Characterization of Low Cost Ion Conducting Poly(AAc-co-DMAPMA) Membrane for Fuel Cell Application

Poly(AAc-co-DMAPMA) membrane (PADMA) is synthesized by free radical aqueous copolymerization of acrylic acid (AAc) and N-3-[dimethylamino)propyl]-methacrylamide (DMAPMA) to check its stability and conductivity. The hydrogel membrane characterized physically to study morphology by SEM, thermal stability by TGA and mechanical stability by measuring compressive strength and ionic conductivity by electrochemical impedance spectroscopy in alkaline as well as in acidic environment at different temperatures. The compression modulus of the hydrogel membrane is 24 kPa at pH = 1.0 and 16 kPa at pH = 7.0, and stable (no fracture) till 72% deformation. The PADMA hydrogel membrane ionic conductivity increased with the increase in temperature and structurally stable up to 190°C. Improvement in ionic conductivity is observed after the heat treatment of the membrane. Compared with ionic conductivity of Nafion? (SE512), the PADMA membrane found to be inferior. However, the PADMA hydrogel membrane conductivity was greater (~1 × 10-4S/cm) at low and high pH compared with neutral pH (~1 × 10-5S/cm) indicating the possibility of using the membrane as either a proton and hydroxyl ion conductor.

Crop productivity,soil health,and energy dynamics of Indian Himalayan intensified organic maize-based systems

The sustainability of prevailing maize-fallow system in rainfed ecosystems of the Eastern Himalayan region(EHR)of India is often questioned due to poor economic return and negative impact on soil health.Hence,the six cropping systems,maize-fallow(M-F),maize t cowpea-rapeseed(M t C-Rs),maize t cowpea-buckwheat(M t C-Bw),maize t cowpea-barley(M t CeB),maize t cowpea-garden pea(M t C-GP)and maize t cowpeaerajmash(M t C-R)in the main plot and three soil moisture conservation measures,no-mulch(NM),maize stover mulch(MSM)and maize stover t weed biomass mulch(MSM t WBM)in sub-plot were evaluated for four consecutive years(2014-18)at a Research Farm in fixed plot fashion.Results indicated that cowpea co-culture with maize and inclusion of winter crop increased maize yield by 6.2e23.5%over M-F.Among the systems,the M t C-GP recorded the highest crop productivity.The residual effect of MSM t WBM increased maize grain yield by 19.1%over NM.Cultivation of maize t cowpea-winter crops significantly improved the available N(3.2e12.9%),P(3.6 e12.7%),K(1.9e26.3%),organic carbon(9.2e16.8%),microbial biomass carbon-MBC(15.2e43.9%)and dehydrogenases-DHA(17.2e42.3%)in soil at 0e15 cm depth as compared to M-F.The M t C-GP also recorded maximum net return(US$2460 ha1),benefit:cost(B:C)ratio(2.86)and energy use efficiency(7.9%).The MSM t WBM recorded higher net return(US$1680 ha1)and B:C ratio(2.46)over NM.Hence,cowpea t maize-garden pea(M t C-GP)along with the application of MSM t WBM is a sustainable production practice to intensify the organically managed maize-fallow system in rainfed regions of the EHR of India and other similar ecosystems.

Potential of conservation tillage and altered land configuration to improve soil properties,carbon sequestration and productivity of maize based cropping system in eastern Himalayas,India

Poor soil properties especially low soil organic carbon(SOC)and nutrient and water retention capacities are major concern for sustainable agriculture in Himalayas.Field experiments were conducted to assess the effects of six combinations of tillage[conventional tillage(CT)and no-till(NT)]and land configurations[flat bed planting(FB),ridge and furrow planting(RF),and raised bed planting(RB)]on productivity and carbon(C)-sequestration potential of maize[(Zea mays L.)for green-cob in summer]-maize(for grains in rainy season)-field pea[(Pisum sativum L.in winter]cropping system under humid mildtropical climate of Tripura,India.The maize under NT-FB in 2012 and NT-RF in 2013 produced significantly higher green cob yield than that under CT-RF.However,in rainy season,CT produced higher maize grain yield than NT systems.Field pea seed yield was significantly the highest under NT-RB.After two cropping cycles,NT systems had higher available N,P,K and 18.6e31.4%higher soil moisture content after rainy season maize than CT system.The highest SOC-stock(0e30 cm)was observed under NT-FB,whereas,SOC-sequestration rate was maximum under NT-RB(0.85 Mg ha1 year1).Therefore,NT based systems can enhance the productivity and improve SOC-sequestration in cultivated soils of eastern Himalayas.Hence,study recommended adoption of NT-RB/NT-FB to raise maize-maize-field pea system for improving productivity,improving C-sequestration and soil properties in the eastern Himalayas and similar eco-regions elsewhere.

Double mulching improves soil properties and productivity of maize-based cropping system in eastern Indian Himalayas

A field experiment was conducted for two consecutive years at North Eastern Indian Himalayan region to assess the effect of soil moisture conservation measures on soil and water productivity of different rainfed maize(Zea mays L.)-based cropping sequences.Results revealed that double mulching with in-situ maize stover mulch(MSM)+fresh biomass of white hoary pea(WHP-Tephrosia candida)and MSM+fresh biomass of ragweed(RW-Ambrosia artemisiifolia)improved soil moisture content(SMC)and leaf relative water content of crops during dry season.The soil organic carbon(SOC)content and stocks under MSM+WHP and MSM+RW mulches were significantly higher than that under no mulch at 0-15 cm depth.The soil microbial biomass carbon and dehydrogenase activity were maximum under MSM+WHP/RW.The highest system productivity was obtained from maize-French bean(Pole type-PT)sequence under MSM+RW followed by MSM+WHP.The water productivity was the highest under MSM+WHP.While SOC content was the highest under maize-French bean(PT),the maximum plant available nitrogen and phosphorus were obtained under maize-black gram sequence.Thus,double mulching technology involving MSM and RW(available in plenty)is a viable option for improving soil,crop and water productivity under rainfed hill ecosystems of eastern Indian Himalayas.