新型多层楼房式猪舍智能化机械清粪系统的设计

近年来,由于规模养殖业用地越来越紧张,多层楼房式猪舍逐渐被众多业主所接受。与多层楼房养猪相适应的清粪、环控、喂料等配套工艺技术是这一模式成功应用的关键。文章针对四层楼房式猪舍设计了一种楼房式猪舍自动化刮板清粪工艺,在大跨度小单元全进全出式猪舍,舍内一层每单元采用一拖二刮板清粪机将粪便从湿帘端刮入风机端主粪沟;二、三、四层采用刮粪机刮粪、收集粪便通过落粪管落入一层主粪沟;舍外主粪沟采用一拖一刮粪机清粪。整套工艺采用自动化智能化控制,该系统能够大幅度提高清粪效率,减少人工,节约用水,有效改善猪舍内环境,提高舍内猪群的健康水平,从而提高养殖场的总体效益。

新建与复养规模化猪场中生物安全工艺设计与改造

生物安全是猪场生产管理的关键,也是猪场搞好生产的基本保障。猪场生物安全贯穿于生产管理的各个环节,包括人员、物资、猪只、饲料、粪污等流转运输等。近两年的非洲猪瘟疫情使得很多生物安全设施和管理不健全的养殖场遭受灭顶之灾。为协助众多在疫情中遭受打击的规模养殖企业恢复生产,文章从更严格的生物安全角度出发,在传统猪场工艺设计的基础上,对猪场功能区设置、人员物料流线规划、进出场洗消设施配置等提出了一套较为完整的工艺技术方案,供养猪从业者在新建和改造猪场复养过程中参考。

Gene expression dynamics during the gonocyte to spermatogonia transition and spermatogenesis in the domestic yak

Background:Spermatogenesis is a cellular differentiation process that includes three major events:mitosis of spermatogonia,meiosis of spermatocytes and spermiogenesis.Steady-state spermatogenesis relies on functions of spermatogonial stem cells(SSCs).Establishing and maintaining a foundational SSC pool is essential for continued spermatogenesis in mammals.Currently,our knowledge about SSC and spermatogenesis is severely limited in domestic animals.Results:In the present study,we examined transcriptomes of testes from domestic yaks at four different stages(3,5,8 and 24 months of age)and attempted to identify genes that are associated with key developmental events of spermatogenesis.Histological analyses showed that the most advanced germ cells within seminiferous tubules of testes from 3,5,8 and 24 months old yaks were gonocytes,spermatogonia,spermatocytes and elongated spermatids,respectively.RNA-sequencing(RNA-seq)analyses revealed that 11904,4381 and 2459 genes were differentially expressed during the gonocyte to spermatogonia transition,the mitosis to meiosis transition and the meiosis to post-meiosis transition.Further analyses identified a list of candidate genes than may regulate these important cellular processes.CXCR4,a previously identified SSC niche factor in mouse,was one of the up-regulated genes in the 5 months old yak testis.Results of immunohistochemical staining confirmed that CXCR4 was exclusively expressed in gonocytes and a subpopulation of spermatogonia in the yak testis.Conclusions:Together,these findings demonstrated histological changes of postnatal testis development in the domestic yak.During development of spermatogonial lineage,meiotic and haploid germ cells are supported by dynamic transcriptional regulation of gene expression.Our transcriptomic analyses provided a list of candidate genes that potentially play crucial roles in directing the establishment of SSC and spermatogenesis in yak.

Conversion of NO with a catalytic packedbed dielectric barrier discharge reactor

This paper discusses the conversion of nitric oxide（NO） with a low-temperature plasma induced by a catalytic packed-bed dielectric barrier discharge（DBD） reactor. Alumina oxide（Al2O3）,glass（SiO2） and zirconium oxide（ZrO2）, three different spherical packed materials of the same size, were each present in the DBD reactor. The NO conversion under varying input voltage and specific energy density, and the effects of catalysts（titanium dioxide（TiO2） and manganese oxide（Mn Ox） coated on Al2O3） on NO conversion were investigated. The experimental results showed that NO conversion was greatly enhanced in the presence of packed materials in the reactor, and the catalytic packed bed of Mn Ox/Al2O3 showed better performance than that of TiO2/Al2O3. The surface and crystal structures of the materials and catalysts were characterized through scanning electron microscopy analysis. The final products were clearly observed by a Fourier transform infrared spectrometer and provided a better understanding of NO conversion.

In situ electron-induced reduction of NOx via CNTs activated by DBD at low temperature

In this study,a new in situ electron-induced process is presented with carbon nanotubes(CNTs)as a reduction agent activated by dielectric barrier discharge(DBD)for nitrogen oxide(NOx)abatement at low temperature(<407 K).Compared with a single DBD system and a DBD system with activated carbon(DBD-AC),a DBD system with carbon nanotubes(DBD-CNT)showed a significant promotion of NOx removal efficiency and N2 selectivity.Although the 02 content was 10%,the NOv conversion and N2 selectivity in the DBD-CNT system still reached 64.9%and 81.9%at a specific input energy(SIE)of 1424 J^L,and these values decreased to 16.8%,31.9%and 43.2%,62.3%in the single DBD system and the DBD-AC system,respectively.X-ray photoelectron spectroscopy(XPS)and scanning electron microscopy(SEM)were utilized to investigate surface changes in the CNTs after activation by DBD to explore the NO.t reduction abatement mechanism of this new process.Furthermore,the outlet gas components were also observed via Fourier transform infrared spectroscopy(FTIR)to help reveal the NOr reduction mechanism.Experimental results verified that carbon atoms excited by DBD and the structure of CNTs contributed to the synergistic activity of the DBD-CNT system.The new deNOx process was accomplished through in situ heterogenetic reduction reactions between the NOx and carbon atoms activated by the plasma on the CNTs.In addition,further results indicated that the new deNOv process exhibited acceptable S02 tolerance and water resistance.

Preparation of a novel cross-linked polyetherimide with enhanced breakdown strength and high-temperature energy storage performance

Polymer dielectrics with excellent energy storage performance at high temperature are urgently needed in advanced applications,such as hybrid electric vehicles,smart grid and pulsed power sources.Polyetherimide(PEI),which is supposed to be the most promising candidate among polymer dielectric materials,displays a limitation for high-temperature polymer dielectrics owing to the rapidly decreasing discharged energy density(U_(d))and charge-discharge efficiency(η).Herein,a novel PEI with cross-linked networks was firstly prepared by utilising 2,4,6-Triaminopyrimidine(TAP)as a cross-linker.The results showed that the breakdown strength of the cross-linked PEI(c-PEI)with 2 wt%TAP increased to 399.4 MV/m,showing an increment of 23.3%in comparison with noncross-linked PEI.Additionally,owing to the restrained polarisation loss and relaxation loss by cross-linked networks,the dielectric loss of c-PEI dielectric gradually decreased with the increasing content of TAP.Of particular significance was the c-PEI dielectrics exhibiting improved U_(d)andηat high temperature.The maximum U_(d)of c-PEI with 2 wt%TAP was 2.53 J/cm3 at 150℃,which was 24.8%higher than non-cross-linked PEI(2.11 J/cm^(3)at 150℃).This research provides an innovative strategy to achieve novel PEI dielectrics with improved U_(d)andηat high temperature.

A novel approach to estimate and control denitrification performance in activated sludge systems with respirogram technology

Respirogram technology has been widely applied for aerobic process, however, the response of respirogram to anoxic denitrification is still unclear. To reveal such response may help to design a new method for the evaluation of the performance of denitrification. The size distribution of flocs measured at different denitrification moments demonstrated a clear expansion of flocs triggered by denitrification, during which higher specific endogenous and quasi-endogenous respiration rates(SOUReand SOURq) were also observed. Furthermore,SOURqincreases exponentially with the specific denitrification rate(SDNR), suggesting that there should be a maximum SDNR in conventional activated sludge systems. Based on these findings, an index Rq/t, defined as the ratio of quasi-endogenous(OURq) to maximum respiration rate(OURt), is proposed to estimate the denitrification capacity that higher Rq/tindicates higher denitrification potential, which can be readily obtained without complex measurement or analysis, and it offers a novel and promising respirogram-based approach for denitrification estimation and control by taking measures to extend anoxic time to maintain its value at a high level within a certain range.

Mechanism of ball milled activated carbon in improving the desalination performance of flow-and fixed-electrode in capacitive deionization desalination

Capacitive deionization(CDI)is a novel electrochemical water-treatment technology.The electrode material is an important factor in determining the ion separation efficiency.Activated carbon(AC)is extensively used as an electrode material;however,there are still many deficiencies in commercial AC.We adopted a simple processing method,ball milling,to produce ball milled AC(BAC)to improve the physical and electrochemical properties of the original AC and desalination efficiency.The BAC was characterized in detail and used for membrane capacitive deionization(MCDI)and flow-electrode capacitive deionization(FCDI)electrode materials.After ball milling,the BAC obtained excellent pore structures and favorable surfaces for ion adsorption,which reduced electron transfer resistance and ion migration resistance in the electrodes.The optimal ball-milling time was 10 h.However,the improved effects of BAC as fixed electrodes and flow electrodes are different and the related mechanisms are discussed in detail.The average salt adsorption rates(ASAR)of FCDI and MCDI were improved by 134%and 17%,respectively,and the energy-normalized removal salt(ENRS)were enhanced by 21%and 53%,respectively.We believe that simple,low-cost,and environmentally friendly BAC has great potential for practical engineering applications of FCDI and MCDI.

Bioaerosol emissions variations in large-scale landfill region and their health risk impacts

Landfills are widely complained about due to the long-term odor and landfill gas emissions for local residents,while the bioaerosols are always neglected as another threat to on-site workers.In this study,bioaerosols samples were collected from the typical operation scenes in the large-scale modern landfill,and the emission levels of airborne bacteria,pathogenic species,and fungi were quantified and co-related.The corresponding exposure risks were assessed based on the average daily dose via inhalation and skin contact.It was found that the levels of culturable bacteria and fungi in all landfill samples were around 33–22778 CFU/m3 and 8–450 CFU/m3,and the active-working landfill area and the covered area were the maximum and minimum emission sources,respectively,meaning that the bioaerosols were mainly released from the areas related with the fresh waste operation.Acinetobacter sp.,Massilia sp.,Methylobacterium-Methylorubrum sp.and Noviherbaspirillum sp.were the main bacterial populations,with a percentage of 42.56%,89.82%,70.24%and 30.20%respectively in total bioaerosols measured.With regards to the health risk,the health risks via inhalation were the main potential risks,with four orders of magnitude higher than that of skin contact.Active-working area showed the critical point for non-carcinogenic risks,with a hazard quotient of 1.68,where 80 m protection distance is recommended for on-site worker protection,plus more careful protection measures.