Journal articles on the topic 'Leading edge contamination'

Contamination control has become a high-centered issue for the fabrication yield, performance and reliability of leading-edge ULSI devices. With the progress of sizing down dimensions in higher-density devices, complicated device structures and various novel electronic materials have been introduced, particularly in the latest devices such as CMOS and nonvolatile memory LSIs (Table I). On the other hand, high productivity is a necessity when you consider QTAT (quick turnaround time) and cost-effective flexible ULSI manufacturing lines. Therefore, effective contamination control coupled with adequate protocol has become essential in such production lines. The point of the protocol is minimization of damage caused by impurity metals diffused from these novel electronic materials [1-5].

Abstract This paper describes an investigation of methods of controlling transition and separation in the leading edge region of military aircraft wings. For wings with the high leading edge sweep relevant to some military aircraft, if attachment line contamination can be prevented then transition is predominantly caused by crossflow instability close to the leading edge. The use of surface suction or cooling for suppressing these instabilities in order to delay transition, has been investigated in a parametric study. The placing of a short suction panel close to the leading edge has been found to be an effective means of controlling instability. Conversely, the level of cooling required to suppress crossflow instability may be too high for practical aircraft applications. The use of suction for preventing laminar separation for pressure distributions with a leading edge suction peak has also been included in the parametric study. The suction quantity required is strongly dependent on the peak height. The suction quantity that can be achieved in practice will limit the maximum peak height that can be attained without laminar separation. An investigation of leading edge stall and control has also been carried out. The analysis suggests that it is important to be able to identify whether the stall is due to laminar bubble bursting or turbulent re-separation, since different methods of controlling the stall may be required.

Apabila terjadinya airfoil contaminating berupa icing atau penumpukan partikel es pada leading edge wing dapat menimbulkan hilangnya produksi gaya angkat pada pada sayap pesawat yang dikarenakan faktor cuaca dan kelembaban pada ketinggian tertentu. Untuk mencegah terjadinya icing, yaitu dengan menggunakan anti icing device guna mencegah terjadinya icing. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh geometri pada rasio diameter coil terhadap performa alat heater yang menggunakan panas gas buang engine dan pengaruh geometri heater terhadap efektivitas heater dalam memanaskan airfoil contamination pada leading edge wing. Penelitian ini menggunakan engine genset 1 silinder berkapasitas 2000 Watt dengan variasi beban menggunakan lampu pijar dengan total beban 500 Watt serta menggunakan profil airfoil yang dikondisikan. Hasil penelitian menunjukkan bahwa perubahan geometri coil akan mempengaruhi parameter performa dari alat heater. Parameter performa heater meningkat dengan semakin kecilnya rasio diameter coil. Pemanasan yang memanfaatkan limbah panas gas buang engine dengan menggunakan alat heater helical coil tube feedback memberikan peningkatan performa dan efektivitas dalam melakukan pamanasan leading edge wing dalam mencegah terjadinya kontaminasi. Maka kesimpulan dari penelitian ini menunjukkan bahwa penngunaan alat heater helical coil tube feedback dengan rasio diameter terkecil adalah yang terbaik dalam meningkatkan parameter performa dan efektivitas heater.

Hilangnya gaya angkat pada pesawat bisa terjadi karena airfoil contamination berupa icing atau penumpukan partikel es pada leading edge wing yang dikarenakan faktor cuaca dan kelembaban pada ketinggian tertentu. Untuk mencegah terjadinya icing, yaitu dengan menggunakan anti icing guna mencegah terjadinya icing. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh geometri pada rasio diameter tube yang diberi hole terhadap performa heater yang memanfaatkan panas gas buang dari engine dan pengaruh geometri heater terhadap efisiensi heater dalam mencegah terjadinya airfoil contamination pada leading edge wing. Penelitian ini menggunakan engine genset 1 silinder berkapasitas 2000 W dengan variasi beban menggunakan lampu pijar dengan total beban 500 W serta menggunakan profil wing yang dikondisikan. Perubahan geometri twist pada heater dengan penambahan hole dapat menciptakan aliran turbulen, meningkatkan proses perpindahan kalor, dan meningkatkan koefisien perpindahan kalor konveksi pada tube. Dari tiga geometri twist ratio 1.5, 2.27, 2.45 yang paling baik dalam melepaskan kalor yaitu twist ratio 2.45 dengan nilai perpindahan kalor konveksi pada beban rata-rata terbesar.Kesimpulan dari penelitian ini menunjukkan bahwa penggunaan alat berupa piccolo tube with twisted dengan rasio diameter terbesar adalah yang terbaik dalam meningkatkan parameter performa dan efisiensi heater. Perubahan geometri twist akan mempengaruhi efisiensi dari heater.

Aviation is a high-risk business field. Safety aspects are a top priority to prevent material and non-material losses due to hazards that arise during the flight phase.The stall is one example of a danger that occurs due to the failure of the wing to produce lift.The stall is affected by changes in the wings shape, particularly at the leading edge due to contamination.Contamination occurs in the form of ice particles on the leading edge and regenerates the airflow passing through the wing into turbulent flow.An anti-icing device is needed to overcome this contamination problem by utilizing engine exhaust gas to reduce the consumption of electrical power used in the heating system for the leading edge.Anti-icing design with the helical coil as the main component of the heat exchanger.An experimental method is using to study the effect of the coil diameter ratio on heat transfer characteristics and heat exchanger efficiency.The results showed that the coil diameter ratio affects increasing the secondary flow intensity, creates turbulence flow, increases the heat transfer coefficient, the performance parameters of the heater.

Foil and planform parameters which govern the level of viscous drag produced by the keel of a sailing yacht are discussed. It is shown that the application of laminar boundary-layer flow offers great potential for increased boat speed resulting from the reduction in viscous drag. Three foil shapes have been designed and it is shown that their hydrodynamic characteristics are very much dependent on location and mode of boundary-layer transition. The planform parameter which strongly affects the capabilities of the keel to achieve laminar flow is leading-edge sweep angle. The two significant phenomena related to keel sweep angle which can cause premature transition of the laminar boundary layer are crossflow instability and turbulent contamination of the leading-edge attachment line. These flow phenomena and methods to control them are discussed in detail. The remaining factors that affect the maintainability of laminar flow include surface roughness, surface waviness, and freestream turbulence. Recommended limits for these factors are given to insure achievability of laminar flow on the keel. In addition, the application of a simple trailing-edge flap to improve the hydrodynamic characteristics of a foil at moderate-to-high leeway angles is studied.

As an important remote sensing technology, satellite altimetry provides a large amount of observations of sea surface height over the global ocean. In coastal areas, the accuracy of satellite altimetry data decreases greatly due to issues arise in the vicinity of land, related to poorer geophysical corrections and artifacts in the altimeter reflected signals linked to the presence of land within the instrument footprint. To improve the application of HY-2B altimetry data in coastal areas, this study proposes a coastal waveform retracking strategy for HY-2B altimetry mission, which depends on the effective trailing edge and the leading edge, which are less affected by coastal ‘contamination’, to retrieve accurate waveform information. The HY-2B pass 323 and pass 196 data are reprocessed, and the accuracy of the reprocessing results in the range of 0–40 km offshore is validated against the tide gauge data and compared with the HY-2B standard SGDR data. According to the analysis conclusion, the accuracy of the reprocessed data is higher than that of the SGDR data and has good performance within 15 km offshore. For the pass 323, the mean value of correlation coefficient and RMS of the reprocessed data against the corresponding tide gauge data are 0.893 and 45.1 cm, respectively, in the range within 0–15 km offshore, and are 0.86 and 33.6 cm, respectively, in the range beyond 15 km offshore. For the pass 196, the mean value of correlation coefficient and RMS of the reprocessed data against the corresponding tide gauge data in the range within 0–12 km offshore are 0.84 and 33.0 cm, respectively, and in the range within 0–5 km offshore to the island are 0.90 and 29.3 cm, respectively, and in the range beyond 5 km offshore to the island are 0.92 and 36.2 cm, respectively, which are all better than the corresponding values of the SGDR data, especially in the range closed to the land. The results indicate that the proposed coastal waveform retracking strategy for HY-2B altimetry greatly improves the quality of HY-2B altimetry data in coastal areas.

<p>Rapid development of nanotechnology has revolutionsed various areas of conventional food science and food industry. The novel properties of nanoparticles (NPs) have led to increasing application of nanotechnology in food industry. Nanofood market have a variety of products like the creamy ice-cream, drinks with no fat, enhanced flavour with nutrients and better textured, coloured and fresh looking food. Continuous monitoring for food spoilage or contamination is possible too. Nanotechnology has transformed the food industries which claim health benefits along with better taste. With the increasing use of NPs especially in food products, where humans are in close contact of the engineered nanomaterials (NMs), it is important to ensure safety before use. Bio-nano interactions often result in novel reaction and formation of products leading to toxicity. NPs mediated toxicity mainly includes inflammation, oxidative damage and genotoxicity. Prolong use of these particles can cause detrimental effects on health. Presently, due to lack of appropriate guidelines and regulations for food nanotechnology there are uncertainties regarding risk identification. Hence, it is essential to evaluate the consequences of this technology in terms of general public and occupational health risks associated with the manufacture, use and disposal of NMs, before instigating the same in day to day use.</p>

Damp air with high humidity combined with foggy, rainy weather, and icing in winter weather often is found to cause turbine performance degradation, and it is more concerned with offshore wind farm development. To address and understand the high humidity effects on wind turbine performance, our study has been conducted with spread sheet analysis on damp air properties investigation for air density and viscosity; then CFD modeling study using Fluent was carried out on airfoil and blade aerodynamic performance effects due to water vapor partial pressure of mixing flow and water condensation around leading edge and trailing edge of airfoil. It is found that the high humidity effects with water vapor mixing flow and water condensation thin film around airfoil may have insignificant effect directly on airfoil/blade performance; however, the indirect effects such as blade contamination and icing due to the water condensation may have significant effects on turbine performance degradation. Also it is that found the foggy weather with microwater droplet (including rainy weather) may cause higher drag that lead to turbine performance degradation. It is found that, at high temperature, the high humidity effect on air density cannot be ignored for annual energy production calculation. The blade contamination and icing phenomenon need to be further investigated in the next study.

Abstract An anti-icing system has the purpose of protecting the leading edge of the tailplane from contamination during aircraft flight. An anti-icing system in a turboprop aircraft employs heaters that use electrical energy as their power source or heat generated by the bleed air. Protecting the tailplane from contamination is preventing the aircraft stall from occurring that triggers dangerous flight conditions. The aluminum prototype tailplane is assembled with a variable of twisted tape insert and wire coil. The twisted tape insert comes in three different geometries with twist ratio T3 = 9.3; T4 = 7; and T5 = 5.6, as well as a wire coil with fixed geometry. This study shows the best heat transfer rate occurs in T3 with a value of 33.90 W. The consequence of this condition is an decrease in pressure drop that occurs. Twisted 3 has the greatest pressure drop when compared to other geometry, with an average value of 4.72 Pa.

The unsteady spreading of an insoluble monolayer containing a fixed mass of surface-active material over the initially horizontal free surface of a viscous fluid layer is investigated. A flow driving the spreading is induced by gradients in surface tension, which arise from the nonuniform surfactant distribution. Distinct phases in the flow's dynamics are distinguished by a time T = H02/v, where H0 is the fluid depth and v its viscosity. For times t [Lt ] T, i.e. before the lower boundary has any significant influence on the flow, a laminar sub-surface boundary-layer flow is generated. The effects of gravity, capillarity, surface diffusion or surface contamination may be weak enough for the flow to drive a substantial unsteady displacement of the free surface, upward behind the monolayer's leading edge and downward towards its centre. Similarity solutions are identified describing the spreading of a localized planar monolayer strip (which spreads like t1/2) or an axisymmetric drop (which spreads like t3/8); using the Prandtl transformation, the associated boundary-layer problems are solved numerically. Quasi-steady sub-layers are shown to exist at the centre and at the leading edge of the monolayer; that due to surface contamination, for example, may eventually grow to dominate the flow, in which case spreading proceeds like t3/4. Once t = O(T), vorticity created at the free surface has diffused down to the lower boundary and the flow changes character, slowing appreciably. The dynamics of this stage are modelled by reducing the problem to a single nonlinear diffusion equation. For a spreading monolayer strip or drop, the transition from an inertia-dominated (boundary-layer) flow to a viscosity-dominated (thin-film) flow is predicted to be largely complete once t ≈ 85 T.

A Numerical simulation on the influence of airfoil surface contamination on the aerodynamic performance of wind turbines was performed. It chose the dedicated wind turbine airfoil as the research object. The k-ω Shear Stress Transmission (SST) turbulence model was selected for CFD calculation. The roughness height which arranged evenly on the airfoil was changed from 0.03mm to 2.0mm to obtain the sensitive roughness. The airfoil was divided into 18 sections for analyzing the effect on the lift & the drag coefficient, due to various locations of sensitive roughness. By comparing the result computed by XFOIL and CFD calculation, it can be known this airfoils sensitive locations in suction surface and pressure surface. The sensitive locations in suction surface were 53% and 92% from the chord line towards the leading edge, while 44% and 88% in pressure surface. The sensitive roughness in sensitive locations delayed the location of the transition point.

Satellite altimetry is a unique system that provides repeated observations of significant wave height (SWH) globally, but its measurements could be contaminated by lands, slicks, or calm water with smooth surface. In this study, capability of subwaveform retrackers against 20 Hz Jason-2 measurements is examined in the calm Celebes Sea. Distances between contamination sources and Jason-2 observation points can be determined using sequentially assembled adjacent waveforms (radargram). When no contamination sources are present within a Jason-2 footprint, subwaveform retrackers are in excellent agreement with the Sensor Geophysical Data Records (SGDR) MLE4 retracker that uses full-length waveforms, except that Adaptive Leading Edge Subwaveform (ALES) retracker has a positive bias in a calm sea state (SWH < 1 m), which is not unusual in the Celebes Sea. Meanwhile, when contamination sources exist within 4.5 km from Jason-2 observation points, SGDR occasionally estimates unrealistically large SWH values, although they could be partly eliminated by sigma0 filters. These datasets are then compared with WAVEWATCH III model, resulting in good agreement. The agreement becomes worse if swells from the Pacific is excluded in the model, suggesting constant presence of swells despite the semi-enclosed nature. In addition, outliers are found related with locally-confined SWH events, which could be inadequately represented in the model.

HACCP (Hazard analysis critical control point) is a WHO (World Health Organization) recommended, renowned and widely practiced control tool towards food safety to counter the possibilities of FBD (food borne diseases) be it chemical or biological in food handling areas. Experimental Approach the study embarks upon the identification and controlling the possibilities of food contamination in each and every step even before it may occur. In the modern scenario, guests visiting the hotels are health and hygiene conscious and are also equipped with latest knowledge. Apart from that, Government with its rules and regulations is highly attentive towards public health. The study suggests that adherence to HACCP procedures helps in establishing maintain better hygiene leading to better rapport between the service providers and the customers. Methods this paper is an attempt to find out HACCP practical implications and its effect on operations of food production areas of 12 five-star category hotels in Delhi NCR (National Capital Region) during two months period of June and July 2021. The responses of the staff members from food production department were recorded in a questionnaire on a Likert scale of 5. Therefore, implication of HACCP can prove out to be really helpful as an effective and efficient control process in coping up with the possibilities of food contamination. Adherence to the same will give competitive edge to the hotels at the same time contributing significantly towards improvising the food production process, reducing the various costs involved enhancing the quality and quantity of the final product, increased guest satisfaction and hence leading to more revenue generation. Keywords: Food borne diseases, Food contamination, HACCP, Health and hygiene.

Traffic activities are one of major sources leading to roadside soil contamination due to their long-term accumulation effect. The typical elements of Cd, Pb, Zn, and Cu in the roadside soil can transport through food chain to human body and result in a strong toxicity to people. In agricultural area, intake of heavy metals through the soil-crop system could play a predominant role on human exposure to environmental heavy metals. The study investigates concentrations and distributions of the four heavy metals’ in herbaceous plants growing in the roadside farmland around Kathmandu, Nepal. Totally, 60 plant samples including 26 samples from rural mountainous farmland and 34 samples from suburban farmland were collected from April 2011 to May 2011. The sampling distances to the road edge are 0 m, 10 m, 30 m, 50 m, and 100 m. The samples are classified into tree protection or no tree protection. It is found that the heavy metals’ distributions are not consistently decreasing as roadside distance; the heavy metal concentration in rural area is significantly lower than those in suburban area; and tree has a significant protection effect on roadside plants from the Cu contamination.

Abstract Due to the construction of a new North-South subway in Cologne, Roman time harbour sediments were exposed and were sampled for luminescence dating. A very good independent age control was given by the precise knowledge of the chronology of Roman activity and by radiocarbon ages of charcoal samples. Hence, different methodological approaches within luminescence dating were applied for Holocene heterogeneously bleached fluvial samples and were compared to the known ages. For one sample, optically stimulated luminescence (OSL) dating was applied to coarse-grained quartz using a single aliquot regenerative-dose (SAR) protocol. After De-measurements, different statistical approaches were tested (i.e. arithmetic mean, median, minimum age model, finite mixture model, leading edge method and the Fuchs and Lang approach). It is demonstrated that the Fuchs and Lang approach along with the leading edge method yielded the best matching OSL ages with respect to the known ages. For the other sample which showed feldspar contamination within the quartz signal, the post-IR blue stimulated luminescence (double SAR protocol) was measured in three different ways to calculate the Devalue: with continuous wave (CW) stimulation with an IR-bleach at 50°C and at 225°C for 100 s prior to the OSL, and pulsed OSL (POSL). It was demonstrated that the IR-stimulation at 225°C has very good potential to remove the feldspar signal contribution as well as pulsed OSL, but the former might deplete parts of the quartz OSL signal.

Off-surface integral solutions to an inhomogeneous wave equation based on acoustic analogy could suffer from spurious wave contamination when volume integrals are ignored for computation efficiency and vortical/turbulent gusts are convected across the integration surfaces, leading to erroneous far-field directivity predictions. Vortical gusts often exist in aerodynamic flows and it is inevitable their effects are present on the integration surface. In this work, we propose a new sound extrapolation method for acoustic far-field directivity prediction in the presence of vortical gusts, which overcomes the deficiencies in the existing methods. The Euler equations are rearranged to an alternative form in terms of fluctuation variables that contains the possible acoustical and vortical waves. Then the equations are manipulated to an inhomogeneous wave equation with source terms corresponding to surface and volume integrals. With the new formulation, spurious monopole and dipole noise produced by vortical gusts can be suppressed on account of the solenoidal property of the vortical waves and a simple convection process. It is therefore valid to ignore the volume integrals and preserve the sound properties. The resulting new acoustic inhomogeneous convected wave equations could be solved by means of the Green’s function method. Validation and verification cases are investigated, and the proposed method shows a capacity of accurate sound prediction for these cases. The new method is also applied to the challenging airfoil leading edge noise problems by injecting vortical waves into the computational domain and performing aeroacoustic studies at both subsonic and transonic speeds. In the case of a transonic airfoil leading edge noise problem, shocks are present on the airfoil surface. Good agreements of the directivity patterns are obtained compared with direct computation results.

Traditional sheep and cattle grazing in natural semiarid Mediterranean, Asian and African regions is based on night corrals, where animal secretions accumulate. Lack of management and disregard for the long-term effects of using the same sites for corrals on underground soil characters may negatively affect soil values. This locally increases the content of organic matter and nutrients such as nitrogen, potassium, phosphorus and others that are stockpiled in the corrals. As these activities are long-lasting, they affect the soil parameters, leading to nutrient leakage and contamination of the upper and sub-soil surface. This alarming situation demands a technique to reveal and estimate sub-soil contamination in corrals by using the frequency domain electromagnetic method (FDEM) for measuring soil salinity. The aim of this study is to correlate electrical conductivity measurement with the FDEM to study the influence of sheep corrals on the changes within the sub-soils of corrals in the semiarid region of the northern Negev desert. The results show that a correlation was found between the laboratory soil analysis and the electromagnetic analysis in all sites. Plugot forest site results found to be anomalous indicated sub-surface conductivity resulting from the presence of the corral, with a higher conductivity value of about 230 mS/m, while no differences were found between the soil layers outside the active corral and the corral edge. High values were found in the center of the active corral: 960 mS/m by the laboratory analysis and 200 mS/m by the FDEM. The values obtained in the abandoned corral in the laboratory were about 10 times lower than those obtained from the active corral and six times lower that those found with the FDEM. At the Beit Nir site, high values were found in the center of the active corral: 300 mS/m by the laboratory analysis and 130 mS/m by the FDEM. With different sources of manure, cattle and sheep have shown similar patterns of electrical conductivity (EC) obtained in the sub-soil layers between active and abandoned corrals: high in the center and low at the edge and outside the corral and decreased with depth.

Purpose Reviews the latest management developments across the globe and pinpoints practical implications from cutting-edge research and case studies. Design/methodology/approach This briefing is prepared by an independent writer who adds their own impartial comments and places the articles in context. Findings What is cynicism? To the manager, it is a cancerous, evil flow of negativity that stops employees from getting on with the job they are paid to do; it is the holding back of a company on the rise; it is the contamination of enthusiastic, young employees with so-called wise words from more experienced members of staff. In short, it is nothing less than the almost willful sabotage of all the good things a company tries to do. Practical Implications Provides strategic insights and practical thinking that have influenced some of the world’s leading organizations. Originality/value The briefing saves busy executives and researchers hours of reading time by selecting only the very best, most pertinent information and presenting it in a condensed and easy-to-digest format.

Wire feeding can be combined with different heat sources, for example, arc, laser, and electron beam, to enable additive manufacturing and repair of metallic materials. In the case of titanium alloys, the vacuum operational environment of electron beam systems prevents atmospheric contamination during high-temperature processing and ensures high performance and reliability of additively manufactured or repaired components. In the present work, the feasibility of developing a repair process that emulates refurbishing an “extensively eroded” fan blade leading edge using wire-feed electron beam additive manufacturing technology was examined. The integrity of the Ti6Al4V wall structure deposited on a 3 mm thick Ti6Al4V substrate was verified using X-ray microcomputed tomography with a three-dimensional reconstruction. To understand the geometrical distortion in the substrate, three-dimensional displacement mapping with digital image correlation was undertaken after refurbishment and postdeposition stress relief heat treatment. Other characteristics of the repair were examined by assessing the macro- and microstructure, residual stresses, microhardness, tensile and fatigue properties, and static and dynamic failure mechanisms.

AbstractA novel approach for the multi-objective design optimisation of aerofoil profiles is presented. The proposed method aims to exploit the relative strengths of global and local optimisation algorithms, whilst using surrogate models to limit the number of computationally expensive CFD simulations required. The local search stage utilises a re-parameterisation scheme that increases the flexibility of the geometry description by iteratively increasing the number of design variables, enabling superior designs to be generated with minimal user intervention. Capability of the algorithm is demonstrated via the conceptual design of aerofoil sections for use on a lightweight laminar flow business jet. The design case is formulated to account for take-off performance while reducing sensitivity to leading edge contamination. The algorithm successfully manipulates boundary layer transition location to provide a potential set of aerofoils that represent the trade-offs between drag at cruise and climb conditions in the presence of a challenging constraint set. Variations in the underlying flow physics between Pareto-optimal aerofoils are examined to aid understanding of the mechanisms that drive the trade-offs in objective functions.

Maize silage, which in Europe is the main feed for dairy cattle in winter, can be contaminated by mycotoxins. Mycotoxigenic Fusarium spp. originating from field infections may survive in badly sealed silages or re-infect at the cutting edge during feed-out. In this way, mycotoxins produced in the field may persist during the silage process. In addition, typical silage fungi such as Penicillium spp. and Aspergillus spp. survive in silage conditions and produce mycotoxins. In this research, 56 maize silages in Flanders were sampled over the course of three years (2016–2018). The concentration of 22 different mycotoxins was investigated using a multi-mycotoxin liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, and the presence of DNA of three Fusarium spp. (F. graminearum, F. culmorum and F. verticillioides) was analyzed in a selection of these samples using quantitative polymerase chain reaction (qPCR). Every maize silage contained at least two different mycotoxins. Nivalenol (NIV) and deoxynivalenol (DON) were the most prevalent (both in 97.7% of maize silages), followed by ENN B (88.7%). Concentrations often exceeded the EU recommendations for DON and zearalenone (ZEN), especially in 2017 (21.3% and 27.7% of the maize silages, respectively). No correlations were found between fungal DNA and mycotoxin concentrations. Furthermore, by ensiling maize with a known mycotoxin load in a net bag, the mycotoxin contamination could be monitored from seed to feed. Analysis of these net bag samples revealed that the average concentration of all detected mycotoxins decreased after fermentation. We hypothesize that mycotoxins are eluted, degraded, or adsorbed during fermentation, but certain badly preserved silages are prone to additional mycotoxin production during the stable phase due to oxygen ingression, leading to extremely high toxin levels.

Abstract Flip chip technology is widely used in advanced integrated circuit (IC) package. Chip package interaction (CPI) became critical in flip chip technology that needed to be addressed to avoid electrical or mechanical failure in products. When addressing CPI challenges, different areas have to be considered, ranging from silicon BEOL design and processing, bumping design and process, package assembly process, assembly bill of material (BOM), and substrate technology. Controlled collapse chip connection (C4) bump technology provided the inter-connection between the IC to package substrate for high-performance, leading-edge microprocessors. It is very critical for chip package interaction (CPI). With the transfer to lead free technology, bumping process plays more and more important role for chip package interaction reliability. In this paper, we focused on bumping process effect on the CPI reliability. The bumping process has been reviewed and CPI reliability issues induced by the bumping process like particles, Ti seed layer deposition, UBM undercut, Cu pad oxidation and contamination, photoresist opening damage have been discussed. Bumping process optimization and corrective actions have been taken to reduce those defects and improve CPI reliability.

The Australian Defence Science and Technology Organisation (DSTO) has established a leading-edge program to enable the development and transitioning of innovative Smart Materials and Structures technology across the spectrum from fundamental science to use in the field. This program extends and harnesses technology in the area of Smart Materials, Sensors and Systems, in order to increase safety of Defence aircraft, ships, submarines and vehicles, increase availability, reduce the cost of asset ownership and operations, and enhance overall military capability. The program has linkages into broad networks, with strong university and industry relationships, and is also very relevant to the management of civil infrastructure and other equipment. We present here an overview of some key research areas within the DSTO Smart Materials and Structures Initiative, highlighting developments in : (i) Smart Materials, including environmentallyfriendly coatings that exhibit properties of greater flexibility and durability for aerospace applications, nano-crystalline coatings that provide increased wear resistance, and Defence applications for carbon nanotubes; (ii) Smart Sensing, including chemical, structural fatigue, fuel contamination, environmental degradation, corrosion and its precursors, and overheating and mechanical wear; and (iii) Smart Systems that employ innovative techniques to acquire and process data from a range of sensors by harvesting energy from local structures to power microelectronic circuits.

Land use has always been a factor in developing site-specific cleanup objectives for contaminated property. However, land use is taking on major new significance in the “brownfield” legislation being enacted in a growing number of states. Under this method, a tiered approach is used to analyze the risk posed by contaminants and to derive cleanup objectives based on that risk. By many accounts on the leading edge of the brownfield movement, the Illinois Environmental Protection Agency (IEPA) is going so far as to propose a tiered approach to cleanup objectives (TACO) generally across its land pollution programs. TACO relies heavily on restricting land use to obtain less stringent cleanup objectives, and it is this aspect of TACO that represents both an opportunity and a challenge to Illinois transportation agencies and the shape of things to come nationally. The opportunity lies in much lower cleanup costs that these agencies will incur in dealing with contamination in their own yards and rights-of-way. The challenge lies in considering requests from property owners adjoining the rights-of-way for land use restrictions on the rights-of-way, in dealing with land use restrictions on property acquired through eminent domain, and in processing land use restrictions that will be imposed for IEPA’s own cleanups.

Expansion of the North West Shelf Venture (NWSV) production infrastructure is driving plans for sequential development of the small satellite fields. The desire for additional gas reserves has fuelled increased exploration and appraisal drilling in recent years with encouraging results. The NWSV area is a complex geologic environment with multiple play levels, petroleum systems and trapping styles. Seismic imaging is poor in many areas, primarily due to multiple contamination. In 2004, the NWSV acquired the leading edge, regional Demeter 3D Seismic Survey. Since then, continuous application of improved processing techniques, such as 3D Surface-related Multiple Elimination (SRME) and Pre-Stack Depth Migration (PreSDM), have been key to providing significant imaging enhancements. Exploration drilling based on Demeter data resulted in three significant new gas discoveries. Pemberton–1 (2006) explored Triassic sub-cropping sands in a horst block at the southwestern end of the Rankin Trend. The well encountered an upside gas column due to the presence of intra-Mungaroo Formation shales providing a base-seal trapping geometry. Lady Nora–1 (2007) tested the fault block west of the Pemberton horst and encountered a 102 m gross gas column with gas on rock. The upside result accelerated a near term appraisal opportunity at Lady Nora–2 (2008). Persephone–1 (2006) drilled a down-thrown Legendre Formation dip closure in the Eaglehawk graben. Success relied on the sealing potential of the North Rankin Field bounding fault. In spite of pressure depletion associated with over 20 years of production, Persephone–1 encountered a 151 m gross gas column at virgin pressures and a different gas-water contact to North Rankin. The result demonstrated active and significant fault seal along the major North Rankin Field bounding fault. These recent, successful exploration wells have resulted in identification of follow-up drilling opportunities and a drive for ongoing seismic imaging improvements. The discoveries have material impacts on NWSV development plans for the Greater Western Flank and in the vicinity of the Perseus, North Rankin and Goodwyn gas fields.

The newly acquired 3,590 km2 Demeter 3D high resolution seismic survey covers most of the North West Shelf Venture (NWSV) area; a prolific hydrocarbon province with ultimate recoverable reserves of greater than 30 Tcf gas and 1.5 billion bbls of oil and natural gas liquids. The exploration and development of this area has evolved in parallel with the advent of new technologies, maturing into the present phase of revitalised development and exploration based on the Demeter 3D.The NWSV is entering a period of growing gas market demand and infrastructure expansion, combined with a more diverse and mature supply portfolio of offshore fields. A sequence of satellite fields will require optimised development over the next 5–10 years, with a large number of wells to be drilled.The NWSV area is acknowledged to be a complex seismic environment that, until recently, was imaged by a patchwork of eight vintage (1981–98) 3D seismic surveys, each acquired with different parameters. With most of the clearly defined structural highs drilled, exploration success in recent years has been modest. This is due primarily to severe seismic multiple contamination masking the more subtle and deeper exploration prospects. The poor quality and low resolution of vintage seismic data has also impeded reservoir characterisation and sub-surface modelling. These sub-surface uncertainties, together with the large planned expenditure associated with forthcoming development, justified the need for the Demeter leading edge 3D seismic acquisition and processing techniques to underpin field development planning and reserves evaluations.The objective of the Demeter 3D survey was to re-image the NWSV area with a single acquisition and processing sequence to reduce multiple contamination and improve imaging of intra-reservoir architecture. Single source (133 nominal fold), shallow solid streamer acquisition combined with five stages of demultiple and detailed velocity analysis are considered key components of Demeter.The final Demeter volumes were delivered early 2005 and already some benefits of the higher resolution data have been realised, exemplified in the following:Successful drilling of development wells on the Wanaea, Lambert and Hermes oil fields and identification of further opportunities on Wanaea-Cossack and Lambert- Hermes;Dramatic improvements in seismic data quality observed at the giant Perseus gas field helping define seven development well locations;Considerably improved definition of fluvial channel architecture in the south of the Goodwyn gas field allowing for improved well placement and understanding of reservoir distribution;Identification of new exploration prospects and reevaluation of the existing prospect portfolio. Although the Demeter data set has given significant bandwidth needed for this revitalised phase of exploration and development, there remain areas that still suffer from poor seismic imaging, providing challenges for the future application of new technologies.

Abstract. In this paper, we show that in mixed phase clouds FSSP-100 measurements may be contaminated by ice crystals, inducing wrong interpretation of particle size and subsequent bulk parameters. This contamination is generally revealed by a bimodal feature of the particle size distribution; in other words, in mixed phase clouds bimodal features could be an indication of the presence of ice particles. The combined measurements of the FSSP-100 and the Polar Nephelometer give a coherent description of the effect of the ice crystals on the FSSP-100 response. The FSSP-100 particle size distributions are characterized by a bimodal shape with a second mode peaked between 25 and 35 μm related to ice crystals. This feature is observed with the FSSP-100 at airspeed up to 200 m s−1 and with the FSSP-300 series. In order to assess the size calibration for clouds of ice crystals the response of the FSSP-100 probe has been numerically simulated using a light scattering model of randomly oriented hexagonal ice particles and assuming both smooth and rough crystal surfaces. The results suggest that the second mode measured between 25 μm and 35 μm, does not necessarily represent true size responses but likely corresponds to bigger aspherical ice particles. According to simulation results, the sizing understatement would be neglected in the rough case but would be major with the smooth case. Qualitatively, the Polar Nephelometer phase function suggests that the rough case is the more suitable to describe real crystals. Quantitatively, however, it is difficult to conclude. Previous cloud in situ measurements suggest that the FSSP-100 secondary mode, peaked in the range 25–35 μm, is likely to be due to the shattering of large ice crystals on the probe tips. This finding is supported by the rather good relationship between the concentration of particles larger than 20 μm (hypothesized to be ice shattered-fragments measured by the FSSP) and the concentration of (natural) ice particles larger than 100 μm (CPI data). The shattering efficiency is defined as the ratio of the measured ice shattered-fragments to the number of natural ice particles (with d>100 μm) impacting the probe leading edge. In the present study the shattering efficiency is evaluated to ~7%. It is found that about 400 ice fragments may result from the shattering of one equivalent irregular shaped ice crystal with a mean volume diameter of 310 μm. Obviously, these values could be strongly dependent on the inlet design, the airspeed and the robustness of ice crystals via the impact kinetic energy to surface energy ratio providing the particle breakup.

The emission variation of SSE from surface fragments of protrusions in a silicon plate is evaluated during prolonged scanning in low energy SEM. Emission dynamic variation that is especially complex near the edges of protrusion upper bases and slopes is discovered that affects the sizes of all protrusion fragments. Emission variation is explained with changes of unevenly localized charge state at different surface fragments of protrusions in a natural silica and a contamination film. Contamination is occurred in vacuum and depends on a surface charge state so it is not uniform along protrusion surface. The total absence of contamination on some protrusions is fixed so its initial linewidth size is occurred a constant during a scanning. The limiting uprising of a linewidth size to 4.5 at a one case and the limiting decrease to -0.8 at another case are fixed. Yu. V. Larionov, Senior Researcher, A.M. Prokhorov General Physics Institute, RAS, Moscow, 119991, Russian Federation, E-mail: luv@kapella.gpi.ru, Yu. V. Ozerin, Leading Engineer, yozerin@mikron.ru Mikron Co., Zelenograd, Russia

Abstract The contamination of feed with mycotoxins is a continuing feed quality and safety issue, leading to significant losses in livestock production and potential human health risks. Consequently, various methods have been developed to reduce the occurrence of mycotoxins in feed; however, feed supplementation with clay minerals or mineral adsorbents is the most prominent approach widely practiced by farmers and the feed industry. Due to a negatively charged and high surface area, pore volume, swelling ability, and high cation exchange capacity, mineral adsorbents including bentonite, zeolite, montmorillonite, and hydrated sodium calcium aluminosilicate can bind or adsorb mycotoxins to their interlayer spaces, external surface, and edges. Several studies have shown these substances to be partly or fully effective in counteracting toxic effects of mycotoxins in farm animals fed contaminated diets and thus are extensively used in livestock production to reduce the risk of mycotoxin exposure. Nevertheless, a considerable number of studies have indicated that these agents may also cause undesirable effects in farm animals. The current work aims to review published reports regarding adverse effects that may arise in farm animals (with a focus on pig and poultry) and potential interaction with veterinary substances and nutrients in feeds, when mineral adsorbents are utilized as a technological feed additive. Furthermore, results of in vitro toxicity studies of both natural and modified mineral adsorbents on different cell lines are reported. Supplementation of mycotoxin-contaminated feed with mineral adsorbents must be carefully considered by farmers and feed industry.

The objective of the study was to develop the problem of complex treatment of surgical infections of the skin and soft tissues (SISST).The studies were carried out in 201 patients with SISST who were treated at the Department of Purulent Surgery of the Hospital Surgery Clinic of the EE “Vitebsk State Medical University” in 2017–2020. As a result, it was developed: a protocol for a rational use of antibiotics in the patients with SISST, an effective regimen for use of antiseptic drugs, a method for treating purulent wounds with autologous bone marrow aspirates.For 13 years, there have been significant changes in the etiological structure of gram-negative problematic pathogens in patients with purulent wounds. The share of K.pneumoniae increased approximately 8 times (by 12.25 %; p < 0.05), and A.baumannii ‒ 9 times (by 14.69 %; p < 0.05). The share of MRSA remained virtually unchanged. The resistance of problem microorganisms to almost all antibacterial drugs significantly increased. For MRSA-induced SISST, glycopeptides (vancomycin) should be recommended as a drug of choice, and oxazolidinones (linezolid) and glycylcyclines (tigecycline) should be recommended as a reserve; K. pneumoniae ‒ colistat and tigecycline; P. aeruginosа ‒ carbapenems (doripenem) and colistat; A. baumannii ‒ penicillins or cephalosporins with sulbactam (ampicillin + sulbactam) and colistat.It was found that septomyrin and 0.02 % chlorhexidine bigluconate have the greatest activity against the leading representatives of the microflora of purulent wounds. With a combined use of septomirin and chlorhexidine, the bacterial contamination of wounds decreased below the critical level already on the 2nd day after surgical treatment (p < 0.01).To stimulate wound healing, sternocentesis is performed and automyeloaspirate is taken. The curettage of the wound and the aspirate introduction into the wound edges and the application to the wound surface are performed. It has been established that, along with the pelvic bones, the sternum can be an alternative source of red bone marrow. The myeloaspirate volume obtained by sternal puncture varied from 10 to 140 ml. The developed method allows us to reliably reduce the duration of the 2 phase of the wound process by 7 days (р < 0.01).

Трансформация агроэкосистем и природных ландшафтов в систему экологически сбалансированных лесоаграрных экосистем является ведущим звеном лесоаграрной организации территории аридной зоны. Защитные лесные насаждения выполняют многофункциональную средообразующую роль и улучшают экологическую обстановку в агролесоландшафтах, изменяя микроклимат, влажность, инсоляцию в биотопах и определяя тем самым условия формирования вредной и полезной энтомофауны и микрофлоры. Исследования проводили в защитных насаждениях и смежных к ним участках на территории Самарской, Волгоградской областей. Оценивали видовое богатство и численность энтомофауны. Учетные площадки закладывали непосредственно в лесополосах, на их опушках и в прилегающих биотопах. Сравнительный анализ структуры населения сообществ проводили с использованием общепринятых методик. Создание системы взаимодействующих многопородных полифункциональных защитных лесных насаждений обеспечивает повышение разнообразия фаунистических сообществ в 1,8-3,0 раза, усложнение трофических связей и активизацию биологических факторов регуляции численности вредных организмов. В зерновых агроценозах, защищенных лесными полосами из энтомофильных пород (робинии, черемухи, ирги, жимолости, смородины и др.), отмечали в 1,6–3,5 раза меньше вредителей, чем на полях под защитой вязовых или дубовых насаждений. Общая численность полезной биоты здесь была в 2,3-6,1 раза выше, чем на полях среди монокультур вяза. Наиболее многочисленными оказались паразиты (Ichneumonidae, Braconidae, Chalcidoidea). Хищные насекомые и пауки в меньшей степени реагировали на введение в лесополосы указанных кустарников. Повышению активности полезных агентов в агроценозах способствует засеивание опушек по всему периметру лесозащищенного поля нектароносами – горчицей, гречихой, фацелией и другими. Активизация паразитов и хищников в лесопастбищных ландшафтах достигается за счет обогащения флористического разнообразия насаждений. Введение в состав посадок тамариксов (Tamarix laxa, T. meyeri x hohenackeri) и джузгуна (Calligonum caput medusae) способствует увеличению численности энтомофагов в 1,4–3,9 раза, количество Aranea – в 3-5 раз выше. Привлечение комплекса полезной биоты в агролесоландшафт позволяет существенно снизить объем применения средств защиты растений и предотвратить загрязнение агросферы. Особый интерес для адаптивного растениеводства и экологичного земледелия представляет использование нетрадиционного агрохимического сырья, в частности бишофита – природный минерала, единственное месторождение которого в стране находится на территории Волгоградской области. Перспективна предпосевная обработка семян – при орошении оздоравливающий эффект бишофита повышается в 1,2-4,8 раза. Использование бишофита для некорневой подкормки в период кущение-трубкование ведет к снижению численности вредителей на 8,5-50,6%. Хороший эффект от применения бишофита отмечен в зерновых агроценозах при сочетании обработки семян с некорневой подкормкой вегетирующих растений. Численность насекомых-фитофагов снижается на 8,2-68,4% при одновременном увеличении количества энтомофагов на 65,7–82,2%. Широкое внедрение в производство приемов беспестицидной технологии защиты растений обеспечивают сохранение биоразнообразия, максимальную активизацию природных механизмов биотической саморегуляции, улучшение питания растений, что способствует восстановлению биологического равновесия в лесомелиоративных комплексах и получению высококачественной растениеводческой продукции. В лесоаграрных ландшафтах потоки энтомофауны находятся в тесной взаимосвязи со структурой опушек, на которых находят дополнительное питание энтомофаги, гнездятся насекомые-опылители. Введение в состав лесопастбищных посадок Tamarix laxa T. meyeri х hohenackeri и Calligonum caput-medusae способствует увеличению численности насекомых-энтомофагов в 1,4-3,9 и пауков в3,0-5,0 раз. Привлечение полезной биоты в агролесоландшафт позволяет существенно снизить объем применения средств защиты растений и предотвратить загрязнение агросферы. Transformation of agroecosystems and natural landscapes into a system of ecologically balanced forest-agrarian ecosystems is the leading link of forest-agrarian organization of the arid zone territoryProtective forest plantations is perform a multifunctional environmental role and improve the environmental situation in the agroforestry landscape, changing the climate, humidity, insolation in the biotopes and the conditions defininging for the formation of harmful and the beneficial community of entomofauna and microflora. The research was carried out in protective plantations and adjacent areas on the territory of Samara, Volgograd regions. Is estimated the species richness and the abundance of entomofauna. Test sites were laid directly in the forest belts, on their edges and in the adjacent biotopes. Comparative analysis of the structure of the community population was carried out using common methods. The creation of a system of interacting multi-breed multifunctional protective forest plantations provides an increase in the diversity of faunal communities in 1,8-3,0 times, the complexity of the trophic relations and activization of biological factors regulating the numbers of pests. In grain agrocenoses, which are protected by forest strips ofrom the abundantly flowering rocks (robinia, cherry, irgi, honeysuckle, currants, etc.), noted in 1.6-3.5 times less pests, than in the fields under the forest protection of elm or oak. The total number of useful biota here was 2.3-6.1 times higher than in the fields among of elm monocultures. The most numerous were parasites (Ichneumonidae, Braconidae, Chalcidoidea). Predatory insects and spiders is reacted less to the introduction of these bushes into the forest belts. Is promotes increase activity of the beneficial agent in the agrocenoses by sowing field honey herbs – mustard, buckwheat, phacelia and other to the around the perimeter of the protected forest belts field. Activation of parasites and predators in pastures that are protected by forest belts is achieved by enriching the floral diversity of plants. Introduction to the composition of Tamarix plantings (Tamarix laxa, T. meyeri x hohenackeri) и джузгуна (Calligonum caput medusae) contributes to the increase in the number of entomophages in 1,4-3,9 times, number of Aranea - 3-5 times higher. The involvement of the complex of useful biota in the agroforestry landscape can significantly reduce the amount of use of plant protection products and prevent contamination of the agricultural sphere. Of particular interest for adaptive crop production and organic farming is the use of non-traditional agrochemical raw materials, in particular bischofite - a natural mineral, the only deposit of which in the country is located on the territory of the Volgograd region. Is promising pre-sowing treatment of seeds - with irrigation, the healing effect of bischofite increases by 1.2-4.8 times. The use of bischofite for foliar top dressing during in the period of tillering-tubing leads to a decrease in the number of pests by 8.5-50.6%. A good effect from the use of bischofite was noted in the cereal agrocenoses when combined with seed treatment with foliar top dressing of vegetative plants. The number of phytophagous insects decreases by 8.2-68.4% with a simultaneous increase in the number of entomophages by 65.7-82.2%. The wide introduction of methods the non-pesticidal technologies into production ensures the preservation of biodiversity, maximum activation of natural mechanisms of biotic self-regulation, improvement of plant nutrition, which contributes to the restoration of biological balance in forest reclamation complexes and the production of high-quality crop products. In forest landscape , entomofauna streams are in close relationship with the structure of the edges of the forest belt, on which additional nutrition of the entomophages is found, insect pollinators nest. Introduction to the composition of forest pasture landings Tamarix laxa T. meyeri х hohenackeri and Calligonum caput-medusae contributes to an increase in the number of insect entomophages at 1.4-3.9 and spiders to 3.0-5.0 times. Attraction of useful biota in the agroforestry landscape can significantly reduce the use of plant protection products and prevent contamination of the agrosphere.

New developments covered in Recommended Practices revised recently by the Contamination Control Division of IEST include a test method for characterizing outgassed organic compounds; design and testing of Type IV (vee-bed) modular gas-phase adsorber cells; an automated surface cleaning efficiency test procedure; and production testing of filter types H through K.

During the last decades, riblets have shown a potential for viscous drag reduction in turbulent boundary layers. Several investigations and measurements of skin-friction in the boundary layer over flat plates and on turbomachinery-type blades with ideal riblet geometry have been reported in the literature. The question of where riblets must be applied on the surface of a compressor blade is still not sufficiently answered. In a first step, the profile loss reduction by ideal triangular riblets with a trapezoidal groove and a constant geometry along the surface on the suction and pressure sides of a compressor blade is investigated. The results show a higher potential on the profile loss reduction by riblets on the suction side. In a second step, the effect of laser-structured ribs on the laminar separation bubble and the influence of these structures on the laminar boundary layer near the leading edge are investigated. After clarifying the best choices where riblets should be applied on the blade surface, a strategy for locally adapted riblets is presented. The suction side of a compressor blade is laser-structured with segmented riblets with a constant geometry in each segment. The measured profile loss reduction shows the increasing effect on the profile loss reduction of this locally adapted structure compared to a constant riblet-geometry along the surface. Furthermore, the particle deposition on a riblet-structured compressor blade is investigated and compared to the particle deposition on a smooth surface. Results show a primary particle deposition on the riblet tips followed by an agglomeration. The particle deposition on the smooth surface is stochastic.

Purpose Some recent effort showed that usage of Krueger flaps helps to maintain laminar flow in cruise flight. Such flaps are positioned higher relative to the chord to shield the leading edge from the insect contamination during take-off. The flap passes several through critical intermediate position during the deployment to its design position. The purpose of this paper is to analyse the aerodynamics. Design/methodology/approach To better understand such flow phenomena, the combined approach of computational fluid dynamics and experimental methods were used. Flow simulation was performed with in-house finite volume Navier–Stokes solver in fully turbulent unsteady RANS regime. The experimental data were obtained by means of force and pressure measurements and some areas of the flow field were examined with 2 C particle image velocimetry. Findings The airfoil with flap in critical position has a very limited maximum lift coefficient. The maximum achievable lift coefficient during the deployment is significantly affected by the vertical position of the trailing edge of the flap. The most unfavourable position during the deployment is not the flap perpendicular to the chord, but the flap inclined closer to it is the retracted position. Research limitations/implications The flap movement was not simulated either in the simulation or in the experiment. Only intermediate static positions were examined. Practical implications A better understanding of aerodynamic phenomena connected with the deployment of a Krueger flap can contribute to the simpler and lighter of kinematics and also to decrease time-to-market. Originality/value Limited experimental and computational results of Krueger flap in critical positions during the deployment are published in the literature.

Theoretical analysis of attachment-line instabilities is performed for supersonic swept flows using the compressible Hiemenz approximation for the mean flow and the successive approximation procedures for disturbances. The theoretical model captures the dominant attachment-line modes in wide ranges of the sweep Mach number ${M_e}$ and the wall temperature ratio. It is shown that these modes behave similar to the first and second Mack modes in the boundary layer flow. This similarity allows us to extrapolate the knowledge gained for Mack modes to the attachment-line instabilities. In particular, we find that at sufficiently large ${M_e}$ , the dominant attachment-line instability is associated with the synchronisation of slow and fast modes of acoustic nature. Point-by-point comparisons of the theoretical predictions with the experiments of Gaillard et al. (Exp. Fluids, vol. 26, 1999, pp. 169–176) demonstrate that at ${M_e} > 4$ , the theory captures a significant drop of the transition onset Reynolds number, which is below the contamination criterion of Poll $({R_\mathrm{\ast }} = 250)$ at ${M_e} > 6$ . This contradicts the generally accepted assumption that the attachment-line flow is stable for ${R_\mathrm{\ast }} \le 250$ . The theoretical critical Reynolds numbers lie well below the experimental transition-onset Reynolds numbers. Stability computations using the Navier–Stokes mean flow and accounting for the leading-edge curvature effect do not eliminate this discrepancy. Most likely, in the experiments of Gaillard et al., we face with an unknown effect that does not fit to the concept of transition arising from linear instability.

Introduction «I have never worked in the technocratic exaltation, solving a constructive problem and that’s it. I’ve always tried to interpret the space of human life» (Vittorio Garatti). Vittorio Garatti (Milan, April 6, 1927) is certainly one of the last witnesses of one “heroic” season of Italian architecture. In 1957 he graduated in architecture from the Polytechnic of Milan with a thesis proposing the redesign of a portion of the historic centre of Milan: the area between “piazza della Scala”, “via Broletto”, “via Filodrammatici” and the gardens of the former Olivetti building in via Clerici. These are the years in which Ernesto Nathan Rogers established himself as one of the main personalities of Milanese culture. Garatti endorses the criticism expressed by Rogers to the approval of the Rationalist “language” in favour of an architecture that recovers the implications of the place and of material culture. The social responsibility of architecture and connections between architecture and other forms of artistic expression are the invariants of all the activity of the architect, artist and graphic designer of Garatti. It will be Ernesto Nathan Rogers who will offer him the possibility of experiencing these “contaminations” early: in 1954, together with Giuliano Cesari, Raffaella Crespi, Giampiero Pallavicini and Ferruccio Rezzonico, he designs the preparation of the exhibition on musical instruments at the 10th Milan Triennale. The temporary installations will be a privileged area in which Garatti will continue to experiment and integrate the qualities of artist, graphic designer and architect with each other. Significant examples of this approach are the Art Schools in Cuba 1961-63, the residential complex of Cusano Milanino in 1973, the Attico Cosimo del Fante in 1980, the fittings for the Bubasty shops in 1984, the Camogli residence in 1986, his house atelier in Brera in 1988 and the interiors of the Hotel Gallia in 1989. True architecture generates itself1: an approach that was consolidated over the years of collaboration with Raúl Villanueva in Venezuela and is fulfilled in Cuba in the project of the Art Schools, where Garatti makes use of a plurality of tools that cannot be rigidly confined to the world of architecture. In 1957, in Caracas, he came into contact with Ricardo Porro and Roberto Gottardi. Ricardo Porro, who returned to Cuba in 1960, will be the one to involve Vittorio Garatti and Roberto Gottardi in the Escuelas Nacional de Arte project. The three young architects will be the protagonists of a happy season of the architecture of the Revolution, they will be crossed by that “revolutionary” energy that Ricardo Porro has defined as “magical realism”. As Garatti recalls: it was a special moment. We designed the Schools using a method developed in Venezuela. We started from an analysis of the context, understood not only as physical reality. We studied Cuban poets and painters. Wifredo Lam was a great reference. For example, Lezama Lima’s work is clearly recalled in the plan of the School of Ballet. We were pervaded by the spirit of the revolution. The contamination between knowledge and disciplines, the belief that architecture is a “parasitic” discipline are some of the themes at the centre of the conversation that follows, from which a working method that recognizes architecture as a “social transformation” task emerges, more precisely an art with a social purpose. Garatti often cites Porro’s definition of architecture: architecture is the poetic frame within which human life takes place. To Garatti architecture is a self-generating process, and as such it cannot find fulfilment within its disciplinary specificity: the disciplinary autonomy is a contradiction in terms. Architecture cannot be self-referencing, it generates itself precisely because it finds the sense of its social responsibility outside of itself. No concession to trends, to self-referencing, to the “objectification of architecture”, to its spectacularization. Garatti as Eupalino Valery shuns “mute architectures” and instead prefers singing architectures. A Dialogue of Luigi Alini with Vittorio Garatti Luigi Alini. Let’s start with some personal data. Vittorio Garatti. I was born in Milan on April 6, 1927. My friend Emilio Vedova told me that life could be considered as a sequence of encounters with people, places and facts. My sculptor grandfather played an important role in my life. I inherited the ability to perceive the dimensional quality of space, its plasticity, spatial vision from him. L.A. Your youth training took place in a dramatic phase of history of our country. Living in Milan during the war years must not have been easy. V.G. In October 1942 in Milan there was one of the most tragic bombings that the city has suffered. A bomb exploded in front of the Brera Academy, where the Dalmine offices were located. With a group of boys we went to the rooftops. We saw the city from above, with the roofs partially destroyed. I still carry this image inside me, it is part of that museum of memory that Luciano Semerani often talks about. This image probably resurfaced when I designed the ballet school. The idea of a promenade on the roofs to observe the landscape came from this. L.A. You joined the Faculty of Architecture at the Milan Polytechnic in May 1946-47. V.G. Milan and Italy were like in those years. The impact with the University was not positive, I was disappointed with the quality of the studies. L.A. You have had an intense relationship with the artists who gravitate around Brera, which you have always considered very important for your training. V.G. In 1948 I met Ilio Negri, a graphic designer. Also at Brera there was a group of artists (Morlotti, Chighine, Dova, Crippa) who frequented the Caffè Brera, known as “Bar della Titta”. Thanks to these visits I had the opportunity to broaden my knowledge. As you know, I maintain that there are life’s appointments and lightning strikes. The release of Dada magazine provided real enlightenment for me: I discovered the work of Kurt Schwitters, Theo Van Doesburg, the value of the image and three-dimensionality. L.A. You collaborated on several projects with Ilio Negri. V.G. In 1955 we created the graphics of the Lagostina brand, which was then also used for the preparation of the exhibition at the “Fiera Campionaria” in Milan. We also worked together for the Lerici steel industry. There was an extraordinary interaction with Ilio. L.A. The cultural influence of Ernesto Nathan Rogers was strong in the years you studied at the Milan Polytechnic. He influenced the cultural debate by establishing himself as one of the main personalities of the Milanese architectural scene through the activity of the BBPR studio but even more so through the direction of Domus (from ‘46 to ‘47) and Casabella Continuità (from ‘53 to ‘65). V.G. When I enrolled at the university he was not yet a full professor and he was very opposed. As you know, he coined the phrase: God created the architect, the devil created the colleague. In some ways it is a phrase that makes me rethink the words of Ernesto Che Guevara: beware of bureaucrats, because they can delay a revolution for 50 years. Rogers was the man of culture and the old “bureaucratic” apparatus feared that his entry into the University would sanction the end of their “domain”. L.A. In 1954, together with Giuliano Cesari, Raffella Crespi, Giampiero Pallavicini and Ferruccio Rezzonico, all graduating students of the Milan Polytechnic, you designed the staging of the exhibition on musical instruments at the 10th Milan Triennale. V.G. The project for the Exhibition of Musical Instruments at the Milan Triennale was commissioned by Rogers, with whom I subsequently collaborated for the preparation of the graphic part of the Castello Sforzesco Museum, together with Ilio Negri. We were given a very small budget for this project. We decided to prepare a sequence of horizontal planes hanging in a void. These tops also acted as spacers, preventing people from touching the tools. Among those exhibited there were some very valuable ones. We designed slender structures to be covered with rice paper. The solution pleased Rogers very much, who underlined the dialogue that was generated between the exhibited object and the display system. L.A. You graduated on March 14, 1957. V.G. The project theme that I developed for the thesis was the reconstruction of Piazza della Scala. While all the other classmates were doing “lecorbusierani” projects without paying much attention to the context, for my part I worked trying to have a vision of the city. I tried to bring out the specificities of that place with a vision that Ernesto Nathan Rogers had brought me to. I then found this vision of the city in the work of Giuseppe De Finetti. I tried to re-propose a vision of space and its “atmospheres”, a theme that Alberto Savinio also refers to in Listen to your heart city, from 1944. L.A. How was your work received by the thesis commission? V.G. It was judged too “formal” by Emiliano Gandolfi, but Piero Portaluppi did not express himself positively either. The project did not please. Also consider the cultural climate of the University of those years, everyone followed the international style of the CIAM. I was not very satisfied with the evaluation expressed by the commissioners, they said that the project was “Piranesian”, too baroque. The critique of culture rationalist was not appreciated. Only at IUAV was there any great cultural ferment thanks to Bruno Zevi. L.A. After graduation, you left for Venezuela. V.G. With my wife Wanda, in 1957 I joined my parents in Caracas. In Venezuela I got in touch with Paolo Gasparini, an extraordinary Italian photographer, Ricardo Porro and Roberto Gottardi, who came from Venice and had worked in Ernesto Nathan Rogers’ studio in Milan. Ricardo Porro worked in the office of Carlos Raúl Villanueva. The Cuban writer and literary critic Alejo Carpentier also lived in Caracas at that time. L.A. Carlos Raul Villanueva was one of the protagonists of Venezuelan architecture. His critical position in relation to the Modern Movement and the belief that it was necessary to find an “adaptation” to the specificities of local traditions, the characteristics of the places and the Venezuelan environment, I believe, marked your subsequent Cuban experience with the creative recovery of some elements of traditional architecture such as the portico, the patio, but also the use of traditional materials and technologies that you have masterfully reinterpreted. I think we can also add to these “themes” the connections between architecture and plastic arts. You also become a professor of Architectural Design at the Escuela de Arquitectura of the Central University of Caracas. V.G. On this academic experience I will tell you a statement by Porro that struck me very much: The important thing was not what I knew, I did not have sufficient knowledge and experience. What I could pass on to the students was above all a passion. In two years of teaching I was able to deepen, understand things better and understand how to pass them on to students. The Faculty of Architecture had recently been established and this I believe contributed to fuel the great enthusiasm that emerges from the words by Porro. Porro favoured mine and Gottardi’s entry as teachers. Keep in mind that in those years Villanueva was one of the most influential Venezuelan intellectuals and had played a leading role in the transformation of the University. Villanueva was very attentive to the involvement of art in architecture, just think of the magnificent project for the Universidad Central in Caracas, where he worked together with artists such as the sculptor Calder. I had recently graduated and found myself catapulted into academic activity. It was a strange feeling for a young architect who graduated with a minimum grade. At the University I was entrusted with the Architectural Design course. The relationships with the context, the recovery of some elements of tradition were at the centre of the interests developed with the students. Among these students I got to know the one who in the future became my chosen “brother”: Sergio Baroni. Together we designed all the services for the 23rd district that Carlos Raúl Villanueva had planned to solve the favelas problem. In these years of Venezuelan frequentation, Porro also opened the doors of Cuba to me. Through Porro I got to know the work of Josè Martì, who claimed: cult para eser libre. I also approached the work of Josè Lezama Lima, in my opinion one of the most interesting Cuban intellectuals, and the painting of Wilfredo Lam. L.A. In December 1959 the Revolution triumphed in Cuba. Ricardo Porro returned to Cuba in August 1960. You and Gottardi would join him in December and begin teaching at the Facultad de Arcuitectura. Your contribution to the training of young students took place in a moment of radical cultural change within which the task of designing the Schools was also inserted: the “new” architecture had to give concrete answers but also give “shape” to a new model of society. V.G. After the triumph of the Revolution, acts of terrorism began. At that time in the morning, I checked that they hadn’t placed a bomb under my car. Eisenhower was preparing the invasion. Life published an article on preparing for the invasion of the counterrevolutionary brigades. With Eisenhower dead, Kennedy activated the programme by imposing one condition: in conjunction with the invasion, the Cuban people would have to rise up. Shortly before the attempted invasion, the emigration, deemed temporary, of doctors, architects, university teachers etc. began. They were all convinced they would return to “liberated Cuba” a few weeks later. Their motto was: it is impossible for Americans to accept the triumph of the rebel army. As is well known, the Cuban people did not rise up. The revolutionary process continued and had no more obstacles. The fact that the bourgeois class and almost all the professionals had left Cuba put the country in a state of extreme weakness. The sensation was of great transformation taking place, it was evident. In that “revolutionary” push there was nothing celebratory. All available energies were invested in the culture. There were extraordinary initiatives, from the literacy campaign to the founding of international schools of medicine and of cinema. In Cuba it was decided to close schools for a year and to entrust elementary school children with the task of travelling around the country and teaching illiterate adults. In the morning they worked in the fields and in the evening they taught the peasants to read and write. In order to try to block this project, the counter-revolutionaries killed two children in an attempt to scare the population and the families of the literate children. There was a wave of popular indignation and the programme continued. L.A. Ricardo Porro was commissioned to design the Art Schools. Roberto Gottardi recalls that: «the wife of the Minister of Public Works, Selma Diaz, asked Porro to build the national art schools. The architecture had to be completely new and the schools, in Fidel’s words, the most beautiful in the world. All accomplished in six months. Take it or leave it! [...] it was days of rage and enthusiasm in which all areas of public life was run by an agile and imaginative spirit of warfare»2. You too remembered several times that: that architecture was born from a life experience, it incorporated enthusiasm for life and optimism for the future. V.G. The idea that generated them was to foster the cultural encounter between Africa, Asia and Latin America. A “place” for meeting and exchanging. A place where artists from all over the third world could interact freely. The realisation of the Schools was like receiving a “war assignment”. Fidel Castro and Ernesto Che Guevara selected the Country Club as the place to build a large training centre for all of Latin America. They understood that it was important to foster the Latin American union, a theme that Simón Bolivar had previously wanted to pursue. Il Ché and Fidel, returning from the Country Club, along the road leading to the centre of Havana, met Selma Diaz, architect and wife of Osmany Cienfuegos, the Cuban Construction Minister. Fidel Castro and Ernesto Che Guevara entrusted Selma Diaz with the task of designing this centre. She replied: I had just graduated, how could I deal with it? Then she adds: Riccardo Porro returned to Cuba with two Italian architects. Just think, three young architects without much experience catapulted into an assignment of this size. The choice of the place where to build the schools was a happy intuition of Fidel Castro and Ernesto Che Guevara. L.A. How did the confrontation develop? V.G. We had total freedom, but we had to respond to a functional programme defined with the heads of the schools. Five directors were appointed, one for each school. We initially thought of a citadel. A proposal that did not find acceptance among the Directors, who suggest thinking of five autonomous schools. We therefore decide to place the schools on the edge of the large park and to reuse all the pre-existing buildings. We imagined schools as “stations” to cross. The aim was to promote integration with the environment in which they were “immersed”. Schools are not closed spaces. We established, for example, that there would be no doors: when “everything was ours” there could not be a public and a private space, only the living space existed. L.A. Ricardo Porro recalled: I organised our study in the chapel of the former residence of the Serrà family in Vadado. It was a wonderful place [...]. A series of young people from the school of architecture came to help us […]. Working in that atmosphere, all night and all day was a poetic experience (Loomis , 1999). V.G. We felt like Renaissance architects. We walked around the park and discussed where to locate the schools. Imagine three young people discussing with total, unthinkable freedom. We decided that each of us would deal with one or more schools, within a global vision that was born from the comparison. I chose the Ballet School. Ivan Espin had to design the music school but in the end I did it because Ivan had health problems. Porro decided to take care of the School of Plastic Arts to support his nature as a sculptor. Gottardi had problems with the actors and directors, who could not produce a shared functional programme, which with the dancers was quite simple to produce. The reasons that led us to choose the different project themes were very simple and uncomplicated, as were those for identifying the areas. I liked hidden lands, I was interested in developing a building “embedded” in the ground. Ricardo, on the other hand, chose a hill on which arrange the school of Modern Art. Each of us chose the site almost instinctively. For the Classical Dance School, the functional programme that was provided to me was very meagre: a library, a deanery, an infirmary, three ballet classrooms, theoretical classrooms and one of choreography. We went to see the dancers while they were training and dancing with Porro. The perception was immediate that we had to think of concave and convex spaces that would welcome their movements in space. For a more organic integration with the landscape and to accommodate the orography of the area, we also decided to place the buildings in a “peripheral” position with respect to the park, a choice that allowed us not to alter the nature of the park too much but also to limit the distances to be covered from schools to homes. Selma Diaz added others to the first indications: remember that we have no iron, we have little of everything, but we have many bricks. These were the indications that came to us from the Ministry of Construction. We were also asked to design some large spaces, such as gyms. Consequently, we found ourselves faced with the need to cover large spans without being able to resort to an extensive use of reinforced concrete or wood. L.A. How was the comparison between you designers? V.G. The exchange of ideas was constant, the experiences flowed naturally from one work group to another, but each operated in total autonomy. Each design group had 5-6 students in it. In my case I was lucky enough to have Josè Mosquera among my collaborators, a brilliant modest student, a true revolutionary. The offices where we worked on the project were organised in the Club, which became our “headquarters”. We worked all night and in the morning we went to the construction site. For the solution of logistical problems and the management of the building site of the Ballet School, I was entrusted with an extraordinary bricklayer, a Maestro de Obra named Bacallao. During one of the meetings that took place daily at the construction site, Bacallao told me that in Batista’s time the architects arrived in the morning at the workplace all dressed in white and, keeping away from the construction site to avoid getting dusty, they transferred orders on what to do. In this description by we marvelled at the fact that we were in the construction site together with him to face and discuss how to solve the different problems. In this construction site the carpenters did an extraordinary job, they had considerable experience. Bacallao was fantastic, he could read the drawings and he managed the construction site in an impeccable way. We faced and solved problems and needs that the yard inevitably posed on a daily basis. One morning, for example, arriving at the construction site, I realised the impact that the building would have as a result of its total mono-materiality. I was “scared” by this effect. My eye fell on an old bathtub, inside which there were pieces of 10x10 tiles, then I said to Bacallao: we will cover the wedges between the ribs of the bovedas covering the Ballet and Choreography Theatre classrooms with the tiles. The yard also lived on decisions made directly on site. Also keep in mind that the mason teams assigned to each construction site were independent. However the experience between the groups of masons engaged in the different activities circulated, flowed. There was a constant confrontation. For the workers the involvement was total, they were building for their children. A worker who told me: I’m building the school where my son will come to study. Ricardo Porro was responsible for the whole project, he was a very cultured man. In the start-up phase of the project he took us to Trinidad, the old Spanish capital. He wanted to show us the roots of Cuban architectural culture. On this journey I was struck by the solution of fan windows, by the use of verandas, all passive devices which were entrusted with the control and optimisation of the comfort of the rooms. Porro accompanied us to those places precisely because he wanted to put the value of tradition at the centre of the discussion, he immersed us in colonial culture. L.A. It is to that “mechanism” of self-generation of the project that you have referred to on several occasions? V.G. Yes, just that. When I design, I certainly draw from that stratified “grammar of memory”, to quote Luciano Semerani, which lives within me. The project generates itself, is born and then begins to live a life of its own. A writer traces the profile and character of his characters, who gradually come to life with a life of their own. In the same way the creative process in architecture is self-generated. L.A. Some problems were solved directly on site, dialoguing with the workers. V.G. He went just like that. Many decisions were made on site as construction progressed. Design and construction proceeded contextually. The dialogue with the workers was fundamental. The creative act was self-generated and lived a life of its own, we did nothing but “accompany” a process. The construction site had a speed of execution that required the same planning speed. In the evening we worked to solve problems that the construction site posed. The drawings “aged” rapidly with respect to the speed of decisions and the progress of the work. The incredible thing about this experience is that three architects with different backgrounds come to a “unitary” project. All this was possible because we used the same materials, the same construction technique, but even more so because there was a similar interpretation of the place and its possibilities. L.A. The project of the Music School also included the construction of 96 cubicles, individual study rooms, a theatre for symphonic music and one for chamber music and Italian opera. You “articulated” the 96 cubicles along a 360-metre-long path that unfolds in the landscape providing a “dynamic” view to those who cross it. A choice consistent with the vision of the School as an open place integrated with the environment. V.G. The “Gusano” is a volume that follows the orography of the terrain. It was a common sense choice. By following the level lines I avoided digging and of course I quickly realized what was needed by distributing the volumes horizontally. Disarticulation allows the changing vision of the landscape, which changes continuously according to the movement of the user. The movements do not take place along an axis, they follow a sinuous route, a connecting path between trees and nature. The cubicles lined up along the Gusano are individual study rooms above which there are the collective test rooms. On the back of the Gusano, in the highest part of the land, I placed the theatre for symphonic music, the one for chamber music, the library, the conference rooms, the choir and administration. L.A. In 1962 the construction site stopped. V.G. In 1962 Cuba fell into a serious political and economic crisis, which is what caused the slowdown and then the abandonment of the school site. Cuba was at “war” and the country’s resources were directed towards other needs. In this affair, the architect Quintana, one of the most powerful officials in Cuba, who had always expressed his opposition to the project, contributed to the decision to suspend the construction of the schools. Here is an extract from a writing by Sergio Baroni, which I consider clarifying: «The denial of the Art Schools represented the consolidation of the new Cuban technocratic regime. The designers were accused of aristocracy and individualism and the rest of the technicians who collaborated on the project were transferred to other positions by the Ministry of Construction [...]. It was a serious mistake which one realises now, when it became evident that, with the Schools, a process of renewal of Cuban architecture was interrupted, which, with difficulty, had advanced from the years preceding the revolution and which they had extraordinarily accelerated and anchored to the new social project. On the other hand, and understandably, the adoption of easy pseudo-rationalist procedures prevailed to deal with the enormous demand for projects and constructions with the minimum of resources» (Baroni 1992). L.A. You also experienced dramatic moments in Cuba. I’m referring in particular to the insane accusation of being a CIA spy and your arrest. V.G. I wasn’t the only one arrested. The first was Jean Pierre Garnier, who remained in prison for seven days on charges of espionage. This was not a crazy accusation but one of the CIA’s plans to scare foreign technicians into leaving Cuba. Six months after Garnier, it was Heberto Padilla’s turn, an intellectual, who remained in prison for 15 days. After 6 months, it was my turn. I was arrested while leaving the Ministry of Construction, inside the bag I had the plans of the port. I told Corrieri, Baroni and Wanda not to notify the Italian Embassy, everything would be cleared up. L.A. Dear Vittorio, I thank you for the willingness and generosity with which you shared your human and professional experience. I am sure that many young students will find your “story” of great interest. V.G. At the end of our dialogue, I would like to remember my teacher: Ernesto Nathan Rogers. I’ll tell you an anecdote: in 1956 I was working on the graphics for the Castello Sforzesco Museum set up by the BBPR. Leaving the museum with Rogers, in the Rocchetta courtyard the master stopped and gives me a questioning look. Looking at the Filarete tower, he told me: we have the task of designing a skyscraper in the centre. Usually skyscrapers going up they shrink. Instead this tower has a protruding crown, maybe we too could finish our skyscraper so what do you think? I replied: beautiful! Later I thought that what Rogers evoked was a distinctive feature of our city. The characters of the cities and the masters who have consolidated them are to be respected. If there is no awareness of dialectical continuity, the city loses and gets lost. It is necessary to reconstruct the figure of the architect artist who has full awareness of his role in society. The work of architecture cannot be the result of a pure stylistic and functional choice, it must be the result of a method that takes various and multiple factors into analysis. In Cuba, for example, the musical tradition, the painting of Wilfredo Lam, whose pictorial lines are recognisable in the floor plan of the Ballet School, the literature of Lezama Lima and Alejo Carpentier and above all the Cuban Revolution were fundamental. We theorised this “total” method together with Ricardo Porro, remembering the lecture by Ernesto Nathan Rogers.