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On April 2020, during the outburst of the COVID-19 pandemic in Italy, the SIAARTI (“Società Italiana di Anestesia, Analgesia, Rianimazione e Terapia Intensiva”) Research Group on Vascular Access has formulated some essential recommendations for the optimization of the selection, insertion, and maintenance of the vascular access devices, with the aim of guarantee the operator safety, ensure the effectiveness of the maneuvers, and reduce the risk of complications. Here we describe the key elements of clinical management of vascular access in patients affected by COVID-19.

In patients undergoing thoracoabdominal aorta repair, spinal cord ischemia (SCI) remains one of the most common and important complications resulting in transient paraparesis through to permanent flaccid paraplegia. In this manuscript, after a brief introduction to spinal cord ischemia complication and its prevention in thoracoabdominal endovascular aortic repair (TEVAR), we propose a new clinical protocol potentially able to prevent such complication. The proposed protocol suggests the use of high dosages of corticosteroids by epidural route, along with drainage of cerebrospinal fluid and controlled vascular hypertension, to reduce the incidence of SCI in TEVAR. Moreover, we paid particular attention to the control of the hemodynamic parameters to obtain adequate peripheral tissue perfusion (oxygen delivery), including in the spinal cord. We applied this new protocol in 50 consecutive patients treated with TEVAR for thoracoabdominal aortic aneurysms (TAAs); 47 patients completed the procedure: 27 patients Crawford type I and 20 Crawford type II. Three patients died during surgery because of untreatable aneurysm rupture. The results show that in all patients there were no cases of SCI, after 5 days from TEVAR. To the best of our knowledge, there are no clinical studies on the use of epidural corticosteroids in patients undergoing treatment of aortic syndrome (both in “open surgery” and endovascular aortic repair). This initial study on 50 consecutive patients has shown that the clinical protocol used could be of great interest to prevent one of the worse complications of TEVAR. Its limitations are the low number of patients studied till now, and the non-randomized protocol adopted. Further studies would be necessary. Our experience and the results obtained with this new perioperative protocol with epidural corticosteroid and accurate hemodynamic control have been encouraging and it seems a valid proposal to be explored in future by well-structured prospective, randomized protocols.

This work focuses on the evaluation of the effective thermal conductivity of ultra-light materials, as the highly porous two-phase systems (foams). The main aim of the paper is to show that the exact mathematical solution of the heat conduction equation, based on the constitutive Fourier law and without any empirical constant nor ad hoc assumptions, is possible under an assumed thermal condition. To cover the range of real thermal conditions the present theoretical approach employs the two extreme thermal assumptions, i.e. parallel isothermal lines and parallel heat fluxes. The analysis is carried out upon an elementary cubic cell investigating the effect of structure, porosity, saturating fluid and solid material of open-cells foams. Comparisons among the present purely theoretical results and some experimental data of the literature confirm favorably the present approach.

Herpes Zoster (HZ) is the reactivation of a well-known viral disease which manifests itself with painful skin lesions. An effective analgesic method during the acute phase of HZ can contribute to decrease the incidence of postherpetic neuralgia (PHN) by reducing neural sensitization. Sciatic nerve block (SNB) is useful in the management of distal lower extremity pain sustained by the sciatic nerve. We describe our experience with a continuous ultrasound guided subgluteus sciatic nerve block in a patient with herpetic neuralgia- (HN-) related refractory acute left leg pain.

Experimental thermal conductivity of alumina nanoparticles in water is measured with the transient thermal probe, in the presence of sonication (i.e., with ultrasounds), or not. We investigate two types of alumina particles, with the diameter equal to 7 nm and 50 nm. The experimental results, with and without sonication, show that the effective thermal conductivity is greater for the alumina nanoparticle with the smaller diameter. The effective thermal conductivity is greater in the presence of sonication, with a larger relative increase for the smaller diameter nanofluid. We compare the present experimental thermal conductivity with the empirical/theoretical prediction models of the literature with a reasonable good agreement.

The frequent finding of thrombocytopenia in patients with severe SARS-CoV-2 infection (COVID-19) and previous evidence that several viruses enter platelets suggest that SARS-CoV-2 might be internalized by platelets of COVID-19. Aim of our study was to assess the presence of SARS-CoV-2 RNA in platelets from hospitalized patients with aconfirmed diagnosis of COVID-19. RNA was extracted from platelets, leukocytes and serum from 24 COVID-19 patients and 3 healthy controls, real-time PCR and ddPCR for viral genes were carried out. SARS-CoV-2 RNA was not detected in any of the samples analyzed nor in healthy controls, by either RT-PCR or ddPCR, while RNA samples from nasopharyngeal swabs of COVID-19 patients were correctly identified. Viral RNA was not detected independently of viral load, of positive nasopharyngeal swabs, or viremia, the last detected in only one patient (4.1%). SARS-CoV-2 entry in platelets is not acommon phenomenon in COVID-19 patients, differently from other viral infections.

Aim The use of PecS block 1 as perioperative analgesia for a central catheter removal -reimplantation combined procedure. Methods A 55-year-old woman suffering from peritoneal metastases from gastric cancer needed to have a port-a-cath implanted for infection removed and to have a central venous catheter (CVC) implanted in the homolateral axillary vein due to patient’s history of deep vein thrombosis of the right upper limb. We used PECS 1 block for perioperative analgesia. Results Compared to the traditional catheter implantation technique, reduction in the doses of local anaesthetics, shortening in the execution time, less intra-procedural bleeding, better patient’s compliance, and no need for a rescue dose of local anaesthetic were observed. Conclusion The PEC1 block was effectively and safely used to remove an infected port-a-cath and to place a CVC on the same side. We hypothesize that it may be useful also for simple port-a-cath positioning.

The aim of the present paper is to study experimentally the enhancement of heat transfer, due to the presence of a layer of aluminum foam covering a smooth circular cylinder. The measurements are carried on with the impingement of a rectangular jet of air, which has a transversal dimension equal or smaller than the cylinder diameter, or jet flow, and full flow (or uniform flow, which has a greater dimension than the cylinder diameter). Literature does not report any paper dealing with this multiple problem. Experimental heat transfer and fluid dynamics measurements are carried out at Reynolds number ranging from ReD=2200 to ReD=24,750. The layer of the aluminum foam, 8 mm thick, is glued onto the smooth cylinder, with an external diameter of D = 10 mm. The height of the slot jet is H = 10 mm, with a width of W = 135 mm. Jet flow visualizations are performed for the smooth and the foam-covered cylinder to explain the heat transfer results from the fluid dynamics point of view. The flow visualizations show that the jet flow always penetrates into the foam, wetting it completely, while the reattachment never occurs downstream. In the smooth cylinder, the jet completely envelops the cylinder, at greater Reynolds numbers and a distance of x/H = 7, with a small recirculation zone, showing that the rear surface also participates in the heat transfer. The heat transfer on the foam-covered cylinder increases, mainly, because of the large increase in the exchange surface, while it is somewhat penalized, at the higher Reynolds values and at the greater distance from the slot exit, because the rear surface is little involved in the heat transfer.

Magnetic nano drug targeting, with an external magnetic field, can potentially improve the drug absorption in specific locations of the body. However, the effectiveness of the procedure can be reduced due to the limitations of the magnetic field intensity. This work investigates this technique with the Computational Fluid Dynamics (CFD) approach. A single rectangular coil generates the external magnetic field. A patient-specific geometry of the Trachea, with its primary and secondary bronchi, is reconstructed from Digital Imaging and Communications in Medicine (DICOM) formatted images, throughout the Vascular Modelling Tool Kit (VMTK) software. A solver, coupling the Lagrangian dynamics of the magnetic nanoparticles with the Eulerian dynamics of the air, is used to perform the simulations. The resistive pressure, the pulsatile inlet velocity and the rectangular coil magnetic field are the boundary conditions. The dynamics of the injected particles is investigated without and with the magnetic probe. The flow field promotes particles adhesion to the tracheal wall. The particles volumetric flow rate in both cases has been calculated. The magnetic probe is shown to increase the particles flow in the target region, but at a limited extent. This behavior has been attributed to the small particle size and the probe configuration.

The paper carries on numerical mass transfer and fluid flow of a Non-Newtonian (Casson-like) blood in a complete patient specific Circle of Willis (CoW), for the first time in the literature. Pressures, fluid flow and mass transfer variables are presented. As far as the distribution of Wall Shear Stress (WSS) is concerned, the paper shows that regions with WSS greater than the fisiologic limit (equal to 150 dyne/cm2) tend to superimpose to vascular zones, typical of saccular cerebral aneurysms. Zones with high WSS coincide with those of high MGS, where, according to literature, the formation of cerebral aneurysms is more probable, as close to arterial branchings and cross section changes. As far as mass transfer of LDL and Glucose are concerned, greater concentrations are observed in zones more exposed to atherosclerosis risk. Zones with greater values of Sherwood number coincide with the regions with greater frequency of atherosclerotic plaques.

Magnetic nano drug targeting, through the use of an external magnetic field, is a new technique for the treatment of several diseases, which can potentially avoid the dispersion of drugs in undesired locations of the body. Nevertheless, due to the limitations on the intensity of the magnetic field applied, the hydrodynamic forces can reduce the effectiveness of the procedure. This technique is studied in this paper with the Computational Fluid Dynamics (CFD), focusing on the influence of the magnetic probe position, and the direction of the circulating electric current. A single rectangular coil is used to generate the external magnetic field. A patient-specific geometry of the coeliac trunk is reconstructed from DICOM images, with the use of VMTK. A new solver, coupling the Lagrangian dynamics of the nanoparticles with the Eulerian dynamics of the blood, is implemented in OpenFOAM to perform the simulations. The resistive pressure, the Womersley’s profile for the inlet velocity and the magnetic field of a rectangular coil are implemented in the software as boundary conditions. The results show the influence of the position of the probe, as well as the limitations associated with the rectangular coil configuration.

The influence of the degree of residual stenosis (DOR) on the hemodynamics inside coronary arteries is investigated through three-dimensional (3D) numerical simulations. The vascular wall permeability is investigated and the effect of the non-Newtonian viscosity discussed. The results agree in predicting an abrupt increase in wall permeability above 45% DOR, indicating that the implant could lead to a massive restenosis. This behavior is considered to be due to the shift of the regions involved by low and oscillatory wall shear stress (WSS), from the zone adjacent to the struts toward the center of the stent meshes.

Natural convection around a vertical cylindrical, immersed in a fluid-saturated porous medium, is investigated experimentally. The porous medium is made of glass beads with particles of the same diameter, 3 mm, and is saturated with water. The vertical cylinder, with diameter of 1.5 mm and long 150 mm, is a thermal probe, containing an electric heater and a thermocouple. Natural convection around the vertical cylinder is investigated experimentally with the help of three temperature sensors, at different heights on the external surface of the cylinder. Average and local Nusselt numbers along the vertical cylinder are calculated and compared with the available theoretical-numerical data of the literature.

The paper investigates the mean mass transfer/passive scalar spreading in turbulent submerged round jets. Two regions of flow are present in the jet evolution: the Near-Field Region (NFR) and the Fully Developed Region (FDR). This group of research investigates from some years the mean evolution of turbulent rectangular jets with the new physical finding that two sub-regions (not a single one) are present in the NFR. The first region of the two is the newly discovered Undisturbed Region of Flow (URF), while the second one is the known Potential Core Region (PCR). In a recent paper we showed that the flow evolution of turbulent round jets, as far as momentum spreading is concerned, is self-similar also in the NFR. Literature shows that mass transfer spreading is self-similar only in FDR. The present paper presents new mean mass transfer results of the numerical Large Eddy Simulation (LES) in turbulent round jets. Four Reynolds numbers, from 2492 to 19,988, and two laminar Schmidt numbers, 1 and 10, are investigated. The first novel result of this paper is that mass transfer is self-similar in the NFR. The second result is that two new analytical models describe the passive scalar spreading in the URF and PCR. The third result is that two new self-similar laws describe the passive scalar spreading in the FDR. The fourth result states that the well-known power-law relationship, between passive scalar and axial momentum in the FDR, holds regardless of the modeling of turbulent viscosity and turbulent Schmidt number.

The present work extends the approach of using the mass and energy-capital conservation equations to forecast the price evolution of oil when accumulation or depletion is present. The price evolution is then dependent on the consumption rate of the oil, besides the ratio of mass extraction to mass consumption rates, and the usual economic parameters, e.g. the interest rates of non-extracted and extracted resources. The main conclusions are that a ratio of mass extraction to consumption rates different from unity, i.e. when accumulation or depletion of the oil is present, can modify the approach of the oil price forecast without accumulation or depletion of the resources.

The paper investigates the anisotropic thermal efficiency of symmetric composites made of two components, matrix and fiber reinforcement. The anisotropic degree of the composite is the ratio between the effective thermal conductivity in the direction parallel to the fiber reinforcement, and that in the perpendicular direction. The potential anisotropy of the materials is the ratio between the thermal conductivity of the fiber to that of the matrix. The anisotropic thermal efficiency is the ratio between the anisotropy degree of the composite, and the potential anisotropy of the two materials. The theoretical model solves the heat conduction equation under the two thermal assumptions of parallel isotherms and parallel heat fluxes, and without any empirical constant nor analogy with other phenomena, evaluating the anisotropic thermal efficiency of the symmetric composite. The variation of the anisotropic thermal efficiency is investigated versus the potential anisotropy of the materials and the ratio between fiber and matrix thicknesses. The anisotropic thermal efficiency has a maximum versus the ratio between fiber and matrix thicknesses, and decreases with the increase of the potential anisotropy, reaching a minimum, which is only dependent on the geometrical configuration of the symmetric composite.

Fluid dynamics in two different stent configurations, peak-to-valley (S1) and peak-to-peak (S2), within a fully expanded situation and a 30% restenosis is investigated. Numerical simulations are carried out in order to evaluate the conditions promoting atherosclerotic events when a self-expanding bare metal stent is applied. The conclusions are that the two configurations, S1 and S2, have a similar fluid dynamics behavior as far as wall shear stress is concerned, but oscillatory shear and relative residence time maps suggest that the peak-to-peak configuration, S2, has a better behavior than the peak-to-valley, S1.

Experimental results for the Sherwood number variation near the lateral edge of the active surface of a smooth, finite-width flat plate in turbulent boundary layer flow are presented. Using naphthalene sublimation, local mass transfer rates are found for two different free stream velocities. A semi-empirical correlation of the experimental data is presented, allowing calculation of the increase of mass transfer near the edge and the size of the region affected by the lateral edge. The effect is shown to scale more so with the diffusion thickness than the boundary layer thickness.

An important problem in metagenomic data analysis is to identify the source organism, or at least taxon, of each sequence. Most methods tackle this problem in two steps by using an alignment-free approach: first the DNA sequences are represented as points of a real n-dimensional space via a mapping function then either clustering or classification algorithms are applied. Those mapping functions require to be genomic signatures: the dissimilarity between the mapped points must reflect the degree of phylogenetic similarity of the source species. Designing good signatures for metagenomics can be challenging due to the special characteristics of metagenomic sequences; most of the existing signatures were not designed accordingly and they were tested only on error-free sequences sampled from a few dozens of species.In this work we analyze comparatively the goodness of existing and novel signatures based on tetranu-cleotide frequencies via statistical models and computational experiments; we also study how they are affected by the generalized Chargaff’s second parity rule (GCSPR), which states that in a given sequence longer than 50kbp, inverse oligonucleotides are approximately equally frequent. We analyze 38 million sequences of 150 bp-1,000 bp with 1% base-calling error, sampled from 1,284 microbes. Our models indicate that GCSPR reduces strand-dependence of signatures, that is, their values are less affected by the source strand; GCSPR is further exploited by some signatures to reduce the intra-species dispersion. Two novel signatures stand out both in the models and in the experiments: the combination signature and the operation signature. The former achieves strand-independence without grouping oligonucleotides; this could be valuable for alignment-free sequence comparison methods when distinguishing inverse oligonucleotides matters. Operation signature sums the frequencies of reverse, complement, and inverse tetranucleotides; having 72 features it reduces the computational intensity of the analysis.

Can we exploit our burgeoning understanding of molecular evolution to slow the progress of drug resistance? One role of an infection clinician is exactly that: to foresee trajectories to resistance during antibiotic treatment and to hinder that evolutionary course. But can this be done at a hospital-wide scale? Clinicians and theoreticians tried to when they proposed two conflicting behavioral strategies that are expected to curb resistance evolution in the clinic, these are known as “antibiotic cycling” and “antibiotic mixing.” However, the accumulated data from clinical trials, now approaching 4 million patient days of treatment, is too variable for cycling or mixing to be deemed successful. The former implements the restriction and prioritization of different antibiotics at different times in hospitals in a manner said to “cycle” between them. In antibiotic mixing, appropriate antibiotics are allocated to patients but randomly. Mixing results in no correlation, in time or across patients, in the drugs used for treatment which is why theorists saw this as an optimal behavioral strategy. So while cycling and mixing were proposed as ways of controlling evolution, we show there is good reason why clinical datasets cannot choose between them: by re-examining the theoretical literature we show prior support for the theoretical optimality of mixing was misplaced. Our analysis is consistent with a pattern emerging in data: neither cycling or mixing is a priori better than the other at mitigating selection for antibiotic resistance in the clinic. Key words: antibiotic cycling, antibiotic mixing, optimal control, stochastic models.

The paper employs a theoretical model to evaluate the thermal conductivity of composites under two thermal assumptions which allow to solve the heat conduction equation. The composite is made of a ceramic-silica matrix and a fiber reinforcement. Three different materials are investigated as reinforcement, i.e. asbestos, steel and copper. The theoretical effective thermal conductivity is calculated along the three directions for a non-consumed composite and during its consumption. Numerical solutions of heat conduction in the composite are carried out. The anisotropy degree of the composite is investigated for the composite during its consumption. The anisotropic efficiency of the composite is defined as ratio between the anisotropy degree of the composite and the potential anisotropy of the two materials, i.e. the ratio between the thermal conductivity of the fiber and the matrix. The theoretical model allows to evaluate, under the two thermal assumptions, the anisotropic efficiency of the composites which decreases with the increase of the potential anisotropy reaching a minimum, which is only dependent on the geometry of the composite.

The mass and energy-capital conservation equations are employed to study the time evolution of mass and price of nonrenewable energy resources, extracted and sold to the market, in case of no-accumulation and no-depletion, that is, when the resources are extracted and sold to the market at the same mass flow rate. The Hotelling rule for nonrenewable resources, that is, an exponential increase of the price at the rate of the current interest multiplied the time, is shown to be a special case of the general energy-capital conservation equation when the mass flow rate of extracted resources is unity. The mass and energy-capital conservation equations are solved jointly to investigate the time evolution of the extracted resources.

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link. Self-Similarity in turbulent round jets has been the object of investigation from several decades. The evolution of turbulent submerged jets is characterized by the presence of two regions: the region of flow establishment, or near field region (NFR) and the fully developed region (FDR), or far-field region (FFR). The momentum spreading in the FDR is known to be self-similar and few mathematical models have been presented in the past to describe it. The flow evolution in the NFR has been rarely studied since there is a certain consensus on the idea that the flow in the NFR is not self-similar. In this work, we study the flow evolution of a turbulent submerged round jet by means of large eddy simulation (LES) at several Reynolds numbers ranging from 2492 to 19,988. Three new self-similar laws are proposed to describe the flow evolution in the NFR, one for the initial region, called Undisturbed Region of Flow, (URF), and two for the final region, the potential core region (PCR). The numerical results presented in this work are also validated with the self-similar laws for the FDR proposed by Tollmien (1926) and Görtler (1942), and the experimental data of Hussein et al. (1994), and Panchapakesan and Lumley (1993), in the FDR; those of Davies et al. (1963), in the PCR; and van Hout et al. (2018), in the URF. The conclusion is that previous inability to find the self-similarity law in the NFR is due to the attempt to find a unique self-similar variable to describe the momentum spreading in both the URF and the PCR.

The two main problems in the cooling of a cylinder with a rectangular jet of the same width are the choice of the jet height and the distance between the jet exit and the cylinder. The present paper presents experimental measurements of the heat transfer on a cylinder, with diameter D = 10 mm, cooled by rectangular jets with low turbulence, the same width of the cylinder but different height, H, 2.5 and 5 mm, respectively, in order to study their influence on the local and the mean cooling rates. The cylinder to be cooled is heated by electric current and is set on the symmetrical plane of symmetry, i.e. the geometry is two-dimensional, at several distances from the jet exit, x, in order to find the position which realizes the maximum heat transfer. The experimental measurements of the local heat transfer are performed along the circumference of the cylinder at several angles from the impingement for Reynolds number, defined with the cylinder diameter, D, and the average velocity, in the range ReD = 5000–22,000. The comparison between the two slots is performed at the same Reynolds number, ReD, which means that the smaller slot has a slightly greater maximum velocity. The experiments show that on the impinging point the local Nusselt number is greater for the slot with H = 2.5 mm, while at greater angles from the impingement, i.e. 45°, 90°, 135° and 180°, the local Nusselt numbers have different behaviors. The mean Nusselt numbers are similar for the two slots, at the same Reynolds number, ReD. Local and mean Nusselt numbers, obtained with the two jets, are in qualitative agreement if they are compared with the dimensionless distance, x/H, which can be interpreted as the ratio of the Reynolds numbers, Rex/ReH, independent of the mass flow rate or per unit of mass flow rate. The maximum of the local Nusselt number on the impinging point is obtained at greater distances for smaller Reynolds numbers, e.g. in the range from x/H = 15 at Re = 5000 to x/H = 9 at Re = 22,000, while the distance is shorter along the cylinder at greater angles from the impingement. The maximum of the mean Nusselt number is similar to that on the impingement for the two jets. The experimental heat transfer is also examined from the point of view of the slot efficiency, i.e. taking into account the mechanical power necessary to move the fluid in the slot jet. The conclusion is that the smaller slot, H = 2.5 mm or D/H = 4, has a greater efficiency as cooling system because it removes more heat at the same mechanical power.

In the "Design4All" project, a hardware and software architecture is under development for the implementation of adaptable and adaptive applications aimed to support all people in carrying out an independent life at home. In this paper, the problems of interactions with applications implemented in the Android platform, chosen for the experiments of interaction with the developed applications, are discussed with main emphasis on two main aspects: (i) the use of facilities supporting accessibility available in the most commonly used operating systems (mainstreaming) and (ii) the portability of solutions across different platforms.

The present work is aimed to evaluate the effective thermal conductivity of an ablative composite material in the state of virgin material and in three paths of degradation. The composite material is undergoing ablation with formation of void pores or char and void pores. The one dimensional effective thermal conductivity is evaluated theoretically by the solution of heat conduction under two assumptions, i.e. parallel isotherms and parallel heat fluxes. The paper presents the theoretical model applied to an elementary cubic cell of the composite material which is made of two crossed fibres and a matrix. A numerical simulation is carried out to compare the numerical results with the theoretical ones for different values of the filler volume fraction.

The present work deals with the enhancement of heat transfer on a cylinder due to the turbulence of the impinging jet. Experiments are carried out to cool a smooth cylinder, electrically heated, with a submerged slot jet of air at Reynolds numbers equal to Re = 4180 and Re = 7630. The increase of turbulence is obtained by the introduction of a metallic grid and by the natural evolution of the jet with the distance from the slot exit. Turbulence, velocity and heat transfer measurements are presented in order to show the relation with the slot-to-cylinder distance. The metallic grid is set in two positions: just on the slot exit or at a constant distance in front of the cylinder. In the natural evolution of the free jet the turbulence increases with the distance because of the interaction with stagnant air, reaches a maximum and then decreases. If the grid is on the slot exit the turbulence increases at first, then decreases according to the degeneration law, and finally increases again due to the interaction with the stagnant air. Turbulence at a distance of 10 times the slot height is about the same whether is present or not the grid. Heat transfer measurements are presented as local and mean Nusselt numbers. Without grid local and mean Nusselt numbers increase with the distance from the slot exit reaching the maximum at a distance of about 8 time the slot height. With the grid on the slot exit the local Nusselt number has a maximum immediately after the grid and a minimum at 4–5 time the slot height. With the grid in front of the cylinder at the distance of the slot height the local Nusselt number has the maximum immediately after the grid and then is about constant up to 10 times the slot height. The mean Nusselt number with the grid in front of the cylinder is greater than without the grid only at the higher Reynolds number experimented.

This work presents new experimental results in the cooling of an externally finned cylinder with a submerged slot jet of air. Two slots are employed with D/H equal to 2 and 4, where D is the diameter of the cylinder without fins and H the slot height. Local and mean Nusselt numbers are evaluated at several Reynolds numbers and distances from the slot exit. Empirical expressions are proposed to correlate the experimental mean Nusselt numbers and the convective heat transfer coefficients. The two slots are compared also according to the concept of efficiency, which takes into account the cooling rate and the mechanical power necessary to drive the flow.

A new equation for the dissipation rate of turbulent kinetic energy is derived exactly in conservative form for a Generalized Newtonian Fluid (GNF). The transport equations for mass, momentum, and turbulent kinetic energy are written along to the transport equation for the shear rate. A new transport equation for the apparent viscosity is derived assuming the viscosity as dependent only on the shear rate. The assumption is of incompressible two-dimensional GNF flow.

The price evolution of non-renewable resources versus the consumption rate is investigated with the aim of constructing the energy supply curve. The case studied is without accumulation nor depletion of the resources and the mass and energy-capital conservation equations are solved under the condition of the same mass flow rate of extraction and sale. The energy supply curve of extracted resource is dependent on the newly defined parameter, RINE, Rate of Interest of Non-extracted resources on the Extraction rate. The energy supply curve of sold resource is dependent on the newly defined parameter, RISE, Rate of Interest of Sold resources on the Extraction rate, in case the rate of interest of non-extracted resources, rN, is nil. In general, the energy supply curve of sold resource is dependent also on two dimensionless parameters, Dimensionless Critical Initial Price of Sold resources, i.e. DCIPS, and Dimensionless Critical Initial Price Extreme of Sold resources, i.e. DCIPES. The energy supply curve of sold resources is investigated under different relations between three parameters, i.e. extraction rate and interest rates of non-extracted and extracted/sold resources. New trends are observed in the economic market of non-renewable energy resources. The energy supply curve of the difference between sold and extracted resource is also obtained and is dependent on two dimensionless parameters, Critical Initial Price Difference, i.e. CIPD, and Critical Extreme of the Initial Price Difference, i.e. CEIPD. Finally, the predictions obtained with the present approach are compared to the real evolution of the world price of oil and the European price of gas versus the world consumption during the last three decades, i.e. from 1980 until 2005 for oil and from 1984 until 2005 for gas, taking into account inflation, discount and prime rates of the economic market. The agreement is acceptable but, more important, the trend is correctly predicted. The price difference between sold and extracted resources is also investigated versus the dimensionless mass flow rate of extraction. The evolution is dependent on four parameters: RINE, RISE, DCIPS, and DCIPES.

According to the current literature on the cooling of two cylinders in row, by a uniform flow of air, the first cylinder is always a heat transfer promoter versus the second one. The aim of the present paper is to summarize the state of art of the literature on the cooling of two cylinders in row by a slot jet of air. Additional experiments are carried on in order to investigate the possible application of jet cooling to heat transfer apparatuses, including electronics, in order to study the positions of the two cylinders in row which realize the same heat transfer on each cylinder. In the experiments a slot jet of air with low turbulence is employed with a slot height, S , equal to the impinged cylinder diameter, D , i.e. D / S = 1.0. The first cylinder is set at two distances H from the slot exit, H / S = 4 and 6, while the distance of the second cylinder from the first one, L , is variable from L / S = 2–11. The Reynolds number, Re , defined with the cylinder diameter D , spans in the range Re = 11,000–22,200. If the first cylinder is set at the dimensionless distance from the slot exit which realizes the maximum mean heat transfer on the first cylinder, i.e. H / S = 6, the second one has generally a lower mean Nusselt number. The only exception is when the second cylinder is set at the dimensionless distance L / S = 4 and the Reynolds number is at the maximum value experimented, i.e. Re = 22,200. If the first cylinder is set at the dimensionless distance H / S = 4 the mean Nusselt number on the second cylinder is greater if its distance from the first one is in the range L / S = 3.5–7 for Re = 14,300–22,200. The first cylinder acts as a heat transfer promoter, as happens in uniform flow, only for Re = 22,200.

Efficacy of epidural local anesthetics plus steroids for the treatment of cervicobrachial pain is uncertain.A prospective study randomized 160 patients with cervicobrachial pain resistant to conventional therapy. Patients were divided into 4 groups on the basis of the time between pain onset and treatment initiation: group A, 40 patients with pain onset 15 to 30 days; group B, 40 patients with pain from 31 to 60 days; group C, 40 patients, 61 to 180 days; and group D, 40 patients with pain180 days. Patients of each group were randomized to receive an epidural block with bupivacaine and methylprednisolone at intervals of 4 to 5 days (Single injection) or continuous epidural bupivacaine every 6, 12, or 24 hours plus methylprednisolone every 4 to 5 days (Continuos epidural). The maximum duration of treatment (9 blocks in Single injection, and 30 days in Continuos epidural) was dependent on achieving Pain Control (PC)or =80% [PC is defined by this formulae: (100) (VAS(initial)-VAS(final))/VAS(initial)]. Follow-up at 1 month and 6 months compared PC and the number of pain-free hours of sleep.One hundred forty-one patients completed the study. The 4 groups had similar characteristics. At the 1-month and 6-month follow-up analysis based on the time between pain onset and treatment initiation showed that patients of group D, who received the Continuous epidural treatment, had significantly greater PC and significantly more pain-free hours of sleep compared with similar patients in Single injection.Therapy with continuous epidural local anesthetic and methylprednisolone provides better control of chronic cervicobrachial pain compared with Single injection. These results are discussed with respect to the possible mechanism of action of the drugs and may relate to the physiopathologic mechanisms associated with neuronal plasticity that result in chronic pain.

Flow visualisation and heat/mass transfer measurements in a linear turbine cascade with tip/casing clearances ranging from 0.60% to 6.90% of chord show the influence of blade tip geometry for a standard flat tip, a squealer tip and a geometry with a winglet on the pressure side and a squealer on the suction side of the blade. Oil-lampblack and oil-dot techniques show the surface flow on the blade endwall and tip while a laser light-sheet and a smoke wire indicate the three-dimensional flow in the tip clearance and blade passages. Local heat/mass transfer from the blade tips is measured using the naphthalene sublimation technique. Experiments with the standard flat tip blade clearly show that a separation bubble exists at the pressure side edge of the tip surface at all tip clearance levels. The effect of the tip leakage vortex on the secondary flows in the blade passage is also evident: with an increase of tip clearance, the horseshoe vortices disappear while the passage vortex is weakened and pus...

A theoretical investigation is carried out to study natural convection around a vertical thin cylinder, or a needle, heated at uniform and constant wall heat flux in order to compare the analytical solutions of the present work with previous experimental results. The local non-similarity solution with the first level of truncation, proposed by Minkowycz and Sparrow, is used. The temperature and velocity distributions are calculated for fluids with several Prandtl numbers. The analytical solutions of this work are compared to experimental results carried out with needles of diameters ranging from 0.6 to 1.5 mm and fluids with Prandtl numbers in the range Pr = 0.7–730. The agreement is reasonable good.

The time evolution of the price of resources sold to the market and of the price difference, between sold and extracted resources, is investigated in case of no accumulation of the resources; i.e. when the resources are extracted and sold to the market at the same mass flow rate. The price evolution of sold resources varies with time according to the relation between the price increase factor, PIF, of sold and extracted resources. The price evolutions of sold resources and price difference are investigated according to the relation between extraction rate and interest rate of extracted and sold resources. The price of sold resources and the price difference increase with time if the PIF of sold resources is greater than the PIF of extracted resources and the initial price is greater than the critical price of sold resources, which depends on the initial price of extracted resources and the interest rate of non-extracted and extracted resources. The price of sold resources and the price difference decrease with time if the PIF of sold resources is greater than the PIF of extracted resources and the initial price is smaller than the critical price of sold resources. The other cases are discussed extensively in the paper.

Mass conservation equation of non-renewable resources is employed to study the resources remaining in the reservoir according to the extraction policy. The energy conservation equation is transformed into an energy-capital conservation equation. The Hotelling rule is shown to be a special case of the general energy-capital conservation equation when the mass flow rate of extracted resources is equal to unity. Mass and energy-capital conservation equations are then coupled and solved together. It is investigated the price evolution of extracted resources. The conclusion of the Hotelling rule for non-extracted resources, i.e. an exponential increase of the price of non-renewable resources at the rate of current interest, is then generalized. A new parameter, called “Price Increase Factor”, PIF, is introduced as the difference between the current interest rate of capital and the mass flow rate of extraction of non-renewable resources. The price of extracted resources can increase exponentially only if PIF is greater than zero or if the mass flow rate of extraction is lower than the current interest rate of capital. The price is constant if PIF is zero or if the mass flow rate of extraction is equal to the current interest rate. The price is decreasing with time if PIF is smaller than zero or if the mass flow rate of extraction is higher than the current interest rate.

The electrical resistivity (ER) of Flexinol nickel-titanium shape memory alloys (SMA) has been measured in the range from -15 to 105 degrees C. The investigated Flexinol wires have two diameters, 150 and 375 mu m. The experimental results show new temperatures of phase transformation (TTR) evidencing the unexpected presence of the R-phase. The transformations from austenite to martensite, from austenite to R-phase, and vice versa are simultaneous. In the range [20 to 110 degrees C] the hysteresis is almost negligible, whereas in the range [-15 to 105 degrees C] the accommodation process of the hysteresis is observed.

A submerged slot jet of air is used as cooling system for an externally finned cylinder ensemble, heated by electric current. The cylinder ensemble is made with a stainless steel finned tube and a Teflon® bar as core. Five thermocouples, pressed inside the steel tube by the Teflon bar, measure the wall temperature in order to determine local and mean convective heat transfer coefficients. The local Nusselt number has its maximum on the impinging point and its minimum on the opposite position. The variation of the local and mean Nusselt number with the distance from the slot exit is investigated. An empirical expression is proposed to correlate the experimental data. The cooling with a jet flow of a finned cylinder realizes a higher heat transfer as compared to that of a smooth cylinder.

Experimental results are presented for heat transfer cooling of an electrically heated circular cylinder, of diameter D=10 mm, by a slot jet, of height S=2.5 mm, i.e. with D/S=4. Mean and local Nusselt numbers are presented versus the Reynolds numbers, the distance of the cylinder from the slot exit, H, and the angle from the impinging point. Mean Nusselt numbers, defined according to the cylinder diameter, D, are higher than the values in an infinite flow. The maximum mean Nusselt number is measured when the cylinder is set at a distance H, from the slot exit, such that H/S=8. The minimum local Nusselt number is measured at an angle of 180° from the impinging point, i.e. on the rear of the cylinder. Comparisons have been done among the mean Nusselt numbers of this work and previous experimental results of the same authors, carried out with diameter to slot height ratios equal to D/S=1 and 2. The conclusion is that the mean Nusselt number, defined as , is higher for D/S=4, versus the Reynolds number, defined as ReD=WD/ν. On the contrary, the mean Nusselt number, defined on the basis of the slot height, , has similar values, for the different slot heights, versus the Reynolds number, defined as ReS=WS/ν, with the trend of higher results for the slot with D/S=2.

The thermal conductivity of olivine, dry and mixed with water, up to saturation, has been measured with a thermal probe, using the step heating method. The olivine is composed of solid particles with dimensions in the range from 0.8 to 1 mm. Dry olivine has been measured in the range of temperatures between −17° to +50°C. Olivine mixed with water has been measured at +50°C. The cubic cell model has been used to make predictions to compare with the measured data. Comparisons of the experimental thermal conductivities and the predicted values of dry and water-mixed olivine show good agreement. The cubic cell model can be used to evaluate the porosity of olivine and the thermal conductivity of the solid particles, from the values measured at dryness and saturation, with reasonably good agreement. In this way, it is not necessary to measure the mineral composition of the particles of the porous media. Also, the porosity of the medium is predicted with reasonable agreement, which takes into account the phenomenon of the porosity increase near the probe, since the diameter of the probe is smaller than that of the solid particles.

The paper presents numerical simulations of heat conduction around a circular vertical cylinder immersed in liquids. A finite volume formulation is used, and the numerical analysis is performed in unsteady state with an explicit scheme. The numerical predictions are compared with experiments performed on liquids to find the temperature inside the cylinder, where a thermocouple is located, and at the wall of the insulated coaxial container, where the liquid is poured. The cylinder is immersed vertically. The numerical results are in good agreement with the temperature at the wall of the container. The experimental temperature measurement of the thermocouple located inside the probe is intermediate between the numerical temperatures on the axis and on the surface of the probe. The natural convection phenomenon is evidenced in the experiments, after a certain time from the beginning of heating, in some of the liquids used, except glycerol. Natural convection is not considered in the present numerical simulations, which solve only the heat conduction equation.