Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "transactions" wg kryterium: Wszystkie pola

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 134
Tytuł:
Airfoil Tonal Noise Prediction Using Urans
Autorzy:
Klimczyk, Witold
Sieradzki, Adam
Powiązania:
https://bibliotekanauki.pl/articles/36829323.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
airfoil tonal noise
aeroacoustics
CFD
Opis:
To examine the feasibility of the laminar boundary layer (LBL), vortex shedding (VS) tonal noise modelling using unsteady Reynolds-averaged Navier-Stokes (URANS) was investigated for the non-symmetric S834 airfoil. A transition SST turbulence model was used to model the laminar-turbulent transition and its vital influence on the laminar bubble and hydrodynamic instabilities generation. The influence of turbulence on the unsteady vortex patterns was investigated. Hence, the hybrid aeroacoustic analysis with Lighthill analogy was conducted to obtain the acoustic pressure field. The approach allowed us to model hydrodynamic instabilities and the resulting VS tonal noise. The frequency of VS matched the experimental data, giving the same 1/3 octave tonal peak only for a limited freestream turbulence regime. The simplification of the present method did not allow us to model the aeroacoustic feedback loop, and resulted in lack of instabilities for higher freestream turbulence.
Źródło:
Transactions on Aerospace Research; 2023, 4 (273); 1-17
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vibroacoustic Helicopter Impact on Elevated Helipad
Autorzy:
Cieślak, Sławomir
Krzymień, Wiesław
Powiązania:
https://bibliotekanauki.pl/articles/36809460.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
mechanical engineering
helipad
helicopter
noise
vibrations
impact
Opis:
A helicopter landing and taking off on an elevated helipad is a source of noise that affects the environment and causes vibrations of the landing pad or the building infrastructure. Vibrations are also excited by the air stream flowing through the main rotor and transferred to the landing pad by contact of the helicopter chassis. Vibrations are transferred to the building through the structure of the helipad. Depending on the damping properties of the structure and the vibro-isolating elements used, vibrations can be felt in rooms used by people and also transmitted to devices located in the building. The subject of the study described in this paper is the vibroacoustic effects of an EC-135 helicopter on an elevated landing pad during landing, standstill with the propulsion system engaged and take-off. Measurements of vibrations and noise were made at points located both on the landing pad and in the building. The paper presents selected results of measurements in various phases of flight and helicopter manoeuvres. The frequency analyses of the fragment of the measurement data for the flight phase, in which the highest levels of impact were recorded, were also performed and included. The results are presented as graphs and annotated.
Źródło:
Transactions on Aerospace Research; 2023, 1 (270); 1-9
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bionics in aviation
Bionika w lotnictwie
Autorzy:
Skalski, P.
Powiązania:
https://bibliotekanauki.pl/articles/36389475.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
bionics
aviation
butterfly wing
bionika
lotnictwo
skrzydło motyla
Opis:
In the paper bionics as a field of knowledge and inspiration in the aviation technologies is presented. Bionics is a branch of science on the borderline of art and biology that studies the way living organisms work, as well as their structure, in order to use the results to build technical devices. In the introduction part definition of bionics is described. In the next part of this document the aviation technologies inspired by nature is depicted. Then, technologies inspired by the butterfly wing are presented. The paper ends with conclusions.
W niniejszej publikacji bionika jest przedstawiona jako obszar wiedzy i inspiracji w technologiach lotniczych. Bionika jest dziedziną nauki na pograniczu sztuki i biologii, która bada funkcjonowanie żywych organizmów, a także ich budowę, w celu wykorzystania uzyskanych wyników do budowy urządzeń technicznych. We wprowadzeniu została opisana definicja bioniki. W kolejnej części pracy omówiono technologie lotnicze inspirowane naturą. Następnie, są zaprezentowane technologie inspirowane skrzydłem motyla. Praca kończy się podsumowaniem.
Źródło:
Transactions on Aerospace Research; 2018, 3 (252); 99-108
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultralight and Very Light Helicopter Rotor Data
Autorzy:
Dudnik, Vitaly
Karabut, Victor
Powiązania:
https://bibliotekanauki.pl/articles/36818712.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
ultralight helicopter
main rotor
blade
preliminary design
Opis:
In recent years, a significant number of one- and two-seat lightweight helicopters have come into existence, and this makes it possible to analyse parameters and determine dependencies for this class of helicopters. The knowledge of such dependencies is necessary at the preliminary design stage. The analysis performed in this paper and its comparison with the statistical data of all categories of helicopters made it possible to determine the necessary corrections in the methods of determining the parameters of the helicopter’s rotor systems.
Źródło:
Transactions on Aerospace Research; 2023, 2 (271); 17-24
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Performance of quiet helicopter
Osiągi cichego śmigłowca
Autorzy:
Stanisławski, Jarosław
Powiązania:
https://bibliotekanauki.pl/articles/36412016.pdf
Data publikacji:
2020
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
helicopter
noise
rotor loads
śmigłowiec
hałas
obciążenia wirnika
Opis:
Noise generated by helicopters is one of the main problems associated with the operation of rotorcrafts. Requirements for reduction of helicopter noise were reflected in the regulations introducing lower limits of acceptable rotorcraft noise. A significant source of noise generated by helicopters are the main rotor and tail rotor blades. Radical noise reduction can be obtained by slowing down the blade tips speed of main and tail rotors. Reducing the rotational speed of the blades may decrease rotor thrust and diminish helicopter performance. The problem can be solved by attaching more blades to main rotor. The paper presents results of calculation regarding improvement of the helicopter performance which can be achieved for reduced rotor speed but with increased number of rotor blades. The calculations were performed for data of hypothetical light helicopter. Results of simulation include rotor loads and blade deformations in chosen flight conditions. Equations of motion of flexible rotor blades were solved using the Galerkin method which takes into account selected eigen modes of the blades. The simulation analyzes can help to determine the performance and loads of a quiet helicopter with reduced rotor speed within the operational envelope of helicopter flight states.
Hałas generowany przez śmigłowce jest jednym z głównych problemów związanych z eksploatacją wiropłatów. Wymagania ograniczenia hałasu śmigłowców znalazły odzwierciedlenie w przepisach zakładających zmniejszenie hałasu wytwarzanego przez wiropłaty. Znaczącym źródłem hałasu generowanego przez śmigłowce są łopaty wirnika nośnego oraz śmigła ogonowego. Znaczące obniżenie hałasu może być uzyskane w wyniku zmniejszenia prędkości końcówek łopat wirnika i śmigła ogonowego. Zmniejszenie prędkości obrotowej łopat pociąga za sobą spadek wytwarzanego ciągu wirnika i zmniejszenie osiągów śmigłowca. Rozwiązaniem problemu może być zastosowanie większej liczby łopat wirnika. W pracy przedstawiono obliczeniowe wyniki dotyczące możliwych do uzyskania osiągów śmigłowca przy obniżonej prędkości obrotowej wirnika i zwiększonej liczbie łopat. Obliczenia przeprowadzono dla danych masowych hipotetycznego śmigłowca lekkiego. Wykonano symulacyjne obliczenia obciążeń wirnika i odkształceń łopat w kilku stanach lotu śmigłowca rozwiązując równania ruchu elastycznych łopat wirnika z zastosowaniem metody Galerkina przy uwzględnieniu wybranych postaci własnych łopat. Uwzględniono możliwość regulacji obrotów wirnika w zależności od stanu lotu. Przeprowadzone analizy mogą znaleźć zastosowanie przy określaniu parametrów wirnika cichego śmigłowca ze zmniejszoną prędkością wirnika dla obwiedni stanów lotu śmigłowca.
Źródło:
Transactions on Aerospace Research; 2020, 1 (258); 1-17
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Easy Risk Assessment for Unmanned Aircraft Systems: Outline of the Method
Autorzy:
Wyszywacz, Wiktor
Powiązania:
https://bibliotekanauki.pl/articles/36783950.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
easy risk assessment
UAS
safety
threats
risk analysis
Opis:
The key element of safety systems in air transport is risk management. The rules for the safety of unmanned aircraft system (UAS) operations are established by the Commission Implementing Regulations (European Union [EU]) and national regulations. Risk assessment is the foundation of all activities. The broadest scope is covered by the special category of flights for which the Joint Authorities for rulemaking on Unmanned Systems (JARUS) developed the Specific Operations Risk Assessment (SORA) analysis. The primary purpose of the SORA analysis is to create a comprehensive safety portfolio, which is attached to the National Aviation Authority (NAA) application for permission to perform specific category flights. Aviation authorities may accept the use of other risk analysis methods to demonstrate risk reduced to a safe level. Easy Risk Assessment (ERA) for UASs is an attempt to determine the risk for UAS flights in a simple way by considering a range of factors influencing risk management in a similar way to the SORA. It is an uncomplicated method, which determines threats and their sources, provides risk management, and allows the determination of the level of risk tolerance. The ERA is intended to be an alternative to the SORA methodology for those looking to carry out risk assessment.
Źródło:
Transactions on Aerospace Research; 2022, 3 (268); 32-47
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnostic model of aircraft turbine engine governor pump
Autorzy:
Ohanian, Ihor
Yepifanov, Sergiy
Powiązania:
https://bibliotekanauki.pl/articles/36455739.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
aircraft turbine engine
hydromechanical governor
governor pump
diagnostics
model
influence coefficients
Opis:
This paper presents a mathematical model for a hydromechanical fuel governor pump, to be used in parametric diagnostics. The design and operation of the governor are described. The main requirements of the model are formulated, its structure is determined, corresponding to the specifics of the diagnostic task, and assumptions to make the model simpler are presented (single-dimensional flow and absence of heat exchange). The presented model consists of idealized elements with lumped parameters (such as pressure and mass consumption of the working fluid), accounting for the compressibility of the substance and the design arrangement of the governor (presence of mechanical rests, metering orifices of complex shapes, relay switchers, etc.). Equations of elements with lumped parameters, linked by hydraulic channels in one node, are presented. The model - a system of first-order differential-algebraic equations - is solved and the parameters of the governor pump are determined for different steady-state and transient operation modes. We compare our results to the requirements for the corresponding parameters outlined in the Engineering Specifications. The model is matched to the specifications by correcting setting parameters (tightening of elastic springs, areas of throttles, etc.), and a method of initial model linearization is developed. Based on the results, we conclude that our model can be used as a diagnostic algorithm for a governor pump, at the testing and development stages, during manufacturing, repair and maintenance.
Źródło:
Transactions on Aerospace Research; 2022, 2 (267); 80-95
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Issues in Designing of Mechanical Parts Models in CAD Programs
Autorzy:
Grygorcewicz, Paweł
Raczko, Konrad
Powiązania:
https://bibliotekanauki.pl/articles/36815516.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
designing
design
model 3D
mechanical parts
lever
support
Opis:
The article describes methods of creating mechanical parts in 3D programs, together with presenting very significant issues that emerge during the designing process employed in this creation, the main goal being to show the most important factors playing a role in the design process. Resultantly, it is ascertained that the most important factors needing to be considered by a designer are, inter alia, mass of the parts, strength, and kind of material. The article indicates the different types of parts used in different load cases, the objective being to explain various aspects relevant to design. The parts were different in particular in their nature of work and purpose. The article also presents illustrations after finite element method (FEM) analysis. It was important and interesting to observe how the stress in the tested parts was distributed under load and how the structure changed when the used material changed. The stress had a very large influence for the design of every airplane part; a case in point would be the illustration available from the lever example. The main role of this article is to describe different designing factors that could help a specialist create new designs in the future.
Źródło:
Transactions on Aerospace Research; 2023, 2 (271); 33-44
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electricity Storage in Energy Clusters
Magazynowanie energii elektrycznej w klastrach
Autorzy:
Kunikowski, G.
Powiązania:
https://bibliotekanauki.pl/articles/36391932.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
energy clusters
electricity storage
microgrid
klastry energetyczne
magazynowanie energii
mikrosieci
Opis:
The article aims to present the results of analysis and evaluation of using energy clusters as a bulk electricity storage. There were developed an analytical model of a sample microgrid (on-grid) and analysed using a software dedicated for optimizing such microgrids. The model of microgrid consist on electricity commercial and residential loads, photovoltaic and wind installations and batteries.
Celem artykułu jest przedstawienie wyników analizy i oceny wykorzystania klastrów energetycznych jako magazynu energii elektrycznej. Wykorzystując oprogramowanie do optymalizacji mikrosieci opracowano i poddano analizie przykładowy model mikrosieci współpracującej z siecią elektroenergetyczną. W modelu wykorzystano profile zużycia energii odbiorców przemysłowych i indywidualnych, instalacji fotowoltaicznych i wiatrowych oraz akumulatorów energii elektrycznej.
Źródło:
Transactions on Aerospace Research; 2018, 4 (253); 33-47
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical Models and Computer Simulations of Aerial Spraying and Droplets Distribution in a Target Site
Autorzy:
Rowiński, Robert S.
Powiązania:
https://bibliotekanauki.pl/articles/36406214.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
agricultural aviation
aerial spraying
drift
Opis:
Mathematical models describing aerial spraying and the distribution of liquid droplets on a target were presented. Relationships based on “free models” with Gaussian distribution of droplet concentrations and “bound models” that account for the impact of disturbances in the velocity field behind agricultural aircraft were expanded, and the hybrid model too. The results of experimental studies were presented and compared with theoretical calculations. The “bound model” was found to be the most effective solution for describing the physical phenomena that accompany the aerial spraying process.
Źródło:
Transactions on Aerospace Research; 2019, 3 (256); 24-42
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of the Airline Business Macroeconomics Dynamics Models
Autorzy:
Kasianov, Vladimir
Goncharenko, Andriy
Powiązania:
https://bibliotekanauki.pl/articles/36819387.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
aviation transportation
operational effectiveness
objective functional optimisation
simplest macroeconomic problem
entropy
Opis:
This paper proposes a solution to a certain macroeconomic model. A multi-alternative problem of aviation transportation optimal organisation in conditions of uncertainty of the subjective preference functions is considered. Conditional optimisation of the objective functional containing the entropy of the individuals’ operational effectiveness functions preferences is carried out in the framework of the simplest macroeconomic problem. The principle of the Solow and Cobb-Douglas models, likewise for economic growth, is modified with the Subjective Entropy Maximum Principle. The advantages of the described optimisation approach are demonstrated in generalised terms of the operational effectiveness functions for aviation transportation organisation.
Źródło:
Transactions on Aerospace Research; 2023, 2 (271); 25-32
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rotorcraft in the performance based navigation international civil aviation organization implementation
Autorzy:
Fellner, Andrzej
Konieczka, Robert
Powiązania:
https://bibliotekanauki.pl/articles/36399661.pdf
Data publikacji:
2019
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
PBN
ATM
integrity
accuracy
continuity
availability
integralność
precyzja
ciągłość
dostępność
Opis:
European Commision adopted in July new regulations about laying down airspace usage requirements and operating procedures concerning performance based navigation. It is next step in realization of the the global program PBN ICAO. At the 36th General Assembly of ICAO held in 2007, the Republic of Poland agreed to ICAO resolution A36-23 which urges all States to implement PBN. In future aviation concepts the use of Performance Based Navigation (PBN) is considered to be a major Air Traffic Management (ATM) concept element. ICAO has drafted standards and implementation guidance for PBN in the ICAO Doc 9613 “PBN Manual”. The Based Performance Navigation Concept represents and shift from sensor-based to performance based navigation connected with criteria for navigation: accuracy, integrity, availability, continuity and functionality depending on the phase of the flight. Through PBN and changes in the communication, surveillance and ATM domain, many advanced navigation applications are possible to improve airspace efficiency, improve airport sustainability, reduce the environmental impact of air transport in terms of noise and emission, increase safety and improve flight efficiency.
Źródło:
Transactions on Aerospace Research; 2019, 1 (254); 53-64
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Efficient Positioning of Two Long-Range Passenger Aircraft in Formation Flight
Autorzy:
Antczak, Adam
Lasek, Maciej
Sibilski, Krzysztof
Powiązania:
https://bibliotekanauki.pl/articles/36782619.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
formation flight
optimisation
strip theory
dynamics of flight
Opis:
In today’s world, each airline is forced to look for new savings opportunities. One of the methods may be the use of formation flights in daily flight operations, which may allow a reduction in fuel consumption by several percentages. The paper presents the genesis of how the consideration of such flights and the possibility of their implementation in an airline had started. The leader’s plane generates vortices, which, with the proper alignment of the planes to one another, can reduce the drag on the wingman. However, the wrong position may not only have no positive effect but also may be a threat to stable wingman flight. The article presents a method of using these vortices in such a way as to have a positive impact on the aerodynamics of the wingman. A favourable position in the vertical and horizontal axes will be determined in relation to the vortex generated by the leader’s plane in order to obtain the greatest benefit in reducing fuel consumption. The paper presents an operational analysis of the possibility of maintaining such a distance to obtain profit on fuel but also to ensure the highest level of safety of the flight.
Źródło:
Transactions on Aerospace Research; 2022, 3 (268); 21-31
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Science, Technology and Systems Engineering Educational Activities with Stratospheric Balloons
Autorzy:
Marcuccio, Salvo
Gemignani, Matteo
Cataldi, Giuseppe
Powiązania:
https://bibliotekanauki.pl/articles/36784548.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
high-altitude ballooning
stratospheric platform
student experiment
sounding balloon
Opis:
In 2021, the Space Systems Laboratory of the University of Pisa (UniPi) started a student-oriented high-altitude ballooning programme intended to provide an opportunity for hands-on experience in support of the teaching of scientific and technical courses. The programme provides mentoring on scientific, technical and management issues, along with financial support and assistance with integration and launch on a sounding balloon platform. The goal is to conduct flying experiments in the stratosphere, retrieve them after landing and process the results; by doing so, the students experience all phases of a scientific mission project, from conceptual design to realisation, operations and post-flight analysis. Following a call for proposal open to all students of the UniPi across all study areas, three experiments were selected featuring multidisciplinary teams. This paper summarises the features of the programme’s first edition and presents the main lessons learned.
Źródło:
Transactions on Aerospace Research; 2022, 4 (269); 18-27
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cavitating Venturi as a Mass Flow Controller in a Deep Throttling Liquid Rocket Engine
Autorzy:
Sekrecki, Michał
Powiązania:
https://bibliotekanauki.pl/articles/36825330.pdf
Data publikacji:
2023
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
cavitating venturi
throttling
regulatory valve
HTP
ethanol
green propulsion
Opis:
The most common solutions for rocket engines are the single operation point (thrust level) units. Oxidiser and fuel mass flow rates and the oxidiser-to-fuel mass flow rate ratio (OFR) are some of the determinants of the thrust level. Based on these, planetary ascent and descent; space rendezvous; orbital manoeuvring, including orientation and stabilisation in space; hovering, hazard avoidance during planetary landing; and ballistic missile trajectory control propulsion systems could use throttleable liquid engines. Several engine throttling methods, such as supply pressure variation and variable injector area, can be applied. Among others, a cavitating venturi propellant regulatory valve is one of the most promising throttling method. This type of valve can provide steady mass flow, despite the downstream pressure disturbance (i.e. from the combustion chamber), which sustains a stable engine thrust as the mass flow is kept. The article presents the valve sizing method, design and prototype test results of the cavitating venturi valve that has potential for utilisation in a deep throttling rocket engine. Mass flow stability and repeatability are presented for valve operating points in the 10%-110% nominal mass flow range. Valve design optimisation, based on CFD, to sustain cavitation for a higher downstream-to-upstream pressure ratio is shown.
Źródło:
Transactions on Aerospace Research; 2023, 3 (272); 72-86
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 134

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies