Cold Feed Research Articles

PSIV-24 Evaluation of different colostrum feeding volumes on serum immunoglobulin G concentration and metabolic profiles of calves in high altitude area

Abstract Qinghai-Tibet Plateau is the highest plateau in the world, reputed as “the roof of the world” and “the world’s third pole”. Its ecological environment is characterized by low atmospheric oxygen pressure, cold, and limited feed supplies. This study aimed to investigate the serum immunoglobulin G (IgG) concentration and metabolic profiles of calves in high altitude area (3,650 m) fed different volumes of colostrum [8, 12, or 15% of birth body weight (BW)] using untargeted metabolomics strategies. Neonatal Holstein hybrid heifer calves (n = 44) were randomly divided into 1 of the 3 colostrum feeding amounts: 8% of birth BW (Low volume, L), 12% of birth BW (Middle volume, M), and 15% of birth BW (High volume, H) in colostrum. To safeguard the efficiency of colostrum intake, the colostrum was fed to calves within 0.5 h and 6 h after birth. The serum samples at 24 h after birth were collected for IgG concentration determination by indirect enzyme-linked immunosorbent assay (ELISA) and for LC-MS/MS metabonomic analysis. As the volumes of colostrum increased, there was a linearly increased in the serum IgG concentration (P < 0.01). Differential metabolites were selected according to the following 3 conditions: minimum fold change (FC) > 2, P-value < 0.01 in single-dimensional statistical analysis, and variable importance in projection (VIP) > 1 in the OPLS-DA model. Multivariate statistical analyses were performed to visualize differences among groups. Based on the screening criteria, a total of 3 differential metabolites (22 alpha-Hydroxy-campesterol, N-Myristoyl Histidine, and Calcitetrol) were detected between L and M, of which all differential metabolites were down-regulated. Six differential metabolites were detected between M and H, of which PC[P-18:1(11Z)/18:1(12Z)-2OH(9,10)] was up-regulated and 5 differential metabolites including 1-arachidonoyl-2-hydroxy-sn-glycero-3-phosphate, propanoyl phosphate, ascorbic acid 6-palmitate, 20-hydroxyecdysone, and 6’’’-deamino-6’’’-hydroxyparomomycin II were down-regulated. There were 28 differed metabolites (including leucyl-tryptophan, calcitetrol, 3’’-Oxoribostamycin) between L and H, of which 9 differential metabolites were up-regulated and 19 differential metabolites were down-regulated (Figure 1). Based on KEGG metabolic enrichment pathway analysis and pathway topology analysis, porphyrin metabolism was identified as the most impacted pathway between L and H (Figure 2). In conclusion, increasing colostrum volumes significantly increased serum IgG concentrations at 24 h after birth, favoring the success of the transfer of passive immunity. Alterations in serum metabolome of calves in the Qinghai-Tibet Plateau fed different volumes of colostrum were successfully revealed by untargeted metabolomics. The role of the identified differential metabolites and enriched pathway in the transfer of passive immunity in calves at high altitude deserves further investigation. Keywords: calf, colostrum volumes, high altitude area

CFD modeling of a mini-pilot scale CO2 hydrogenation to hydrocarbons reactor using both direct and indirect pathway-based kinetic model

Both indirect CO2 hydrogenation (reverse water gas shift (RWGS) followed by CO-based Fischer-Tropsch synthesis (FTS)) and direct CO2-based FTS were considered for CO2 hydrogenation, and a kinetic model for the chain-length distribution of hydrocarbon products was developed. For independent estimation, the kinetic parameters were estimated by fitting the experimental data using powder catalysts under various conditions, mainly including CO/CO2 ratios. The contribution of indirect CO2 hydrogenation (RWGS followed by CO-FTS) was more favorable than that of direct CO2-FTS, and CO2 conversion and product selectivity were significantly dependent on the temperature and hydrogen fraction. The effectiveness factor was estimated for the pellet-type catalysts, and values less than one validated the existence of mass-transfer resistance. Computational fluid dynamics (CFD) modeling was used to simulate the three-dimensional thermal behaviors of a mini-pilot-scale reactor with a substantially large diameter loaded with a pellet-type catalyst and inert materials. Both a low catalyst loading in the early stage of the reactor and the use of an additional inner cooling tube showed a stable temperature profile, with the peak temperature maintained below 350 °C (the critical temperature to prevent the thermal decomposition of chemicals) and fast heating of cold feed in the early stage. The CFD results with no inner tube showed thermal runaway in the second reactor, and the simulation with arbitrarily reduced heat of the reaction (70 % of the actual value) resulted in a peak temperature higher than 410 °C. Further quantitative analysis indicated that the no-inner-tube case's reduced heat transfer area per unit volume was responsible for its thermally unstable behavior.

Effect of Wire Preheat and Feed Rate in X80 Steel Laser Root Welds: Part 1 — Microstructure

Laser welding with cold versus hot wire feed was employed as a root pass to weld X80 pipeline steel. The influences of wire feed rate and preheat on the fusion zone microstructure were investigated. Increasing the wire feed rate helped generate acicular ferrite in the weld metal, and preheating the wire further suppressed the formation of bainite. The acicular ferrite in the upper region of the fusion zone was finer than that in the lower region, which was due to an increase in nucleation sites available. Five fill and cap passes were applied by gas metal arc welding to fill the remaining top part of the groove. Compared to arc welding with a higher heat input, laser welding led to finer prior austenite grains and smaller bainite packet size in the coarse-grained heat-affected zone and limited the formation of martensite-austenite constituents in the intercritically reheated coarse-grained heat-affected zone.

Effect of Wire Preheat and Feed Rate in X80 Steel Laser Root Welds: Part 2 — Mechanical Properties

In Part 1 of this study, the influences of feed rate and preheat of the wire on the fusion zone microstructure of X80 steel laser root welds were investigated. Part 2 of this study reveals the effect of cold versus hot wire feed on mechanical properties. Although strength overmatching with the X80 base metal was maintained, the wire alloying elements reduced the hardness of the upper region of the laser fusion zone but had limited effect on the bottom of the fusion zone due to the incomplete mixing of the filler material with the base metal in the bottom root region of the joint. The addition of ER70S-6 filler wire improved the impact toughness of the weld metal at 0°C, due to the formation of an acicular ferrite microstructure. As the temperature decreased to –20°C (–4°F) and –45°C (–49°F), ductile to brittle transition occurred, leading to lower weld metal toughness.

Identification of genomic characteristics and selective signals in Guizhou black goat

BackgroundGuizhou black goat is one of the indigenous black goat breeds in the southwest region of Guizhou, China, which is an ordinary goat for mutton production. They are characterized by moderate body size, black coat, favorite meat quality with tender meat and lower odor, and tolerance for cold and crude feed. However, little is known about the genetic characteristics or variations underlying their important economic traits.ResultsHere, we resequenced the whole genome of Guizhou black goat from 30 unrelated individuals breeding in the five core farms. A total of 9,835,610 SNPs were detected, and 2,178,818 SNPs were identified specifically in this breed. The population structure analysis revealed that Guizhou black goat shared a common ancestry with Shaanbei white cashmere goat (0.146), Yunshang black goat (0.103), Iran indigenous goat (0.054), and Moroccan goat (0.002). However, Guizhou black goat showed relatively higher genetic diversity and a lower level of linkage disequilibrium than the other seven goat breeds by the analysis of the nucleotide diversity, linkage disequilibrium decay, and runs of homozygosity. Based on FST and θπ values, we identified 645, 813, and 804 selected regions between Guizhou black goat and Yunshang black goat, Iran indigenous goat, and cashmere goats. Combined with the results of XP-EHH, there were 286, 322, and 359 candidate genes, respectively. Functional annotation analysis revealed that these genes are potentially responsible for the immune response (e.g., CD28, CD274, IL1A, TLR2, and SLC25A31), humility-cold resistance (e.g., HBEGF, SOSTDC1, ARNT, COL4A1/2, and EP300), meat quality traits (e.g., CHUK, GAB2, PLAAT3, and EP300), growth (e.g., GAB2, DPYD, and CSF1), fertility (e.g., METTL15 and MEI1), and visual function (e.g., PANK2 and NMNAT2) in Guizhou black goat.ConclusionOur results indicated that Guizhou black goat had a high level of genomic diversity and a low level of linkage disequilibrium in the whole genome. Selection signatures were detected in the genomic regions that were mainly related to growth and development, meat quality, reproduction, disease resistance, and humidity-cold resistance in Guizhou black goat. These results would provide a basis for further resource protection and breeding improvement of this very local breed.

150 Repeatability of Rangeland Behavioral and Social Traits Derived from Gps Collars

Abstract The ability of an individual to cope with stressors in their environment is going to be paramount in the face of climate change. Rangeland livestock experience harsh conditions including heat and/or cold stress, water and feed restrictions and risk of predation. In extensive management systems, the ability to capture the capacity to cope with stressors of an individual in its environment is encumbered by remote locations with difficult terrain and no access to power or the internet. GPS collars can provide insights into individual land-use behavior, e.g., their impact on the environment or ability to cope with stressors, and social interactions, e.g., mothering ability. GPS collars (n = 112) developed at the University of Idaho were deployed on 57 ewes and 55 lambs (45 ewe-lamb pairs) in an extensive rangeland environment at the Great Basin Research and Extension Center in Eureka, NV. The collars recorded location data every 10 minutes from July 27th to August 18, 2022. Coordinate fixes were successfully recorded 67.11 ± 27.12% of the time and resulted in a kept record occurring every 60 ± 202 minutes. Of the ewe-lamb pair devices, 43 pairs contributed 801 ± 703 paired records (i.e., records that occurred within 5 minutes of each other). GPS coordinate locations, and their respective capture times, allow for the analysis of distance traveled, water usage, dispersion, and ewe-lamb distance. Distance traveled was analyzed on a daily basis with a weighted median distance imputed for all travel times that lasted more than 900 seconds. Dispersion was defined as the distance of an individual from the centroid of the flock in meters, and was transformed to a Z-score based on the position of individuals with GPS coordinates captured within 10 minutes of the measurement of the individual. Ewe-lamb pair distances were cube root transformed. Twin status, dam line, age, and day were fitted as fixed classes to estimate the repeatability of records for mature ewes. Repeatability estimates of daily distance traveled, daily water usage, and daily dispersion were 0.22 ± 0.05, 0.30 ± 0.06 and 0.10 ± 0.03, respectively. Daily ewe-lamb distances had a repeatability estimate of 0.45 ± 0.08. Day of recording was significant for daily distance traveled (P-value = 2.72×10-4) and water usage (P-value = 1.06×10-3). No other effects were significant in any of the models. In conclusion, PLF tools are an enabling technology that allow for passive data capture in remote locations. Our findings suggest that GPS collars can elucidate a variety of land use and social behavior traits that could serve as meaningful criteria for selection in extensive livestock production settings. Selection on these indicators of resilience may increase livestock productivity and welfare by increasing heat stress tolerance via the analysis of novel behavioral traits seen on extensive rangelands.

Permeate Flux Enhancement in Air Gap Membrane Distillation Modules with Inserting Λ-Ribs Carbon-Fiber Open Slots.

A novel design of an air gap membrane distillation (AGMD) module was proposed to enhance the permeate flux improvement for the desalination of pure water productivity. The modeling equations for predicting permeate flux in the AGMD module by inserting Λ-ribs carbon-fiber open slots under various hydrodynamic angles were developed theoretically and experimentally. The temperature distributions of both hot and cold feed streams were represented graphically with the hot saline flow rate, inlet saline temperature, and carbon-fiber hydrodynamic angles as parameters. The results showed a good agreement between the experimental results and theoretical predictions. Designed by inserting Λ-ribs carbon-fiber open slots into the flow channel, the membrane distillation module was implemented to act as an eddy promoter and yield an augmented turbulence flow. The effect of Λ-ribs carbon-fiber open slots not only assured the membrane stability by preventing vibration but also increased the permeate flux by diminishing the temperature polarization of the thermal boundary layer. The permeate flux improvement by inserting Λ-ribs carbon-fiber open slots in the AGMD module provided the maximum relative increment of up to 15.6% due to the diminution of the concentration polarization effect. The experimental data was incorporated with the hydrodynamic angle of Λ-ribs carbon-fiber open slots to correlate the enhancement factor with the Nusselt numbers to confirm the theoretical predictions. The accuracy derivation between the experimental results and theoretical predictions was pretty good, within 9.95≤E≤1.85. The effects of operating and designing parameters of hot saline flow rate, inlet saline temperature, and hydrodynamic angle on the permeate flux were also delineated by considering both the power consumption increment and permeate flux enhancement.

Numerical and Experimental Performance Evaluation of a Photovoltaic Thermal Integrated Membrane Desalination System

Membrane desalination (MD) is preferred over other desalination techniques since it requires a lower temperature gradient. Its performance can be further enhanced by preheating the intake of saline water. In this context, a novel solar-assisted air gap membrane desalination (AGMD) system was hypothesized. The motivation was derived from the fact that the use of solar energy to provide power and a pre-heating source for the intake of saline water can offer a sustainable alternative that can further enhance the acceptance of MD systems. Since solar panels suffer from a loss of efficiency as they heat up during operation, a solar-assisted air gap membrane desalination (AGMD) system can help to improve the overall system performance by (1) providing the necessary pumping power to operate the system and (2) improving solar panel performance by exchanging heat using water that is (3) used to pre-heat the saline water necessary for increased performance of the AGMD system. To verify the hypothesis, a solar-assisted AGMD system for freshwater production was theoretically designed, fabricated locally, and then tested experimentally. The effect of the process operating parameters and the ambient conditions on the overall performance of the proposed solar-assisted AGMD desalination unit is presented in detail, both theoretically and experimentally. The results indicated a direct correlation between the permeate flux, saline hot feed temperature, and hot feed flow rate. In addition, an inverse relationship between the cold feed temperature, cold feed flow rate, and the air gap thickness of the module was also observed and reported, thus, validating the hypothesis that a solar-assisted air gap membrane desalination (AGMD) system can help to boost performance.

Development and monitoring of the MEED high efficient shower heat recovery unit

In well isolated dwellings especially with multiple residents domestic hot water (DHW) accounts often for more than 50% of the energy consumption.Currently there exist shower heat recovery units which recover 40 - 70 percent of the heat in the shower water. This efficiency can drop due to fouling of the heat exchanger, which is often not accessible. Further this is a component efficiency. The system efficiency also depends on the cooling down of the shower water due to evaporation and conduction losses to wall and floor tiles. During renovation it is often practically only possible to preheat the cold water port of the thermostat with the shower heat recovery unit. The cold water feed to the boiler would then not be preheated. In apartments it is not possible to install the highly efficient pipe-in-pipe heat exchangers as they have to be installed on the floor below the bathroom. Which only leaves shower tray heat recovery units which are in the lower range of the mentioned efficiency. In practice therefore during renovation shower heat recovery is not often applied.To address these problems a new patented concept for shower heat recovery has been developed. The Multi Energy Efficient Shower cabin (MEED) involves an insulated shower cabin (tray and walls) which is closed to minimize evaporation losses. The hot shower water is pumped up and flows over an integrated helix heat exchanger. This heat exchanger is able to extract 82% of the heat and is accessible for cleaning. In the shower cabin also an electrical 10 liter 6 kW boiler is integrated, so all cold water is preheated and directly hot water is provided which minimalizes pipeline losses. The MEED has enough capacity to shower endlessly. The MEED has been installed in existing social rental housing, private housing and in hotels. First monitoring results indicate a system efficiency of more than 70%. Aside the shower the MEED is able to provide all DHW, which makes a storage vessel superfluous. This is provides important space gain in smaller dwellings.

Optimization of Sour Water Stripping Unit Using Artificial Neural Network–Particle Swarm Optimization Algorithm

Sour water stripping can treat the sour water produced by crude oil processing, which has the effect of environmental protection, energy saving and emission reduction. This paper aims to reduce energy consumption of the unit by strengthening process parameter optimization. Firstly, the basic model is established by utilizing Aspen Plus, and the optimal model is determined by comparative analysis of back propagation neural network (BPNN), radial basis function neural network (RBFNN) and generalized regression neural network (GRNN) models. Then, the sensitivity analysis of Sobol is used to select the operating variables that have a significant influence on the energy consumption of the sour water stripping system. Finally, the particle swarm optimization (PSO) algorithm is used to optimize the operating conditions of the sour water stripping unit. The results show that the RBFNN model is more accurate than other models. Its network structure is 5-66-1, and the expected value has an approximately linear relationship with the output value. Through sensitivity analysis, it is found that each operating parameter has an impact on the sour water stripping process, which needs to be optimized by the PSO algorithm. After 210 iterations of the PSO algorithm, the optimal system energy consumption is obtained. In addition, the cold/hot feed ratio, sideline production position, tower bottom pressure, hot feed temperature, and cold feed temperature are 0.117, 18, 436 kPa, 146 °C, and 35 °C, respectively; the system energy consumption is 5.918 MW. Compared with value of 7.128 MW before optimization, the energy consumption of the system is greatly reduced by 16.97%, which shows that the energy-saving effect is very significant.

Performance analysis of a prototype solar photovoltaic/wickless heat pipe embedded aluminum curtain wall-heat pump water heating system

In this study, a novel glazed photovoltaic heat pipe based curtain wall (PV-HPCW) heat pump system composes of the wickless heat pipe embedded aluminum veneer curtain wall as solar thermal collecting system and heat pump water heating system is proposed. This system assists in heat redistribution on the outer wall of the room to increase solar collection rather than transmission, and in which the collected heat is then transferred to the cold feed of the domestic hot water heating system. A dynamic model is developed to analyze the energy conversion and heat transfer process in the entire system by utilizing the energy balance approach to understand inter-connection and definition of the sorted equations. An experiment is executed and tested under the real outdoor weather conditions in Hong Kong, which is done by measuring the operational parameters, such as solar radiation, PV power generation, temperature at various points and compressor consumption. The simulation results reflect good consistency with the observation data, and indicating that the established model has reasonable accuracy to predict system performance. In outdoor condition, the results indicate that the average electrical and thermal efficiency of PV-HPCW module are around 9.44% and 20.22%, respectively; Similarly, the overall thermal efficiency and overall electrical efficiency (exergy) of the system are 44.6% and 12.8%, respectively; whilst the mean coefficient of performance, COP and the comprehensive coefficient of performance, COPpvt of the system are 3.64 and 5.12 respectively. The PV-HPCW heat pump system has a significant potential and benefits relating to solar heat and electricity. Thus, this innovative PVT technology based building envelop could be a promising building energy supply system with the advantage of proper resource utilization and compact structure, and all these positive implication would encourage the development of such high performance technology, which will contribute to the reduction of carbon emissions in the building sector and ultimately to reduce the urban heat island effect.

Intensifying petroleum fractionators through internal partial condensation in place of pump-around

Conventional crude distillation unit uses pump-around, or direct contact heat exchange, to remove extra heat and provide internal reflux flow. From the perspective of heat and mass transfer, pump-around streams experience two heat transfer processes in low efficiency, while essentially not contributing to distillation. Novel internal partial condensation sections are proposed to replace unwelcomed pump-around zones by cooling the rising vapor with the cold feed crude oil via a new plate-type heat exchanger inside the column. According to a simulative case study through building up the virtually assembled process within Aspen Plus, equipment size and pressure drop are reduced as the required vapor/liquid flow rate is decreased. For an existing petroleum fractionator, energy consumption reduction touches 11.88% while product yield is improved by 0.74%. This achievement is inspired by novel patented internal condensers featured of very low pressure drop, invented for ultrahigh vacuum distillation cases. These results infer industrial application prospects for advanced design or revamp for larger production capacity, or higher energy efficiency, or both. The developments and innovations in equipment facilitate the progress or intensification of the process as shown in this paper.

Flow of Rubber Compounds in a Plasticating Unit of a Reciprocating-screw Injection Molding Machine

Abstract An experimental study of the distribution of material and internal flow patterns in the cold feed screw injection molding machine for rubber compounds is presented. Experimental studies are carried out by vulcanizing rubber compounds in the screw of the plasticating unit at various positions in the molding cycle. The screw is then removed and the rubber strip unwound from the flights. It is found that transverse flow patterns begin at the feed port and proceed down the channel. Various kinds of starvation behavior are observed especially at low back pressures and with narrow feed strips.

Experimental and Theoretical Study of the Flow Characteristics of Rubber Compounds in an Extruder Screw

AbstractWe describe an experimental and theoretical study of the mechanisms of flow of rubber compounds in a screw extruder. Two compounds, a typical synthetic rubber (butadiene-styrene copolymer-cis-1, 4 polybutadiene) based passenger tire tread (PTT) and a natural rubber based truck tire tread (TTT), were investigated in a 112${}^{1}/{}_{2}$inch NRM cold feed screw extruder using a screw with a constant channel depth and constant channel pitch along the whole screw length. The rubber was cured in place and the screw removed. The screw exhibited starvation behavior except near the die. The length of the rubber strip in the screw is proportional to the pressure developed at the die. Marker studies showed transverse circulating flows beginning in the region immediately downstream from the hopper. These observations indicate that cold feed extruders exhibit a metering region flow, albeit sometimes starved, from entry port to die. Under these conditions the extruder is independent of the pressure developed in the screw channel. A simple non-Newtonian isothermal mathematical model for the metering zone is described. The rubber compound is considered as a pseudoplastic material with a yield value. A comparison of theory and experiment shows that a one dimensional isothermal model quite accurately predicts the flow rate pressure development of the rubber compound in our screw (with a shallow prismatic channel) when starvation is considered. The yield value of the rubber compound influences screw characteristic curves only for very high values of the dimensionless pressure gradient.

A case study on elimination of premature failure source from manufacture of fluoroelastomer inflatable seals for Sodium-cooled Fast Reactor towards sustainability

An innovative model of engineering failure analysis leading to a prospective model of sustainability and decarbonisation, supported by design-material-failure threads, emerge from two defective test inflatable seals (Seals; ∼2 m dia) subjected to laboratory investigations i.e. visual, dimensional, physico-mechanical, material fingerprinting and analysis of variation. The Seals of 500 MW(e) Prototype Fast Breeder Reactor (PFBR) design were industrially manufactured (year: 2007) by cold feed extrusion and continuous cure (CFECC) of a peroxide cured, Viton GBL 200S:600S blend compound, APA-1, 2007. Primary aim was to implement life maximization (global design thread) potential (≥30 y) of advanced polymer architecture (APA) fluoroelastomer (FKM) in reactor inflatable seals (∼6.3 m/∼4.2 m dia) with repeatability and reproducibility by eliminating premature failure source from improper manufacture.Unfeasibility of or unlikely value addition from validation-modelling-simulation-microstructure study necessitated innovative treatment i.e. extracting maximum from the minimalist investigation by maximizing interpretation-data mining-cross verification and utilizing past (validated) FEA results of standard FKM PFBR inflatable-backup seals (life: 10 y) through design-material threads. The treatment was reinforced by reorientation of perspective. Distribution of laboratory data along Seal circumference was interpreted as phenomenological manifestation of thermomechanical-electrochemical interactions in the APA-1, 2007 macromolecular realm, brought about by thermomechanical loads from the progressing CFECC with time. The data was thus utilised to reconstruct the CFECC (2007) in terms of processing parameter variance with respect to a benchmark CFECC study on identical seal design. Incorrect cure index (of APA-1, 2007; global failure thread) was ascertained as the source of premature failure by tracing the origin of departures e.g. tracking the straying of APA-1, 2007 tensile stress-strain behaviour (structure property correlation) and cracking failure limits (global material thread) from the desired (i.e. ≥30 y) along the abstracted echelons (i.e. reconstructing manufacture, molecular-phenomenological interplay) of the CFECC in terms of unacceptable macromolecular transitions. The novel approach and methodology predict new-seal-failure-situation in reactor (by residual stress) and/or continuing operation-safety uncertainty of inflatable seal and reactor (by undercure) from the incorrect cure index. The identified source and template for permanent rectification are crucial for FBR-Gen IV cover gas elastomeric sealing. The applicability extends to other nuclear and inaccessible-hazardous, critical/very critical elastomeric usage (marine, air, space, oilfield, gas etc.) as well.The research findings provide complete description of (APA-FKM) residual stress and tensile stress-strain behaviour by the first principles and an analogy of mechanical-entropy spring, accompanied by a new commentary on structure-property-performance correlation of APA-FKM. The findings are expected to enrich understanding of rubber failure. The failure analysis of a very critical nuclear component grows vastly in connotation using global threads to suggest a prospective conceptual benchmark template for sustainability-decarbonisation-augmentaion i.e. better realization of life maximization potentials in applications by synthesizing improved specifying-manufacturing-quality monitoring with the global threads.This study could provide basis for new research on defect modeling-simulation-validation and encourage formulation-modeling-validation of new constitutive relations, considering incorrect cure index and its effects. The concepts and routes of maximum from minimum, working by first principal, reconstruction, threads and molecular-phenomenological interplay are expected to find wider scope beyond this research.

Distillate Flux Enhancement of Direct Contact Membrane Distillation Modules with Inserting Cross-Diagonal Carbon-Fiber Spacers.

A new design of direct-contact membrane distillation (DCMD) modules with cross-diagonal carbon-fiber spacers of various hydrodynamic angles in flow channels to promote turbulence intensity was proposed to enhance pure water productivity. Attempts to reduce the temperature polarization coefficient were achieved by inserting cross-diagonal carbon-fiber spacers in channels, which create wakes and eddies in both heat and mass transfer behaviors to enhance the permeate flux enhancement. A simplified equation was formulated to obtain the theoretical predictions of heat transfer coefficients in the current DCMD device. The permeate fluxes and temperature distributions of both hot and cold feed streams are represented graphically with the inlet volumetric flow rate and inlet temperature of the hot saline feed stream as parameters. The higher distillate flux of countercurrent-flow operations for saline water desalination was accomplished as compared to the concurrent-flow operations of various hydrodynamic angles. The results show that the agreement between the theoretical predictions and experimental results is reasonably good. The effects of countercurrent-flow operations and inserting carbon fiber spacers have confirmed technical feasibility and device performance enhancement of up to 45%. The influences of operating and design parameters on the pure water productivity with the expense of energy consumption are also discussed.

Environmental Stress in Chickens and the Potential Effectiveness of Dietary Vitamin Supplementation

Environmental stressors can promote the vulnerability of animals to infections; it is therefore, essential to understand how stressors affect the immune system, the adaptive capacity of animals to respond, and effective techniques in managing stress. This review highlights scientific evidence regarding environmental stress challenge models and the potential effectiveness of vitamin supplementation. The major environmental stressors discussed are heat and cold stress, feed restriction, stocking density, and pollutants. Much work has been done to identify the effects of environmental stress in broilers and layers, while few involved other types of poultry. Studies indicated that chickens' performance, health, and welfare are compromised when challenged with environmental stress. These stressors result in physiological alterations, behavioral changes, decreased egg and meat quality, tissue and intestinal damage, and high mortalities. The application of vitamins with other nutritional approaches can help in combating these environmental stressors in chickens. Poultry birds do not synthesize sufficient vitamins during stressful periods. It is therefore suggested that chicken diets are supplemented with vitamins when subjected to environmental stress. Combination of vitamins are considered more efficient than the use of individual vitamins in alleviating environmental stress in chickens.

Effect of Double Wire Cold Feed on Characteristics of Additive Manufactured Components

Effect of Double Wire Cold Feed on Characteristics of Additive Manufactured Components

Globular-to-Spray Transition in Cold Wire Gas Metal Arc Welding

The electrical current required for a transition from globular to spray droplet transfer during gas metal arc welding (GMAW) is determined by the specified wire feed speed in the case of constant-voltage power supplies. Generally, in narrow groove welding, spray transfer is avoided, be-cause this transfer mode can severely erode the groove sidewalls. This work compared the globular-to-spray transition mechanism in cold wire gas metal arc welding (CW-GMAW) vs. standard GMAW. Synchronized high-speed imaging with current and voltage samplings were used to characterize the arc dynamics for different cold wire mass feed rates. Subsequently, the droplet frequency and diameter were estimated, and the parameters for a globular-to-spray transition were assessed. The results suggest that the transition to spray occurs in CW-GMAW at a lower current than in the standard GMAW process. The reason for this difference appears to be linked to an enhanced magnetic pinch force, which is mainly responsible for metal transfer in higher welding current conditions.

Scaling Relations for Autothermal Operation of Catalytic Reactors

Autothermal operation (AO) has several advantages for carrying out highly exothermic catalytic partial oxidation (CPO) and/or oxidative dehydrogenation (ODH) reactions compared to traditional cooled multitubular reactors. In steady-state autothermal operation (AO), there is no heat addition to the reactor or intentional heat removal by cooling through reactor walls; the heat of reaction is removed mainly by convective flow of the cold feed. The existence of an ignited high temperature (and conversion) state at the lowest possible feed temperature and/or space time is essential. This work examines the impact of various design and operating variables on the feasibility and economic scale-up of shallow packed-bed catalytic reactors for autothermal operation. Specifically, we present scaling relations that can be used to examine the impact of effective bed thermal conductivity, bed length, particle size, catalyst activity, reaction kinetics, and operating pressure on the extinction (blow-out) flow rate or feed temperature for large scale autothermal CPO and ODH reactors operated close to the adiabatic limit. The scale-up relations derived for a single-step CPO/ODH reaction are verified by numerical simulations. They are also validated using the highly complex oxidative coupling of methane (OCM) as an example.