Poligonų ir aplinkinių miškų medžių pažeidimų kulkomis ir skeveldromis tyrimas

Poligonuose dalis šovinių ir sprogmenų skeveldrų perskrenda apsauginius pylimus, kelia grėsmę saugumui, bei gadina ir žaloja vertingus išteklius. Darbe matematiniais metodais atlikta Kairių poligono aplinkinių miškų medžių pažeidimų kulkomis ir skeveldromis analizė. Pateiktos matematinės formulės kulkos nukrypimo nuotoliui nuo taikymo centro tikimybėms apskaičiuoti, saugaus pylimo aukščiui nustatyti, zonų, kuriose kulkų skridimo greitis gali būti pavojingas, pasiskirstymo modeliavime.Trees surrounding a training ground are damaged by bullets during shooting practice. A part of splinters of cartridges and explosives fly over the protective ramparts, thus causing a threat for safety and damaging trees of surrounding forests deteriorating the valuable resources. In the paper, an analysis of damage caused by bullets and splinters to trees of forests surrounding Kairiai training ground is carried out by applying mathematical methods. The mathematical formulas for calculation of the probabilities of the distance of deviation of a bullet from the center of the target, for identification of the safe height of the rampart and simulation of distribution of the zones where the speed of shot bullets can be dangerous for humans are provided. &nbsp

The influence of the cetane number and lubricity improving additives on the quality parameters of aviation-turbine fuel

In order to recommend jet fuel for powering diesel engines the quality parameters of the following fuels were determined: diesel fuel (NATO code F-54) according to standard LST EN 590: 2014, jet fuel (NATO code F-35 and F-34) according to standard ASTM D 1655 and U.S.MIL-DTL-83133E, and jet fuel was treated with additives at the Centre of Quality research laboratory located at “ORLEN Lietuva” Ltd. Basic quality parameters of alternative jet fuels were analysed and compared with the reference parameters of diesel fuel. It was determined that the use of additives in jet fuel improves its parameters up to a level which satisfies the corresponding characteristics of normal diesel fuel: cetane number, lubricating properties, net heating value per unit of mass, sulphur content and, therefore, can be recommended for the use in land-based transport means and power generators

Evaluation of noise around military installations / Triukšmo karinėse teritorijose įvertinimas

Noise is one of the most common adverse environmental factors. Military bases and airports and the areas surrounding them are affected by acoustic impact. The problem of military noise is researched in this article. Since 2004 Šiauliai Airport has been the site of NATO forces’ base in the Baltic States for the protection of the region's airspace. Military aircraft are used for the mission. The Kairiai military grounds on the Curonian Lagoon is the only site in Lithuania where all kinds of military forces may arrange their training. Measurement of the level of noise caused by Šiauliai Airport in residential and public areas of the surrounding areas and by the Kairiai military grounds was carried out using a Nor121 digital sound analyser. It was found that the maximum noise level (Lmax) in the surroundings of Šiauliai Airport sometimes exceeds the permissible maximum noise level specified in HN 33:2007. Exceeding of Lmax on aircraft flights was short (up to 5 minutes). The calculated level of noise Lden and Lnight at all points of measurement within the territories surrounding Šiauliai Airport does not exceed the limit values and causes no damage to the health of the population in Šiauliai. The noise generated by shooting at Kairiai military grounds causes no damage to the health of residents. Santrauka Vienas iš plačiausiai paplitusių kenksmingų aplinkos veiksnių yra triukšmas. Akustinį poveikį patiria karinių poligonų ir aerodromų aplinka. Šiame straipsnyje nagrinėjama karinio triukšmo problema. Nuo 2004 m. Šiaulių oro uostas tapo Baltijos šalių NATO pajėgų dislokacijos vieta, iš kurios vykdoma Baltijos šalių oro apsauga. Šiai apsaugai atlikti naudojami kariniai lėktuvai. Prie Kuršių marių įsikūręs Kairių poligonas yra vienintelis Lietuvoje, kuriame gali treniruotis visų rūšių karinės pajėgos. Šiaulių oro uosto triukšmo matavimai aplinkinių teritorijų gyvenamojoje ir viešosios paskirties aplinkoje bei Kairių poligone atlikti skaitmeniniu garso analizatoriumi Nr. 121. Nustatyta, kad maksimalus triukšmo lygis (L max) Šiaulių oro uosto aplinkoje kartais viršija leistinąjį maksimalų triukšmo lygį pagal HN 33:2007. L max viršijimai, siejami su orlaivių skrydžiais, buvo trumpalaikiai (iki 5 min.). Apskaičiuoti dienos, vakaro, nakties triukšmo lygis L dvn ir nakties triukšmo rodiklis L nakties neviršija ribinių triukšmo dydžių, Šiaulių miesto gyventojų sveikatai grėsmės nekelia. Kairių poligone šaudymo pratybų keliamas triukšmas gyventojų sveikatai grėsmės nekelia. First published online: 22 May 2011 Reikšminiai žodžiai: triukšmo lygis, lauko pratybos, karinės teritorijos, poveikis aplinka

The influence of the cetane number and lubricity improving additives on the quality parameters of aviation-turbine fuel

Elektroninė forma: eISSN 1822-4180In order to recommend jet fuel for powering diesel engines the quality parameters of the following fuels were determined: diesel fuel (NATO code F-54) according to standard LST EN 590: 2014, jet fuel (NATO code F-35 and F-34) according to standard ASTM D 1655 and U.S.MIL-DTL-83133E, and jet fuel was treated with additives at the Centre of Quality research laboratory located at “ORLEN Lietuva” Ltd. Basic quality parameters of alternative jet fuels were analysed and compared with the reference parameters of diesel fuel. It was determined that the use of additives in jet fuel improves its parameters up to a level which satisfies the corresponding characteristics of normal diesel fuel: cetane number, lubricating properties, net heating value per unit of mass, sulphur content and, therefore, can be recommended for the use in land-based transport means and power generatorsGenerolo Jono Žemaičio Lietuvos karo akademijaVytauto Didžiojo universitetasŽemės ūkio akademij

Alternatyvių degalų panaudojimas dyzeliniame variklyje

Generolo Jono Žemaičio Lietuvos karo akademijoje Inžinerinės vadybos katedroje vykdomas mokslo projektas „Aviacinio ir kito alternatyvaus kuro panaudojimo galimybių Lietuvos kariuomenės sausumos transporto priemonėse tyrimas“ kartu su Aleksandro Stulginskio universiteto Transporto ir jėgos mašinų instituto mokslininkais. Siekiant dyzeliniuose varikliuose panaudoti reaktyvinius degalus AB „ORLEN Lietuva“ Kokybės tyrimų centro laboratorijoje buvo nustatomi degalų: dyzelino (NATO kodas F-54) pagal LST EN 590, reaktyvinių degalų (NATO kodas F-35 ir F-34) pagal ASTM-D1655 ir U.S.MIL-DTL-83133E bei reaktyvinių degalų su priedais kokybės rodikliai. Išanalizavus ir palyginus pagrindinius degalų kokybės rodiklius nustatyta, kad reaktyviniai degalai su priedais atitinka dyzelinių degalų technines charakteristikas: cetaninį skaičių, tepimo savybes, šiluminę vertę masės vienetui, sieros koncentraciją ir gali būti naudojami sausumos transporteAt Department of Engineering management of The General Jonas Žemaitis Military Academy of Lithuania scientific project „The research on possibilities of using aviation and other alternative fuels in ground transport means of Lithuanian army“ together with the scientists of Power and transport machinery engineering institute of Aleksandras Stulginskis university was perfomed. In order to recommend the jet fuel for diesel enginess powering in the Centre of quality research laboratory located at Ltd. Company „ORLEN Lietuva“ the quality parameters of fuels were determined: diesel fuel (NATO code F-54) according standard LST EN 590, jet fuel (NATO code F-35 and F-34) according standard ASTM-D 1655 and U.S.MIL-DTL-83133E and the jet fuel treated with additives. Basic quality parameters of alternative jet fuels tested were analyzed and compared with baseline diesel fuel parameters. It was determined that the use of additives the jet fuel parameters improves up to the level, which satisfies corresponding characteristics of the normal diesel fuel: cetane number, lubricating properties, net heating value per unit of mass, sulphur concentration and thus can be used in ground transport vehiclesVytauto Didžiojo universitetasŽemės ūkio akademij

Reaktyvinių degalų panaudojimas dyzeliniame variklyje

Straipsnyje pateikiama normaliais 95vol% (klasė C) dyzeliniais degalais + 5 vol) RME (DF), reaktyviniais F-34 degalais (JF) ir apdorotais cetano priedais (JF+0,12 vol) F-34 degalais maitinamo keturtakčio, keturių cilindrų, tiesioginio įpurškimo dyzelinio variklio darbo efektyvumo ir pagrindinių deginių emisijos komponentų palyginamoji analizė. Tyrimų tikslas yra ištirti galimybę reaktyvinius F-34 degalus panaudoti antžeminės karinės technikos tiesioginio įpurškimo dyzeliniuose varikliuoseI ir išstudijuoti reaktyvinių F-34 degalų ir 0.12vol% 2-ethylhexyl nitrato cetano priedais apdorotų reaktyvinių F-34 degalų įtaką savaiminio užsiliepsnojimo periodo trukmei, degimo procesui, variklio darbo efekvumui ir deginių emisijos rodikliams. Reaktyviniais JF ir JF+0.12vol% degalais maitinamas variklis išvysto -imalų dujų slėgį cilindre 4.3% ir 2.8% mažesnį, esant 1400 min"1 sūkiams, ir - bei 5.7%, esant sūkiams 2200 min"1, palyginti su 86.6 MPa ir 82.5 MPa uialaus dyzelinio variklio išvystomu slėgiu. Pasėkoje apdorotais reaktyviniais galais maitinamas variklis veikia mikščiau ir, esant vardiniams 2200 min"1 finams, maksimalus dujų slėgio padidėjimas cilindre sumažintas 9.4% palyginti K 15.9 barų/0 normalaus variklio naudojimo atveju. Minimaliosios lyginamosios irgilų sąnaudos (bsfc) reaktyvinių degalų F-34 ir priedais apdorodų F-34 degalų aemažėjo 4.8% ir 3.5% esant 1400 min"1 sūkiams ir padidėjo 2.7% ir 3.7%, esant II 10 min"1 sūkiams, palyginti su 249.5 g/kWh ir 251.8 g/kWh normalaus variklio ^naudomis. Maximali NO emisija, panaudojus reaktyvinius degalus JF ir JF+0.12vol%, —ažėjo 11.5% ir 7.0%, esant 1400 min"1, ir 17.1% bei 17.3%, esant 2200 min"1 sCkiams, palyginti su 1705 ppm ir 1389 ppm sklindančių iš normalaus dyzeliniovariklioThe article presents a comparative analysis of the bench test results of a fourstroke, four-cylinder, direct-injection diesel engine operating on the normal 95vol% (class C) diesel fuel + 5vol% RME (DF), F-34 jet fuel (JF) and F-34 jet fuel treated with the cetane improver (JF+0.12vol%). The purpose of the research was to investigate the possibility to use of military jet F-34 fuel in the land-based direct injection diesel engine and examine the effect of F-34 and F-34 fuel treated with 0.12vol% 2-ethylhexyl nitrate on the autoignition delay, combustion, performance, emissions and the smoke opacity. The maximum cylinder gas pressure produced from fuel JF and JF+0.12vol% was lower 4.3% and 2.8% at speed of 1400 rpm, and 2.5% and 5.7% at speed of 2200 rpm compared to 86.6 MPa and 82.5 MPa of the normal diesel. At rated 2200 rpm speed, the use of the jet fuel treated with the cetane improver led to smoother engine performance under all loads and the maximum cylinder pressure gradients were reduced by 9.4% as against 15.9 bar/deg of the normal diesel. The minimum brake specific fuel consumption (bsfc) for F-34 fuel and treated F-34 fuel was decreased by 4.8% and 3.5% at 1400 rpm and increased by 2.7% and 3.7% at 2200 rpm compared to 249.5 g/kWh and 251.8 g/kWh of the normal diesel. Maximum NO emissions produced from JF fuel and JF+0.12vol% fuel were reduced by 11.5% and 7.0% at 1400 rpm, and 17.1% and 17.3% at speed of 2200 rpm compared to 1705 ppm and 1389 ppm emanating from the normal diesel. Maximum CO emissions were suppressed by 39.3% and 16.8% compared to 4988 ppm produced from the normal diesel running at 1400 rpm speed. At speed of 2200 rpm, the ecological effect of using F-34 fuel was minimal and the CO emissions sustained over the whole load range at the same level and increased by 2.5% and 3.0% with regard to the normal diesel operating under high loadVytauto Didžiojo universitetasŽemės ūkio akademij

The effect of aviation fuel jp-8 and diesel fuel blends on engine performance and exhaust emissions

The article presents bench test results of a four-stroke, four-cylinder, naturally aspirated, DI diesel engine operating with neat JP-8 fuel (J) and its blends with Diesel fuel (D) in following proportions by volume: 90/10 (J+10D), 70/30 (J+D30), 50/ 50 (J+D50), 30/70 (J+D70), and 100% diesel fuel (DF). The purpose of the research was to analyse and compare changes occurred in the autoignition delay, combustion events, engine performance efficiency, emissions, and smoke of the exhaust when running on JP-8 fuel, jet-diesel fuel blends, and diesel fuel at a full (100%) engine load and speed of 1400 min-1 at which maximum torque occurs and rated speed of 2200 min-1. It was found that the start of injection (SOI) and the start of combustion (SOC) occurred earlier in an engine cycle and the autoignition delay decreased by 9.0% and 12.7% due to replacement of aviation JP-8 fuel with diesel fuel at a full load and the latter speeds. Maximum in-cylinder pressure was 6.8% and 4.0% higher when operating with diesel fuel, whereas brake thermal efficiency was 3.3% and 7.7% higher, and brake specific fuel consumption 2.8% and 7.0% lower when using fuel blend J+D50 compared with the respective values measured with neat JP-8 fuel. Emissions of nitric oxide (NO) and nitrogen oxides (NOx) were 13.3% and 13.1% higher from a straight diesel running at speed of 1400 min-1, and 19.0% and 19.5% higher at a higher speed of 2200 min-1. The carbon monoxide emissions and total unburned hydrocarbons decreased 2.1 times and by 12.3% when running with fuel blend J+D70 at speed of 2200 min-1compared with those values measured with jet fuel. Smoke of the exhaust was 53.1% and 1.9% higher when using fuel blend J+D10 than that of 46.9% and 70.0% measured with jet fuel at speeds of 1400 and 2200 min-1Generolo Jono Žemaičio Lietuvos karo akademijaVytauto Didžiojo universitetasŽemės ūkio akademij

Combustion, performance and exhaust emissions of the diesel engine operating on jet fuel

The article focuses on bench testing results of a four-stroke, four-cylinder, direct-injection, naturally aspirated, diesel engine i ting on the normal 95vol% (class C) diesel fuel + 5vol% RME (DF), F-34jet fuel (JF) andjet fuel F-34 treated with the : improver (JF+0.12vol%). The purpose of the research is to investigate the availability to use of military F-34 jet fuel bland-based direct injection diesel engine powering and examine the effect ofF-34fuel and F-34fuel treated with 0.12vol% tylhexyl nitrate on the autoignition delay, combustion, engine performance, emissions and smoke opacity of the exhausts. The peak in-cylinder gas pressure generated from JF and JF+0.12vol% is lower by 4.3% and 2.8% at 1400 min' , and 2.5% and 5.7% at 2200 min'' speed compared to that 86.6 MP a and 82.5 MP a of the normal diesel. At rated i min~' speed, the use of treated jet fuel leads to smoother engine performance under all loads and the maximum der pressure gradient lowers by 9.4% as against that 15.9 bar/deg of base diesel. The minimum brake specific fuel mption (bsfc) for F-34 and treated F-34 fuels decreases by 4.8% and 3.5% at 1400 min'1 speed, and increases by and 3.7% at. 2200 min'1 speed compared to 249.5 g/kWh and 251.8 g/kWh values of base diesel. Maximum NO emissions produced from fuels JF and JF+0.12vol% decrease by 11.5% and 7.0% at 1400 min', and J% and 17.3% at 2200 min'1 speed compared to 1705 ppm and 1389 ppm emanating from the normal diesel. ' rtum CO emissions produced from jet fuel JF and JF+0.12vol% decrease by 39.3% and 16.8% compared to that W0!f8ppm producedfrom base diesel running at 1400 min'1 speed, At 2200 min' speed, the ecological effect of using fuel "M fuel decreases and the CO sustains over the whole load range at the same level and increases by 2.5% and 3.0% I regard to the normal diesel operating under high load... [et al.]Vytauto Didžiojo universitetasŽemės ūkio akademij

Dependency of the autoignition delay, combustion and exhaust emissions of a diesel engine on the cetane number of aviation-turbine JP-8 fuel

The article presents the bench test results of a fully instrumented, four cylinder, naturally aspirated, (60 kW) DI diesel engine running on the normal (class C) diesel fuel (DF) and aviation-turbine (JP-8) fuel. Analysis of changes in the autoignition delay, maximum in-cylinder pressure, performance efficiency of an engine and exhaust emissions caused by the variation of the cetane number of JP-8 fuel was provided. The series of engine tests were conducted running on the normal JP-8 fuel and JP-8 treated with 0.04vol%, 0.08vol%, 0.12vol%, 0.16vol%, and 0.24vol% of 2-ethylhexyl nitrate. Studies on operating characteristics of an engine were carried out for the fully loaded (100%) engine and the two ranges of speed, - 1400 rpm at which maximum torque occurs and rated 2200 rpm speed. Adding of 2-ethylhexyl nitrate to aviation-turbine fuel in the above proportions the cetane number (CN) of JP-8 fuel improved from 42.3 to 46.1, 47.6, 48.5, 49.4, and 49.8, respectively, enhancing ignition properties of the fuel to adapt it for using in ground-based military transport. The increase of CN from the reference value of 42.3 to optimum value of 48.5 suggested the brake specific fuel consumption lower 1.4%, both total unburned hydrocarbons (THCs) 7.5% and exhaust smoke 5.7% higher with almost unchangeable the NOx emissions behaviour and 11.9% lower CO emissions when running under a fully (100%) opened throttle at rated 2200 rpm speed. The brake thermal efficiency increased to maximum value of 0.309 (1.3%) for given operating conditions. Analysis of the results revealed that the improved cetane number can be considered as an effective but not the only measure to be applied for an intended use of JP-8 fuel in ground-based diesel enginesVytauto Didžiojo universitetasŽemės ūkio akademij

Numerical and experimental analyses of injection characteristics using jet fuel

The article presents experimental and numerical analysis of the diesel and aviation fuel Jet A-1 injection characteristics. The injection experiments were conducted using a high pressure common rail injection system. The injection characteristics were analyzed using an injection rate measuring instrument according to the Bosch method. The injection rate, cycle injection quantity, injection delay and injection duration were analyzed at 85.0 MPa, 115.0 MPa and 140.0 MPa injection pressures and 1.3 ms injection energizing time. As the results show, the peak mass injection rate of jet fuel was at 85.0 MPa injection pressure lower by 2.3 % only compared to diesel fuel. By increasing the injection pressure this difference decreases. However, the volumetric injection rates were slightly lower for diesel fuel. The injection delay was 0.3 ms for diesel fuel and 0.27 ms for jet fuel at 85.0 MPa and 115.0 MPa injection pressure, and 0.3 ms for both fuels at 140.0 MPa injection pressure. The injection duration in all cases was longer than the energizing duration of the injector. The discharge coefficient of jet fuel was by 6.5 % higher than that of diesel fuel. The experimental results were compared with the numerical simulation results. The common rail injector model was created with AVL BOOST Hydsim software. The measured pressure in the injection duct was used to validate the model in addition to the discharge coefficient and injection rate. The comparison of the simulated injection rate with the experimental data shows that the Boost-Hydsim common rail injector model gives good results for both standard diesel fuel and jet fuelGenerolo Jono Žemaičio Lietuvos karo akademijaVytauto Didžiojo universitetasŽemės ūkio akademij