Ppm Ethylene Research Articles

Facile Fabrication of Lilac-Like Multiple Self-Supporting WO3 Nanoneedle Arrays with Cubic/Hexagonal Phase Junctions for Highly Sensitive Ethylene Glycol Gas Sensors.

Metal oxides with nanoarray structures have been demonstrated to be prospective materials for the design of gas sensors with high sensitivity. In this work, the WO3 nanoneedle array structures were synthesized by a one-step hydrothermal method and subsequent calcination. It was demonstrated that the calcination of the sample at 400 °C facilitated the construction of lilac-like multiple self-supporting WO3 arrays, with appropriate c/h-WO3 heterophase junction and highly oriented nanoneedles. Sensors with this structure exhibited the highest sensitivity (2305) to 100 ppm ethylene glycol at 160 °C and outstanding selectivity. The enhanced ethylene glycol gas sensing can be attributed to the abundant transport channels and active sites provided by this unique structure. In addition, the more oxygen adsorption caused by the heterophase junction and the aggregation of reaction medium induced by tip effect are both in favor of the improvement on the gas sensing performance.

Exploitation of Post-Ripening Treatment for Improving Cold Tolerance and Storage Period of Jin Huang Mango

The limited cold tolerance of the Jin Huang mango represents a significant impediment to its potential for international trade. Therefore, this study evaluated the quality index changes of green maturity Jin Huang mangoes with different post-ripening treatments and then when stored at different storage periods (7, 14, 21, and 28) at 4 °C followed by 6 days at 20 °C. This study showed that the mangoes treated with 500 ppm ethylene were slow to ripen during 4 °C storage, which could be sustainable even under 20 °C storage. In addition, the control (CK) group failed to mature or ripen unevenly after storage at 4 °C. Moreover, the T3 group (ethylene ripening for 1 day and post-ripening at 20 °C for 1 day) minimized the occurrence of CI during storage compared to the CK group while contributing to a 30% decrease in anthracnose incidence and a decrease in firmness and titratable acid (TA), while total soluble solids (TSS) notably increased, yet the ascorbic acid content in this group was lower. Hence, the treatment conditions of Jin Huang mango using T3 helped extend its shelf-life at 20 °C, stocking and minimizing CI and anthracnose, thereby maintaining a certain quality.

ZnO quantum dots decorated on graphene oxide and graphene nanoplatelets: Comparison the structure and sensing properties

In this study, we successfully synthesized ZnO quantum dots decorated on graphene oxide (GO) and graphene nanoplatelets (GNP) using a simple hydrothermal method. The synthesized ZnO/GO and ZnO/GNP nanocomposites were thoroughly characterized using various techniques, including X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), Raman and photoluminescence spectroscopies, Transmission electron microscopy (TEM), and Brunauer–Emmett–Teller analysis (BET). We further evaluated the gas sensing capabilities of the synthesized samples. Excitingly, our results demonstrated that the ZnO/GNP sensor exhibited significantly enhanced gas sensing performance for ethylene glycol compared to both the ZnO/GO and pure ZnO sensors. Specifically, at 280 °C, the ZnO/GNP nanocomposite sensor displayed impressive responses of approximately 51 and 183 towards 50 ppm and 200 ppm ethylene glycol, respectively. Moreover, the ZnO/GNP sensor exhibited exceptional selectivity in detecting ethylene glycol. These findings suggest that ZnO quantum dots decorated on commercial graphene nanoplatelets could be a promising candidate for highly sensitive ethylene glycol gas sensors.

ZnO nanowire/NiO foam 3D nanostructures for high-performance ethylene glycol sensing

Ethylene glycol is widely used in industrial production but poses potential safety hazards to human life and health. Unfortunately, conventional glycol gas sensors have limitations that impede their effectiveness, such as sluggish response rates, high operational temperatures, and complex preparation procedures. A new approach has been explored to address these challenges. A ZnO nanowire/NiO foam nanostructured sensor was developed specifically for rapid ethylene glycol detection. The NiO/ZnO heterojunction-based gas sensor (NZO-6) has inherent p-type gas-sensitive characteristics. Notably, it delivers a response of 58.98–100 ppm of ethylene glycol at a relatively low operating temperature of 175 ℃. At a relatively low operating temperature of 175 ℃, it exhibits a response of 58.98–100 ppm ethylene glycol, 2.28 times higher than NiO foam, and a fast response/recovery time (4 s/26 s). This improvement is attributed to the porous structure of NiO foam/ZnO nanowires, with a large specific surface area and numerous oxygen vacancies generated during synthesis. Additionally, the catalysis of Ni metal and the formation of p/n heterojunctions further contribute to the improved sensing performance. This research offers a promising solution for developing high-performance ethylene glycol gas sensors with potential environmental monitoring, industrial safety, and public health applications. Further, this synthesis method provides an effective strategy for constructing other NiO-based heterostructure-based gas sensors.

Flexible waterborne polyurethane nanocomposite foams incorporated with halloysites as fresh-keeping packaging inserts for fresh fruits

Food losses due to the deterioration of fresh fruits and related economic problems can be prevented by the use of active food packaging materials. Here, waterborne polyurethane (WPU)/halloysite nanotube (HNT) nanocomposite foams with ethylene and moisture absorption properties are presented, which can be inserted into existing food packages as fresh-keeping packaging materials for the improvement of the shelf life of fruits. WPU with moisture absorption properties has been utilized as a carrier for HNTs, which have a large capacity to absorb ethylene gas, the plant hormone responsible for the ripening of climacteric fruits. HNTs were incorporated into WPUs during a foaming process, resulting in open-cell foams with average pore sizes of 316 µm and a density of 0.136 g/cc. The resulting WPU-HNT foams were shown to absorb moisture by 7 % when they were incubated in a closed container of 100 % relative humidity for 14 days. The WPU-HNT foams were also demonstrated to absorb 2.5 ppm of ethylene gas per gram of foam when kept in a sealed container injected with 90 ppm ethylene gas for 3 days. Tomatoes stored together with the nanocomposite foams in plastic boxes at 4 °C for 14 days presented significantly higher firmness values than the tomatoes stored without the foams. Similarly, bananas stored in polyethylene bags containing the nanocomposite foam remained firmer and free of brown spots for at least 2 days longer than the bananas stored without the nanocomposite foam. The WPU-HNT foams have a strong potential as low-cost, environmentally friendly food packaging inserts that can prevent spoilage of fruits.

Petal-like ZnO-based ultra-sensitive ethylene glycol sensors synthesized by solvent regulation

The ZnO-10, ZnO-20, ZnO-30, and ZnO-40 nanopetal-shaped samples were successfully synthesized by a hydrothermal method. The results of XRD, SEM, TEM, and BET indicate that the micro–nano petal-like samples have the advantages of high purity, good crystallinity, and large specific surface area. The ZnO-20 sample with the largest specific surface area and pore volume was prepared by adjusting the scheme without changing the sample morphology. The specific surface area and pore volume of the sample were 33.6914[Formula: see text]m2/g and 0.1561[Formula: see text]ml/g. The results of gas sensitivity test show that the sample has the highest response and super good gas sensitivity selectivity. At 250∘C, the responses to 5[Formula: see text]ppm and 50[Formula: see text]ppm ethylene glycol can reach 14.4 and 293, respectively. Because of the excellent gas performance of ZnO nanosheets, this work can provide a theoretical basis for the research and development of ultra-sensitive ethylene glycol gas sensors in the industry.

A high-performance ethylene glycol sensor based on fibrous ErFeO3 prepared by electrostatic spinning

Ethylene glycol is a toxic industrial solvent and the detection of traces is important for human health. ErFeO3 nanofibers provide a different strategy to fabricate high-performance ethylene glycol sensors. Here, an ethylene glycol gas sensor based on ErFeO3 nanofibers was fabricated by uniaxial electrospinning combined with high-temperature calcination. The crystal structure, morphology and elemental composition of the materials have been studied using various techniques. The results show that ErFeO3 nanofibers with uniform morphology and perovskite structure have been successfully prepared. Gas sensing test indicated that ErFeO3 nanofibers showed the greatest response (15.8) to 100 ppm ethylene glycol with a low optimal temperature (230 °C). Furthermore, the sensor has outstanding reproducibility, high selectivity, great stability and a low detection base limit (35 ppb). The reason for the sensor's high sensitivity to ethylene glycol is that the pores on the ErFeO3 nanofibers provide effective diffusion channels and sufficient gas-sensitive active sites for gas molecules. Therefore, the research carried out in this thesis will contribute to developing new high-performance ethylene glycol sensors.

Heterostructure engineering of NiO foam /In2S3 film for high-performance ethylene glycol gas sensors

Ethylene glycol, widely used as antifreeze for planes and motor cars, is odorless and harmful to humans; thus, high-performance ethylene glycol gas sensors are highly demanded. Herein, a type-II heterostructure of p-type nickel oxide foam/ n-type indium sulfide (NIS) was prepared for ethylene glycol gas sensing. The assembled NIS sensor exhibits a unique response (Rg/Ra=180.39) to 100 ppm ethylene glycol at a low temperature of 150 ℃ and a fast response/ recovery time (11.43 s/ 6.16 s), as well as excellent repeatability and long-term stability. The excellent gas-sensitive performance of the NIS sensors can be attributed to the formation of p-NiO/n-In2S3 heterojunctions resulting in a large change in the potential barrier, which leads to an increased sensing response. These results suggest that elaborate heterostructure engineering of NiO can potentially achieve highly sensitive ethylene glycol gas sensors.

Effect of Maturity Stages and Ripening Process on the Colour (L*, a* and b*) Values and Physico-chemical Composition of Mango (Mangifera indica L.) var. Manjeera

Background: Mangoes are a tremendous source of nutrients that are vital for human nutrition and health. The concentrations of these nutrients vary across different kinds according to the environmental factors, ripening processes and maturity stages. Hence, the study was undertaken to study the influence of maturity stages, ripening process and days of storage on the colour values and physicochemical properties of Manjeera variety of mango. Methods: Mangoes that were gathered and processed at the FRS, SKLTSHU, Sangareddy. The mangoes’ physico-chemical examination and colour value were performed. Mangoes were collected at two maturity stages- 7-9Úbrix and 9-11Úbrix and processed using three different methods, control, 100 ppm ethylene treatment and 150 ppm ethylene treatment, before being stored for 12 days. At the fourth, eighth and twelfth days of storage, samples were taken for further evaluation. Result: The colour L*, a*, b* values gradually increased from day 4 to day 12 in all the treatments with the exception of L* value for 100 ppm ethylene treated mangoes harvested at 7-9°brix TSS and 9-11°brix TSS. It was found that acidity in all treatments reduced as ripening progressed. With the exception of control samples at 9-11°brix TSS, all 8th day samples for all treatments in the 7-9°brix and 9-11°brix TSS were found to have a high sugar: acid ratio. TSS, a measure of mango sweetness, was found to be highest on the eighth day in 150 ppm treated mangoes with 7-9°brix TSS, followed by 12 ppm ethylene-treated mangoes with 7-9°brix and 9-11°brix TSS and control mangoes with 9-11°brix TSS. Physical and chemical characteristics revealed that mangoes collected at 7-9°brix TSS have high TSS, total sugar and sugar: acid ratios in both 100 ppm and 150 ppm ethylene-treated mangoes.

Mesoporous Zn2SnO4 for efficient sensing of ethylene glycol vapor

Within this study, mesoporous Zn2SnO4 nanostructures have been prepared by a facile and eco-friendly hydrothermal method. Through X-ray diffraction analysis, a polycrystalline zinc tin oxide structure is recognized with a cubic inverse spinel phase crystal structure. By Field emission scanning electron microscopy method, various morphologies based on the hydrothermal time ranging from the cubic-like morphology, irregular hexagonal plates, and large quantity of microspheres to the truncated octahedron have been observed. By the aid of Energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy analyses, the atomic ratio and characteristic vibration peaks of Zn2SnO4 have been evaluated. By the help of Brunauer–Emmett–Teller analysis, specific surface area, mean pore diameter, and total pore volume were measured. The nanostructured Zn2SnO4 prepared in 36 h hydrothermal treatment (as a selected sample) showed a higher BET specific surface area (9.10 m2/g) and total pore volume (0.078 cm3/g) than the other samples. The gas-sensing performance of the samples was investigated towards different vapors. The optimum operating temperature (270 °C), transient response, response/recovery times, and long-term stability (eight months) of the samples have been evaluated. For the selected sample, appreciable sensing response (92.92 toward 100 ppm ethylene glycol), the ultra-fast response time (1 s), excellent selectivity (about 6–23 times more than other tested vapors) and excellent long-term stability (the response decay of about 10% after eight months) has been perceived which makes it a promising gas sensor. It seems that the selected sample has shown relatively better performance for two reasons: Firstly, high crystalline quality (largest crystallite size and lowest strain value) which can affect the combination or separation of adsorbed oxygen species on the surface of the material. Secondly, the higher specific surface area and the relatively larger total pore volume can lead to more gas adsorption sites leading to further narrowing of the depletion layer and resulting in a high and very fast response.

Effect of Maturity Stages and Ripening Process on the Nutritive and β-carotene of Mango [Mangifera indica (L.) var. Manjeera

Background: Mango is one of the few fruits that is used at every stage of ripeness, from the very young, immature stage to the completely mature state. The concentrations of nutrients vary across different kinds according on the environmental factors, ripening processes and maturity stages. The process of ripening, which can be carried out either naturally or artificially, brings the fruit to maturity before it is consumed or processed. The best time for mango intake with the most nutrient and phytochemical potential can be determined rationally by new facts about mango consumption. Methods: Materials utilized for the study were mangoes harvested at two maturity stages i.e. 7-9°brix and 9-11°brix and processed by three treatments methods viz, control, 100 ppm and 150 ppm ethylene treatment followed by 12 days storage. The samples were withdrawn periodically for analysis on 4th, 8th and 12th day of the storage. Nutritive composition and β-carotene analysis for the mangoes were done using the standard methods. Result: According to the findings of the proximate analysis, the ash content was greater in the control on the 12th and 4th days, respectively, in the 9-11°brix TSS and 7-9°brix TSS. Mangoes harvested at 7-9°brix TSS had the maximum protein content on the fourth day, followed by mangoes treated with 150 ppm ethylene on the twelfth day. In all the treatments, the maximum levels of crude fiber and crude fat were found on day 12th and 8th, respectively, in mangoes harvested at 7-9°brix TSS and 9-11°brix TSS. On the fourth day, mangoes treated with 100 ppm ethylene and harvested at 9-11°brix TSS had the highest carbohydrate content. On the eighth day, all treatments had the most energy. 7-9°brix TSS harvested mangoes showed good nutrient content in control samples, showing that artificial ripening treatments had a substantial impact on the nutrient composition, according to the data.

Highly sensitive and selective glycol gas sensor based on SmFeO3 microspheres

Powdered SmFeO 3 samples were prepared by hydrothermal method combined with high temperature calcination. The samples' crystal structure was discovered by XRD, their morphology and microstructure were assessed by SEM and TEM, and chemical makeup and valence state were investigated by XPS. These characterizations confirmed that the prepared samples were SmFeO 3 microspheres with a perovskite structure. A resistive gas sensor was prepared using it as a sensing material, and its gas sensing performance was tested. Test results show that the SmFeO 3 sensor has a higher response (117) to 100 ppm ethylene glycol gas at lower operating temperatures (180 °C). In addition, SmFeO 3 sensor offers outstanding repeatability, stability, and selectivity. Hence, SmFeO 3 microspheres are a promising ethylene glycol sensor.

Facile fabrication of NiO foam@Sn-doped In2O3 nanowire heterosturctures for highly sensitive ethylene glycol gas sensors at low temperatures

Ethylene glycol is odorless and harmful to human beings. However, the high operating temperature and the low gas response of the ethylene glycol sensors limit their wide applications. Herein, p-type nickel oxide foam/ n-type tin-doped indium oxide nanowires composite (NTO) has been fabricated for ethylene glycol gas sensing. The NTO composite was prepared by complete oxidation of Ni foam at high temperature, then Sn-doped indium oxide (ITO) nanowires were grown on NiO foam by chemical vapor deposition. The assembled NTO sensor exhibits a unique response (Rg/Ra=160.72) to 100 ppm ethylene glycol at a low temperature of 125 ℃, and a fast response/ recovery time (8.7 s/ 19.3 s). This excellent gas-sensitive performance of NTO sensors can be attributed to the formation of p/n heterojunctions and the In and Sn doping of NiO during ITO growth. This fabrication method provides an effective strategy for building NiO-based heterostructures for high-performance gas sensors.

Highly sensitive ethylene glycol gas sensor based on ZnO/rGO nanosheets

ZnO/rGO nanosheets are fabricated by combining chemical precipitation and hydrothermal method. At the same time, high temperature annealing treatment is performed to further improve the gas-sensitive performance for ethylene glycol. The response value of ZnO/rGO-based gas sensor is up to 277 for 100 ppm ethylene glycol at an optimum operating temperature of 220 ℃. Compared with intrinsic ZnO gas sensor, the operating temperature is reduced and the response is increased by 1.1 times. The sensor has a fast response/recovery time of about 38 s/26 s and exhibits excellent cycle repeatability and stability. The detection limit is as low as 1 ppm. These excellent gas sensing properties are mainly attributed to a large specific surface and more active sites in ZnO/rGO nanosheets. In addition, based on the density functional theory (DFT), the charge transfer and the band structures are simulated. It is further confirmed theoretically our proposed gas sensing mechanism. It provides an effective research idea for real-time and ultra-rapid detection of ethylene glycol gas.

Assembled Reduced Graphene Oxide/Tungsten Diselenide/Pd Heterojunction with Matching Energy Bands for Quick Banana Ripeness Detection.

The monitoring of ethylene is of great importance to fruit and vegetable quality, yet routine techniques rely on manual and complex operation. Herein, a chemiresistive ethylene sensor based on reduced graphene oxide (rGO)/tungsten diselenide (WSe2)/Pd heterojunctions was designed for room-temperature (RT) ethylene detection. The sensor exhibited high sensitivity and quick p-type response/recovery (33/13 s) to 10–100 ppm ethylene at RT, and full reversibility and excellent selectivity to ethylene were also achieved. Such excellent ethylene sensing behaviors could be attributed to the synergistic effects of ethylene adsorption abilities derived from the negative adsorption energy and the promoted electron transfer across the WSe2/Pd and rGO/WSe2 interfaces through band energy alignment. Furthermore, its application feasibility to banana ripeness detection was verified by comparison with routine technique through simulation experiments. This work provides a feasible methodology toward designing and fabricating RT ethylene sensors, and may greatly push forward the development of modernized intelligent agriculture.

Application of ethylene for ripening of 1-MCP treated pear after cold storage

Abstract This work aimed to evaluate the effect of ethylene treatment on ripening of 1-MCP treated pear after 6 months of cold storage. Pear treated with gaseous 1-MCP at 625–650 ppb for 24 h at 0 °C was stored at 0 °C for 6 months with normal air, and treated groups were exposed to 100 ppm ethylene at 20 °C for 24 h. After that, samples were kept at 0, 10, and 15 °C for 2 weeks. Stiffness, chlorophyll fluorescence, ethylene and CO2 production of fruit were investigated during 2 weeks. Application of ethylene resumed the ripening of pear after long term storage. The results showed that fruit treated with ethylene achieved more homogeneous surface colour in comparison with non ethylene treated pears. In addition, the ethylene and carbon dioxide production of ethylene treated pears had higher values than that of control. The ethylene treatment could accelerate the softening of pear. Temperature also has significant effect on ripening during storage. This study found that ethylene treatment could accelerate the normal ripening of 1-MCP treated pears.

Ethylene Adsorption on Activated Carbon Paper Liner: A Model Kinetic Study

The ability of activated carbon as an adsorber is depended on activating agent used for the activation process. An industrial application of the ethylene adsorption process as well as the design of the necessary equipment requires an accurate model to determine the effect of various factors on the efficiency of the process. The model is needed to predict the efficient activating agent to be applied in carbon activation. One ml of gas containing 200 ppm ethylene was injected into gas-tight jars, to which 4 sheets of nanopore activated carbon paper were placed. The ethylene concentration was measured every 5 minutes until 90 minutes using gas chromatography. The concentration of ethylene absorbed by the nanopore activated carbon paper, then calculated to construct a kinetics model of absorption. Data were analyzed using 4 kinetics models: nonlinear pseudo-first-order, nonlinear pseudo-second-order, Elovich, and Avrami kinetic models. The best adsorption kinetics model that described ethylene adsorption kinetics by nanopore activated carbon paper was the nonlinear pseudo-first-order, with equation model: qt = 1.35734 (1-exp0.15312 t). The compiled model has a match with R2 = 0.9981. The adsorption mechanisms and kinetics aspects was important on the use of adsorbents to remove ethylene in packaging and storage.

Sensing performance for ethylene glycol of hydrothermally self-assembled 3D WO3

A series of hierarchically self-assembled three-dimensional (3D) WO3 with different mass ratios of urea to sodium tungstate were prepared by a one-step hydrothermal method, and the sensing characteristics for ethylene glycol were studied. The results showed that when the mass ratio of urea to sodium tungstate is 0.1:1, the sample WO3-0.1 exhibited the highest response (740.3) to 100 ppm ethylene glycol at 200 °C. In addition, sample WO3-0.1 had excellent selectivity, repeatability, stability and moisture resistance. Due to the hierarchically self-assembled 3D structure, sample WO3-0.1 possessed the maximum number of mesopores, the vacant oxygen concentration of sample WO3-0.1 was twice as much as the sample WO3-0 without urea. Moreover, the growth mechanism of hierarchically self-assembled 3D WO3 was explored by discussing the synergistic effect of ammonium chloride and oxalic acid. Based on outstanding properties for ethylene glycol, the 3D WO3 prepared in this work will have practical significance and potential applications for environmental monitoring.

Electrospinning synthesis, crystal structure, and ethylene glycol sensing properties of orthorhombic SmBO3 (B[dbnd]Fe, Co) perovskites

The target of this work is to survey the consequences of various B (BFe, Co) sites of SmBO3 perovskite on crystal structure and ethylene glycol gas-sensitive properties. To this end, two samples based on SmFeO3 and SmCoO3 nanofibers with orthorhombic phase were prepared by a straightforward and efficient electrospinning technique and calcined at 700 °C. The XRD Rietveld refinements and tolerance factor (t) were implemented to research the crystal structure by the lattice parameters, size of BOB angles and t value, BET test shows that as-prepared two samples own different pore sizes, and XPS analyzes the composition and chemical state toward two samples, which indicates that more oxygen vacancies exist in SmFeO3 surface. Then, the gas-sensing performance of SmFeO3 and SmCoO3 nanofibers were compared at their optimal working temperature of 200 °C. The gas-sensing inquiries exhibit that the response of sensor based on SmFeO3 nanofiber (14.3) is almost 6.5 times higher than that of SmCoO3 (2.2) toward 100 ppm ethylene glycol. Finally, the sensing mechanisms of SmFeO3 and SmCoO3 nanofibers were also explained based on pore size, oxygen vacancy, lattice distortion and electrical conductance.

Memecik Zeytin Çeliklerinin Köklenmesi Üzerine Etilenin Etkisi

Bu çalışmada, Memecik zeytin çeliklerinin köklenmesi üzerine etilenin etkisinin belirlenmesi amaçlanmıştır. Çalışmada 10 farklı bitki büyüme düzenleyici madde kombinasyonu uygulamasında her uygulamada 3 tekerrür, her tekerrürde 30’ar adet olmak üzere toplam 900 adet zeytin yarı odun çeliği kullanılmıştır. Çalışma sonucunda en yüksek köklenme oranı %44.4 ile 0 etilen+6000 ppm IBA uygulamasından elde edilirken, bunu %42.2 ile 0 etilen+8000 ppm IBA uygulaması izlemiştir. En düşük köklenme oranı %2.2 ile 0 etilen+0 ppm IBA (kontrol) ve 150 etilen+4000 ppm IBA (dikimden 10 gün sonra) uygulamalarında gözlenmiştir. Çeliklerin dikimden itibaren farklı günlerde yapılan bitki büyümeyi düzenleyici maddeleri uygulamalarında en yüksek kallus oranı (% 44.7) 150 etilen+4000 ppm IBA (20.gün)’da, en fazla kök sayısı (13.3 adet) 0 etilen+6000 ppm IBA’da, en fazla kök uzunluğu (7.0 cm) 50 etilen+4000 ppm IBA (10.gün)’da ve en fazla kök çapı (3.0 mm) 150 etilen+4000 ppm IBA (10.gün)’da elde edilmiştir. Sürgün uzunluğu, çapı ve sayısı bakımından uygulamalar arasındaki farklılık önemli bulunmamıştır. Artan etilen dozları Memecik yarı odun çeliklerinin köklenmesini azalttığı için 50 ppm’den daha düşük etilen dozlarının denenmesi tavsiye edilmektedir.