北京地区育龄男性与女性TORCH感染情况回顾分析

目的 回顾分析近2016年7月至2022年12月来我院就诊人群的TORCH感染情况,为本地区优生优育工作提供数据参考。方法 利用酶联免疫吸附实验检测男性和非妊娠期女性血清中TORCH各病原体IgG抗体和IgM抗体的阳性情况,对数据进行处理分析。结果 进行TORCH检测的人群,女性人数远高于男性人数;男性和女性之间TOX、RV、CMV和HSV的IgM抗体阳性率均存在差异,男性和女性之间TOX和HSV的所有感染模式存在差异,且所有差异均表现为女性的抗体阳性率高于男性的抗体阳性率;男性RV和CMV的IgM抗体阳性率在不同的季节存在差异,女性的TOX、RV、CMV和HSV-1的IgM抗体阳性率在不同的季节存在差异;男、女性HSV-1和HSV-2抗体IgM阳性率在各季节均存在差异,且男、女性HSV-2的所有感染模式在各个季节中也完全不同;在合并感染中,男、女性的IgG抗体阳性率均以RV+CMV、RV+HSV-1、CMV+HSV-1和RV+CMV+HSV-1为主,且女性的抗体阳性率高于男性,在IgM抗体的阳性率分析中,女性主要以HSV-1+HSV-2为主,男性主要以RV+HSV-1为主,其女性的抗体阳性率也远高于男性。结论 本地区TORCH感染人群主要为女性,TORCH感染的病原体有季节性差异,可针对此特点进行预防;建议增加育龄男性检测TORCH相关项目,可有助于夫妇备孕期感染的预防。

IVF/ICSI-ET患者TORCH血清学检测与出生缺陷分析:基于倾向性评分匹配法

目的:探讨实施体外受精-胚胎移植(In vitro fertilization and embryo transfer,IVF-ET)和卵泡内单精子注射(In vitro fertilization and embryo transfer,IVF-ET)技术患者TORCH血清学检测与出生缺陷的相关性。方法:,基于倾向性评分匹配(Propensityscorematching,PSM)的方法分析2017年1月-2020年12月期间在山东大学附属生殖医院实施IVF/ICSI-ET治疗患者的临床资料,根据既往妊娠结局分为出生缺陷组与正常组。比较倾向性评分匹配前后的TORCH血清学检测结果。结果:PSM前,不同组别的基线资料分布不均衡。出生缺陷组CMV-IgM、HSV-IgM阳性率高于正常组(P<005)。经倾向性评分匹配后,基线资料分布均衡。出生缺陷组TORCH-IgM阳性率与正常组无显著差异(P>0.05)。出生缺陷组TORCH-IgG阳性率与正常组无显著差异(P>0.05)。结论:行IVF/ICSI-ET治疗的患者TORCH感染与出生缺陷不存在相关性,出生缺陷患儿人数构成以先天性心脏病最多。

北京地区孕产妇TORCH血清流行病学调查研究

目的分析2018-2022年在该院就诊的孕产妇血清TORCH感染情况及流行特点。方法对2018-2022年在该院进行孕期筛查的女性共计27357例结果进行分析,按年龄段、年度进行分组,结果用SPSS软件进行统计分析。结果孕产妇TOX、RV、CMV、HSV-ⅡIgM的阳性率分别为0.03%、1.27%、1.86%和0.08%,IgG的阳性率分别为4.46%、90.31%、92.87%和4.49%。≥35岁高龄孕妇组CMV IgM、RV IgG抗体阳性率显著低于<35岁组,差异有统计学意义(均P<0.05),TOX IgG、HSV-ⅡIgG抗体阳性率显著高于<35岁组,差异有统计学意义(均P<0.05)。CMV IgG阳性率近几年呈递减趋势。结论高龄组CMV IgM、RV IgG抗体阳性率更低,TOX IgG、HSV-ⅡIgG抗体阳性率更高。CMV IgG阳性率有呈逐年下降趋势,RV IgG和HSV-ⅡIgG阳性率逐年上升。

TORCH感染流行病学、诊断与治疗策略的研究进展

TORCH感染,包括弓形虫(Toxoplasma gondii,TOX)、风疹病毒(Rubella virus,RUV)、巨细胞病毒(Cytomegalovirus,CMV)和单纯疱疹病毒(Herpes simplex virus,HSV),是育龄男女面临的重要公共卫生问题。这些病原体可通过母婴传播导致不孕、流产、死胎、死产及胎儿先天畸形等严重后果。本文深入探讨了TORCH感染的流行病学特征,揭示了其在不同年龄段、季节及地区的差异性分布,并强调了不良妊娠史与TORCH感染率之间的显著关联。同时,文章综述了TORCH感染的诊断方法,涵盖血清学检测、病原学检测及影像学与临床评估的综合运用。在治疗策略上,尽管多数病原体尚无特效疗法,但本文提出了针对性的干预措施,旨在减轻病情、降低传播风险。此外,本文还强调了孕前筛查、健康教育、疫苗接种及孕期监测与管理在TORCH感染预防与控制中的关键作用。通过综合分析TORCH感染的流行病学、诊断及治疗,为优化妊娠结局、提高人口素质提供了重要参考。

TORCH联合血清β-hCG、AFP、uE3检测诊断超声软指标异常胎儿价值

目的:探究TORCH联合血清人绒膜促性腺激素(β-hCG)、甲胎蛋白(AFP)和游离雌三醇(uE3)检测对超声软指标异常胎儿产前诊断价值。方法:选取2021年7月-2023年12月于本院产前检查胎儿超声软指标异常的孕妇324例(300例单项软指标异常、24例≥2项软指标异常)纳入异常组,产前检查健康产妇300例纳入对照组。均行TORCH血清学检测,测定血清AFP、freeβ-hCG及uE3水平。对比两组血清TORCH、β-hCG、AFP和uE3检测结果;对比不同软指标异常组血清TORCH、β-hCG、AFP和uE3检测结果;ROC分析TORCH联合血清β-hCG、AFP和uE3对超声软指标异常胎儿产前诊断价值。结果:与对照组相比,异常组血清TORCH阳性率、β-hCG、AFP水平更高,血清uE3水平更低(均P<0.05);与单项软指标异常组相比,多项软指标异常组血清TORCH阳性率、β-hCG、AFP更高,血清uE3水平更低(均P<0.05);ROC工作曲线结果显示,血清TORCH、β-hCG、AFP和uE3联合检测诊断超声软指标异常孕妇的AUC分别为0.927,显著高于指标单独检测,且敏感度和特异度均较高,分别为90.00%和92.59%。结论:对产前检查孕妇行血清TORCH联合β-hCG、AFP和uE3检测,有助于提升超声软指标异常胎儿的产前诊断率,可为临床提供一种准确有效的诊断方法。

拉萨市育龄妇女及孕妇TORCH感染情况分析

目的分析拉萨市育龄妇女及孕妇的TORCH病原体感染情况,为优生优育提供数据支持及指导建议。方法收集从2018年~2021年在本院进行优生优育检查的2020名育龄妇女及孕妇TORCH检测结果。分别从民族、年龄、季节方面进行流行病学分析。结果TORCH四种病原体即弓形虫(Toxoplasma gondii,Tox)、风疹病毒(rubella virus,RV)、巨细胞病毒(cytomegalovirus,CMV)、单纯疱疹病毒(herpes simplex virus,HSV)的IgM阳性率分别为0.94%、0.94%、0.25%和20.74%,而IgG阳性率分别为8.54%、86.92%、97.94%和95.92%。不同民族之间RV-IgM(P=0.01)、HSV-I/II-IgM(P=0.00)和TOX-IgG(P=0.00)、CMV-IgG(P=0.00)差异有统计学意义。只有HSV-I/II-IgG在不同年龄组间差异有统计学意义(P=0.04)。而不同季节间只有RV-IgG差异有统计学意义(P=0.03)。结论TORCH四种病原体中,RV和CMV对拉萨地区育龄妇女及孕妇威胁性较国内其它地区小,而TOX和HSV威胁性较大。

Analysis of TORCH results of retinal exudative changes in neonates

AIM:To explore the relationship between retinal exudative changes in neonates and perinatal toxoplasmosis,others,rubella,cytomegalovirus,and herpes simplex virus(TORCH)infections,as well as the characteristics of TORCH infection in neonates with retinal exudative changes.METHODS:Retrospective study.A total of 612 neonates with retinal exudative changes detected during ophthalmic screening in our hospital from May 2019 to March 2023 were selected.TORCH tests were performed on these neonates,and the results were subjected to statistical analysis to determine the infection characteristics.The neonates with retinal exudative changes were grouped by sex and age,the characteristics of TORCH infection were analyzed,and the positive rates were compared.RESULTS:Among the 612 neonates with retinal exudative changes,the highest positive rate was observed for cytomegalovirus(CMV-IgG)(96.7%),followed by rubella virus(RV-IgG)(73.9%).Mixed infections with two or three viruses were also observed,with the highest positive rate for mixed infection of RV-IgG and CMV-IgG reaching 71.2%.There was no statistically significant difference in TORCH infection among neonates of different sex(P>0.05).However,there were statistically significant differences in RV-IgG and CMV-IgM infections with retinal exudative changes among neonates of different age groups(P<0.05).CONCLUSION:Perinatal TORCH infection may be an important factor causing retinal exudative changes in neonates.The differences in various infections are not related to sex but are related to different age groups.

Study on the ignition process of a segmented plasma torch

Direct current plasma torches have been applied to generate unique sources of thermal energy in many industrial applications. Nevertheless, the successful ignition of a plasma torch is the key process to generate the unique source （plasma jet）. However, there has been tittle study on the underlying mechanism of this key process. A thorough understanding of the ignition process of a plasma torch will be helpful for optimizing the design of the plasma torch structure and selection of the ignition parameters to prolong the service life of the ignition module. Thus, in this paper, the ignition process of a segmented plasma torch （SPT） is theoretically and experimentally modeled and analyzed. Corresponding electrical models of different stages of the ignition process axe set up and used to derive the electrical parameters, e.g. the variations of the arc voltage and arc current between the cathode and anode. In addition, the experiments with different ignition parameters on a home-made SPT have been conducted. At the same time, the variations of the arc voltage and arc current have been measured, and used to verify the ones derived in theory and to determine the optimal ignition parameters for a particular SPT.

Influence of the Laminar Plasma Torch Construction on the Jet Characteristics

Based on two typical laminar plasma torches （LPT）, i.e. a multi-electrode plasma torch （MEPT） with segmented anode structure and a two-electrode plasma torch （TEPT） with conventional structure, this paper studied the influence of the LPTs construction on the jet characteristics. Experiments were designed to measure their arc voltage, jet length, thermal efficiency and specific enthalpy using a home-made data acquisition system. With them, the jet characteristics of the two different LPTs were compared in detail. Results show that different plasma torch construction leads to distinctively different characteristics of the generated plasma jet. Based on the different jet characteristics, a plasma torch with appropriate construction could be used to meet the different application requirements.

皖南地区8199例婴幼儿TORCH感染血清学检测结果分析

目的探讨皖南地区近年来TORCH病原体,即弓形虫(Toxoplasma gondii,TOX)、风疹病毒(rubella virus,RV)、巨细胞病毒(cytomegalovirus,CMV)和单纯疱疹病毒(herpes simplex virus,HSV)在婴幼儿人群的感染状况及流行特点,为儿童相关疾病的预防、诊断和治疗提供参考。方法回顾性分析2016年4月—2023年3月皖南医学院第一附属医院接诊的0~3岁婴幼儿TORCH感染血清IgM和IgG抗体检测结果,并对不同年龄、年份的TORCH阳性率进行比较分析。结果共有8199例0~3岁婴幼儿进行TORCH感染血清学筛查检测,其中男性4631例,女性3568例。婴幼儿TOX、RV、CMV、HSVⅠ和HSVⅡ的IgM抗体阳性率分别为0.11%、0.20%、0.89%、0和0,差异有统计学意义(χ^(2)=100.000,P<0.05);相对应的IgG抗体阳性率分别为10.81%、78.36%、98.32%、82.38%和13.45%,差异有统计学意义(χ^(2)=22828.211,P<0.05)。不同年龄组比较,婴儿组CMV-IgM阳性率(11.90%)高于新生儿组(0.20%)和幼儿组(1.40%),差异均有统计学意义(χ^(2)=672.920、20.569,P均<0.017);新生儿组TOX-IgG、RV-IgG、CMV-IgG、HSVⅠ-IgG和HSVⅡ-IgG阳性率(11.01%、79.88%、98.76%、85.35%、13.72%)高于婴儿组(6.71%、49.35%、96.54%、50.87%、9.74%),差异均有统计学意义(χ^(2)=8.369、237.184、16.033、373.121、5.902,P均<0.017)。不同年份比较,CMV-IgM阳性率2016年最高,各年差异有统计学意义(χ^(2)=15.816,P<0.05);不同年份TOX-IgG、RV-Ig G、CMV-IgG、HSVⅠ-IgG、HSVⅡ-IgG阳性率差异均有统计学意义(χ^(2)=216.002、90.545、37.047、59.527、57.623,P均<0.05)。结论皖南地区0~3岁婴幼儿中TORCH既往感染以CMV、HSVⅠ和RV为主,现症感染主要为CMV,对婴幼儿进行TORCH感染筛查检测对于保护儿童的健康至关重要。此外,应做好妊娠规划、产前保健和筛查,预防TORCH感染。

Preliminary Study of Thermal Treatment of Coke Wastewater Sludge Using Plasma Torch

Thermal plasma was applied for the treatment of coke wastewater sludge derived from the steel industry in order to investigate the feasibility of the safe treatment and energy recovery of the sludge. A 30 kW plasma torch system was applied to study the vitrification and gas production of coke wastewater sludge. Toxicity leaching results indicated that the sludge treated via the thermal plasma process converted into a vitrified slag which resisted the leaching of heavy metals. CO2 was utilized as working gas to study the production and heat energy of the syngas. The heating value of the gas products by thermal plasma achieved 8.43 k J/L, indicating the further utilization of the gas products. Considering the utilization of the syngas and recovery heat from the gas products, the estimated treatment cost of coke wastewater sludge via plasma torch was about 0.98 CNY/kg sludge in the experiment. By preliminary economic analysis, the dehydration cost takes an important part of the total sludge treatment cost. The treatment cost of the coke wastewater sludge with 50 wt.% moisture was calculated to be about 1.45 CNY/kg sludge dry basis. The treatment cost of the coke wastewater sludge could be effectively controlled by decreasing the water content of the sludge. These findings suggest that an economic dewatering pretreatment method could be combined to cut the total treatment cost in an actual treatment process.

Experimental Investigation on the Plasma Torch Used for Scramjet Ignition Enhancement

A high frequency arc discharge plasma torch was specially designed for ignition enhancement in scramjet combustor. At first, the process of plasma injection into quiescent air was investigated experimentally through CCD camera and schlieren technology. Then, the energy property characterization of active particle distribution was measured by emission spectrometry. Several kinds of working gas under different injection pressures were compared. Finally, the typical supersonic flow-field structure with plasma cross-injection was obtained. The results show that plasma jet energy is concentrated near the jet axis, which has the maximum attenuation in the downstream as far as 2 cm from the outlet. The working gas and injection pressure have great effect on emission spectrometry and the process of jet expansion. The case with N2 under higher injection pressure shows better performance of energy exchanging process when comparing with air and argon. From the emission spectroscopy, we can see that plasma from nitrogen consists of nitrogen and oxygen atom mainly, whose intensity decreases with increasing distance from the nozzle, while it increases with the increase of pressure. When plasma was vertically injected into supersonic flow-field, bow shock wave and mixing layer structure were formed with thicken mixing layer, which helps enhance the mixing process between active particle and incoming air.

Experimental study on the jet characteristics of a steam plasma torch

Thermal steam plasma jet is promising for applications in environmental industries due to its distinctive characteristics of high enthalpy and high chemical reactivity. However, the performance of the steam plasma torch for its generation is limited by the problems of the large arc voltage fluctuation and serious erosion of the electrodes. In this study, a gas-stabilized steam plasma torch which can operate continuously and stably was designed. Experiments were conducted to reveal the effect of the different working parameters, including the anode diameter, the cooling water temperature, the arc current and the steam flow rate, on its Volt-Ampere characteristics, arc voltage fluctuation, thermal efficiency, jet characteristics and electrodes erosion. Results showed that the use of hot water to cool the electrodes can effectively prevent the condensation of steam on the inner wall of the electrodes, thus significantly reducing the arc voltage fluctuations and electrodes erosion. This is crucial for increasing the working life of the electrodes and ensuring long-term stability of the steam plasma torch. In addition, suitable anode diameter can greatly reduce the arc voltage fluctuation of the steam plasma torch and effectively improve the stability of the steam plasma jet. Furthermore, high arc current can effectively reduce the fluctuations of the arc voltage and increase the length and the volume of the steam plasma jet. Finally, using steam as the plasma forming gas can achieve higher thermal efficiency compared to air. An ideal thermal efficiency can be achieved by properly reducing the arc current and increasing the steam flow rate.

Modelling Study on the Plasma Flow and Heat Transfer in a Laminar Arc Plasma Torch Operating at Atmospheric and Reduced Pressure

A modelling study is performed to investigate the characteristics of both plasma flow and heat transfer of a laminar non-transferred arc argon plasma torch operated at atmospheric and reduced pressure. It is found that the calculated flow fields and temperature distributions are quite similar for both cases at a chamber pressure of 1.0 atm and 0.1 atm. A fully developed flow regime could be achieved in the arc constrictor-tube between the cathode and the anode of the plasma torch at 1.0 atm for all the flow rates covered in this study. However the flow field could not reach the fully developed regime at 0.1 atm with a higher flow rate. The arc-root is always attached to the torch anode surface near the upstream end of the anode, i.e. the abruptly expanded part of the torch channel, which is in consistence with experimental observation. The surrounding gas would be entrained from the torch exit into the torch interior due to a comparatively large inner diameter of the anode channel compared to that of the arc constrictor-tube.

2015-2021年新疆阿克苏地区孕妇和新生儿TORCH感染情况分析

目的调查2015-2021年新疆阿克苏地区孕妇和新生儿TORCH感染趋势,分析孕妇和新生儿TORCH感染特征。方法回顾性分析,收集于2015-2021年在新疆阿克苏地区接受TORCH感染筛查的4349名孕妇和配对的4058名新生儿临床资料,采用酶联免疫吸附法检测孕妇和新生儿外周血、孕妇产前脐血的TORCH-IgM抗体、IgG抗体并分析结果;比较不同年龄孕妇的TORCH-IgM抗体、IgG抗体阳性率;并比较正常妊娠、不良妊娠孕妇TORCH-IgM抗体阳性率。结果2015年-2021年4349名孕妇TORCH感染呈下降趋势;TORCH感染孕妇中,TORCH-IgM总阳性率为2.23%(97/4349),TORCH-IgG总阳性率为3.66%(159/4349)。风疹病毒(RV)、巨细胞病毒(CMV)病毒IgG抗体的阳性率高于弓形虫(TOX)、单纯疱疹病毒(HSV)(P<0.05)。2015年-2021年4058名新生儿TORCH感染呈下降趋势;TORCH感染新生儿中,TORCH-IgM总阳性率为1.75%(71/4058),TORCH-IgG总阳性率为1.82%(74/4058)。各病毒IgM、IgG抗体阳性率比较,差异无统计学意义(P>0.05)。4349名孕妇经产前脐血检查,TORCH-IgM抗体总阳性率为0.78%(34/4349),其中CMV阳性率最高,占总阳性例数的76.47%。不良妊娠组产前脐血TORCH-IgM抗体阳性率高于正常妊娠组,差异有统计学意义(P<0.05)。≤35岁的孕妇HSV-IgM抗体阳性率、RV-IgG抗体阳性率均高于>35岁孕妇,但CMV-IgG、HSV-IgG抗体阳性率均低于>35岁孕妇,均差异有统计学意义(P<0.05);不同年龄组孕妇TOX-IgM、RV-IgM、CMV-IgM、TOX-IgG抗体阳性率比较,差异无统计学意义(P>0.05)。结论2015-2021年新疆阿克苏地区孕妇和新生儿TORCH感染率逐渐降低,CMV是孕妇及新生儿感染的主要病原体,HSV-IgM阳性率以低龄孕妇为主,应强化孕前TORCH检测,降低感染率。

Comparison of Reynolds average Navier-Stokes turbulence models in numerical simulations of the DC arc plasma torch

Five turbulence models of Reynolds average Navier-Stokes(RANS),including the standard k-ω model,the RNG k-e model taking into account the low Reynolds number effect,the realizable k-ω model,the SST k-ω model,and the Reynolds stress model(RSM),are employed in the numerical simulations of direct current(DC)arc plasma torches in the range of arc current from 80 A to 240 A and air gas flow rate from 10 m^3 h^-1 to 50 m^3 h^-1.The calculated voltage,electric field intensity,and the heat loss in the arc chamber are compared with the experiments.The results indicate that the arc voltage,the electric field,and the heat loss in the arc chamber calculated by using the standard k-ω model,the RNG k-ωmodel taking into account the low Reynolds number effect,and the realizable k-ω model are much larger than those in the experiments.The RSM predicts relatively close results to the experiments,but fails in the trend of heat loss varying with the gas flow rate.The calculated results of the SST k-ω model are in the best agreement with the experiments,which may be attributed to the reasonable predictions of the turbulence as well as its distribution.

Comparative analysis of the arc characteristics inside the convergingdiverging and cylindrical plasma torches

A two-temperature thermal non-equilibrium model is used to simulate and compare the arc characteristics within the converging-diverging and traditional cylindrical plasma torches.The modeling results show that the presence of the constrictor within the converging-diverging torch makes the evolution characteristics of the arc significantly different from that of cylindrical torch.Compared with a cylindrical geometrical torch,a much higher plasma flow velocity and relatively longer high temperature region can be generated and maintained inside the converging-diverging torch.In the constrictor of converging-diverging torch,the normalized radius of arc column increases and the degree of thermodynamic equilibrium of the plasma is significantly improved with the increase of axial distance.The radial momentum balance analysis shows that for the cylindrical torch,the pressure gradient that drives the arc expansion and the Lorentz force that drives the arc contraction dominate the radial evolution of the arc.While at the converging and constrictor region of a converging-diverging plasma torch,the radial gas dynamic forces in arc fringes pointing toward the arc center enhance the mixing of the cold gas of boundary layer with the high temperature gas of the arc center,increasing the average gas temperature and decreasing the thickness of cold boundary layer,thereby facilitating the formation of diffusion type arc anode attachment at the diverging section of torch.

孕妇早孕期血清ALT升高与TORCH感染的相关性研究

目的 分析孕妇早孕期血清谷丙转氨酶(ALT)升高与TORCH感染的相关性。方法 选取本院282例免费孕前优生及早孕TORCH感染患者和同期未感染的282例免费孕前优生及早孕建卡者为研究对象,所有入选对象均接受ALT检测,对比分析两组ALT水平,并应用Logistic多因素回归分析方法对血清ALT升高与TORCH感染的相关性进行分析。结果 不同类型TORCH感染者ALT水平相比差异无统计学意义(P>0.05)。感染组血清ALT水平显著高于健康组,差异有统计学意义(P<0.05)。Logistic多因素回归分析结果显示,孕期血清ALT升高是TORCH感染的影响因素(P<0.05)。结论 孕妇早孕期血清ALT升高与TORCH感染密切相关,孕妇在孕前及孕期需积极加强ALT、TORCH监测。

Numerical investigation on the flow characteristics of a reverse-polarity plasma torch by two-temperature thermal non-equilibrium modelling

A two-temperature(2 T)thermal non-equilibrium model is developed to address the thermal nonequilibrium phenomenon that inevitably exists in the reverse-polarity plasma torch(RPT)and applied to numerically investigate the plasma flow characteristics inside and outside the RPT.Then,a detailed comparison of the results of the 2 T model with those of the local thermal equilibrium(LTE)model is presented.Furthermore,the temperature of the plasma jet generated by a RPT and the RPT’s voltage are experimentally measured to compare and validate the result obtained by different models.The differences of the measured excitation temperature and the arc voltage between the 2 T model and experimental measurement are less than 13%and 8%,respectively,in all operating cases,validating the effectiveness of the 2 T model.The LTE model overestimates the velocity and temperature distribution of the RPT and its plasma jet,showing that thermal non-equilibrium phenomena cannot be neglected in the numerical modelling of the RPT.Unlike other common hot cathode plasma torches,the thermal non-equilibrium phenomenon is found even in the arc core of the RPT,due to the strong cooling effect caused by the big gas flow rate.

Theoretical and experimental investigation of Ti alloy powder production using low-power plasma torches

This study was carried out to investigate the possibility of titanium alloy metal powder production using low-power plasma torches.An argon DC non-transferred arc plasma torch was designed,and numerical analysis was conducted to determine the plasma jet properties and wire temperature.The highest velocities inside the nozzle attachment were between 838 and 1178 m/s.The velocities of the jets at the apex were between 494 and 645 m/s for different gas flow rates.The studied plasma gas flow rates had no significant effect on the effective plasma jet length.It was shown that the plasma jet length can be estimated by numerical analysis using the temperature and velocity changes of the plasma jet over distance.It was observed that the powders produced were spherical without any satellites.As a result of this study,a plasma torch was developed and powder production was performed successfully by using relatively low torch power.