Total Gas Volume Research Articles

ПНЕВМОКОМПЕНСАТОР ДЛЯ ПЛУНЖЕРНОГО НАСОСА С ПОГРУЖНЫМ ЛИНЕЙНЫМ ПРИВОДОМ

Актуальность. Разработана конструкция и принцип работы пневмокомпенсатора для плунжерного насоса с погружным магнитоэлектрическим двигателем, позволяющего снизить амплитуду колебаний давления на выкиде насоса путем выравнивания скорости потока жидкости в лифтовых трубах. При использовании в пневмокомпенсаторах диафрагмы, выполненной из резины с армированием, она становится устойчивой к разрушению, что в целом увеличивает эффективность работы и срок эксплуатации пневмокомпенсатора. Цель: разработать пневмокомпенсатор для плунжерного насоса с погружным магнитоэлектрическим двигателем. Провести прочностной анализ и оценку эффективности применения диафрагмы с армированием в пневмокомпенсаторах, применяемых для снижения пульсаций скорости и давления потока флюида в насосно-компрессорных трубах; обосновать выбор материала диафрагмы пневмокомпенсатора. Объекты: скважинные пневмокомпенсаторы, погружной бесштанговый плунжерный насос с линейным магнитоэлектрическим двигателем, колонна насосно-компрессорных труб. Методы: имитационное моделирование диафрагмы, закрепленной на перфорированной трубе, с применением программного комплекса «Компас 3D» модуль APMFEM; задание в граничных условиях расчетной модели технологических параметров при моделировании численных значений скорости, расхода, давления, температуры аналогичными действующей скважинной установке. Результаты. Установлено, что максимальные напряжения, возникающие в диафрагме в процессе работы пневмокомпенсатора, в 4 раза меньше предельно допускаемых, что показывает работоспособность пневмокомпенсатора в скважинных условиях. Показано положительное влияние армирования диафрагмы с точки зрения снижения максимальных напряжений в эластичной оболочке. Проанализировано влияние технологических параметров пневмокомпенсаторов (суммарного газового объема, начального давления в газовой камере) на эффективность их работы. Обосновано оптимальное давление зарядки пневмокомпенсаторов, которое не должно превышать минимально давление в насосно-компрессорных трубах в течение цикла откачки, чтобы исключить негативное влияние прижатия эластичной оболочки к перфорированной трубе (внутренней стенке пневмокомпенсатора).

Effects of Essential Fatty Acid Supplementation on in vitro Fermentation Indices, Greenhouse Gas, Microbes, and Fatty Acid Profiles in the Rumen.

This study estimated the effect of essential fatty acid (FA) supplementation on fermentation indices, greenhouse gases, microbes, and FA profiles in the rumen. The treatments used pure FAs consisting of C18:2n-6 FA (LA), C18:3n-3 FA (LNA), or a mixture of these FAs at 1:1 ratio (Combo). In vitro rumen incubation was performed in 50 mL glass serum bottles containing 2 mg of pure FAs, 15 mL of rumen buffer (rumen fluid+anaerobe culture medium = 1:2), and 150 mg of synthetic diet (411 g cellulose, 411 g starch, and 178 g casein/kg dry matter) at 39°C for 8 h with five replications and three blanks. In rumen fermentation indices, LA exhibited highest (P < 0.05) ammonia-N and total gas volume after 8 h of incubation. Furthermore, LA presented lower (P < 0.05) pH with higher (P < 0.05) total volatile fatty acid (P = 0.034) than Combo, while LNA was not different compared with those in the other treatments. Additionally, Combo produced highest (P < 0.05) CO2 with lowest (P < 0.05) CH4. In the early hours of incubation, LA improved (P < 0.005) Fibrobacter succinogenes and Ruminococcus flavefaciens, while LNA improved (P < 0.005) Ruminococcus albus. After 8 h of incubation, LNA had lower (P < 0.05) methanogenic archaea than LA and Combo but had higher (P < 0.05) rumen ciliates than LA. R. albus was higher (P < 0.05) in LA than in LNA and Combo. It was observed that the rate of biohydrogenation of n-6 and n-3 FAs was comparatively lowest (P < 0.05) in Combo, characterized by higher C18:2n-6 and/or C18:3n-3 FA and polyunsaturated FA (PUFA) concentrations with lower (P < 0.05) concentrations of C18:0 and saturated FA and the ratio of saturated FAs to PUFAs. Therefore, this study concluded that dietary C18:2n-6 could improve populations of fibrolytic bacteria and rumen fermentation indices, but dietary mixture of pure C18:2n-6 and C18:3n-3 is recommended because it is effective in reducing enteric methane emissions and resisting biohydrogenation in the rumen with less effect on rumen microbes.

Recycling iron from oolitic hematite via microwave fluidization roasting and magnetic separation

Oolitic hematite is an iron ore resource with complex refractory characteristics, abundant reserves, and significant recycling value. In this study, a clean and innovative microwave fluidization roasting method was developed. Iron concentrate with an iron grade of 58.72% and iron recovery of 89.32% was obtained via microwave pretreatment at 1050 °C for 2 min, followed by magnetization roasting at 650 °C for 5 min at a CO content of 30% and total gas volume of 700 mL/min. A vibrating-sample magnetometer analysis indicated that the saturation magnetization increased from 0.33 A·m2/kg for the raw ore to 42.52 A·m2/kg for the roasted products. Scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed that microwave pretreatment promoted the formation of microcracks at the interfaces between minerals, offering the advantages of a rapid reaction and phase transformation during the magnetization roasting. X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy analyses indicated that the iron mineral phase was selectively transformed from weakly magnetic hematite into strongly magnetic magnetite and that the iron mineral was effectively recycled from the roasted samples via magnetic separation.

Controls on Gas Emission Distribution on the Continental Slope of the Western Black Sea

The continental slopes of the Black Sea show abundant manifestations of gas seepage in water depth of &amp;lt;720 m, but underlying controls are still not fully understood. Here, we investigate gas seepage along the Bulgarian and Romanian Black Sea margin using acoustic multibeam water column, bathymetry, backscatter, and sub-bottom profiler data to determine linkages between sub-seafloor structures, seafloor gas seeps, and gas discharge into the water column. More than 10,000 seepage sites over an area of ∼3,000 km2were identified. The maximum water depth of gas seepage is controlled by the onset of the structure I gas hydrate stability zone in ∼720 m depth. However, gas seepage is not randomly distributed elsewhere. We classify three factors controlling on gas seepage locations into depositional, erosional, and tectonic factors. Depositional factors are associated with regionally occurring sediment waves forming focusing effects and mass-transport deposits (MTDs) with limited sediment drape. Elongated seafloor depressions linked to faulting and gas seepage develop at the base between adjacent sediment waves. The elongated depressions become progressively wider and deeper toward shallow water depths and culminate in some locations into clusters of pockmarks. MTDs cover larger regions and level out paleo-topography. Their surface morphology results in fault-like deformation patterns of the sediment drape on top of the MTDs that is locally utilized for gas migration. Erosional factors are seen along channels and canyons as well as slope failures, where gas discharge occurs along head-scarps and ridges. Sediment that was removed by slope failures cover larger regions down-slope. Those regions are devoid of gas seepage either by forming impermeable barriers to gas migration or by removal of the formerly gas-rich sediments. Deep-rooted tectonic control on gas migration is seen in the eastern study region with wide-spread normal faulting promoting gas migration. Overall, gas seepage is widespread along the margin. Gas migration appears more vigorous in shallow waters below ∼160 m water depth, but the number of flare sites is not necessarily an indicator of the total volume of gas released.

Modified biogas digester tank for production of gas from decomposable organic wastes

This research output is focused on the modified design of a low-cost biodigester using a 295L of steel drum. The system has a 15kg bio-methane storage tank of 182L with a water displacement tank of 20L standard steel drum. Incorporated into the design is a cast iron with centrally positioned four impeller shaft to enhance mixing of substrate. A floating storage tank was designed, fabricated, and used for effective storage of bio-methane; biogas was produced from mixture of cowdungs, which was filtered to remove substituent of biogas. The retention time was for 4 weeks during which the pH valve and temperature variation were noted. Maximum biogas production was attained on the 8th, 9th, and 19th day, and the total volume of gas produced ranges between 92.6 and 102 mL/day. The test result showed that methane gas produced the highest percentage of biogas. Additionally, from the result, the displacement of ethane, ethylene, propane, propylene, I-butane, nitrogen, carbon monoxide, carbondioxide and other gases were minimal compared to methane gas.

Development of a 100-Watt-Scale Beta-Type Low Temperature Difference Stirling Engine Prototype

This paper documents the ongoing design process of a Stirling engine prototype for a source temperature of 95 °C, aiming to achieve shaft power on the order of 100 Watts. The engine will serve to produce experimental data for the validation of a numerical low temperature Stirling model. The higher-level motivation is to assess the technical and economical potential of producing power from abundant sources of low temperature heat by using Stirling engines. Design decisions are governed by the goals of minimizing energy losses and maximizing the variability of operating points through variable heat exchanger geometry, compression ratio and charge pressure. The resulting design is a beta engine with a total gas volume around 100 liters. It features displacer and power pistons in a combined cylindrical working space and a mechanism using pivoting links similar to a bellcrank. The stroke of the power piston is adjustable while maintaining a constant top dead center position. A component critical for friction is the power piston seal, for which a low friction rolling seal and a conventional sliding seal were considered. As of June 2021, the development is at an advanced state and the first set of components are entering production.

The effect of a candidate feed additive derived from the essential oils of Pinus merkusii (jungh. &amp; de vriese) and Melaleuca leucadendra (l.) on the kinetics of gas production and methane emitted during in-vitro ruminal fermentation

The study was designed to determine the effect of a candidate natural feed additive on the kinetics of gas production as a representation of feed degradability and methane produced during rumen fermentation. Three blends of essential oil (BEO) as candidates for feed additives were formulated using pine and eucalyptus essential oils in the following ratios: 75:25, 50:50, and 25:75 for BEO1, BEO2, and BEO3, respectively. Every BEO was added to the batch fermentation system at dosages of 0, 100, and 200 l/l in the medium. Furthermore, an in vitro gas production technique was used to simulate rumen feed fermentation. According to the gas production kinetics, all BEO additives did not affect the total potential gas produced, as well as the potential gas produced from the soluble and insoluble substrate. The rates of gas production were similar among treatments. Furthermore, the addition of BEO did not affect the total volume of gas produced during fermentation. Meanwhile, BEO1 at 200 l/l dose and BEO 3 at 100 l/l dose significantly reduced methane production (P0.05). In conclusion, the BEO1 and BEO 3 at dosages of 200 and 100 l/l, respectively, had the potential as a feed additive to reduce methane production without a negative effect on nutrient digestibility.

Improvement of Renewable Bioenergy Production in Microbial Fuel Cells with Saponin Supplementation

Microbial fuel cell (MFC) is one of renewable biofuel production technology that directly converts biomass to electricity. Cellulosic biomass is particularly attractive renewable resources for its low cost and abundance and neutral carbon balance. However, methanogenesis remains as a major factor limiting MFC performance. The current study reports that saponin addition at 0.05% w/v dose to anolyte in MFCs inhibited methanogenesis and improves power generation and cellulose fermentation. Mediator-less two chamber H-type MFCs were prepared using rumen fluid as anode inocula at 20% v/v of anolyte to convert finely ground pine tree (Avicel) at 2%, w/v to electricity. Saponin was added to the anode of MFC at 0.005% or 0.05% v/v dosage for treatment. MFC power and current across an external resistor were measured daily for 10d. On d10, collected gases from anode compartment were measured for total gas volume and analyzed for gas composition on gas chromatography. Supplementation of saponin to MFC at 0.005% did not have any effects on electricity generation or biogas production and composition. Saponin at 0.05% dose reduced 10% of methane production and increased 40% of CO2 production and 6.4% of total gas production for 10d MFC operation. Voltage across resistor prior to treatment addition (d0) was 164.75 ± 9.07 mV. In control group, voltage across resistor did not change (P = 0.9153) with time course and mean was 167.8 ± 8.20 mV ranged from 157 to 174.5 mV during 10d operation. In 0.05% Saponin group, voltage across resistor increased (P 0.0001) after d2 and mean was 187.3 ± 4.30 mV ranged between 161.5 and 204.0 mV and the 10d mean of voltage across resistor in 0.05% Saponin was greater (P 0.0001) than in control group. 0.05% Saponin also had greater voltage across resistor at d5 (P = 0.0030) and d6 (P = 0.0246) than control. End point potential increased (P 0.0001) in 0.05% Saponin after d2. 0.05% Saponin had greater (P 0.0001) in 0.05% Saponin. Power density increased (P 0.0001) after d2 in 0.05% Saponin. 0.05% Saponin MFCs had greater (P 0.0001) overall mean of 10d operation. The current study provides strong background for potential use of saponin and saponin containing natural resources for methanogenesis inhibitor and cellulolysis enhancer in MFC and also cellulolysis reactors.

Gas release rates and properties from Lithium Cobalt Oxide lithium ion battery arrays

Lithium-ion batteries are increasingly being used for residential, commercial, and utility scale energy storage applications, any of which could include hundreds or thousands of individual cells, depending on the capacity of the individual cell. Hazard mitigation for multi-cell batteries should rely on data on the rate of cell-to-cell failure (i.e., thermal runaway propagation) and the rate and composition of flammable gases vented during such failure events. To generate such critically important data, experiments were conducted in a 53.5 L pressure vessel to characterize the gas vented from Lithium Cobalt Oxide (LCO) lithium-ion batteries, including rate of gas release, total gas volume produced, and gas composition. Experiments were conducted at three different states of charge (SOC) for single cells and arrays of five and ten cells. Three cell capacities were studied (5 Ah, 10 Ah, and 18.5 Ah). The data presented on the rate of release of vented gas are a significant addition to the literature. This paper also identifies key differences between single cell and cell array testing. The data provided in this paper can be used to make better decisions for ventilation and other safety systems for lithium-ion battery deployments.

Gas transmission capability curve of natural gas system: Concept and steady-state model

This paper proposes the concept of gas transmission capability curve of natural gas system, which expands the classic gas transmission capability (GTC) index. GTC, defined as the maximum allowable flow rate of a natural gas system, is used to describe the transmission capability limit of the system. However, we find that the complete capability limit should be described by a curve (GTC curve) instead of GTC, because GTC is just one point of the curve and many other critically secure states still exist except for GTC. Based on this finding, firstly, we define and model the GTC curve as the set consisted of all the critically secure states. Secondly, the sampling-based method is proposed to draw the GTC curve. Finally, we propose the related assessment indices of GTC curve. Two typical test systems are used to verify the existence of GTC curve and the proposed methods. In the two systems, there exist about 71% and 77% of critical states on the GTC curve whose total gas volumes are GTC respectively, while 29% and 23% of the critical states are not, their total gas volumes are smaller than GTC with different degrees and the most degree can reach 5.6% and 13.1% respectively. The GTC curve can describe the capability limit of the system completely, which will help the operators better understand the operational limit of the system as well as improve the security and reliability of planning schemes.

In vitro gas production and dry matter degradability of cassava top and maize stover mixture ensiled with Albizia saman pods

In vitro gas production is an indication of microbial degradability of feed samples. Thus varying levels of mixture of cassava top (CT) and maize stover (MS) ensiled with Albizia saman pods (ASP) were examined. The feedstuff were dried and milled for gas determination in a completely randomized design. Samples were incubated using in vitro gas production technique. Gas production was measured at 3, 6, 9, 12, 15, 18, 21 and 24 h post incubation to estimate total gas volume (TGV), methane (CH4), metabolisable energy (ME; MJ/Kg DM), organic matter digestibility (OMD; %) and short chain fatty acids (SCFA; ìmol/200 mg DM). dry matter (DM, %) increased significantly (p&lt;0.05) as inclusion of Albizia saman pods increases across the treatments. The crude protein (CP, %) contents were similar across the treatments. The total gas volume (TGV mL) produced by the diets were similar across the treatments. The values ranged from 4.81 to 5.26 for ME, 35.16 to 36.32 for OMD, 0.13 to 0.21 for SCFA and 5.33 to 7.33 for CH4 production with no significant difference. The result showed that in vitro fermentation of the mixture of cassava top and maize stover ensiled with Albizia saman pods at 0:40:60% increased the dry matter degradability by 15%, enhanced metabolisable energy, organic matter digestibility and short chain fatty acids.

Characteristics of ensiled cassava leaves and maize stover as dry season feed for ruminants

Insufficient quantity and quality of feed for ruminants during the dry season is a major limiting factor for effective production and management. Smallholder farmers generate large crop residues in the wet season, which are rich in nutrients in which ruminants can feed on in the dry season by proper ensiling. Cassava Leaves (CL) and Maize Stover (MS) residues were thus ensiled to evaluate their nutritional qualities as feed for ruminants. Fresh cassava leaves and maize stover were collected, chopped and wilted. Silages were prepared as: T1 (100%CL), T2 (100%MS), T3 (50%CL+50%MS), T4 (25%CL+ 75%MS) and T5 (75%CL+25%MS). Ensiling lasted for 21 days after which they were opened to determine the quality using physical assessment of colour, smell, texture, pH and temperature. Chemical composition of the silages comprising Crude Protein-CP, Crude Fibre-CF, Ether Extract-EE, ash content, Acid Detergent Fibre-ADF, Neutral Detergent Fibre-NDF and Acid Detergent Lignin-ADL were assessed. Nutritive values of the diets were evaluated using in vitro fermentation technique to determine Total Gas Production (TGP), methane, Metabolizable Energy (ME), Short Chain Fatty Acids (SCFA) and Organic Matter Digestibility (OMD). Coefficient of Preference (COP) was determined using a cafeteria feeding technique. Olive-green colour, alcoholic smell and firm texture were observed in the silages. The pH ranged from 4.13 to 4.73 while higher pH was observed in 100%CL. The temperature was between 31°C and 32ºC. The values obtained for the DM ranged from 64.37 to 67.9%. The CP values varied between 8.64 and 19.68%. The lowest CP of 8.64% was observed in T2 (100%MS) while 19.68% was obtained in T1 (100%CL). The ash content ranged from 8.65 to 13.00% and the CF value varied from 33.70 to 40.39%. It was observed that 100%MS had significantly (P&lt;0.05) higher CF (40.39%) compared to other treatments. The EE values varied between 4.45 and 5.22%. The EE value in 100%CL (5.22%) was significantly (P&lt;0.05) higher compared to other silage treatments. The NDF, ADF and ADL values varied from 62.70-69.80%, 43.95-47.90% and 22.95-25.80%, respectively and significant differences were observed. The total gas volume ranged from 8.33 to 13.8mL, methane 5.3 to 7.6, OMD (32.72-42.5%), ME (4.06-5.28kCal) and SCFA (0.15-0.27). The CoPof the silages was ≥to the unity of one with the exception of T2. It can be concluded that, combinations of 50% cassava leaves and 50% maize stover could be used as feed for ruminants.

Effect of some medicinal herbs and spices from Enugu and Kaduna States, Nigeria, on in-vitro rumen fermentation and methanogenesis

A study was carried out to determine the effect of medicinal plants from Enugu (En) and Kaduna (Kd) States on in-vitro rumen fermentation and methanogenesis. Twelve medicinal plants comprising herbs and spices were collected from En and Kd States, respectively. The chemical composition and cell wall component (NDF, ADF and hemicellulose) of the plants were determined. The samples were evaluated in an in-vitro study at an inclusion level of 10 mg/ 200 mg substrate. The experiment was laid out in a factorial arrangement and executed as a randomized complete block design with incubation done in batches. At the completion of the 24-hour incubation period, total gas volume (GV), dry matter digestibility (DMD), fermentation efficiency (FE) and CH were determined while organic matter digestibility 4 (OMD), short chain fatty acids (SCFA) and metabolisable energy (ME) were estimated from established equations. The chemical composition indicated range values of 72.82 (Allium sativum, En) - 95.73% (Aloe barbadense, Kd) for DM, 7.01 (Aframomum elegueta, En) – 30.59% (Allium sativum, En) for CP, 8.94 (Allium sativum, Kd) – 81.41% (Cymbopogon citratus, En) for NDF, 3.58 (Allium sativum, En) – 63.64% (Xylopia aethiopica, En) for ADF, 1.79 (Allium cepa, Kd) - 48.77 % (Aframomum melegueta, En) for hemicellulose, 2.64 (Aframomum melegueta, En) – 22.51% (Ageratum conyzoides, Kd) and 77.49 (Ageratum conyzoides, Kd) – 97.36% (Aframomum melegueta, En) for ash and OM, respectively. The effect of location on chemical composition varied among the plant types with significantly higher (P &lt; 0.05) levels of CP in most of the Kd plants. The range for GV, DMD, CH 4 percentage, CH reduction, FE, OMD, SCFA and ME were 85.00 (Ageratum conyzoides, Kd) 4 - 149.49 mL/g DM (Aloe barbadense, Kd), 525.50 (Sida acuta, Kd) - 764.50 g/Kg DM (Aframomum melegueta, En), 45.75 (Allium sativum, En) - 72.59% (Aframomum melegueta, Kd), 2.36 (Allium cepa, Kd) - 32.86% (Zingiber officinale, Kd), 4.23 (Sida acuta, Kd) - 8.12 (Ageratum conyzoides, Kd), 45.83 (Ageratum conyzoides, Kd) – 57.18% (Cymbopogon citratus, Enugu; Aloe barbadense, Kd), 0.35 (Ageratum conyzoides, Kd) - 0.66 mmol/200 mg DM (Cymbopogon citratus, En) and 5.18 (Ageratum conyzoides, Kd) – 6.93 MJ/Kg DM (Cymbopogon citratus, En; Aloe barbadense, Kd) respectively. Allium sativum bulbs, Zingiber officinale rhizomes, Cymbopogon citratus and Sida acuta (both locations) reduced CH production without adversely affecting the desired fermentation parameters indicating 4 that the medicinal plants have methane reducing potential.

Preliminary in vitro screening of some spices and medicinal plants from Edo and Rivers States, Nigeria for reducing enteric methane production in ruminants

Methane gas produced by ruminants during feed fermentation contributed to global warming as well as poor efficiency of food utilization. Mitigating ruminal methane production through anti-microbial feed additive has serious health implications. A preliminary study of the potential of medicinal plants and spices from Edo and Rivers State, as possible replacement to antibiotic feed additives was carried out. Medicinal plants and spices were purposefully sampled, dried at 40oC, milled and 10 mg was added with 190 mg of substrate in a preweighed nylon incubation bags. Bags and their contents were incubated using 30 mL of buffered rumen liquor in 100 mL syringes following the standard procedure of in vitro fermentation. Variables monitored were 24h total gas volume, short chain fatty acids (SCFA) methane (CH4 ) gas, dry matter degradability (DMD) as well as some chemical, cell wall and anti-nutritive components. Results revealed that adding the medicinal plants and spices as feed additives did not depress gas production in most cases (19.5 – 29.50 mL, 17.75 – 30.00 mL and 12.00 – 29.00 mL for Edo medicinal plants, Edo spices and Rivers medicinal plants respectively) and also did not depress DMD (&gt; 50%). Azadirachta indica stem reduced CH4 production mostly by 53.56% while Dennttia tripetala did by 47.69% among the Edo medicinal plants and spices, respectively. In Rivers State, Amaranthus spinosus gave the highest value of 60.33% CH4 reduction. In the same bracket of similar and good CH4 reduction potentials were Alstonia boonei leaves (49.06%), Newbouldia laevis root (41.50%), Euphorbia heterophyla (37.97%), Allium crispum (47.31%), Allium cepa (46.80%), Aframomum mueguata (46.54%), Capsicum annum (47.32%), Ageratum conyzoides (56.52%), Lagenaria breviflora (48.03%) and Centrosema molle (45.08%). All the medicinal plant and spices with potential for CH4 reduction had corresponding high SCFA values (0.46 – 0.65 Mmol) with tannin (%) and saponin (%) contents of 0.011 – 17.50 and 0.01 – 2.40 respectively. Conclusively, the medicinal plants and spices demonstrated good potentials for reducing rumen methane production in vitro and may be subjected to further in vivo studies.

PSVI-12 Effects of polyphenols (mixed tannins) and saponin (Yucca schidigera), with or without a direct fed microbial (DFM) on in vitro rumen fermentation

Abstract Rumen fluid from fistulated steers receiving a high concentrate diet was utilized to examine the impact of polyphenols and saponin with or without a direct fed microbial (DFM) on in vitro fermentation characteristics. Treatments consisted of: Control (no polyphenols, saponin or DFM); 2) Polyphenols (Mixed Tannins = 15 g/hd/d); 3) Saponin (Y. schidigera = 2 g/hd/d); 4) Polyphenols + DFM (DFM = 1E+7 Lactobacillus animalis + 1E+8 Propionibacteria acidilactici cfu/hd/d); and 5) Saponin + DFM. Rumen fluid was collected and combined in equal amounts from 3 rumen fistulated steers and mixed at a 1:1 ratio of artificial saliva to rumen fluid. Fermentation substrate consisted of 0.5 g of the high concentrate diet. Fermentation bottles were capped with an air-tight rubber stopper and incubated in a water bath for 12 and 18h (7 replicates/treatment/time point). After incubation, the total volume of gas produced was measured and a subsample analyzed for N, CH4 and CO2 concentrations. After gas sampling, pH, VFA concentrations, and DMD were determined. In vitro fermentation parameters were analyzed using a mixed effects model repeated measures analysis for a completely randomized block design. Acetic acid was decreased while valeric acid was increased (P &amp;lt; 0.05) by the Saponin + DFM treatment vs. Control. At 12h DMD was greater in Saponin, Saponin + DFM and Polyphenols + DFM (P &amp;lt; 0.001) treatments compared to Control or Polyphenols alone. Polyphenols produced greater amounts of CH4 /DMD than all other treatments (P &amp;lt; 0.01). Microbial protein production and efficiency were greater (P &amp;lt; 0.001), Saponin + DFM compared to other treatments. Other fermentation parameters measured were not impacted by treatments. Under the conditions of this experiment these data suggest combining DFM with Saponin or Polyphenols produces different ruminal effects from when they are fed alone.

Dynamics and isolation properties for a pneumatic near-zero frequency vibration isolator with nonlinear stiffness and damping

Aiming to isolate disturbance vibration for heavy machines with low frequency, a novel hydro-pneumatic vibration isolator with high-static and low-dynamic (HSLD) stiffness is proposed, which contains bellows structure as elastic element and pressurized gas and incompressible liquid as working media. Due to that the natural frequency of isolation system with such isolator is close to zero and loading capacity can be adjusted by the gas pressure, the proposed device is termed as pneumatic near-zero frequency (NZF) vibration isolator. To obtain the mathematical model of isolator’s stiffness, the quasi-static derivation based on gas state equation is carried out first. Results prove that the presented isolator possesses ideal high-static and low-dynamic stiffness, which is also verified by the experimental data measured by a quasi-static test. The proportion of gas volume to total volume of gas and liquid media, respectively, in bellows and cylinder chambers are significant physical parameters, which dominate the nonlinearity extent of isolator’s stiffness. Different from most existing isolators, the proposed isolator includes fluidic damping and friction damping. The former is expressed by classic square-velocity-type nonlinear model, and the latter is modeled as Coulomb damping. To obtain dynamic response and vibration isolation transmissibility, the harmonic balance method is applied. A direct current term is added in the trial solution, which reflects the asymmetry of dynamic response. In respect of transmissibility analysis, square-velocity nonlinear damping brings a favorable advantage that it can ensure the fine force transmissibility in both resonance region and effective isolation band. This conclusion holds consistently under base motion excitation. Friction damping cannot give the same conclusion. Further comparison with a linear vibration isolator exhibits that the HSLD stiffness characteristics of the NZF isolator breaks through the trade-off between large loading capacity and small static deformation, and the square nonlinearity of fluid damping is able to overcome the dilemma that weak linear vicious damping is beneficial for isolation performance within the effective isolation frequency band, but cannot suppress resonance amplitude and transmissibility. And the experimental transmissibility is in good agreement with the analytical result. Besides, the influences of excitation variation on isolation performance are estimated theoretically. Due to the hardening stiffness, overload acceleration will cause the increase in linearized natural frequency of NZF isolator system, and thus, isolation effectiveness will be reduced.

Equação de regressão para estimar volume de gases ruminais e correlação entre composição química e parâmetros da fermentação

RESUMO: Objetivou-se determinar a equação de regressão para se estimar o volume de gases para implantação da técnica semiautomática de produção de gases in vitro e avaliar a correlação entre os parâmetros de fermentação ruminal e de composição bromatológica de forrageiras tropicais. As espécies avaliadas foram Urochloa brizantha cv. MG-5, Andropogon gayanus, Urochloa humidicola e Digitaria umfolozi. As forrageiras foram avaliadas quanto a composição química e cinética de fermentação ruminal pela técnica de produção de gases in vitro semiautomática. A pressão mínima de gases obtida foi de 0,09 psi, sendo a pressão máxima registrada foi de 4,8 psi, o volume mínimo de gases registrado foi de 0,30 ml e o máximo de 20 mL. A equação linear é a que melhor prediz os dados de volume de gases em relação a pressão, por possuir valor de R2 e correlação variando de 0,94 a 1,00, respectivamente). O aumento no teor de matéria seca, matéria orgânica, proteína bruta e lignina reduzem o volume total de gases produzido. A composição químico-bromatológica correlaciona-se com alguns parâmetros de fermentação ruminal, refletido na cinética da degradação das forrageiras.&#x0D; PALAVRAS-CHAVE: Degradabilidade digestibilidade, forrageiras, graminea, produção de gás, técnica semiautomática.

Report Outlines Knowledge Gained in Gas Hydrate Production Testing

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 29516, “Gas Hydrate Production Testing: Knowledge Gained,” by Timothy Scott Collett, SPE, US Geological Survey, prepared for the 2019 Offshore Technology Conference, Houston, 6-9 May. The paper has not been peer reviewed. Copyright 2019 Offshore Technology Conference. Reproduced by permission. Gas hydrates are an important potential source of unconventional natural gas. Significant progress has been made with regard to understanding geologic and engineering limitations of the ultimate energy potential of gas hydrate; however, more work is required. The complete paper reviews the results of gas hydrate engineering and production testing studies associated with northern Canada and Alaska. The results of the marine gas hydrate producing testing efforts in Japan’s Nankai Trough and in the South China Sea are also summarized. Mallik (Canada) The Mallik gas hydrate research site in northern Canada has been the focus of three important gas hydrate field tests (in 1998, 2002, and 2007-08). The Mallik 2L-38 gas hydrate research well (part of the 1998 testing project) was drilled to evaluate the geologic controls on the occurrence of gas hydrate and to acquire specialized core and well data needed to characterize reservoir properties. During the 2002 project, gas hydrate was produced for the first time by both depressurizing and heating the reservoir. Depressurization alone appeared to be the most-feasible method for producing gas hydrates. However, because of the limited nature and duration of the 2002 tests, it was determined that a longer duration test would be required, leading to the 2007-08 research program. A 12-m-thick sand-rich hydrate-bearing reservoir was tested at a down-hole flowing pressure of approximately 7.3 MPa. The fact that gas hydrates can be produced by depressurization techniques was demonstrated. The winter 2006 operations included a 6-day depressurization flow, which was able to establish a sustained and stable gas flow rate averaging approximately 3000 m3/d. The total volume of gas and water produced over the duration of the test was approximately 13 000 and 100 m3, respectively. Alaska North Slope (US) The occurrence of gas hydrate on the Alaska North Slope is associated closely with well-characterized petroleum systems. The Mount Elbert gas hydrate test well, in 2007, showed a mobile water phase within hydrate-bearing reservoirs even at very high gas hydrate saturations. The recognition of the presence of a mobile water phase within gas hydrate reservoirs was an important development in that it provided the means, or pathway, to draw the pressure down on hydrate-bearing reservoirs. The PBU L-Pad area was identified as the optimal site for the subsequent Iġnik Sikumi gas hydrate production test.

Chemical composition and in vitro fermentation characteristics of legumes using canine fecal inoculum.

Legumes are a popular grain-free alternative carbohydrate source in canine diets, however, information on their fermentative characteristics have not been established. Thus, the objectives of the present study were to 1) quantify the chemical compositions and 2) fermentative profile of select legumes using canine fecal inoculum. Five legume varieties, whole yellow peas (WYP), green lentils (GL), black bean grits (BBG), navy bean powder (NBP), and garbanzo beans, were analyzed and compared to a positive control, beet pulp (BP). Substrates were analyzed for gross energy (GE), dry and organic matter, crude protein (CP), acid hydrolyzed fat, and total dietary fiber (TDF) fractions, beta-glucans, starch-free, and hydrolyzed sugars, as well as fermentative characteristics: pH, short-chain fatty acids (SCFA), branched-chain fatty acids (BCFA), total gas, hydrogen, and methane. Substrates then underwent a two-stage in vitro digestion and subsequent fermentation using canine fecal inoculum for 0, 3, 6, 9, and 12 h. All test substrates contained approximately 8% to 9% moisture and 4.5 kcal/g GE. The highest CP content was observed in GL (27%). Analyzed TDF content of test substrates was greatest for WYP (32%) and GL (36%). Total starch content was greatest for GL (58%) and WYP (56%). Sucrose and stachyose were the most predominant free sugars and glucose was the most predominant hydrolyzed sugar among test substrates. After 3 and 6 h of fermentation, a net negative change in pH was observed among most substrates with a net negative change in all substrates after 9 and 12 h. Values for SCFA did not differ among substrates after 3 or 6 h of fermentation with BP and WYP among the greatest acetate (1,656 and 1,765 umol/g, respectively) and propionate production values (157.7 and 126.1, respectively) after 9 h. All substrates produced greater total gas volumes than WYP after 3 h, with no differences observed after any other time points. However, BP hydrogen production values were greater after 9 and 12 h (P < 0.0001; 726,042 and 394,675 ng/g, respectively) with greater methane production values after 12 h (P < 0.0001; 54,291 ng/g) than all test substrates. These data suggest that legumes offer a diverse macronutrient profile and appear to be a source of slowly fermentable fiber, which may have beneficial implications on the ratios of saccharolytic to proteolytic fermentation toward the distal colon.

Structural and catalytic studies of Mg1-xNixO nanomaterials for gasification of biomass in supercritical water for H2-rich syngas production

Nowadays, catalytic supercritical water gasification (SCWG) is undoubtedly used for production of H2-rich syngas from biomass. The present study reported the synthesis and characterisation of Mg1-xNixO (x = 0.05, 0.10, 0.15, 0.20) nanomaterials that were obtained via self-propagating combustion (SPC) method, and catalysed the SCWG for the first time. It had found that increased the nickel (Ni) content in the catalyst reduced the crystallite size, thus, increased the specific surface area, which influenced the catalytic activity. The specific surface area followed the order of Mg0.95Ni0.05O (36.2 m2 g−1) < Mg0.90Ni0.10O (58.9 m2 g−1) < Mg0.85Ni0.15O (63.6 m2 g−1) < Mg0.80Ni0.20O (67.9 m2 g−1). From the Rietveld refinement, the Ni that was successfully partial substituted in the cubic crystal structure of MgO resulting in a cell contraction which ascribed the reduction of crystallite size. Increased the amount of Ni also narrowed the pore size distribution ranging between 4.17 nm and 6.23 nm, as well as increased the basicity active site up to 5741.0 μmol g−1 at medium basic strength. All the synthesised nanocatalysts were catalysed the SCWG of OPF (oil palm frond) biomass. Among them, the mesoporous Mg0.80Ni0.20O nanocatalyst exhibited the highest total gas volume of 193.5 mL g−1 with 361.7% increment of H2 yield than that of the non-catalytic reaction.