Search

Efficient machine milking requires an optimal interaction of alveolar milk ejection in the udder and milk removal by the milking machine. The aim of the present study was to test whether the equilibrium between continuous milk ejection and milk removal can also be maintained at very fast milking through a particularly high vacuum. Eight Holstein dairy cows were milked at 42, 52, or 60 kPa, with (PS) or without (nPS) prestimulation. Each of the 6 treatments was conducted at 2 afternoon milkings in each animal. The prestimulation lasted 40 s and consisted of forestripping and teat cleaning. The cluster attachment followed after a 20-s latency period. Throughout each milking, B-mode ultrasound videos of the gland cistern of 1 front quarter as well as milk flow and claw vacuum curves were recorded. Total milk yield was neither affected by nPS or PS nor by the vacuum level. Milk removed within the first minute and the first 2 min of milking and average milk flow were higher, and the duration of incline and time until peak milk flow were shorter at PS than at nPS milkings at all vacuum levels. Machine-on time was shorter at PS than at nPS milkings, although only at 42 and 52 kPa vacuum, obviously caused by the high percentage of bimodalities occurring in nPS milkings (17% bimodalities in PS vs. 92% bimodalities in nPS milkings). The frequency of bimodalities was higher at high than at low vacuum both in PS and nPS milkings. Peak flow rate and average milk flow were both higher at higher vacuum levels. The duration of milk flow plateau was shorter at 60 kPa than at 42 kPa milkings. At the highest vacuum (60 kPa), the shorter plateau phase indicated a declining milk ejection rate toward the end of the plateau phase, and milk ejection could no longer keep up with the fast milk removal; hence, a higher milking efficiency at a higher vacuum level could only be achieved as long as the gland cistern remained sufficiently filled by the continuous milk ejection. The ultrasound imaging confirmed this finding as the duration of cisternal area plateau in the recorded front quarter was shorter at high than at low vacuum. Thus, the highest vacuum of 60 kPa did not cause a shorter machine-on time than 52 kPa. In conclusion, milking at a very high vacuum can increase milking efficiency compared with a low vacuum. However, a vacuum reduction at the start and toward the end of milking is required to prevent overmilking if milking is performed at a very high vacuum. [ABSTRACT FROM AUTHOR]

Milking machine design and performance are directly related to the milkability of sheep and goats, with the aim of milking quickly, completely and gently. This leads to an increase in the milk yield with improved quality, and the maintenance of healthy udders. The aim of this study was to carry out laboratory tests to determine the optimal level of vacuum, pulsation rate and pulsation ratio of new milking machines in high and low milk lines for sheep and goats. This study was conducted at the Department of Research and Development, Siliconform, Germany. For this purpose, different levels of vacuum (32, 34, 36, 38 and 40 kPa), milk jet (2, 2.5, 3 and 4 mm), milk line (high line and low line) and pulsation ratio (50:50 and 60:40) were used. First minute water flow (1st WF/kg) was used as an indicator for assessing the best combination in the milking machine. In addition, the cyclic vacuum fluctuation was measured in the inner chamber of the teat cup during the 1st WF/kg with the aid of a Vacuscope device. Statistical analysis was conducted using the mixed procedure in SAS. Our results show that the vacuum level, the milk jet and the pulsation ratio had a significant influence (p < 0.05) on the 1st WF/kg in the two milking machines for goats and sheep. In conclusion, the ideal conditions for milking goats with air inlet teat cups in the milking machine are a vacuum level of 36–38 kPa (low line) and 38–40 kPa (high line), a pulsation rate of 90 cycles/min and a pulsation ratio of 60:40, while the ideal conditions in the sheep milking machines are a vacuum level of 35–36 kPa (low line) and 36–38 kPa (high line), a pulsation rate of 120 cycles/min and a pulsation ratio of 60:40 or 50:50. [ABSTRACT FROM AUTHOR]

Kinetics of water removal and total soluble solid (TSS) content change of black cherry tomato (cv. OG) sauce by rotary vacuum evaporation (RVE) were investigated. The effect of different vacuum conditions (vacuum levels and boiling temperatures of 500 mmHg - 80° C, 550 mmHg - 75°C, 600 mmHg - 70°C and 650 mmHg - 65°C) during evaporation /concentration was examined. Tomatoes puree with an initial TSS of 13.47±0.18° Brix was concentrated to 39.83±0.30° Brix. There was a linear relationship between water removal and time during the concentration of black cherry tomato sauce by RVE. The TSS change of tomato sauce during the concentration was applied to three exponential mathematical models (two-parameter, three-parameter, and four-parameter). In studying the consistency of all models, some statistical indicators, namely the coefficient of determination (R² ), the chi-square (χ² ) as well as the root mean square error (RMSE) were considered. Among the models, the three-parameter exponential model was proven to best describe the concentration behavior of the tomato sauce using rotary vacuum evaporation with the highest R², the lowest χ², and the lowest RMSE. The validation with the experimental data at other vacuum levels had also confirmed the consistency of the selected model. This knowledge is very important for process optimization and product quality improvement. [ABSTRACT FROM AUTHOR]

The energy level alignment of a blended mixture of organic semiconductors is often depicted as having a common vacuum level. However, this is not a universal phenomenon among the vast number of organic semiconductors that currently exist, as in many cases the energy levels align via the Fermi level. In this report, the energy level alignments of the mixtures; poly(9-vinylcarbazole) (PVK) and 2,7-bis(diphenylphosphoryl)-9,9′-spirobifluorene (SPPO13) and poly(3-hexylthiophene-2,5-diyl) (P3HT) and SPPO13, with varying SPPO13 concentrations, are measured. It was found that the blended systems exhibit two different vacuum levels with the dipole between the PVK and SPPO13 increasing with the SPPO13 concentration, whilst the P3HT and SPPO13 vacuum levels only experience a small change. This is attributed to the decreasing electronic screening with increasing SPPO13 concentration. These new observations have an important implication in our understanding of interfacial behaviour for blended systems commonly used in various organic electronic devices. [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: The quality of nutritionally enhanced foods can be determined by evaluating changes in the volatile compounds produced in these foods over time. In this work, selenium‐enriched germinated brown rice (Se‐GBR), germinated brown rice (GBR), and brown rice (BR) stored under 90% relative humidity, 38 °C, and various vacuum levels were investigated. The relative abundance and differences of volatile compounds in Se‐GBR, GBR, and BR over various storage periods were detected. The correlation of volatile compound abundance with vacuum level and storage time was analysed using principal component analysis (PCA). RESULTS: Volatile compounds in the three samples were quantified at various storage periods (0, 90 and 150 days). Approximately 100 volatile compounds and eight species were identified and classified. Various proportions or types of volatile compounds were found in each sample at different sampling times. PCA results showed an isolation of volatile compounds in terms of sampling day and vacuum level at each storage period. CONCLUSION: Changes in volatile compounds over time and vacuum levels can provide bases for assessing of the nutritional quality of Se‐GBR, GBR, and BR. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

This study tested the hypotheses that machine milked dairy sheep have a high prevalence of teat-end hyperkeratosis (TEH), which contributes to udder health problems. A random sample of 1360 milking ewes from 28 dairy sheep farms was monitored. Milking procedures, milking parlour characteristics and maintenance were recorded during a designated on farm audit; records were obtained through observations and interviews with farmers. Number of ewes/milker, ewes/milking unit and milkings/milking unit were calculated. Vacuum level, pulsation rate and ratio were measured. Four combinations of vacuum level and pulsation rate were defined; <40 kPa and <150 cycles/min (VP1), <40 kPa and ≥150 cycles/min (VP2), ≥40 kPa and <150 cycles/min (VP3), ≥40 kPa and ≥150 cycles/min (VP4). California Mastitis Test (CMT; scores 0-4) was done on all ewes. Then the udder of each ewe was assessed for TEH (scores 1-4) and ewes were assigned into three groups according to TEH severity (no or mild, medium and severe TEH). Severe TEH (scores 3 and 4) prevalence at teat-level was ca. 13%. TEH severity was associated with the combination of vacuum level and pulsation rate; ewes milked with VP4 combination were more likely to have a one-level increase on TEH severity compared to ewes milked with VP2 and VP3 combinations. More ewes/milker and less ewes/milking unit increased the likelihood of a one-level increase on TEH severity. Finally, ewes with severe TEH were more likely to have a one-level increase on CMT score. Therefore, our hypotheses that TEH is prevalent in dairy ewes and contributes to udder health problems were confirmed. Additionally, farmers can reduce TEH prevalence by optimising the way they milk and their milking parlour. [ABSTRACT FROM AUTHOR]

The elevated vacuum suspension system (EVSS) has demonstrated unique health benefits for amputees, but the effect of vacuum pressure values on knee contact force (KCF) is still unclear. The objective of this study was to investigate the effect of vacuum levels on KCF for unilateral transtibial amputees (UTA) using the EVSS. Three-dimensional gait was modeled for 9 UTA with five vacuum levels (0–20 inHg [67.73 kPa], 5 inHg [16.93 kPa] increments) and 9 non-amputees based on kinematic and ground reaction force data. The results showed that the vacuum level effects were significant for peak axial KCF, which had a relatively large value at 0 and 20 inHg (67.73 kPa). The intact limb exhibited a comparable peak axial KCF to the non-amputees at 15 inHg (50.79 kPa). At moderate vacuum levels (5 inHg [16.93 kPa] to 15 inHg [50.79 kPa]), co-contraction of quadriceps and hamstrings at peak axial KCF was similar for the intact limb, but was smaller for the residual limb comparing with the non-amputees. The intact limb showed a similar magnitude of quadriceps and hamstrings force at 15 inHg (50.79 kPa) to the non-amputees, but the muscle coordination patterns varied between the residual and intact limbs. These findings indicate that a proper vacuum level may partially compensate for the lack of ankle plantarflexor and reduce the knee loading. Of the tested vacuum levels, 15 inHg (50.79 kPa) appears most favorable, although additional analyses with more amputees are suggested to confirm these results prior to establishing clinical guidelines. [ABSTRACT FROM AUTHOR]

A combination of polyurethane foam and multilayer insulation is adaptive and qualified for cryogenic propellant storage application, both on orbit for long-duration mission and on earth before and during launching. A generalized layer by layer model has been proposed to predict the thermal performance of the “Foam - Variable Density Multilayer Insulation combination” (FMLI) at different vacuum levels. A cryogen boil-off calorimeter system was designed and fabricated to measure the temperature profile and the apparent thermal conductivity of FMLI samples over a wide range of vacuum level (10 −3 - 10 5 Pa). The experimental data verified the validity of the model and indicated that the heat fluxes through the FMLI and the single VDMLI almost made no difference in vacuum of 10 −3 Pa, which were both equal to 0.23 W·m −2 with the boundary temperatures of 77 and 293 K, respectively. However, at the atmosphere level of 10 5 Pa, the heat fluxes through the FMLI and the single VDMLI significantly differed from each other and exacerbated to 45.2 and 147.8 W·m −2 , respectively. In addition, a comparison between FMLI and Aerogel-MLI was also conducted for the same thickness and weight of VDMLI and at the same boundary temperatures and vacuum levels. [ABSTRACT FROM AUTHOR]

Background: The elevated vacuum suspension system has demonstrated unique health benefits for amputees, but the effect of vacuum pressure values on gait characteristics is still unclear. The purpose of this study was to investigate the effects of elevated vacuum levels on temporal parameters, kinematics and kinetics for unilateral transtibial amputees. Methods: Three-dimensional gait analysis was conducted in 9 unilateral transtibial amputees walking at a controlled speed with five vacuum levels ranging from 0 to 20 in Hg, and also in 9 able-bodied subjects walking at self-preferred speed. Repeated ANOVA and Dunnett's t-test were performed to determine the effect of vacuum level and limb for within subject and between groups. Findings: The effect of vacuum level significantly affected peak hip external rotation and external knee adduction moment. Maximum braking and propulsive ground reaction forces generally increased for the residual limb and decreased for the intact limb with increasing vacuum. Additionally, the intact limb experienced an increased loading due to gait asymmetry for several variables. Interpretation: There was no systematic vacuum level effect on gait. Higher vacuum levels, such as 15 and 20 in Hg, were more comfortable and provided some relief to the intact limb, but may also increase the risk of osteoarthritis of the residual limb due to the increased peak external hip and knee adduction moments. Very low vacuum should be avoided because of the negative effects on gait symmetry. A moderate vacuum level at 15 in Hg is suggested for unilateral transtibial amputees with elevated vacuum suspension. [ABSTRACT FROM AUTHOR]

The aim of this paper was to study some of the teat characteristics involved in the milking ability of indigenous Greek goats such as the vacuum level of the milking machine that is required for the opening of the teat canal sphincter and the changes in the teat end wall thickness induced by milking. Thirty-six dams (12 of the first, 12 of the second and 12 of the third and subsequent lactations) were used after weaning (60 ± 5 days). Dams were milked twice a day (8:00 and 18:00 h) for 12 weeks in a milking parlour 1 × 12 side by side of Casse type with 6 milking units and a low milk line and air pipeline. The main functional characteristics of milking machine were: vacuum level 44 kPa, pulsation rate 90 pulsations/min and pulsation ratio 50:50. Every 14 days, during morning and evening milking the vacuum level that was required for the opening of the teat sphincter (VOTS) was measured. The measurement of teat end wall thickness (TEWT) was performed before and after milking. The results of this study showed that during the experimental period the mean VOTS was 23.57 ± 0.36 kPa and decreased significantly as the stage of lactation progressed (P< 0.001). The post-milking TEWT was 3.55% higher in comparison with that before milking (P < 0.01). A continuous and significant decrease in teat thickness was observed during the lactation stage (P < 0.001), which suggests a reaction to intramammary pressure and milk quantity in the udder. The TEWT was affected significantly by the parity (P < 0.01). A positive correlation was found between VOTS and TEWT before and after milking (0.4 and 0.36, respectively). It could be said that a lower vacuum level is required for the opening of the teat sphincter of the udder in goats of the indigenous Greek breed. The thicker teat end wall and more resistant sphincter could be less favourable in the machine milking of goats.

The aim of this study was to assess the effect of alternate and simultaneous pulsation on milking performance (milk yield, machine stripping milk, milking duration, and average milk flow rate) of Alpine goats milked at two different system vacuum levels (38 and 42 kPa). To this end, a field study was carried out in a commercial farm of Northern Italy. A pre-experimental period was carried out and 164 goats with a similar parturition date were selected and distributed into two similar subplots of 82 goats according to their values of milk yield and milking duration. The experiment lasted 24 d and was laid out as a split-plot design. Each treatment lasted 3 days. Once every combination (2 pulsation types × 2 vacuum levels) was tested (Experiment 1), the same experimental design was repeated in reverse order (cross-over design) to control the effect of lactation progress on the results (Experiment 2). Milk traits regarding milking performance (milk yield, machine stripping milk, milking duration, and average milk flow rate) and variables related to vacuum level in the milking cluster (vacuum in the short milk tube and vacuum fluctuation in the short milk tube) were recorded during morning and afternoon milkings. Results showed that the use of alternate pulsation reduced the vacuum fluctuations and increased the average vacuum in the short milk tube. Moreover, when a higher system vacuum level (42 kPa) was set, the use of alternate pulsation reduced the milking duration. We concluded that the use of alternate pulsation offers some advantages compared to simultaneous pulsation in high milk flow conditions. [ABSTRACT FROM AUTHOR]

A model for ‘blown pack’ probability (BPP) caused by spores of C.estertheticum DSM8809 and C.algidicarnis , was developed as a function of vacuum packaging variables: storage temperature(ST:-2, 2, 4 and 15 °C), vacuum level(VL:6 and 9mBar) and heat shrink temperature(HST:83 and 87 °C). Beef meat pieces, were inoculated with spore suspensions individually at 10 2 spores/cm 2 , packed and daily monitored up to 90 days. The lower BPP, estimated by the log-logistic model, for C.algidicarnis was 0.8% at:-1.5 °C/6mBar/87 °C while for C.estertheticum was 99.13% at the same conditions. For both organisms, tested variables were unable to eliminate the risk of blown packaged spoilage, at 10 2 spores/cm 2 contamination level. [ABSTRACT FROM AUTHOR]

Methods and models to determine the vacuum referred binding energy (VRBE) of electrons in luminescence impurity states and in host band states are briefly reviewed. Special attention is focussed on how electron bonding within anion ligands of the host compound and bonding between luminescence center and those ligands affect VRBEs, electronic properties, and luminescence properties. The chemical shift of 4f-electron VRBE, the centroid shift of 5d-electron VRBE and the Coulomb repulsion energy U for Eu appear strongly correlated with bonding and one may predict one from the other. Also conduction band and valence band energies of different compounds can be compared with each other and with reference to the common vacuum energy level. How that provides new insight in luminescence properties will be addressed. All models were derived from lanthanide spectroscopy. First results on the VRBE in transition metal impurities with single d-electron states are also reviewed. [ABSTRACT FROM AUTHOR]

Çal ışmada, pnömatik hassas ekim makinalar ı n ı n en önemli elemanlar ı ndan biri olan ekici delikli plaka üzerinde bulunan deliklerin şekil özelliklerinin, tohumlar ı n tutulma yüksekliklerine etkileri ara şt ı r ı lm ışt ı r. Bu amaçla, küresellik değeri oldukça dü şük olan ayçiçeği tohumlar ı materyal olarak kullan ı lm ışt ı r. Farkl ı 3 vakum seviyesinde -4, -6 ve -8 kPa ve 11 ayr ı delik kesit alan ı nda 7.1, 9.6, 12.6, 15.9, 19.6, 23.7, 28.3, 33.2, 38.5 44.2 ve 50.2 mm 2 ve dört farkl ı delik şeklinde daire, kare, üçgen, oblong denemeler gerçekle ştirilmiştir. Denemelerden elde edilen de ğ erler istatistiksel olarak de ğerlendirilmi ştir. Yap ı lan varyans analizi sonucunda, delik şekli, vakum ve delik kesit alan ı faktörleri aras ı nda üçlü interaksiyon belirlenmi ştir. Elde edilen Duncan gruplamas ı sonuçlar ı na göre; tüm kesit alanlar ı ve vakum bas ı nc ı seviyelerinde en düşük tohum tutulma yüksekliklerine kare kesitli deliklerde rastlanm ışt ı r. Bunu daire, oblong ve üçgen delik şekilleri izlemi ştir. Özellikle -8 kPa vakum bas ı nc ı değ erinde bu s ı ralama belirgin olarak görülmektedir. Ayn ı delik kesit alan ı nda vakum değ erlerinin artmas ı tutulma yüksekliklerinin artmas ı na neden olmu ştur. Ayn ı vakum değerlerinde ve ayn ı şekil özelli ğ indeki deliklerde, delik kesit alan ı değeri artt ı kça tohumlar ı n ortalama tutulma yüksekli ği değerlerinin de artt ığı gözlenmiştir

Spin-coated film of poly(vinylidenefluoride-hexafluoropropylene) (P(VDF-HFP)) acts as a cathode/anode buffer layer in polymer solar cells (PSCs) with conventional/inverted device structures. Such devices show optimized performances comparable with the controlled device, making P(VDF-HFP) a good substitute for LiF/MoO3 as a cathode/anode buffer layer. Ultraviolet photoelectron spectroscopy (UPS) and Kelvin force microscope (KFM) measurements show that increased surface potential of active layers improves cathode contact. In piezoresponse force microscopy (PFM) measurement, P(VDF-HFP) responds to applied bias in phase curve, showing tunable dipole. This tunable dipole renders surface potential under applied bias. As a result, open-circuit voltage of devices alters instantly with poling voltage. Moreover, positive poling of P(VDF-HFP) together with simultaneous oxidation of Ag gradually improves performance of inverted structure device. Integer charge transfer (ICT) model elucidates improved electrode contacts by dipole tuning, varying surface potential and vacuum level shift. Understanding the function of dipole makes P(VDF-HFP) a promising and versatile buffer layer for PSCs. [ABSTRACT FROM AUTHOR]

Abstract: Energy consumption for drying of mushroom slices was evaluated using various drying methods including hot air, microwave, vacuum, infrared, microwave-vacuum and hot air-infrared. Results of data analysis showed that the lowest and highest energy consumption levels in drying mushroom slices were associated with microwave and vacuum dryers, respectively. The use of vacuum in conjunction with microwave drying increased energy consumption relative to microwave drying alone. Energy consumption in the hot air dryer showed a downward trend with increasing temperature and an upward trend with increasing air velocity. In drying mushroom using infrared radiation, it was observed that increased air velocity increases drying time and consequently the amount of consumed energy. Using a combination of hot air and infrared drying decreased energy consumption relative to infrared drying alone and increased it relative to hot air drying. In the combined microwave-vacuum dryer, drying time and consequently energy consumption decreased in comparison to the vacuum dryer. Hot air-infrared drying of mushroom slices proved to have the lowest energy consumption. [Copyright &y& Elsevier]

Abstract: Suction cups are used extensively throughout the packaging industry, as well as most other fields of robotics. In this present work, by means of a theoretical and experimental approach, the minimum value of the vacuum force and the adhesion coefficient able to guarantee the grasp and movement of the object with suction cups have been studied. Using a special test rig, experimental measurements regarding the slipping conditions obtained by stressing plates grasped by a flat suction cup with tangential forces and torque have been carried out. The experimental results have been compared with those obtained from a theoretical model in two suction cup–object contact pressure hypotheses (edge contact and full contact). [Copyright &y& Elsevier]

Abstract: The aim of this work was to study some of the teat characteristics involved in the milking ability of dairy ewes, such as the vacuum level of the milking machine that is required for the opening of the teat canal sphincter, and the changes in the teat end wall thickness induced by milking. After weaning, 48 ewes of the mountainous Greek breed, Boutsiko (16 ewes of the first, 16 of the second and 16 of the third and subsequent lactations) were milked for 12 weeks. Every 14 days, during the morning and evening milking, milk fractions and composition were recorded. The vacuum level that is required for the opening of teat sphincter (VOTS) was also measured before milking. The measurement of teat end wall thickness (TEWT) was performed before and after milking and the milk flow was monitored during the morning milking only. The results of this study show that during the experimental period, the ewes had a mean daily milk yield of 862.9ml, of which the 173.3ml corresponded to the machine stripped milk (MSM). The mean VOTS was 16.59±0.7kPa and tended to decrease as the stage of lactation progressed. The TEWT (4.75±0.04mm) was not modified by milking. A continuous and significant decrease in teat thickness (from 5.03 to 4.3mm, P <0.05) was observed, which suggests a reaction to intramammary pressure and milk quantity in the gland. Parity was affected significantly (P <0.001) only the TEWT. The type of birth did not influence the VOTS and TEWT. Phenotypic correlations showed that by increasing the VOTS, the machine stripped milk increased as well, and so did the TEWT. These results give rise to the need for a possible reduction of the current vacuum level (44kPa), which should be applied in the milking of this particular mountainous Greek breed of sheep. [Copyright &y& Elsevier]

Abstract: Based on experimental observation and theoretical analysis, it explicates that light emission of a carbon nanotube-field emission display (CNT-FED) is mainly caused by electron bombardment on the phosphour if the level of vacuum ranges from 10−4 to 5Pa. In this case, light emission of the phosphour excited by ultraviolet (UV) light derived from gas discharge cannot be observed. If vacuum level is greater than 5Pa, no emitted light is observed, since a large amount of gas ionisation reduces the electric potential difference between the cathode and the anode. To analyze collision between electron and gas under field emission conditions, a mathematical and physical model was built. Based on this model the number of electron–gas collisions is calculated. Calculations results indicate that the product of gas pressure and distance between the electrodes (pd) is a better parameter to characterize the effect of vacuum level for FED than gas pressure only. Calculations results also show that if the distance between the cathode and the anode is increased, it should be to improve the vacuum level to obtain the same effect. [Copyright &y& Elsevier]

Abstract: The aim of this work was to determine the effect of vacuum level of machine milking on milk yield, milk composition, milking efficiency, somatic cells counts (SCC), and teat end thickness of the Greek mountain breed Boutsiko ewes. Seventy two ewes after a suckling period of 45±5 days were divided into three equal groups of 24 animals for level of milk production, prolificacy and lactation number. The overall experiment lasted 14 weeks. All groups were milked with a pulsation rate of 120/min, pulsator ratio of 50/50, and three vacuum levels of 38, 44 and 50 kPa, respectively, were applied for the three groups. Every two weeks, in a.m. and p.m. milking, measurements were taken for machine milk (MM) and machine stripped milk (MSM), milk composition, SCC, milk emission characteristics (only in a.m. milking) and teat end wall thickness (TEWT) before and after milking. The results have shown that the lower vacuum level of 38 kPa increased (P <0.05) the percentage of machine milk (82.9%). There were no significant differences among the groups for milk composition, milk flow rate and SCC, but there was a difference in log SCC (P <0.05) between 38 and 50 kPa. The teat end wall thickness was lower at the lower vacuum level (38 kPa) after milking, and increased (P <0.001) as the vacuum level was raised to 50 kPa. The findings of this study suggest that with a lower vacuum level of 38 kPa, the ewes are milked better than those with 44 or 50 kPa. Also, the irritation of teats is considerably reduced, while no differences were seen regarding the health of the udder. [Copyright &y& Elsevier]

Ultra violet photoelectron spectroscopy has been used in most of the research related to determination of the energy levels of the materials in multilayer devices, such as organic light emitting diodes, to measure the Fermi and HOMO levels of conductors and organic materials, respectively. The variation in the values reported in the literature often remains unexplained despite apparently similar experimental conditions. We report (i) on the methods that we have found are required to achieve reproducible and stable values of work function (WF) and ionization potentials (IP) of ITO and common organic layers, and (ii) on the origin of the variations. Not unexpectedly, we have found that hydrocarbon contamination arising from vacuum pumps (e.g. oil diffusion pumps) can cause significant changes in WF or IP. Of greater possible significance is the observation that continuous exposure to ultraviolet light can enhance these effects and can change the work function of an interface much faster than would occur in the absence of UV light. The major effect probably arises from effects of the secondary electrons produced by the 21.22 eV photons of the He resonance lamp. By dealing with these problems, we have been able to measure stable values for WF and IP over extended periods of time ranging from hours to days. [Copyright &y& Elsevier]

We present a UV photoemission (UPS) and topographic study of the indium–tin-oxide (ITO) anode used in organic light emitting diodes (OLEDs). The performance of these devices has been shown to be improved by introducing a thin layer of copper phthalocyanine (CuPc) between the anode and the hole-transport layer (HTL). While the device current at constant driving voltage increases with increasing CuPc thickness, the efficiency is optimized at 12–18 nm. In this article we address the issue of the charge (hole) injection process at the anode interface and demonstrate the importance of directly measuring the vacuum levels in quantitative study of the energy levels of OLED interfaces. As a result of this insight, many calculations relating to the relative energies of the bands at OLED interfaces may have to be revised and corrected. The interface morphologies were also studied using AFM to determine any changes with film growth. [Copyright &y& Elsevier]

The effects of vacuum level and overmilking on udder health were studied in ewes. Vacuum levels of 36 and 42 kPa were assigned to two groups of 23 Manchega ewes in a crossover study design with two experimental periods of 5 wk for each. Moreover, for each ewe, one teat was overmilked 1.5 to 2 min at all milkings during these 10 wk. The milking machine used had a midlevel milkline and pulsation was fixed at 180 cycles per min and a pulsation ratio of 50:50. Bacterial exposure of all teats was increased by dipping them in a suspension of Staphylococcus simulans at eight milkings of each period. New intramammary infections (IMI) were not significantly affected by the vacuum level used (18 and 23% of ewes infected, at 36 and 42 kPa, respectively) or application of overmilking (9 and 11% of half udders infected without and with overmilking, respectively). Likewise, neither factor significantly affected the somatic cell count (SCC) of the milk. Teat thickness changes after milking varied significantly due to the presence of overmilking (-13.6 and -7.4%, in teats not overmilked and overmilked, respectively) but were not affected by vacuum level. At no time were any lesions variations visibly noted in the teat walls or orifice. So, in this work we were unable to demonstrate that the vacuum and overmilking levels assayed, both used with a pulsation rate of 180 cycles/min, have an important effect on the state of udder health in the short Furthermore, it was also observed that, in absence of IMI, the two factors studied did not cause irritation of any kind in the gland that might influence the SCC of the milk. [ABSTRACT FROM AUTHOR]

This paper presents quantitative analysis of electron emission from nanocrystalline Si dots, and discusses its mechanism based on the calculations of electronic and phononic states. Analysis of emission energy distribution measured from the vacuum level shows that the energy at the peak of the distribution increases linearly with increasing voltage applied across the nanocrystalline Si system. The slope of the linear law is unity, regardless of process conditions. Increasing voltage significantly changes the shape of the distribution at the energies smaller than the peak, while it has minimal impact at the energies larger than the peak. Both the conventional field emission model and the metal-oxide-semiconductor model fail to explain those behaviors. Calculations of electronic and phononic states in a chain of the nanocrystalline Si dots indicate a possibility of strong suppression of electron energy relaxation, which may be a possible mechanism of the high-energy electron emission phenomena. [ABSTRACT FROM PUBLISHER]