The weld lines that occur in injection mouldings are critical areas on which depends on the strength of the mouldings. The flow of the material in the injection mould takes place through the gate and then gradually in the mould cavity. Depending on the shape of the formed object, the weld line may or may not occur. In the case of spreading of plastic streams or bypassing obstacles in the form of cores in the mould, the joining lines run down. Most often, the strength of the moulded part is the lowest in these areas and the resulting lines can cause cracking. The aim of the research presented in the publication was to evaluate the properties of particular parts of mouldings obtained from an experimental injection mould equipped with 4 weld line areas. The tests were performed using the method of thermal analysis by Dynamic Mechanical Analysis DMA. Tensile tests were performed on the parts with weld areas and the maximum crack force was determined. The morphology of the obtained fractures was observed using an optical microscope.

The aim of this study was to compare computer assisted sperm analysis (CASA) results of frozen thawed bull semen using three different chambers. Sixty bull frozen semen samples were thawed (37°C; 30 sec), extended in PBS (30×106 spermatozoa/mL; 37°C) and incubated (37°C; 2 min). Each semen sample was analyzed by CASA [total motility, progressive (pro)/ non-progressive/rapid/medium/slow movement spermatozoa, VCL, VSL, VAP, ALH, BCF, LIN, STR, WOB and hyperactive spermatozoa] using three different chambers: a Makler® chamber (MC; 10 μm); a Leja 4 chamber slide (LC; 20 μm); and a Glass slide covered with a coverslip (GSC; 10.3 μm). The Makler chamber gave higher values compared to both the LC and GSC for almost all examined parameters. No systematic effect was evident between LC and GSC for VCL, VSL, VAP, LIN, STR, WOB, ALH, and BCF. Method agreement between MC and LC was generally moderate, between MC and GSC poor and between LC and GSC moderate to good. In general, narrower limits of agreement were found in samples with lower values. In conclusion, the CASA outcomes could be influenced by the analysis chambers. This finding should be taken into consideration when comparing results from different laboratories.

The essential problem in the process of technological prestressing is the imperfection of web sheets. These elements made of relatively large sheets (about 2 meters high) show significant imperfections of the shape and flatness. Initial deflections have the value equal several times the web thickness, but they tend to grow in the process of straightening. Such a case can particularly occur when stresses that compress the shield of the web sheet between diaphragms are close to the critical buckling stress. Experiments were carried out in a real object. The box girder having I I .Om span and 1.8 m in its height was prestressed by welding the straps on the bottom flange and on the web in the vicinity of the bottom llange. Results of performed investigations are the subject of the paper.

Inflammation together with lipolysis and ketogenesis in early lactation can cause low productivity and may be harmful to the cow health. The objective of the study was to determine if ketoprofen treatment in the first days following parturition would positively affect the milk production and whether it was associated with the metabolic and inflammatory response. The study was conducted on 30 cows divided into two groups of 15 cows each. The experimental group was treated with 3 mg × kg. bw. -1 ketoprofen for three consecutive days after parturition. The blood samples were collected on the first day of treatment and in the first and second week postpartum and they were analyzed for non-esterified fatty acids (NEFA), beta-hydroxybutyrate (BHB), tumour necrosis factor-a(TNF-a) and haptoglobin. The results suggested that ketoprofen-treated cows with a higher milk production had a significantly lower concentration of NEFA, BHB, TNF-a and haptoglobin in the first and second week postpartum. No differences were found in the control group in metabolic status regardless of the achieved level of milk production. Ketoprofen administration in postpartum cows can enhance the milk yield. The higher milk yield in the experimental group might be associated with a lower degree of lipolysis, ketogenesis and reduced inflammatory response in the first two weeks postpartum.