ABSTRACT It is necessary to use new technologies to mitigate water scarcity in the semi-arid region. As such, the aim of this study was to evaluate the operational and energy performance of a ridge ...planter and fertiliser, as well as the deposition depth of maize seeds and fertiliser as a function of the sowing system, and the use of different furrowing mechanisms (disc and shank) for depositing fertilisers. The experimental design was of randomised blocks, in a 6 x 2 factorial scheme with four replications, including six sowing systems: (S1 - intercropped ridge-sown maize; S2 – monocropped ridge-sown maize; S3 - intercropped furrow-sown maize; S4 – monocropped furrow-sown maize; S5 - conventional intercropping system; S6 - conventional monocropped system) and two mechanisms for depositing the fertiliser (offset double disc and shank furrower). The statistical analysis was carried out using the SISVAR software at 5% significance. It was concluded that, irrespective of the sowing system (ridge or furrow) and mechanism employed, there is no difference in the initial plant population or in the depth of the maize seeds. However, greater attention must be paid to the depth of both the fertiliser and forage seeds when these are deposited at the same time. Sowing systems that turn the soil (furrow and ridge) consume more energy, as does the shank mechanism. Sowing system S5 affords better operating performance when used together with the disk mechanism.
Background: Sepsis is a highly mixed ailment that affects patients with numerous conditions of infectious sources and can lead to multi-organ failure with dysregulated host immune response. ...Objective: To determine inflammatory biomarkers in patients with sepsis caused by Gram-negative bacteria and compare their role in the early detection of sepsis. Methods: This cross-sectional study was conducted on patients with sepsis admitted to the intensive care unit at different hospitals in Sulaimaniyah, Iraq, from May to December 2021. Patients (n=147) were enrolled in this study according to the primary diagnosis of sepsis by Sequential Organ Failure Assessment scores. Blood samples were taken from patients to investigate white blood cells, inflammatory biomarkers (pentraxin-3, procalcitonin, adrenomedullin, lipopolysaccharide binding protein, interleukin-17A, lactate dehydrogenase, and C-creative protein), blood culture, antibiotic susceptibility test, and coagulation biomarkers (Prothrombin time, activated partial thromboplastin time, and international normalized ratio). Then, isolated Gram-negative bacteria were tested for extended-spectrum P-lactamase enzymes production by screening and combined disc tests. Results: A total of 51.7% samples were blood culture positive for different Gram-negative bacteria, and P. aeruginosa (51.95%) was a more isolated bacterium. Both males and females were affected by sepsis in a ratio of 1.23:1 with different age groups. Extended-spectrum P-lactamase was estimated to be 77.2% by antibiotic profile, and the rate decreased using two double-disc synergy tests. This was confirmed by combined disc test at a rate of 41.35%. The most prevalent biomarkers were procalcitonin (88.16%), adrenomedullin (84.21%), pentraxin-3 (22.37%), and lipopolysaccharide binding protein (11.84%). Conclusion: Sepsis is a life-threatening condition that can be diagnosed early by several blood biomarkers such as procalcitonin, adrenomedullin, and pentraxin-3 combined with a standard blood culture technique to improve the patient outcome. Keywords: P-Lactamase, double-disc synergy test, SOFA score, sepsis biomarkers, Gram-negative bacteria
Complex geological factures are often encountered in the tunneling boring machine (TBM) excavation leading to many serious problems, especially the mixed ground conditions involving in the different ...geological properties should be paid more attention. To better investigate the effects of the mixed ground characteristics on rock fragmentation process by double TBM cutters, the model embedded crack propagation algorithm combined with M-C failure criterion has been calibrated for the mixed ground by double disc cutters. And then, the cutting simulations are conducted by 3DEC considering joint spacing, joint orientation and confining stress. The results under different conditions indicate that smaller joint spacing implying weaker properties favorably cause more cracks initiation and propagation by double cutters, and the cracks are tending to propagate along the joint plane and facilitate the rock chips beneath the cutters. And it is found that the joints are inclined to the soft rocks, more shear failure induces more cracks propagating inside the soft rocks, indicating that these rocks can be fragmented more completely. Meanwhile, with the increase of confining stress, rock fragmentation is more difficult resulting in the decrease of the cutting efficiency, especially the cracks induced by shear failure in soft rocks propagating along the free surface and interface cannot link the minor cracks by tensile failure in hard rocks to form rock chips. Furthermore, as noted from the variation of fragmentation load and specific energy under different conditions, smaller joints spacing causes smaller fragmentation load and specific energy to improve the cutting efficiency, however, greater confining stress gives more restrain for the cracks propagation, and the rock chips cannot effectively form between two types of rocks, resulting in lower fragmentation efficiency. And in addition, the optimal cutter spacing has also been analyzed under above conditions, which helps to provide appropriate measures for improvement of rock fragmentation efficiency and TBM performance during the TBM excavation process.
Increased wood softening and refining intensity have earlier been utilized to improve refining efficiency in mechanical pulping. We have evaluated a combination of increased softening by low dose ...sulphite chip pretreatment and increased intensity by feeding segment design in a TMP line for production of high quality printing papers.
Norway spruce wood chips were preheated, compressed in an Impressafiner and impregnated with water or sodium sulphite solutions (Na
SO
charges 3.6 and 7.2 kg/t). Chips were refined in two parallel 68” double disc refiners using two different refining conditions: standard bidirectional segments at normal production rate (9 t/h) and feeding segments at increased production rate (11.1–12.1 t/h).
The feeding segments enabled a 30 % increase in production rate. Refining with feeding segments at 12.1 t/h production rate combined with chip pretreatment with 3.6 kg/t sodium sulphite reduced the specific energy 360 kWh/t (19 %) compared to refining with standard segments and no pretreatment. Pulp properties were similar for the two configurations. The combination of feeding segments and chip pretreatment with water reduced the specific energy 180 kWh/t (9 %). Implementation of most of the technology presented has reduced the electrical energy use for the mill by approximately 80 GWh/year.
Various phenotypic methods are recommended in the routine practice to detect the ESBL production in gram negative bacilli. Among them, the Double Disc Synergy Test (DDST) which uses the third ...generation cephalosporins (3GC), is a simple and a reliable method. But the coexistence of AmpC may give false negative results. In such cases, the ESBL detection can be improved by using cefepime along with the third generation cephalosporins in DDST.
A total of 350 urinary isolates (224 Escherichia coli and 126 Klebsiella pneumoniae) were studied for ESBL production by the modified double disc test (MDDST) i.e. by using cefotaxime, ceftriaxone, cefpopdoxime (third generation cephalosporins) and cefepime ( fourth generation cephalosporin) along with a amoxicillin-clavulanate disc.
ESBL production was seen in 63.4% (142/224) Escherichia coli and in 60.3% (76/126) Klebsiella pneumoniae isolates by MDDST. Among these, in twelve E.coli and five K.pneumoniae strains, only cefepime but none of the third generation cephalosporins showed synergism with amoxicillin-clavulanate. All these seventeen strains showed a clear extension of the edge of inhibition which was produced by cefepime towards the amoxicillin-clavulanate disc. These strains were further tested for AmpC co-production by the AmpC disc test and all these strains were found to be AmpC positive, thus revealing the superior activity of cefepime in detecting ESBLs in the bacteria which co-produced AmpC. A high degree of coresistance was found in the ESBL producers.
The ESBL detection can be improved by MDDST by using cefepime along with the third generation cephalosporins.
Klebsiella pneumoniae is one of the main opportunistic pathogens which can cause different types of infections. Production of beta-lactamases like AmpC and ESBL mostly lead to beta-lactam resistance ...in these Gram-Negative bacteria. The aim of this study was the detection of AmpC-producing K. pneumoniae in clinical isolates.
Three hundred and three isolates of K. pneumoniae were identified. Double disc method including cefoxitin with cefepime and using boronic acid with cloxacillin were performed as two phenotypic methods for detection of AmpC. Amplification of AmpC gene was performed by PCR.
Eight and three isolates showed positive results in double disc method and by using boronic acid with cloxacillin, respectively. Five isolates had specific band for AmpC gene after electrophoresis.
Our results were indicated the low prevalence of AmpC-producer-K. pnemoniae in Iran. On the other hand these two tested phenotypic methods showed low sensitivity for detection of AmpC.
This paper addresses challenges in the application of existing colters in Chinese ecological tea plantations due to abundant straw roots and insufficient tillage depth. Aligned with the agronomic ...requirements of hilly eco-tea plantations, our study optimizes the structural advantages of the joint use of rotary tillage blades and double-disc colters to design an efficient trenching device. Our investigation explores the motion characteristics of a double-disc colter during deep trenching operations, in conjunction with rotary tillage blades. Employing discrete element method (DEM) simulations, this paper aims to minimize the working resistance and enhance the tillage depth stability. Single-factor experiments are conducted to determine the impact of key structural parameters on the tillage depth stability and working resistance. The optimal parameters are determined as a relative height of 80 mm to 120 mm, a 280 mm to 320 mm diameter for the double-disc colter, and a 10° to 14° angle between the two discs. The central composite design method is used to optimize the structural parameters of the double-disc colter. The results indicate that when the relative height is 82 mm, the diameter of the double-disc colter is 297 mm, and the angle between the two discs is 14°, the tillage depth stability performance reaches 91.64%. With a working resistance of merely 93.93 N, the trenching device achieves optimal operational performance under these conditions. Field validation testing shows a tillage depth stability coefficient of 92.37% and a working resistance of 104.2 N. These values deviate by 0.73% and 10.93%, respectively, from the simulation results, confirming the reliability of the simulation model. A field validation test further confirms that the operational performance of the colter aligns with the agronomic requirements of ecological tea plantations, offering valuable insights for research on trenching devices in such environments.
Analyzing the dynamic characteristics of an aero-engine rotor-bearing system helps professionals predict and judge the dynamic behavior of aero-engines. It is different from the traditional dynamic ...analysis of rotor system with fixed foundation, this paper considers the dynamics of the rotor-bearing system caused by the horizontal yawing maneuver load. This paper establishes a finite element model of a double-disc rotor-bearing system, and use the Newmark-β algorithm to solve the system. The model established in this paper is compared with the model established in ANSYS software, and the correctness of this model is verified. The influence of the maneuver load on the nonlinear dynamics of the rotor-bearing system under horizontal yawing is analyzed in detail. The study found, the maneuver load can suppress nonlinear vibration; the increase of maneuver load can reduce the nonlinear influence of the system caused by changes in relevant bearing parameters; and between two times the critical speed and three times the critical speed, the system will produce rich and complex nonlinear dynamic phenomena such as single periodic motion, multi periodic motion, and quasi-periodic motion.
The arrangement of disc cutter on a cutter head is important to improve the performance of TBM (tunnel boring machine) cutter, cutter life and cutter disc bearing life, then reduce vibration of TBM ...and reduce the noise. The rock breaking with double disc cutters is the basis of study on the distribution of disc cutter on cutter head, and it plays an important role on optimum arrangement of disc cutter on cutter head. In the process of rock breaking with double disc cutters, the axial vertical distance between two cutters is an important construction parameter, which directly affects rock breaking efficiency. Therefore, research on optimal cutter spacing and analysis of adaptability between cutter spacing and rock characteristics play an important role in optimizing the arrangement of cutter on the cutter head and improving the rock breaking efficiency of TBM. This paper analyzed the breaking rock force of double disc cutters. Taking granite samples as an example, the process of rock breaking with double disc cutters was simulated. Then rock fragmentation analysis based on different cutter spacing was carried out. Finally, the rock of different cutter spacing adaptability was studied. A series of conclusions about double disc cutters breaking rock were drawn.
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