phase particles were prone to develop microscale cracks and local corrosion, respectively. Local corrosion occurred primarily in ferrite and in secondary austenite, which was predicted by thermodynamic calculations to have a low pitting resistance equivalent. To conclude, the influence of sigma phase morphology on the degradation of properties was summarized in two diagrams as functions of the level of static load and the severity of the corrosive environment.
Computational chemistry is an important tool in numerous scientific disciplines, including drug discovery and structural biology. Coarse-grained models offer simple representations of molecular ...systems that enable simulations of large-scale systems. Because there has been an increase in the adoption of such models for simulations of biomolecular systems, critical evaluation is warranted. Here, the stability of the amyloid peptide and organic crystals is evaluated using the Martini 3 coarse-grained force field. The crystals change shape drastically during the simulations. Radial distribution functions show that the distance between backbone beads in β-sheets increases by ∼1 Å, breaking the crystals. The melting points of organic compounds are much too low in the Martini force field. This suggests that Martini 3 lacks the specific interactions needed to accurately simulate peptides or organic crystals without imposing artificial restraints. The problems may be exacerbated by the use of the 12-6 potential, suggesting that a softer potential could improve this model for crystal simulations.
Summary
The microalga Dunaliella salina is the best commercial source of natural β‐carotene. Additionally, different species of Dunaliella can accumulate significant amounts of valuable fine ...chemicals such as carotenoids, glycerol, lipids, vitamins, minerals and proteins. They also have a large potential for biotechnological processes such as expressing of foreign proteins and treatment of wastewater. In this review, we discussed several biotechnological aspects of the mass cultivation of D. salina like strain selection, carotenoid induction, culture conditions, culture systems and downstream processes. We also discuss several traditional and new applications of the genus.
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