► Analysis of non-UV absorbing cationic copolymer by capillary electrophoresis. ► Comparison between indirect UV detection and contactless conductivity detection (C
4D). ► Comparison between neutral ...and double layer cationic coatings. ► Quantification of residual homopolymer and characterization of the distribution in charge density of the copolymer. ► Both indirect UV and C
4D detection modes could be used with better baseline stability and repeatability using indirect UV detection mode.
For many industrial applications, the combination of two different monomers in statistical or diblock copolymers enhances the properties of the corresponding polymer. However, during the polymerization reaction, homopolymers might be formed and can influence the properties for the applications. Consequently, the separation and the quantification of the homopolymers contained in copolymer samples are crucial. In addition, the charge density distribution of the statistical copolymer is an important characteristic for the applications. The purpose of this work was to study the characterization of a statistical copolymer of acrylic acid (AA) and diallyldimethyl ammonium chloride (DADMAC) by capillary electrophoresis (CE) in acidic conditions (cationic copolymers). For that purpose, a free solution electrophoretic separation was carried out according to the charge rate (chemical composition) independently of the molar mass. The second objective was to compare contactless conductivity detection and indirect UV absorbance modes for the quantification of DADMAC homopolymers present in copolymer samples. Different coated capillaries based on neutral or positively charged modification were also compared. The comparison of indirect absorbance UV and contactless conductimetric detection demonstrated that both detection modes can be used for a complete CE characterization of non-UV absorbing PAA-DADMAC copolymers.
For many industrial applications, the combination of two different monomers in statistical or diblock copolymers enhances the properties of the corresponding polymer. However, during the ...polymerization reaction, homopolymers might be formed and can influence the properties for the applications. Consequently, the separation and the quantification of the homopolymers contained in copolymer samples are crucial. In addition, the charge density distribution of the statistical copolymer is an important characteristic for the applications. The purpose of this work was to study the characterization of a statistical copolymer of acrylic acid (AA) and diallyldimethyl ammonium chloride (DADMAC) by capillary electrophoresis (CE) in acidic conditions (cationic copolymers). For that purpose, a free solution electrophoretic separation was carried out according to the charge rate (chemical composition) independently of the molar mass. The second objective was to compare contactless conductivity detection and indirect UV absorbance modes for the quantification of DADMAC homopolymers present in copolymer samples. Different coated capillaries based on neutral or positively charged modification were also compared. The comparison of indirect absorbance UV and contactless conductimetric detection demonstrated that both detection modes can be used for a complete CE characterization of non-UV absorbing PAA-DADMAC copolymers.
This work deals with the determination of polymer effective charge based on the sensitivity of detection in capillary electrophoresis using indirect UV detection. In this detection mode, the ...polyelectrolyte (solute) displaces a certain quantity of probe contained in the background electrolyte and having the same charge as the solute. This quantity of displaced probe is directly correlated to the effective charge of the solute. Contrary to other electrophoretic methods generally used for monitoring changes in effective charge, this methodology is not based on the effective mobility of the polyelectrolyte (i.e., migration times) but on the sensitivity of detection (i.e., peak areas). Experimental values of effective charge obtained for statistical copolymers of poly(acrylamide-co-sodium 2-acrylamido-2-methylpropanesulfonate), for homopolymers of poly(diallyldimethylammonium chloride), poly(acrylic acid), and poly(metacrylic acid), are compared to the Manning theory of charge condensation. Interestingly, this methodology can be used for the characterization of macromolecular architecture since the effective charge of copolymers highly depends on the repartition of the charged monomers along the polymer chain. As an example, this methodology can easily distinguish statistical copolymers from diblock copolymers of similar chemical charge densities. Experiments were carried out on diblock copolymers of poly(acrylic acid)-b-poly(ethylene oxide) (PAA-b-PEO) and poly(methacrylic acid)-b-poly(ethylene oxide) (PMAA-b-PEO). The variation of the sensitivity of detection of statistically charged copolymers in the indirect UV mode with the chemical charge density is also discussed in detail.
Latexes are widely used for industrial applications, including decorative paints, binders for the papermaking industry, and drilling fluids for oil-field applications. In this work, the interest of ...capillary zone electrophoresis (CE) for the characterization of hydrophobic block copolymer latexes obtained by the conventional emulsion polymerization technique consisting of a core of polystyrene (PS) surrounded by a layer of poly(ethyl acrylate) (PEA) has been investigated. The PEA part of the copolymer can be partially hydrolyzed in poly(acrylic acid) (PAA) leading to PS-PEA-AA water-soluble amphiphilic copolymer having high viscosifying properties. The main purpose of this work was to evaluate the potential of CE for the characterization of the latexes at the different stages of the synthesis (PS core, PS-PEA diblock latex, and hydrolyzed PS-PEA-AA gel). The main analytical issues were to state (i) if there was free PS or PEA homopolymer latexes in the PS-PEA latex sample and (ii) if there was free PS, PEA, PS-PEA latexes, or free PAA chains in the PS-PEA-AA gel. Within this scope, this work describes the optimization of the selectivity of the separation between the different species (PS, PEA particles in the not hydrolyzed diblock latex and PS, PEA, PS-PEA particles as well as the polymer PAA chains in the PS-PEA-AA diblock gel sample obtained by latter latex hydrolysis). For that purpose, several experimental parameters were investigated such as pH and ionic strength of the background electrolyte (BGE) or the concentration of neutral surfactant added in the BGE. A challenging issue was to overcome the high viscosity of the PS-PEA-AA gel. This was resolved by the addition of 10 mM neutral surfactant in the gel sample and in the BGE. Finally, it is demonstrated that, within the detection limits, CE is a suitable analytical tool for controlling and monitoring the syntheses of these latexes and for intrinsically characterizing the distribution in charge density of the final PS-PEA-AA gel at different hydrolysis rates.
Rice-based intensive cropping systems require high input levels making them less profitable and vulnerable to the reduced availability of labor and water in Asia. With continuous conventional puddled ...rice transplanting, the situation is exacerbated by damaged soil structure, declining underground water and decreasing land and water productivity. To minimize these negative effects a range of new crop establishment practices have been developed (zero tillage, dry direct seeding, wet direct seeding, water seeding, strip planting, bed planting, non-puddled transplanting of rice, mechanical transplanting of rice crop and combinations thereof) with varying effects on soil health, crop productivity, resource saving and global warming mitigation potential. Some of these allow Conservation Agriculture (CA) to be practiced in the rice-based mono-, double- and triple cropping systems. Innovations in machinery especially for smallholder farms have supported the adoption of the new establishment techniques. Non-puddling establishment of rice together with increased crop residue retention increased soil organic carbon by 79% and total N (TN) in soil by 62% relative to conventional puddling practice. Rice establishment methods (direct seeding of rice, system of rice intensification and non-puddled transplanting of rice) improve soil health by improving the physical (reduced bulk density, increased porosity, available water content), chemical (increased phosphorus, potassium and sulphur in their available forms) and biological properties (microbiome structure, microbial biomass C and N) of the soil. Even in the first year of its practice, the non-puddled transplanting method of rice establishment and CA practices for other crops increase the productivity of the rice-based cropping systems. Estimates suggest global warming potential (GWP) (the overall net effect) can be reduced by a quarter by replacing conventional puddling of rice by direct-seeded rice in the Indo-Gangetic Plains for the rice-based cropping system. Moreover, non-puddled transplanting of rice saves 35% of the net life cycle greenhouse gases (GHGs) compared with the conventional practice by a combination of decreasing greenhouse gases emissions from soil and increasing soil organic carbon (SOC). Though the system of rice intensification decreases net GHG emission, the practice releases 1.5 times greater N2O due to the increased soil aeration. There is no single rice establishment technology that is superior to others in all circumstances, rather a range of effective technologies that can be applied to different agro-climates, demography and farm typologies.
We wished to determine the extent to which number of passengers, driver age, and sex were associated with aggressive driving actions (ADAs) in young drivers involved in a fatal crash.
We used U.S. ...fatal-crash data from Fatality Analysis Reporting System (FARS), 1991 –2008. Proxy measures of aggressive driving included ADA presence and speed differential (posted speed limit minus estimated travel speed). We examined the odds of an ADA and speed differential in young drivers (aged 16 to 25) by passenger status.
Compared to driving alone young drivers (aged 16) had increased odds of an ADA between 14% (OR: 1.14; 95% CI: 1.07; 1.22) and 95% (OR: 1.95; 95% CI: 1.40; 2.74) when accompanied by one and five passengers, respectively. Further, carrying a higher number of passengers was a stronger predictor of speeding in younger drivers.
This study supports the use of graduated licensing approaches. Specifically, developing interventions to reduce aggressive driving appear imperative.
While the results of our study support the use of graduated licensing approaches there is room for improvement. Our study indicates that tackling impaired driving is not sufficient to drastically reduce aggressive driving among the youngest drivers. Further research on young drivers is required to understand the influence of peers and the role of gender on driving behavior. Strategies to reduce aggressive driving behaviors among the youngest drivers may not only prevent crashes during their early driving careers but may also translate into a reduced crash risk over their lifetime.
► We examined the impact of passengers on young drivers committing aggressive driving actions prior to involvement in a fatal crash. ► The presence of passengers was associated with increased odds of a young driver (aged 16) committing an aggressive driving action between 14% (OR: 1.14; 95% CI: 1.07;1.22) and 95% (OR: 1.95; 95%CI:1.40;2.74) when accompanied by one and five passengers respectively. ► Further, carrying a higher number of passengers was a strong predictor of speeding in younger drivers. ► Novice drivers, especially males, had increased odds of driving aggressively in the presence of passengers compared to drivers with a few more years of driving experience. Not wearing a seat-belt was highly predictive of aggressive driving. ► The results of our study support the use of GLS and suggest that by age 25 young adults have drastically improved their driving habits.
Background:
The occurrence of depression in younger adults is related to the combination of long‐standing factors such as personality traits (neuroticism) and more acute factors such as the ...subjective impact of stressful life events. Whether an increase in physical illnesses changes these associations in old age depression remains a matter of debate.
Methods:
We compared 79 outpatients with major depression and 102 never‐depressed controls; subjects included both young (mean age: 35 years) and older (mean age: 70 years) adults. Assessments included the Social Readjustment Rating Scale, NEO Personality Inventory and Cumulative Illness Rating Scale. Logistic regression models analyzed the association between depression and subjective impact of stressful life events while controlling for neuroticism and physical illness.
Results:
Patients and controls experienced the same number of stressful life events in the past 12 months. However, in contrast to the controls, patients associated the events with a subjective negative emotional impact. Negative stress impact and levels of neuroticism, but not physical illness, significantly predicted depression in young age. In old age, negative stress impact was weakly associated with depression. In this age group, depressive illness was also determined by physical illness burden and neuroticism.
Conclusions:
Our data suggest that the subjective impact of life stressors, although rated as of the same magnitude, plays a less important role in accounting for depression in older age compared to young age. They also indicate an increasing weight of physical illness burden in the prediction of depression occurrence in old age.
Kepuasan pelanggan menjadi salah satu tolak ukur perusahaan dalam menjaga kualitas produk. Salah satu tipe pompa non-otomatis yang paling diminati adalah PS-128 BIT. Permasalahan pompa air yang ...terjadi karena persentase cacat masih berada di atas toleransi yang diinginkan perusahaan. Toleransi yang diberikan oleh perusahaan sebesar 3%, tetapi persentase cacat yang diterima oleh perusahaan sebesar 5.93%. Persentase tersebut didapatkan berdasarkan rata-rata persentase cacat dalam lima bulan (Juli – November 2021). Selanjutnya perusahaan perlu melakukan perbaikan terhadap kualitas produk pompa tersebut. Tujuan dari penelitian untuk meminimasi cacat produk untuk meningkatkan kualitas produk serta dapat memenuhi kepuasan pelanggan. Metode yang digunakan yaitu six sigma. Hasil penelitian mengidentifikasi bahwa terdapat dua jenis kecacatan yang dominan pada produk pompa yaitu mseal bocor dan o-ring bocor. Perhitungan nilai defect million per opportunity didapatkan sebesar 51,000 dan dikonversi menjadi tingkat sigma sebesar 3.135 dimana nilai ini masih dapat ditingkatkan agar tingkat produk cacat berkurang. Tindakan yang dapat dilakukan untuk mengatasi mseal bocor adalah berupa penggunaan checklist pemeriksaan part mseal serta o-ring bocor dapat ditangani dengan menggunakan alat bantu seperti air duster gun. Alat ini digunakan untuk membantu pembersihan part secara berkala guna memastikan part tersebut sudah bersih dan dapat dilakukan ke tahap proses produksi selanjutnya. Usulan perbaikan ini sudah dilakukan implementasi dengan hasil akhir tingkat sigma naik sebesar 3.262.
Penelitian yang bertujuan untuk mengenal dan mengetahui hubungan antara tipe kepribadian introvert dalam interaksi di lingkup sosial mahasiswa program studi pengembangan masyarakat islam angkatan ...tahun 2021 UIN Sunan Ampel Surabaya. Hipotesis yang diajukan dalam penelitian ini adalah terdapat pengaruh kepribadian introvert terhadap perubahan lingkungan sosial mahasiswa Program Studi Pengembangan Masyarakat Islam 2021 UIN Sunan Ampel Surabaya. Subjek penelitian ini adalah mahasiswa program studi pengembangan masyarakat islam angkatan tahun 2021 UIN Sunan Ampel Surabaya. Pengumpulan data ini menggunakan Skala Likert yang dikembangkan oleh Rensis Likert pada tahun 1932. Penelitian ini menggunakan metode skala likert dalam bentuk kuesioner untuk memperoleh data yang dibutuhkan. Hasil penelitian menunjukkan bahwa terdapat pengaruh kepribadian introvert terhadap lingkup sosial mahasiswa/i prodi PMI UIN Sunan Ampel Surabaya angkatan 2021. Kepribadian introvert berpengaruh positif dan signifikan terhadap bidang sosial mahasiswa.
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