Reclamation of saline‐sodic soil under a rice–wheat system by horizontal surface flushing

Saline sodic soil with a high content of soluble carbonates is one of the important agricultural soils on the Central Indo‐Gangetic plains and elsewhere. Conventional reclamation procedures using gypsum application followed by vertical leaching (GC) is uneconomic; high ECe and precipitation of applied gypsum, reacting with soluble carbonates, reduce the efficacy of gypsum in these soils. This paper reports results from a project designed to evaluate reclamation by irrigation of the ploughed soil and turning of soil with a power tiller followed by flushing of standing water after 24 h, a second flushing after 7 days and subsequent application of gypsum and vertical leaching (GF2). Average rice and wheat production after GF2 significantly increased (25 and 62%, respectively) over the conventional practice. Compared with conventional treatment, GF2 significantly reduced the ECe and SAR of the soil and improved physical properties such as ζ‐potential, dispersible clay content, water stable aggregates expressed as MWD, and saturated hydraulic conductivity. Split application of gypsum between flushing (GF1/2 and GF2/3) gave similar results to GF2 in terms of soil amelioration and crop production.     

浅谈沥青路面的病害与防治

本文作者对沥青路面的病害成因作了一般性分析及论述,并提出了几项防治措施。     

Effect of short‐term supplementation with rumen‐protected fat during the late luteal phase on reproduction and metabolism of ewes

This study was designed to study the effect of short‐term supplementation with rumen‐protected fat during the late luteal phase on reproduction and metabolism of sheep during breeding season. Seventy‐six ewes (Rahmani, Barki and Awassi × Barki) were allocated to two groups considering genotype: the control ewes (C‐group) received a maintenance diet, and the fat‐supplemented ewes (F‐group) received the maintenance diet plus 50 g/head/day of rumen‐ protected fat (Megalac) for 9 days during which oestrus was synchronized. The latter had been accomplished using double intramuscular injection of prostaglandin F_2α (PGF_2α) 11 days apart. Ovarian activity, serum concentration of cholesterol, glucose, insulin and reproductive performance variables were recorded. Data were analysed considering treatment (group) and genotype. Supplementation had positive effects on the overall mean serum concentrations of cholesterol (p < 0.05), glucose (p < 0.05) on day 6 of nutritional treatment and insulin (p = 0.07) on day 8. Fat supplementation did not affect the total number of follicles, follicle populations and ovulation rate. However, fat‐supplemented Rahmani ewes tended to have higher ovulation rate compared with other breeds (treatment × breed interaction, p = 0.06). Treatment also did not affect the mean concentration of serum estradiol or progesterone. Supplemented ewes had higher conception (p = 0.06) and lambing rates (p < 0.05) compared with control. In conclusion, short‐term supplementation with rumen‐protected fat as a source of energy around breeding time improved metabolism, conception and lambing rates of ewes without effects on steroidogenic capacity and ovarian activity being apparent.     

具有排气功能的毛管末端自动冲洗阀设计与结构优化

该研究创制一种具备自动排气功能（Auto-Exhaust function, AE）的毛管末端自动冲洗阀,以提高冲洗时长和冲洗水量。选取延时流道齿长和齿宽、上腔体容积和冲洗阀进口压力共4个因素,采用L18（37）正交试验设计18种规格的AE冲洗阀,并设置4种无排气装置（Non-Exhaust function, NE）的冲洗阀为对照,探究排气装置提升冲洗阀水力性能的作用机理和AE冲洗阀性能参数对试验因素的响应规律。结果表明,当进口压力为0.06～0.14 MPa时,AE冲洗阀的冲洗时长、冲洗水量和冲洗流速分别为18.2～67.7 s、3 904～12 367 mL和0.88～1.40 m/s。冲洗时长和水量与流道齿长、齿宽和上腔体容积均为正相关关系,与进口压力为负相关关系,冲洗流速只与进口压力有关,为正相关关系。流道齿长、齿宽和上腔体容积对冲洗时长和水量影响显著,进口压力对冲洗时长和流速影响显著（P<0.05）。AE冲洗阀能自动排出上腔体中的空气,增加蓄水容积,使其冲洗时长和水量分别比NE冲洗阀提高83.5%与75.4%以上。综合考虑延时流道抗堵塞性能、冲洗时长和水量等因素,推荐AE冲洗阀流道齿长、齿宽、上腔体容积和进口压力分别为1.2 mm、2.2 mm、19.1 mL和0.06 MPa,其冲洗时长和水量分别是NE冲洗阀的2.8和2.7倍,是进口冲洗阀的7.4和7.0倍,为67.7 s、12 194 mL。研究结果可为具有排气功能的毛管末端自动冲洗阀的研发提供依据。     

气阻致输油泵机械密封过热失效分析与对策

西部管道乌鲁木齐输油首站成品油主泵启输及运行中多次出现机械密封泄漏油气油烟的过热失效现象。针对该问题,通过对机械密封失效现象的观察、气阻机理的探讨以及对气阻和杂质堵塞致机械密封失效的现象和原因进行对比分析,确定了气阻是导致机械密封过热失效泄漏油气油烟的主因。同时,提出了机械密封过热失效的解决方法,包括：启泵前需要反复多次对泵腔灌泵以充分排气;运行过程中若发现机械密封压盖及冲洗冷却循环管路快速升温发烫,则应立即在不停泵的状态下缓开泵腔排气阀排气。相关经验可为输油站现场避免发生此类问题提供实践依据。（图2,参6）     

Ear cleaning: the UK and US perspective

Ear cleaning helps maintain the normal otic environment and is important in the treatment of otitis. Over cleaning, however, may trigger otitis through maceration of the epidermal lining. Simple manual cleaning is useful for routine cleansing but doesn't remove tightly adherent debris. Bulb syringes are more vigorous but may damage the ear in inexperienced hands. Devices using mains water pressure or dental machines are also available. Thorough cleaning of the ear canals and middle ear cavity can only be achieved by retrograde flushing using specially adapted catheters, feeding tubes or video otoscopes under anaesthesia. Myringotomy, inspection and cleaning of the middle should be performed if the tympanic membrane appears abnormal. There are a wide variety of cleaning fluids available. Ceruminolytics soften and dissolve cerumen to facilitate cleaning. Surfactants emulsify debris, breaking it up and keeping it in solution. Astringents dry the ear canal surface, preventing maceration. Maintaining a low pH and incorporating antimicrobial agents can inhibit microbial proliferation and glucocorticoids can be used to reduce inflammation. Adverse effects and contraindications following ear cleaning can include maceration, contact reactions, otitis media, ear canal avulsion, vestibular syndrome, Horner's syndrome, facial nerve paralysis and deafness. Care should be exercised in selecting cleaning fluids if the tympanic membranes are ruptured.     

Comparison of the intravenous and intravaginal route of oxytocin administration for cervical dilation protocol and non‐surgical embryo recovery in oestrous‐induced Santa Inês ewes

This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous‐induced Santa Inês ewes (6‐day treatment with progestin‐releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6–7 days after oestrous onset and mating. All ewes received 37.5 μg of d‐cloprostenol via latero‐vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non‐surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17–40 min) and ~96% of flushing fluid could be recovered (range: 85%–100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep.     

Idiopathic telangiectasia in a Golden Retriever

A case report of a 12-year-old spayed female Golden Retriever with a 4-month history of persistent diffuse erythema involving the right and left antebrachia is presented. Cutaneous biopsies revealed superficial dermal vascular dilation and proliferation with moderate epidermal acanthosis. Diagnostic tests failed to reveal an underlying aetiology. Telangiectasia is defined as a permanent dilation of pre-existing blood vessels creating small focal lesions. Generalized essential telangiectasia of humans is common in women of middle-age and can involve entire segments of the body. Lesions predominantly affect the extremities and can persist for years without any systemic effects. The cutaneous lesions in this case have remained static for 3 years with no manifestation of systemic signs. A diagnosis of idiopathic telangiectasia was made based on the clinical and histological findings in the dog of this report. The lesions described in this dog resemble generalized essential telangiectasia of humans.     

秋季香溪河库湾水体冲淡时间分布特征的成因

针对三峡水库支流库湾的秋季水华问题,以香溪河库湾为研究对象,选取2009和2010两年的9月1日—11月30日作为研究时段,通过建立三维水动力模型,探讨了香溪河库湾水体冲淡时间分布特征及其成因.研究结果表明,在汛末蓄水期,香溪河库湾水体冲淡时间较长的区域均出现在中游,且随着汛末库水位抬高,库湾各层水体冲淡时间最大值均随着增长;因9月三峡库区干流水体主要由中、底层倒灌进入库湾,使得库湾中下游至下游区域表层水体冲淡时间最长,且随着中、底层倒灌持续时间增长,河口附近表层水体冲淡时间较中、底层的差值也有所增长;在支流上游和中上游区域,水体在蓄水期绝大部分时间的流动方式表现为由库湾底层流向干流,使得该区域底层水体冲淡时间较表、中层的短.研究结果可为三峡水库支流库湾秋季水华问题的防治提供借鉴.     

中温高黏度介质双端面主密封热力特性分析

为研究中温高黏度介质双端面机械密封主密封的传热和变形规律以及冲洗液的压力和温度对其影响,从而为密封性能改进和冲洗液的高效控制提供依据.以乳液输送设备双端面机械密封(AR201)为研究对象,建立传热计算模型,采用有限元法分析主密封温度场,研究了密封环温度和变形量随冲洗液压力和温度的变化规律.研究表明:密封环端面的最高温处于动静环接触面靠近密封腔位置处,在冲洗液的作用下,动静环内径侧温度明显低于外径侧,动静环温度自接触面开始沿轴向至环外侧逐渐降低;端面最高温度和最大变形量随冲洗液温度和压力的升高而增大,最大变形量的大小和随冲洗液参数变化的波动幅度与密封材料有关;合理选择冲洗液压力和温度是有效改善主密封性能的措施,对于AR201机械密封,将冲洗液压力控制在0.80~0.85 MPa和较低的温度能减少端面磨损现象.